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Freescale Semiconductor, Inc. 3-Phase BLDC Low-Voltage Power Stage User’s Manual For More Information On This Product, Go to: www.freescale.com A G R E E M E N T Motorola Embedded Motion Control N O N - D I S C L O S U R E Freescale Semiconductor, Inc... R E Q U I R E D MEMC3PBLDCLVUM/D Freescale Semiconductor, Inc. Important Notice to Users Freescale Semiconductor, Inc... While every effort has been made to ensure the accuracy of all information in this document, Motorola assumes no liability to any party for any loss or damage caused by errors or omissions or by statements of any kind in this document, its updates, supplements, or special editions, whether such errors are omissions or statements resulting from negligence, accident, or any other cause. Motorola further assumes no liability arising out of the application or use of any information, product, or system described herein: nor any liability for incidental or consequential damages arising from the use of this document. Motorola disclaims all warranties regarding the information contained herein, whether expressed, implied, or statutory, including implied warranties of merchantability or fitness for a particular purpose. Motorola makes no representation that the interconnection of products in the manner described herein will not infringe on existing or future patent rights, nor do the descriptions contained herein imply the granting or license to make, use or sell equipment constructed in accordance with this description. Trademarks This document includes these trademarks: Motorola and the Motorola logo are registered trademarks of Motorola, Inc. Motorola, Inc., is an Equal Opportunity / Affirmative Action Employer. © Motorola, Inc., 2000; All Rights Reserved User’s Manual 3-Phase BLDC Low-Voltage Power Stage 2 MOTOROLA For More Information On This Product, Go to: www.freescale.com Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage List of Sections Section 1. Introduction and Setup . . . . . . . . . . . . . . . . . . 11 Freescale Semiconductor, Inc... Section 2. Operational Description . . . . . . . . . . . . . . . . . 17 Section 3. Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . 21 Section 4. Schematics and Parts List . . . . . . . . . . . . . . . 29 Section 5. Design Considerations . . . . . . . . . . . . . . . . . . 43 3-Phase BLDC Low-Voltage Power Stage MOTOROLA List of Sections For More Information On This Product, Go to: www.freescale.com User’s Manual 3 Freescale Semiconductor, Inc. Freescale Semiconductor, Inc... List of Sections User’s Manual 4 3-Phase BLDC Low-Voltage Power Stage List of Sections For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage Table of Contents Freescale Semiconductor, Inc... Section 1. Introduction and Setup 1.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3 About this Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.4 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.5 Setup Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Section 2. Operational Description 2.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.3 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.4 Modification for 42 Volts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Section 3. Pin Descriptions 3.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 40-Pin Ribbon Connector J13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Power Connectors J19 and J20 . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Motor Connectors J16, J17, and J18 . . . . . . . . . . . . . . . . . . . . . . . 26 External Brake Connectors J14 and J15 . . . . . . . . . . . . . . . . . . . . 26 Bias Power Connectors J21 and J22 . . . . . . . . . . . . . . . . . . . . . . . 27 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Table of Contents For More Information On This Product, Go to: www.freescale.com User’s Manual 5 Freescale Semiconductor, Inc. Table of Contents Section 4. Schematics and Parts List 4.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.2 Mechanical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.3 Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.4 Parts Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Freescale Semiconductor, Inc... Section 5. Design Considerations User’s Manual 6 5.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 5.2 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 5.3 Phase Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 5.4 Bus Voltage and Current Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . 45 5.5 Cycle-by-Cycle Current Limiting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 5.6 Temperature Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5.7 Back EMF Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 5.8 Phase Current Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 5.9 Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 3-Phase BLDC Low-Voltage Power Stage Table of Contents For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage List of Figures Freescale Semiconductor, Inc... Figure Title 1-1 1-2 1-3 Systems’ Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3D Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2-1 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3-1 40-Pin Ribbon Connector J13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 3-Phase BLDC Low-Voltage Power Stage Overview . . . . . . . . . . . . 30 Gate Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 3-Phase H-Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Current and Temperature Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Back EMF Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 dc Bus Voltage Sense and Brake Gate Drive . . . . . . . . . . . . . . . . . . . 35 Identification Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 5-1 5-2 5-3 5-4 5-5 5-6 5-7 Phase A Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Bus Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Cycle-by-Cycle Current Limiting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Temperature Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Phase A Back EMF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Phase A Current Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Page List of Figures For More Information On This Product, Go to: www.freescale.com User’s Manual 7 Freescale Semiconductor, Inc. Freescale Semiconductor, Inc... List of Figures User’s Manual 8 3-Phase BLDC Low-Voltage Power Stage List of Figures For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage List of Tables Freescale Semiconductor, Inc... Table Title 2-1 2-2 2-3 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Resistor Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 JP801 Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3-1 Connector J13 Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4-1 4-2 Power Substrate Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Printed Circuit Board Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Page List of Tables For More Information On This Product, Go to: www.freescale.com User’s Manual 9 Freescale Semiconductor, Inc. Freescale Semiconductor, Inc... List of Tables User’s Manual 10 3-Phase BLDC Low-Voltage Power Stage List of Tables For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage Section 1. Introduction and Setup Freescale Semiconductor, Inc... 1.1 Contents 1.