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User’s Manual
Camera Phone Flash
Evaluation Board
Dual Cell APPEB1007
All information contained herein is strictly confidential
© CAP-XX Pty Limited 2005
APPEB1007 User Manual rev1.0, 31-May-2005
page 1 of 6
Camera Phone Flash Evaluation Board User’s Manual
Board Features
FLASH mode with adjustable voltage and current
TORCH/MOVIE/GPRS mode with adjustable voltage and current
VOUT/GND connector to evaluate GPRS Power Amplifier
On-board or External triggering
On-board or External white LEDs
LED and inductor current measurement ability
Auto run for flash or torch
Quick Setup
The following jumpers should be in place J1, J4, J5, J8, J9, J10, J12 and J15. Connect the
positive terminal of a single cell Lithium Ion rechargeable battery (3.3V-4.2V) to any pin on J2
and connect the negative terminal to any pin of J3. The red LED (D2) should come on
immediately.
TORCH
Flick the toggle switch (SW2) to the left (towards the TORCH pushbutton SW1). Pressing
SW1 will now cause 100mA (factory set) to flow through each of the white LEDs (D5 & D6).
With the factory setting of 100mA per white LED, SW1 can be held down continuously.
FLASH
Flick the toggle switch (SW2) to the right (towards the FLASH pushbutton SW3). Pressing
SW3 will now cause 1A (factory set) to flow through each of the white LEDs (D5 & D6) for
approximately 80ms. If the button is held down continuously the