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3 About this Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.4 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.5 Setup Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.2 Introduction Motorola’s 3-phase, brushless dc (BLDC) low-voltage power stage (LV BLDC power stage) is an integral part of Motorola’s embedded motion control series of development tools. It operates from a nominal 12-volt motor supply, and delivers up to 30 amps of rms motor current from a dc bus that can deliver peak currents up to 46 amps. The LV BLDC power stage is supplied in kit number ECLOVACBLDC. In combination with one of the Embedded Motion Control series Control boards, it provides a ready made software development platform for fractional horsepower Brushless DC motors. Feedback signals are provided to facilitate control with sensorless algorithms. An illustration of the systems architecture is shown in Figure 1-1. A 3D model appears in Figure 1-2. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Introduction and Setup For More Information On This Product, Go to: www.freescale.com User’s Manual 11 Freescale Semiconductor, Inc. Introduction and Setup Freescale Semiconductor, Inc... The LV BLDC power stage’s features are: • dc-bus brake MOSFET and brake current limiting resistors • 3-phase bridge inverter (6-MOSFETs) • Individual phase and dc bus current sensing shunts with Kelvin connections • Power stage temperature sensing diodes • MOSFET gate drivers • Current and temperature signal conditioning • 3-phase back-EMF voltage sensing and zero cross detection circuitry • Board identification processor (MC68HC705JJ7) • Low-voltage on-board power supplies • Cooling fans EMULATOR CONTROL BOARD DSP EVM BOARD WORKSTATION WORKSTATION POWER STAGE POWER STAGE MOTOR a) MICROCONTROLLER MOTOR b) 56800 DSP Figure 1-1. Systems’ Configurations User’s Manual 12 3-Phase BLDC Low-Voltage Power Stage Introduction and Setup For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Freescale Semiconductor, Inc... Introduction and Setup About this Manual Figure 1-2. 3D Model 1.3 About this Manual Key items can be found in the following locations in this manual: • Setup instructions are found in 1.5 Setup Guide. • Schematics are found in Section 4. Schematics and Parts List. • Pin assignments are shown in Figure 3-1. 40-Pin Ribbon Connector J13, and a pin-by-pin description is contained in 3.3.1 40-Pin Ribbon Connector J13. • For those interested in the reference design aspects of the board’s circuitry, a description is provided in Section 5. Design Considerations. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Introduction and Setup For More Information On This Product, Go to: www.freescale.com User’s Manual 13 Freescale Semiconductor, Inc. Introduction and Setup 1.4 Warnings The LV BLDC Power Stage kit includes power components that can reach temperatures hot enough to cause burns. The motor that it operates may also reach high temperatures. Freescale Semiconductor, Inc... The user should be aware that: • To facilitate safe operation, input power should come from a DC laboratory power supply that is current limited to no more than 55 Amps. • Before moving scope probes, making connections, etc., it is generally advisable to power down the motor supply. • Operation in lab setups that have grounded tables and/or chairs should be avoided. • Wearing safety glasses, avoiding ties and jewelry, and using shields are also advisable. 1.5 Setup Guide Setup and connections are very straightforward. The LV BLDC power stage connects to an embedded motion control series control board via 40-pin ribbon cable. The motor’s power leads plug into output connectors, J16 – J18, and its Hall sensors plug into the control board’s Hall sensor/encoder input connector. Figure 1-3 depicts a completed setup. 1. Mount four standoffs to the LV BLDC Power Stage at the locations indicated in Figure 1-3. Standoffs, screws, and washers are included in the kit. NOTE: This step and step 3 are optional when making connections with DSP control boards such as the DSP56F805EVM. The DSP boards may be placed flat on a bench, next to the EVM motor board. 2. Plug one end of the 40-pin ribbon cable that is supplied with the kit into input connector J13, located on the right hand side of the top board. The other end of this cable connects to the control board’s 40-pin output connector. User’s Manual 14 3-Phase BLDC Low-Voltage Power Stage Introduction and Setup For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Introduction and Setup Setup Guide 3. Mount the control board on top of the standoffs with screws and washers from the ECLOVACBLDC kit. This step is optional with DSP control boards. 4. Plug the free end of the cable connected to input connector J13 into the control board’s 40-pin output connector. Freescale Semiconductor, Inc... 5. Connect a 12-Vdc power supply to fast-on connectors J19 and J20. Connector J19 is located on the back-left corner of the top board, and connector J20 is in the front-left corner of the top board. The positive lead goes to J19, labeled +12V. The return is connected to J20, labeled 0V. Voltage range for the power supply is 10 to 16 Vdc. The power supply’s current limit should be set to less than 55 amps. In the as-shipped configuration, jumper JP401 is set to INT. and a bias supply at connector J21 or power jack J22 is not needed. One power supply connected to J19 and J20 is all that is required. 6. Connect motor phase A to fast-on connector J16, labeled phase A. Connector J16 is located along the back edge of the top board. 7. Connect motor phase B to fast-on connector J17, labeled phase B. Connector J17 is located along the back edge of the top board. 8. Connect motor phase C to fast-on connector J18, labeled phase C. Connector J18 is located along the back edge of the top board. 9. Apply power. The green power-on LED lights when power is present. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Introduction and Setup For More Information On This Product, Go to: www.freescale.com User’s Manual 15 Freescale Semiconductor, Inc. Introduction and Setup STANDOFFS MOTOR 56800 EVALUATION MODULE OR Freescale Semiconductor, Inc... MOTOR SUPPLY LV BLDC POWER STAGE HC08 CONTROL BOARD 40-PIN RIBBON CABLE STANDOFFS Figure 1-3. Setup User’s Manual 16 3-Phase BLDC Low-Voltage Power Stage Introduction and Setup For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage Section 2. Operational Description Freescale Semiconductor, Inc... 2.1 Contents 2.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.3 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.4 Modification for 42 Volts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2 Description Motorola’s embedded motion control series low-voltage (LV) brushless dc (BLDC) power stage operates from a nominal 12-volt motor supply, and delivers up to 30 amps of rms motor current from a dc bus that can deliver peak currents up to 46 amps. In combination with one of Motorola’s embedded motion control series control boards, it provides a software development platform that allows algorithms to be written and tested, without the need to design and build a power stage. It supports a wide variety of algorithms for controlling BLDC motors. Input connections are made via 40-pin ribbon cable connector J13. Pin assignments for the input connector are shown in Figure 3-1. 40-Pin Ribbon Connector J13. Power connections to the motor are made with fast-on connectors J16, J17, and J18. They are located along the back edge of the board, and are labeled Phase A, Phase B, and Phase C. Power requirements are met with a 12-volt power supply that has a 10- to 16-volt tolerance. Fast-on connectors J19 and J20 are used for the power supply. J19 is labeled +12V and is located on the back edge of the board. J20 is labeled 0V and is located along the front edge. Current measuring circuitry is set up for 50 amps full scale. Both bus and phase leg currents are measured. A cycle by cycle overcurrent trip point is set at 46 amps. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Operational Description For More Information On This Product, Go to: www.freescale.com User’s Manual 17 Freescale Semiconductor, Inc. Operational Description Freescale Semiconductor, Inc... The LV BLDC power stage has both a printed circuit board and a power substrate. The printed circuit board contains MOSFET gate drive circuits, analog signal conditioning, low-voltage power supplies, and some of the large passive power components. This board also has a 68HC705JJ7 microcontroller used for board configuration and identification. All of the power electronics that need to dissipate heat are mounted on the power substrate. This substrate includes the power MOSFETs, brake resistors, current-sensing resistors, bus capacitors, and temperature sensing diodes. Figure 2-1 shows a block diagram. POWER INPUT BIAS POWER BRAKE MOSFET POWER MODULE SIGNALS TO/FROM CONTROL BOARD GATE DRIVERS TO MOTOR PHASE CURRENT PHASE VOLTAGE BUS CURRENT BUS VOLTAGE MONITOR BOARD ID BLOCK ZERO CROSS BACK-EMF SENSE Figure 2-1. Block Diagram User’s Manual 18 3-Phase BLDC Low-Voltage Power Stage Operational Description For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Operational Description Electrical Characteristics 2.3 Electrical Characteristics The electrical characteristics in Table 2-1 apply to operation at 25°C with a 12-Vdc supply voltage. Table 2-1. Electrical Characteristics Freescale Semiconductor, Inc... Characteristic Symbol Min Typ Max Units Motor Supply Voltage Vac 10 12 16 V Quiescent current ICC — 175 — mA Min logic 1 input voltage VIH 2.0 — — V Max logic 0 input voltage VIL — — 0.8 V Analog output range VOut 0 — 3.3 V Bus current sense voltage ISense — 33 — mV/A Bus voltage sense voltage VBus — 60 — mV/V IPK — — 46 A Continuous output current IRMS — — 30 A Brake resistor dissipation (continuous) PBK — — 50 W Brake resistor dissipation (15 sec pk) PBK(Pk) — — 100 W Pdiss — — 85 W Peak output current (300 ms) Total power dissipation 2.4 Modification for 42 Volts The LV BLDC power stage can be modified for operation with a 42-volt nominal motor supply. To change input voltage range: 1. Remove power and wait until the power-on LED is off. 2. Make the resistor value changes shown in Table 2-2. With the values shown for 42 volts, voltage-feedback signals are scaled at 60 mV per volt. Table 2-2. Resistor Values Resistors 12 Volts 42 Volts R207, R522, R523, R524 0Ω 39 kΩ 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Operational Description For More Information On This Product, Go to: www.freescale.com User’s Manual 19 Freescale Semiconductor, Inc. Operational Description 3. Configure identification coding jumper JP801 with the settings that are indicated in Table 2-3. This procedure allows software to interpret the new analog values correctly. Freescale Semiconductor, Inc... Table 2-3. JP801 Settings Position 12 Volts 42 Volts 1-2 Open Open 3-4 Open Open 5-6 Open Open 7-8 Open Short 4. Set jumper JP401 to the EXT. position. JP401 is located on left side of the top board adjacent to one of the bus capacitors. The EXT. setting allows bias circuitry to be powered from a 12-volt source that is separate from the motor supply. 5. Connect a 12-Vdc power supply either to connector J21, labeled - EXT. 12V +, or power jack J22. Either one, but not both may be used. Polarity does not matter, since these inputs are connected to a full-wave bridge. Connectors J21 and J22 are located on the front left-hand corner of the top board. The 12-volt power supply should have its current limit set between 500 mA and 1 amp. The input voltage range is 10 volts to 16 volts. Once these modifications have been made, the input voltage range for the motor supply is 10 Vdc to 55 Vdc. User’s Manual 20 3-Phase BLDC Low-Voltage Power Stage Operational Description For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage Section 3. Pin Descriptions Freescale Semiconductor, Inc... 3.1 Contents 3.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 40-Pin Ribbon Connector J13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Power Connectors J19 and J20 . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Motor Connectors J16, J17, and J18 . . . . . . . . . . . . . . . . . . . . . . . 26 External Brake Connectors J14 and J15 . . . . . . . . . . . . . . . . . . . . 26 Bias Power Connectors J21 and J22 . . . . . . . . . . . . . . . . . . . . . . . 27 3.2 Introduction There are ten connectors on the top board for making input and output connections. They are listed as follows. • J13 — 40-pin input and feedback connector • J19 — Motor supply fast-on connector • J20 — Motor supply fast-on connector • J16 — Phase A fast-on connector • J17 — Phase B fast-on connector • J18 — Phase C fast-on connector • J14 — Brake fast-on connector • J15 — Brake fast-on connector • J21 — Bias supply connector • J22 — Bias supply power jack • Pin assignments for input connector J13 are shown in Figure 3-1. Signal descriptions for each of these connectors are identified in Table 3-1. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Pin Descriptions For More Information On This Product, Go to: www.freescale.com User’s Manual 21 Freescale Semiconductor, Inc. Pin Descriptions 3.3 Signal Descriptions Control and feedback signals are grouped together on 40-pin ribbon connector J13. Motor outputs each have separate fast-on connectors that are designated J16 –J18. Power is supplied through fast-on connectors J19 and J20. The signals associated with each of these connectors, and the optional use of connectors J14, J15, J21, and J22 are discussed as follows. Freescale Semiconductor, Inc... 3.3.1 40-Pin Ribbon Connector J13 40-pin ribbon cable connector J13 is located on the right side of the board. Pin assignments are shown in Figure 3-1. In this figure, a schematic representation appears on the left, and a physical layout of the connector appears on the right. The physical view assumes that the board is oriented such that its title is read from left to right. Signal descriptions are listed in Table 3-1. User’s Manual 22 3-Phase BLDC Low-Voltage Power Stage Pin Descriptions For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Pin Descriptions Signal Descriptions J13 BEMF_sense_C BEMF_sense_B BEMF_sense_A Shielding Zero_cross_C Zero_cross_B Zero_cross_A Freescale Semiconductor, Inc... Serial_Con Brake_control Shielding Temp_sense I_sense_C I_sense_B I_sense_A I_sense_DCB V_sense_DCB –12V_A +12V_A GNDA GNDA +3.3V_A +5V_A +5V_A GND GND PWM_CB Shielding PWM_CT Shielding PWM_BB Shielding PWM_BT Shielding PWM_AB Shielding PWM_AT 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 PWM_AT PWM_AB PWM_BT PWM_BB PWM_CT PWM_CB GND_PS +5V_D GNDA +12_A V_sense_DCB I_sense_A I_sense_C Brake_control Zero_cross_B Shielding BEMF_sense_B 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Shielding Shielding Shielding Shielding Shielding GND +5V_D +3.3V_A GNDA –12V_A I_sense_DCB I_sense_B Temp_sense Shielding Serial_Con Zero_cross_A Zero_cross_C BEMF_sense_A BEMF_sense_C PHYSICAL VIEW SCHEMATIC VIEW Figure 3-1. 40-Pin Ribbon Connector J13 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Pin Descriptions For More Information On This Product, Go to: www.freescale.com User’s Manual 23 Freescale Semiconductor, Inc. Pin Descriptions Table 3-1. Connector J13 Signal Descriptions Signal Name 1 PWM_AT PWM_AT is the gate drive signal for the top half-bridge of phase A. A logic high turns phase A’s top switch on. 2 Shielding Pin 2 is connected to a shield wire in the ribbon cable and ground on the board. 3 PWM_AB PWM_AB is the gate drive signal for the bottom half-bridge of phase A. A logic high turns phase A’s bottom switch on. 4 Shielding Pin 4 is connected to a shield wire in the ribbon cable and ground on the board. 5 PWM_BT PWM_BT is the gate drive signal for the top half-bridge of phase B. A logic high turns phase B’s top switch on. 6 Shielding Pin 6 is connected to a shield wire in the ribbon cable and ground on the board. 7 PWM_BB PWM_BB is the gate drive signal for the bottom half-bridge of phase B. A logic high turns phase B’s bottom switch on. 8 Shielding Pin 8 is connected to a shield wire in the ribbon cable and ground on the board. 9 PWM_CT PWM_CT is the gate drive signal for the top half-bridge of phase C. A logic high turns phase C’s top switch on. 10 Shielding Pin 10 is connected to a shield wire in the ribbon cable and ground on the board. 11 PWM_CB PWM_CB is the gate drive signal for the bottom half-bridge of phase C. A logic high turns phase C’s bottom switch on. 12 GND Digital and power ground 13 GND Digital and power ground, redundant connection 14 +5V digital Digital +5-volt power supply 15 +5V digital Digital +5-volt power supply, redundant connection 16 +3.3V analog 17 GNDA Analog power supply ground 18 GNDA Analog power supply ground, redundant connection 19 +15V_A Analog +12-volt power supply 20 –15V_A Analog –12-volt power supply 21 V_sense_DCB V_sense_DCB is an analog sense signal that measures dc bus voltage. It is scaled at 206 mV per volt of dc bus voltage. 22 I_sense_DCB I_sense_DCB is an analog sense signal that measures dc bus current. It is scaled at 33 mV per amp of dc bus current. Freescale Semiconductor, Inc... Pin No. User’s Manual 24 Description Analog +3.3-volt power supply 3-Phase BLDC Low-Voltage Power Stage Pin Descriptions For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Pin Descriptions Signal Descriptions Freescale Semiconductor, Inc... Table 3-1. Connector J13 Signal Descriptions (Continued) Pin No. Signal Name Description 23 I_sense_A I_sense_A is an analog sense signal that measures current in phase A. It is scaled at 33 mV per amp of dc bus current. 24 I_sense_B I_sense_B is an analog sense signal that measures current in phase B. It is scaled at 33 mV per amp of dc bus current. 25 I_sense_C I_sense_C is an analog sense signal that measures current in phase C. It is scaled at 33 mV per amp of dc bus current. 26 Temp_sense Temp_sense is an analog sense signal that measures power module temperature. 27 No connection 28 Shielding 29 Brake_control 30 Serial_Con Pin 28 is connected to a shield wire in the ribbon cable and analog ground on the board. Brake_control is the gate drive signal for the brake MOSFET. Serial_Con is an identification signal that lets the controller know which power stage is present. 31 No connection 32 No connection 33 No connection 34 Zero_cross_A Zero_cross_A is a digital signal used for sensing phase A back-EMF zero crossing events. 35 Zero_cross_B Zero_cross_B is a digital signal used for sensing phase B back-EMF zero crossing events. 36 Zero_cross_C Zero_cross_C is a digital signal used for sensing phase C back-EMF zero crossing events. 37 Shielding Pin 37 is connected to a shield wire in the ribbon cable and analog ground on the board. 38 BEMF_sense_A BEMF_sense_A is an analog sense signal that measures phase A back EMF. It is scaled at 206 mV per volt of dc bus voltage. 39 BEMF_sense_B BEMF_sense_B is an analog sense signal that measures phase B back EMF. It is scaled at 206 mV per volt of dc bus voltage. 40 BEMF_sense_C BEMF_sense_C is an analog sense signal that measures phase C back EMF. It is scaled at 206 mV per volt of dc bus voltage. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Pin Descriptions For More Information On This Product, Go to: www.freescale.com User’s Manual 25 Freescale Semiconductor, Inc. Pin Descriptions 3.3.2 Power Connectors J19 and J20 Freescale Semiconductor, Inc... Motor power is supplied through fast-on connectors J19 and J20. J19 is labeled +12V, and is located on the back left-hand corner of the top board. J20 is labeled 0V, and is located on the front left-hand corner of the top board. These connectors will accept a power supply voltage from 10 volts to 16 volts as the LV BLDC power stage is shipped. When the LV BLDC power stage has been reconfigured for 42-volt nominal operation, this power supply input will accept inputs from 10 volts to 55 volts. The power supply should be current limited to less than 55 amps. 3.3.3 Motor Connectors J16, J17, and J18 Power connections to the motor are made with fast-on connectors J16, J17, and J18, located on the back edge of the top board. These connections are identified as follows. • J16: Phase A — Connector J16, labeled Phase A, supplies power to motor phase A. This is a 30-amp RMS fast-on connection. • J17: Phase B — Connector J17, labeled Phase B, supplies power to motor phase B. This is a 30-amp RMS fast-on connection. • J18: Phase C — Connector J18, labeled Phase C, supplies power to motor Phase C. This is a 30 amp RMS fast-on connection. 3.3.4 External Brake Connectors J14 and J15 An optional external brake resistor can be connected to external brake fast-on connectors J14 and J15, labeled BRAKE 1 Ext. and BRAKE 2 Ext. These connectors are located on the back left-hand corner of the top board. The external resistor allows power dissipation to be increased beyond the 50 watts that brake resistors R1–R4 provide. Note that operation of the brake at 100 percent duty cycle for more than 15 seconds at 12 volts will overdissipate R1–R4. For bus voltages higher than 12 volts, maximum duty cycle is restricted to less than 100 percent. The total power dissipation limit for these four resistors combined is 50 watts continuous and 100 watts for 15 seconds. User’s Manual 26 3-Phase BLDC Low-Voltage Power Stage Pin Descriptions For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Pin Descriptions Signal Descriptions 3.3.5 Bias Power Connectors J21 and J22 Freescale Semiconductor, Inc... Two connectors, labeled J21 and J22, are provided for an optional 12-volt bias supply. This input is only used when the LV BLDC power stage has been reconfigured for operation with a 42-volt nominal motor supply. J21 and J22 are located on the front left-hand corner of the board. Connector J22 is a 2.1-mm power jack for 12-volt plug-in type power supply connections. Connector J21 has screw terminal inputs labeled + and – for accepting wire inputs. Power is supplied to one or the other, but not both. The power supply should be current-limited to at least 500 mA, and less than 1 amp. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Pin Descriptions For More Information On This Product, Go to: www.freescale.com User’s Manual 27 Freescale Semiconductor, Inc. Freescale Semiconductor, Inc... Pin Descriptions User’s Manual 28 3-Phase BLDC Low-Voltage Power Stage Pin Descriptions For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage Section 4. Schematics and Parts List Freescale Semiconductor, Inc... 4.1 Contents 4.2 Mechanical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.3 Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.4 Parts Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 4.2 Mechanical Characteristics Mechanically, the LV BLDC power stage consists of an FR-4 circuit board, a 3.2-mm aluminum power substrate, two fans, a fan bracket, a heat sink, inter-board connectors, and standoffs. Construction is depicted in Figure 1-2. 3D Model. The aluminum circuit board, fans, and heat sink provide the thermal capability for D2PAK MOSFETs to drive fractional horsepower motors at continuous currents up to 30 amps. The FR-4 board contains most of the circuit complexity. The two boards plug together via 10 vertical connectors to, in effect, form a discrete power module. Four holes on the top board are spaced to allow mounting standoffs such that a control board can be placed on top of the power stage. This configuration allows mounting control and power functions in one compact mechanical assembly. 4.3 Schematics A set of schematics for the LV BLDC Power Stage appears in Figure 4-1 through Figure 4-8. An overview appears in Figure 4-1. H-bridge gate drive is shown in Figure 4-2. The 3-phase H-Bridge appears in Figure 4-3. Current and temperature feedback circuits are shown in Figure 4-4. Back EMF feedback circuitry appears in Figure 4-5. Brake gate drive is shown in Figure 4-6. The identification block is shown in Figure 4-7, and finally the power supply is shown in Figure 4-8. Unless otherwise specified, resistors are 1/8 watt, have a ±5% tolerance, and have values shown in ohms. Interrupted lines coded with the same letters are electrically connected. Parts lists for the printed circuit board and power substrate appear in Table 4-1 and Table 4-2. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Schematics and Parts List For More Information On This Product, Go to: www.freescale.com User’s Manual 29 Motor Supply J20 J19 i R1 SG260 FAN2 100nF FAN 2 1 C2 FAN1 FAN 2 1 +V Bias Power Power_neg_12V 2 -V -V J22 Power Jack Power_pos_12V J21 2 1 J9 J1 GNDA GND +3.3V_A +12V_D 1 2 3 4 5 6 7 8 Gate_Brake 3 J10 J12 I_T_Processing GNDA GND +3.3V_A +12V_D I_sense_DCB1 I_sense_DCB2 GNDA 1 2 3 4 5 6 1 100nF -FAN Temp_sense_2 POWER MODULE 1 3 5 7 9 11 13 15 17 19 J11 Brake_gate +12V_D Gate_Brake J6 Gate_AT J2 J15 Brake 2 Ext. 1 J5 GND J14 Brake1 Ext. DCB_Cap_pos 1 GND Gate_CT Temp_sense_2 GNDA Source_CB Gate_CB Source_BB Gate_BB Source_AB Gate_AB J7 Gate_BT J8 -12V_A +12V_A +3.3V_A +12V_D +5V_D J3 Gate_BT Power_neg_12V Power_pos_12V J4 GNDA GND MOSFET_Drivers PWM_CB PWM_CT PWM_BB PWM_BT PWM_AB PWM_AT Gate_CT Gate_AT +12V_D +5V_D GND +FAN -FAN V_sense_DCB_half Back_EMF +12V_D +5V_D J18 J17 J16 1 1 1 Phase C Phase B Phase A Outputs Zero_cros_C Zero_cros_B Zero_cros_A BEMF_sense_C BEMF_sense_B BEMF_sense_A GNDA GND Figure 4-1. 3-Phase BLDC Low-Voltage Power Stage Overview Temp_sense_1 Temp_sense_2 Shut_Down_Open C. Temp_sense I_sense_C I_sense_B I_sense_A I_sense_DCB I_sense_B2 I_sense_B1 -12V_A GND C1 1 Brake__DC_Bus 2 4 6 8 10 12 14 16 18 20 Brake_control 1 3 5 7 9 11 13 15 17 19 I_sense_A2 I_sense_A1 V_sense_DCB V_sense_DCB_half 1 2 3 4 I_sense_C2 I_sense_C1 +12V_D 1 3 5 7 9 2 4 6 8 10 2 4 6 8 10 DCB_Cap_neg 2 4 6 8 10 +12V_D 1 3 5 7 9 Power_Supply Gate_BT Phase_B 2 4 6 8 10 +5V_D 1 3 5 7 9 2 4 6 8 10 +5V_D 1 3 5 7 9 Shut_Down +12V_D Power_pos Gate_AT Phase_A 1 3 5 7 9 Gate_CT Phase_C +3.3V_A Power_pos_12V Power_neg 2 4 6 8 10 1 3 5 7 9 -FAN +FAN GNDA +12V_A Power_neg_12V 1 3 5 7 9 2 4 6 8 10 +12V_D +5V_D GND GNDA Phase_A Phase_B Phase_C +FAN 1 For More Information On This Product, Go to: www.freescale.com GND 2 4 6 8 10 12 14 16 18 20 Freescale Semiconductor, Inc... GND GNDA +3.3V_A +5V_D +12V_A -12V_A GNDA 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 J13 GND Identification +5V_D Identification PWM_CB Shielding PWM_CT Shielding PWM_BB Shielding PWM_BT Shielding PWM_AB Shielding PWM_AT Temp_sense I_sense_C I_sense_B I_sense_A I_sense_DCB V_sense_DCB Serial_Con Brake_control Shielding BEMF_sense_C BEMF_sense_B BEMF_sense_A Shielding Zero_cross_C Zero_cross_B Zero_cross_A GND +5V_D Freescale Semiconductor, Inc. For More Information On This Product, Go to: www.freescale.com GND +5V_D +12V_D PWM_CB PWM_CT PWM_BB PWM_BT PWM_AB PWM_AT C120 1nF C118 1nF R109 10k +12V_D R114 10k VCC GND C117 1nF GND VCC C121 1nF C119 1nF +5V_D R104 10k R110 10k GND GND R103 10k R113 10k GND C116 1nF 4 3 8 9 12 13 10nF C122 U104F DM74ALS1034M 10 11 U104E DM74ALS1034M U104D DM74ALS1034M 2 1 U104A DM74ALS1034M U104B DM74ALS1034M 6 5 U104C DM74ALS1034M Shut_Down GND + C111 4.7uF/16V GND + C106 4.7uF/16V R106 100 +5V_D GND + C101 4.7uF/16V IR2112S n/c n/c VDD HIN SD LIN VSS n/c IR2112S n/c n/c VDD HIN SD LIN VSS n/c C115 8.2pF 9 10 11 12 13 14 15 16 U103 C110 8.2pF 9 10 11 12 13 14 15 16 U102 HO VB VS n/c n/c VCC COM LO HO VB VS n/c n/c VCC COM LO +5V_D HO VB VS n/c n/c VCC COM LO +5V_D +5V_D IR2112S n/c n/c VDD HIN SD LIN VSS n/c U101 C105 8.2pF 9 10 11 12 13 14 15 16 Figure 4-2. Gate Drive C112 100nF +5V_D C107 100nF +5V_D R105 10k C102 100nF +5V_D C114 470nF/50V 8 7 6 5 4 3 2 1 C123 33uF/25V D108 GND + C125 33uF/25V MBRM140T3 D105 GND + MBRM140T3 D102 GND + C124 33uF/25V MBRM140T3 C113 470nF/50V C109 470nF/50V 8 7 6 5 4 3 2 1 C108 470nF/50V C104 470nF/50V 8 7 6 5 4 3 2 1 C103 470nF/50V Freescale Semiconductor, Inc... +12V_D +12V_D +12V_D MBRM140T3 MBRM140T3 MBRM140T3 MBRM140T3 MBRM140T3 MBRM140T3 R112 470 D109 R111 470 D107 R108 470 D106 R107 470 D104 R102 470 D103 R101 470 D101 Source_CB Gate_CB Phase_C Gate_CT Source_BB Gate_BB Phase_B Gate_BT Source_AB Gate_AB Phase_A Gate_AT Freescale Semiconductor, Inc. J1 DCB_Cap_Neg DCB_Cap_Pos DCB_Cap_Pos C1 4700uF + + C2 4700uF J12 Source_Brake Gate_Brake 0.001 R8 SM/CON/MCRD_SR_500_F-Male For More Information On This Product, Go to: www.freescale.com J7 J8 I_sense_C2 I_sense_C1 Source_CB Gate_CB Phase_C Gate_CT SM/CON/MCRD_SR_500_G-Male R6 0.001 Q5 MTB75N06HD Q2 MTB75N06HD D3 BAV99LT1 BAV99LT1 Temp_sense2 Temp_sense1 J4 SM/CON/MCRD_SR_500_G-Male D2 Figure 4-3. 3-Phase H-Bridge J11 SM/CON/MCRD_SR_500_E-Male 1 2 3 4 5 6 7 8 I_sense_B2 SM/CON/MCRD_SR_500_G-Male J3 SM/CON/MCRD_SR_500_G-Male J10 SM/CON/MCRD_SR_500_B-Male J2 SM/CON/MCRD_SR_500_G-Male Temp_sense2 Gate_BB Temp_sense1 Source_BB I_sense_B2 I_sense_B1 1 2 3 4 5 6 J9 SM/CON/MCRD_SR_500_I-Male SM/CON/MCRD_SR_500_F-Male I_sense_A2 I_sense_B1 R5 0.001 I_sense_A1 Phase_B Gate_BT Gate_BB Q4 MTB75N06HD Source_BB Q1 MTB75N06HD Source_AB Gate_AB Phase_A Gate_AT I_Sense_DCB2 D1 MBRB2060CT J6 SM/CON/MCRD_SR_500_G-Male I_Sense_DCB1 Q7 MTB75N06HD R4 0.33 R3 0.33 Brake_Res R2 0.33 R1 0.33 1 3 5 7 9 11 13 15 17 19 2 4 6 8 10 12 14 16 18 20 Source_Brake Gate_Brake Gate_AB Source_AB I_Sense_DCB1 I_Sense_DCB2 I_sense_A2 I_sense_A1 R7 0.001 Q6 MTB75N06HD Q3 MTB75N06HD SM/CON/MCRD_SR_500_G-Male J5 2 4 6 8 10 1 3 5 7 9 DCB_Cap_Neg 1 3 5 7 9 11 13 15 17 19 2 4 6 8 10 12 14 16 18 20 Gate_BT 2 4 6 8 10 1 3 5 7 9 Gate_AT 2 4 6 8 10 1 3 5 7 9 Phase_B 2 4 6 8 10 1 3 5 7 9 Gate_CT 2 4 6 8 10 1 3 5 7 9 Phase_A 2 4 6 8 10 1 3 5 7 9 Gate_CB Source_CB I_sense_C2 I_sense_C1 1 2 3 4 Phase_C 2 4 6 8 10 1 3 5 7 9 Brake_Res Freescale Semiconductor, Inc... Freescale Semiconductor, Inc. C307 100nF +3.3V_A GNDA I_sense_C2 I_sense_C1 I_sense_B2 I_sense_B1 I_sense_A2 I_sense_A1 GND + GNDA 5 1.65V ref R321 3k-1% R320 3k-1% R313 3k-1% R311 3k-1% R304 3k-1% R301 3k-1% C306 3.3uF/10V LM285M U304 R323 390 GND GNDA +3.3V_A GNDA +12V_D +12V_D 1.65V ref R325 33.2k-1% R324 100k-1% 1.65V ref GNDA C301 100nF +3.3V_A U302A MC33502D 1 R322 100k-1% 5 6 U302B MC33502D 7 R318 100k-1% R314 100k-1% 3 2 GNDA R307 100k-1% U301B MC33502D 7 I_sense_C I_sense_B I_sense_A - + GND I_sense_DCB2 I_sense_DCB1 I_sense_DCB C304 680pF R308 1.2k 7 GND R317 3k-1% R316 3k-1% DC Bus Current Sensing R310 470 2 3 - + GND LM393D 3 2 1 100nF C305 +3.3V_A U301A MC33502D GNDA GNDA 1 U303A +12V_D R306 680k GNDA C302 100nF R302 2.21k-1% +3.3V_A R315 100k-1% R319 100k-1% GNDA R312 10k R309 1.2k Temp_sense_1 Temp_sense_2 +12V_D +3.3V_A C303 100nF LM393D GNDA Over-current Detection GNDA 6 5 U303B +12V_D Temperature Sensing Figure 4-4. Current and Temperature Feedback R305 100k-1% 5 6 R303 100k-1% Phase Current Sensing 8 4 +3.3V_A 8 + - 4 4 + - For More Information On This Product, Go to: www.freescale.com 8 + 8 8 4 4 + - Freescale Semiconductor, Inc... I_sense_DCB I_sense_DCB Shut_Down_Open C. Temp_sense Freescale Semiconductor, Inc. For More Information On This Product, Go to: www.freescale.com Phase_C Phase_B Phase_A (3.30V @ Phase_C = 16V) BEMF_sense_C R524 0 GNDA R521 3.32k-1% R518 1.18k-1% R516 11.5k-1% (3.30V @ Phase_B = 16V) BEMF_sense_B R523 0 GNDA C504 100pF R517 10k GNDA R514 3.32k-1% R511 1.18k-1% R508 11.5k-1% (3.30V @ Phase_A = 16V) BEMF_sense_A GNDA GNDA R513 470k C501 100pF R506 470k R502 10k C505 1.8nF R520 470k 4 5 6 7 8 9 - + GND 14 U501A LM339D 2 100nF C503 R515 10M U501B LM339D 1 U501C LM339D R510 10M +12V_D - + - + R503 10M Figure 4-5. Back EMF Signals V_sense_DCB_half C502 100pF R509 10k GNDA GNDA R507 3.32k-1% R504 1.18k-1% R501 11.5k-1% 3 12 R522 0 GND +5V_D +5V_D +5V_D R519 10k R512 10k R505 10k Freescale Semiconductor, Inc... Zero_cross_C Zero_cross_B Zero_cross_A GND 10 11 GNDA + U501D LM339D 13 GNDA GND +5V_D +5V_D GND +12V_D +12V_D Freescale Semiconductor, Inc. For More Information On This Product, Go to: www.freescale.com GND +12V_D Brake_control 1nF C203 GND +12V_D GND R206 10k GND DCB_Cap_neg DCB_Cap_pos GND 0 R207 100 R201 3.4k-1% R202 Figure 4-6. DC Bus Voltage Sense and Brake Gate Drive GND MC33152D 5 OutB 8 GND 4 InB NC C202 100nF 7 3 OutA VCC C201 10uF/35V + 2 InA U201 1 NC 6 +12V_D Freescale Semiconductor, Inc... 4.75k-1% R203 V_sense_DCB R205 3.32k-1% (3.30V @ DC Bus = 16V) R204 4.53k-1% V_sense_DCB_half (8.00V @ DC Bus + 16V) Brake_gate Freescale Semiconductor, Inc. For More Information On This Product, Go to: www.freescale.com GND +5V_D Identification GND +5V_D +5V_D GND C801 + 10uF/6.3V GND 4MHz X801 R801 +5V_D 20 14 15 16 17 11 12 13 18 PB0 IRQ RESET OSC2 OSC1 PA2 PA1 PA0 GND 7 6 5 4 3 2 1 10 9 8 3 2 1 Coding bit # R802 R803 R804 R805 10k 10k 10k 10k Figure 4-7. Identification Block GND +5V_D 19 +5V_D PB7 PB6 PB5 PB4/TCMP PB3/TCAP PB2/AN2 PB1/AN1 U801 PA3 PA4 PA5 VCC MC68HC705JJ7DW_MOD Coding bit # 0 10k C802 10nF Freescale Semiconductor, Inc... 7 5 3 1 SM/JUMPER4x2 8 6 4 2 JP801 +5V_D GND DEFAULT SETTINGS: 0 - PTB0 = H 1 - PTB1 = L 2 - PTB2 = H 3 - PTB3 = H 4 - PTB4 = H 5 - PTB5 = H 6 - PTA6 = H 7 - PTA7 = H Coding bit # 7 6 5 4 Freescale Semiconductor, Inc. 2 1 +12V_A -12V_A +12V_A -12V_A +FAN -FAN -FAN GND +FAN GND GNDA +12V_D +12V_D GNDA +3.3V_A +5V_D +5V_D Power_neg Power_neg +3.3V_A Power_pos Power_neg_12V Power_pos D407 GND 100uF/16V + C406 D408 MBRM140T3 EXT. INT. JP401 3 2 1 U402 Power_neg D406 MBRM140T3 DCB_Cap_Neg +12V MBRM140T3 Power_neg_12V J20 J19 i D405 MBRM140T3 Power_pos_12V R1 SG260 2 -V -V Power_pos_12V J21 +V 3 1 1 3 1 1 Power_pos -FAN +FAN D402 MBRM140T3 330uH L401 GND C411 1uF +12V 3 2 23 22 + DC 330uF/16V C413 +Vout R403 1.2k -Vout -12V/125mA COM COM 12V/125mA R401 4.7k DC TRACO/TEG1222 -Vin -Vin 9V-18V +Vin +Vin U401 Figure 4-8. Power Supply 2 LM2575D2T-ADJ 4 5 DCB_Cap_Pos 11 16 9 14 Ground_Connection GC401 2 C402 3.3uF/10V C412 100nF 1 + 3 6 C401 100nF 4 5 C404 100uF/16V 3 1 GNDA -CE U404 MC78PC33NTR 5 Vin Vout 100uF/16V + C414 + C408 100uF/16V + 100uF/16V + C409 D404 MBR0530T1 Reset Delay GND HS Input Output U403 MC33267D2T D403 MBR0530T1 FLT402 DS306-55Y5S222M50 1 3 2 J22 Power Jack GND For More Information On This Product, Go to: www.freescale.com 2 Freescale Semiconductor, Inc... + +12V_A C410 3.3uF/10V +3.3V_A GND LED Green D401 +5V_D -12V_A GNDA R402 1.5k C405 100nF 100nF C407 GND 100nF C403 +12V_D Freescale Semiconductor, Inc. Freescale Semiconductor, Inc. Schematics and Parts List 4.4 Parts Lists The LV BLDC power stage’s parts content is described in Table 4-1 for the power substrate and in Table 4-2 for the printed circuit board. Table 4-1. Power Substrate Parts List Freescale Semiconductor, Inc... Designators Qty Description Manufacturer Part Number C1, C2 2 4700 µF D1 1 20 A/60 V Schottky ON Semiconductor MBRB2060CT D2, D3 2 Dual diode – temp sensing ON Semiconductor BAV99LT1 J1, J12 2 SM/CON/MCRD_SR_500_F Fischer Elektronik SL 11 SMD 104 10 Z J2, J3, J4, J5, J6, J7, J8 7 SM/CON/MCRD_SR_500_G Fischer Elektronik SL 11 SMD 104 5 Z J9 1 SM/CON/MCRD_SR_500_I Fischer Elektronik SL 10 SMD 104 8 Z J10 1 SM/CON/MCRD_SR_500_B Fischer Elektronik SL 10 SMD 104 6 Z J11 1 SM/CON/MCRD_SR_500_E Fischer Elektronik SL 10 SMD 104 4 Z Q1, Q2, Q3, Q4, Q5, Q6, Q7 7 75 A/60 V MOSFET ON Semiconductor MTB75N06HD R1, R2, R3, R4 4 0.33 Ω/25 W Caddock Electronics MP725-0.33-5.0% R5, R6, R7, R8 4 0.001 Ω sense resistor Isabellenhütte Heusler BVS-M-R001-1.0 1 Substrate CUBEcz 46615772 User’s Manual 38 3-Phase BLDC Low-Voltage Power Stage Schematics and Parts List For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Schematics and Parts List Parts Lists Freescale Semiconductor, Inc... Table 4-2. Printed Circuit Board Parts List (Sheet 1 of 3) Designators Qty Description Manufacturer C1, C2, C102, C107, C112, C202, C301, C302, C303, C305, C307, C401, C403, C405, C407, C412, C503 17 100 nF/25 V Vitramon VJ0805U104MXXA_ C101, C106, C111 3 4.7 µF/16 V Sprague 293D475X_016B2_ C103, C104, C108, C109, C113, C114 6 470 nF/50 V Vitramon VJ1206U474MXAA_ C105, C110, C115 3 8.2 pF Vitramon VJ0805A8R2DXA_ C116, C117, C118, C119, C120, C121, C203 7 1 nF/50 V Vitramon VJ0805A102KXAA_ C122, C802 2 10 nF/25 V Vitramon VJ0805U103MXXA_ C123, C124, C125 3 33 µF/25 V AVX TPSE336K025R0200 C201 1 10 µF/35 V Sprague 293D106X0035D2_ C304 1 680 pF Vitramon VJ0805A681JXA_ C306, C402, C410 3 3.3 µF/10 V Sprague 293D335X0010A2_ C404, C406, C408, C409, C414 5 100 µF/16 V Sprague 293D107X0016D2_ C411 1 1 µF Siemens B32529-C105-K C413 1 330 µF/16 V Vishay Roederstein EKA00PB333D00 C501, C502, C504 3 100 pF Vitramon VJ0805A101KXAA_ C505 1 1.8 nF Vitramon VJ0805A182KXAA_ C801 1 10 µF/6.3 V Sprague 293D106X06R3B2_ D101, D102, D103, D104, D105, D106, D107, D108, D109, D402, D405, D406, D407, D408 14 1 A/40 V Schottky ON Semiconductor MBRM140T3 D401 1 LED green Kingbright L-934GT D403, D404 2 0.5 A/30 V Schottky ON Semiconductor MBR0530T1 JP401 1 Power jumper Fischer Elektronik SL 1/53 3 G FLT401 1 EMI filter muRata DS306-55Y5S222M50 GC401 0 Ground connection N/A N/A JP401 1 Power jumper Fischer Elektronik CAB 4 G JP801 0 4x2 jumper pads N/A N/A J1, J12 2 20-pin female header Fischer Elektronik BL 2 10 Z 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Schematics and Parts List For More Information On This Product, Go to: www.freescale.com Part Number User’s Manual 39 Freescale Semiconductor, Inc. Schematics and Parts List Table 4-2. Printed Circuit Board Parts List (Sheet 2 of 3) Freescale Semiconductor, Inc... Designators Qty Description J2, J3, J4, J5, J6, J7, J8 7 10-pin female header Fischer Elektronik BL 2 5 Z J9 1 8-pin female header Fischer Elektronik BL 1 8 Z J10 1 6-Pin female header Fischer Elektronik BL 1 6 Z J11 1 4-pin female header Fischer Elektronik BL 1 4 Z J13 1 40-pin connector Fischer Elektronik ASLG40G J14, J15, J16, J17, J18, J19, J20 7 Fast-on AMP 140814-2 J21 1 2-pole terminal block WAGO 237-132 J22 1 Power jack CUI Stack PJ-002A L401 1 330 µH Pulse Engineering 53146 R1 1 30 A current limiter Rhopoint Components SG260 R101, R102, R107, R108, R111, R112 6 470 Ω Dale CRCW0805-471J R103, R104, R105, R109, R110, R113, R114, R206, R312, R502, R505, R509, R512, R517, R519, R801, R802, R803, R804, R805 20 10 kΩ Dale CRCW0805-103J R201, R106 2 100 Ω Dale CRCW0805-101J R205, R507, R514, R521 4 3.32 kΩ–1% Dale CRCW0805-3321F R202 1 3.4 kΩ–1% Dale CRCW0805-3401F R203 1 4.75 kΩ–1% Dale CRCW0805-4751F R204 1 4.53 kΩ–1% Dale CRCW0805-4531F R207, R522, R523, R524 4 0 Dale CRCW0805-000 R301, R304, R311, R313, R316, R317, R320, R321 8 3 kΩ–1% Dale CRCW0805-3001F R302 1 2.21 kΩ–1% Dale CRCW0805-2211F R303, R305, R307, R314, R315, R318, R319, R322, R324 9 100 kΩ–1% Dale CRCW0805-1003F R306 1 68 kΩ Dale CRCW0805-683J R308, R309, R403 3 1.2 kΩ Dale CRCW0805-122J R310 1 470 Ω Dale CRCW0805-221J User’s Manual 40 Manufacturer Part Number 3-Phase BLDC Low-Voltage Power Stage Schematics and Parts List For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Schematics and Parts List Parts Lists Table 4-2. Printed Circuit Board Parts List (Sheet 3 of 3) Freescale Semiconductor, Inc... Designators Qty Description Manufacturer Part Number R323 1 390 Ω Dale CRCW0805-391J R325 1 33.2 kΩ–1% Dale CRCW0805-3322F R401 1 4.7 kΩ Dale CRCW0805-473J R402 1 1.5 kΩ Dale CRCW0805-152J R501, R508, R516 3 11.5 kΩ–1% Dale CRCW0805-1152F R503, R510, R515 3 10 MΩ Dale CRCW0805-106J R504, R511, R518 3 1.18 kΩ–1% Dale CRCW0805-1181F R506, R513, R520 3 470 kΩ Dale CRCW0805-474J U101, U102, U 103 3 Gate driver International Rectifier IR2112S U104 1 Hex driver Fairchild DM74ALS1034M U201 1 Gate driver ON Semiconductor MC33152D U301, U302 2 Op amp On Semiconductor MC33502D U303 1 Dual comparator On Semiconductor LM393D U304 1 Voltage reference National Semiconductor LM285M U401 1 DC/DC convertor Traco Power TEG1222 U402 1 Voltage regulator ON Semiconductor LM2575D2T-ADJ U403 1 Voltage regulator ON Semiconductor U404 1 Voltage regulator ON Semiconductor MC78PC33NTR U501 1 Dual comparator ON Semiconductor LM339D U801 1 Programmed MCU Motorola MC68HC705JJ7DW X801 1 4-MHz resonator muRata CSTCC4.00MG 7 Tubular rivet INDUSTRIAL RIVET N/A 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Schematics and Parts List For More Information On This Product, Go to: www.freescale.com User’s Manual 41 Freescale Semiconductor, Inc. Freescale Semiconductor, Inc... Schematics and Parts List User’s Manual 42 3-Phase BLDC Low-Voltage Power Stage Schematics and Parts List For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. User’s Manual — 3-Phase BLDC Low-Voltage Power Stage Section 5. Design Considerations Freescale Semiconductor, Inc... 5.1 Contents 5.2 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 5.3 Phase Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 5.4 Bus Voltage and Current Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . 45 5.5 Cycle-by-Cycle Current Limiting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 5.6 Temperature Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5.7 Back EMF Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 5.8 Phase Current Sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 5.9 Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 5.2 Overview From a systems point of view, the LV BLDC power stage fits into an architecture that is designed for software development. In addition to the hardware that is needed to run a motor, a variety of feedback signals that facilitate control algorithm development are provided. Circuit descriptions for the LV BLDC power stage appear in these subsections. 5.3 Phase Outputs The output stage is configured as a 3 phase H-Bridge with 60-volt MOSFET output transistors. It is simplified considerably by integrated gate drivers that have a cycle by cycle current limit feature. A schematic that shows one phase is illustrated in Figure 5-1. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Design Considerations For More Information On This Product, Go to: www.freescale.com User’s Manual 43 Shut_Down PWM_AB PWM_AT GND C116 1nF R103 10k R104 10k C117 1nF 4 3 U104B DM74ALS1034M 6 5 U104C DM74ALS1034M For More Information On This Product, Go to: www.freescale.com R105 10k R106 100 +5V_D GND + IR2112S n/c n/c VDD HIN SD LIN VSS n/c U101 C105 8.2pF 9 10 11 12 13 14 15 16 +5V_D HO VB VS n/c n/c VCC COM LO C123 GND 33uF/25V + I_Sense_DCB2 I_sense_A2 I_sense_A1 R102 470 MBRM140T3 D103 +12V_D R101 470 MBRM140T3 D101 DCB_Cap_Pos C103 D102 470nF/50V MBRM140T3 C104 470nF/50V 8 7 6 5 4 3 2 1 Figure 5-1. Phase A Output C102 100nF C101 4.7uF/16V +5V_D Freescale Semiconductor, Inc... sense sense R5 0.001 Q4 MTB75N06HD Q1 MTB75N06HD Freescale Semiconductor, Inc. Freescale Semiconductor, Inc. Design Considerations Bus Voltage and Current Feedback 5.4 Bus Voltage and Current Feedback Feedback signals proportional to bus voltage and bus current are provided by the circuitry shown in Figure 5-2. Bus voltage is scaled down by a voltage divider consisting of R202–R205. The values are chosen such that a 16-volt maximum bus voltage corresponds to 3.3 volts at output V_sense_DCB. An additional output, V_sense_DCB_half, provides a reference that is used in zero-crossing detection. Freescale Semiconductor, Inc... Bus current is sampled by resistor R8 in Figure 4-3. 3-Phase H-Bridge and amplified by the circuit in Figure 5-2. This circuit provides a voltage output suitable for sampling with A/D inputs. An MC33502 is used for the differential amplifier. With R316 = R317 and R315 = R319, the gain is given by: A = R315/R316 The output voltage is shifted up by 1.65 V to accommodate both positive and negative current swings. A ±50 mV voltage drop across the sense resistor corresponds to a measured current range of ±50 amps. In addition to providing an A/D input, this signal is also used for cycle-by-cycle current limiting. A discussion of cycle-by-cycle current limiting follows in 5.5 Cycle-by-Cycle Current Limiting. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Design Considerations For More Information On This Product, Go to: www.freescale.com User’s Manual 45 Freescale Semiconductor, Inc. DC Bus Voltage Sensing R207 R202 R203 0 3.4k-1% 4.75k-1% DCB_Cap_pos V_sense_DCB_half R204 4.53k-1% V_sense_DCB R205 3.32k-1% DCB_Cap_neg DC Bus Current Sensing R315 100k-1% 4 I_sense_DCB I_sense_DCB2 3 GNDA R317 3k-1% 1 I_sense_DCB U301A MC33502D 8 (+/- 50mV @ +/- Imax) 2 + R316 3k-1% I_sense_DCB1 - R319 100k-1% +3.3V_A C305 100nF GNDA R323 390 1.65V ref + C306 3.3uF/10V C307 100nF 8 +3.3V_A 5 U304 LM285M 4 Freescale Semiconductor, Inc... (3.30V @ Vbus = 16V) GNDA R324 100k-1% R325 33.2k-1% GNDA Figure 5-2. Bus Feedback For More Information On This Product, Go to: www.freescale.com ______________________________________________________________________ Freescale Semiconductor, Inc. Design Considerations Cycle-by-Cycle Current Limiting 5.5 Cycle-by-Cycle Current Limiting Cycle-by-cycle current limiting is provided by the circuitry illustrated in Figure 5-3. Bus current feedback signal I_sense_DCB is filtered with R308 and C304 to remove spikes, and then compared to a 3.15-volt reference in U303A. The open collector output of U303A is pulled up by R105. Additional filtering is provided by C105, C110, and C115. The resulting signal is fed into the IR2112 gate driver’s shutdown input on all three phases. Therefore, when bus current exceeds 46 amps, all six output transistors are switched off. Freescale Semiconductor, Inc... The IR2112’s shutdown input is buffered by RS latches for both top and bottom gate drives. Once a shutdown signal is received, the latches hold the gate drive off for each output transistor, until that transistor’s gate drive signal is switched low, and then is turned on again. Hence, current limiting occurs on a cycle-by-cycle basis. 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Design Considerations For More Information On This Product, Go to: www.freescale.com User’s Manual 47 Freescale Semiconductor, Inc. Design Considerations U101 PWM A TOP PWM A BOTTOM 9 10 11 12 13 14 15 16 N/C N/C VDD HIN SD LIN VSS N/C HO VB VS N/C N/C VCC COM LO 8 7 6 5 4 3 2 1 A TOP OUT 8 7 6 5 4 3 2 1 B TOP OUT 8 7 6 5 4 3 2 1 C TOP OUT A BOTTOM OUT IR2112S C105 8.2 pF Freescale Semiconductor, Inc... +5V_D U102 PWM B TOP R306 680 kΩ PWM B BOTTOM +5V_D +12V_D I_sense_DCB R308 1.2 kΩ C304 680 pF 8 R309 1.2 kΩ 3 2 +3.3V_A R310 470 Ω GNDA R312 10 kΩ + – U303A 1 R105 10 kΩ 9 10 11 12 13 14 15 16 N/C N/C VDD HIN SD LIN VSS N/C HO VB VS N/C N/C VCC COM LO B BOTTOM OUT IR2112S R106 100 Ω LM393D C110 8.2 pF +5V_D 4 GND U103 GNDA PWM C TOP PWM C BOTTOM 9 10 11 12 13 14 15 16 N/C N/C VDD HIN SD LIN VSS N/C HO VB VS N/C N/C VCC COM LO C BOTTOM OUT IR2112S C115 8.2 pF +5V_D Figure 5-3. Cycle-by-Cycle Current Limiting User’s Manual 48 3-Phase BLDC Low-Voltage Power Stage Design Considerations For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Design Considerations Temperature Sensing 5.6 Temperature Sensing Cycle-by-cycle current limiting keeps average bus current within safe limits. Current limiting by itself, however, does not necessarily ensure that a power stage is operating within safe thermal limits. For thermal protection, the circuit in Figure 5-4 is used. It consists of four diodes connected in series, a bias resistor, and a noise suppression capacitor. The four diodes have a combined temperature coefficient of –8.8 mV/°C. The resulting signal, Temp_sense, is fed back to an A/D input where software can be used to set safe operating limits. Freescale Semiconductor, Inc... Due to unit-to-unit variations in diode forward voltage, it is highly desirable to calibrate this signal. To do so, a value for Temp_sense is read at a known temperature and then stored in nonvolatile memory. The measured value, rather than the nominal value, is then used as a reference point for further readings. +3.3V_A R302 2.2 kΩ –1% D3 BAV99LT1 D2 BAV99LT1 Temp_sense PIN 26, CONNECTOR J13 C302 100 nF GNDA Figure 5-4. Temperature Sensing 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Design Considerations For More Information On This Product, Go to: www.freescale.com User’s Manual 49 Freescale Semiconductor, Inc. Design Considerations 5.7 Back EMF Signals Freescale Semiconductor, Inc... Back EMF and zero crossing signals are included to support sensorless algorithms. Referring to Figure 5-5, which shows circuitry for phase A, the raw phase voltage is scaled down by a voltage divider consisting of R501, R504, R507, and R522. One output from this divider produces back EMF sense voltage BEMF_sense_A. Resistor values are chosen such that a 16-volt maximum phase voltage corresponds to a 3.3-volt maximum A/D input. A zero crossing signal is obtained by comparing motor phase voltage with one-half the motor bus voltage. Comparator U501C performs this function, producing zero crossing signal Zero_cross_A. R522 Phase_A 0Ω R501 11.5 kΩ –1% R504 1.18 kΩ –1% BEMF_sense_A 3.30 V @ Phase_A = 16 V R506 470 kΩ R507 3.32 kΩ –1% C501 100 pF GNDA GNDA +5V_D R503 R502 10 kΩ 10 MΩ 9 + 8 – R505 10 kΩ 14 U501C LM339D Zero_cross_A V_sense_DCB_half C505 1.8 nF GNDA Figure 5-5. Phase A Back EMF User’s Manual 50 3-Phase BLDC Low-Voltage Power Stage Design Considerations For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. Design Considerations Phase Current Sensing 5.8 Phase Current Sensing Lower half-bridge sampling resistors provide phase current information for all three phases. Since these resistors sample current in the lower phase legs, they do not directly measure phase current. However, given phase voltages for all three phases, phase current can be constructed mathematically from the lower phase leg values. This information can be used in a variety of motor control algorithms. The measurement circuitry for one phase is shown in Figure 5-6. Freescale Semiconductor, Inc... DCB_Cap_Pos Q1 MTB75N06HD Gate_AT Phase_A Q4 MTB75N06HD Gate_AB R303 100 kΩ –1% Source_AB sense R5 0.01 Ω R301 3 kΩ –1% 6 5 sense R304 3 kΩ –1% I_Sense_DCB2 + 7 U301B MC33502D I_sense_A R305 100 kΩ –1% R323 390 Ω +3.3V_A C307 100 nF – + C306 3.3 µF 1.65 Vref R324 100 kΩ –1% 8 5 LM285M U304 R325 3.23 kΩ –1% GNDA 4 GNDA Figure 5-6. Phase A Current Sensing 3-Phase BLDC Low-Voltage Power Stage MOTOROLA Design Considerations For More Information On This Product, Go to: www.freescale.com User’s Manual 51 Freescale Semiconductor, Inc. Design Considerations Referencing the sampling resistors to the negative motor rail makes the measurement circuitry straightforward and inexpensive. Current is sampled by resistor R5, and amplified by differential amplifier U301B. This circuit provides a voltage output suitable for sampling with A/D inputs. An MC33502 is again used for the differential amplifier. The gain is given by: Freescale Semiconductor, Inc... A = R303/R301 The output voltage is shifted up by 1.65 V to accommodate both positive and negative current swings. A ±50-mV voltage drop across the shunt resistor corresponds to a measured current range of ±50 amps. 5.9 Brake A brake circuit is included to dissipate re-generative motor energy during periods of active deceleration or rapid reversal. Under these conditions, motor back EMF adds to the dc bus voltage. Without a means to dissipate excess energy, an overvoltage condition could easily occur. The circuit shown in Figure 5-7 connects R1–R4 across the dc bus to dissipate energy. Q7 is turned on by software when the bus voltage sensing circuit in Figure 5-2 indicates that bus voltage could exceed safe levels. On-board power resistors R1–R4 will safely dissipate up to 50 watts continuously or up to 100 watts for 15 seconds. Additional power dissipation capability can be added externally via brake connectors J14 and J15. Note that operation of the brake at 100% duty cycle for more than 15 seconds at 12 volts will over dissipate R1–R4. For bus voltages higher than 12 volts, maximum duty cycle is restricted to less than 100%. User’s Manual 52 3-Phase BLDC Low-Voltage Power Stage Design Considerations For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc. DCB_Cap_Pos R1 0.33 J14 Brake1 EXT. 1 J15 Brake 2 EXT. 1 R3 0.33 D1 MBRB2060CT R4 0.33 +12V_D + C201 10uF/35V U201 1 NC VCC 2 InA Brake_control GND 6 C202 100nF NC 8 OutA 7 Q7 MTB75N06HD R201 100 OutB 4 InB R206 10k C203 1nF MC33152D 5 GND 3 Freescale Semiconductor, Inc... R2 0.33 GND GND GND GND Figure 5-7. Brake For More Information On This Product, Go to: www.freescale.com GND Freescale Semiconductor, Inc. Freescale Semiconductor, Inc... Design Considerations User’s Manual 54 3-Phase BLDC Low-Voltage Power Stage Design Considerations For More Information On This Product, Go to: www.freescale.com MOTOROLA Freescale Semiconductor, Inc... Freescale Semiconductor, Inc. For More Information On This Product, Go to: www.freescale.com Freescale Semiconductor, Inc... Freescale Semiconductor, Inc. Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. 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Customer Focus Center, 1-800-521-6274 JAPAN: Motorola Japan Ltd.; SPS, Technical Information Center, 3-20-1, Minami-Azabu, Minato-ku, Tokyo 106-8573 Japan. 81-3-3440-8573 ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; Silicon Harbour Centre, 2 Dai King Street, Tai Po Industrial Estate, Tai Po, N.T., Hong Kong. 852-26668334 HOME PAGE: http://motorola.com/semiconductors/ © Motorola, Inc., 2000 For More Information On This Product, Go to: www.freescale.com MEMC3PBLDCLVUM/D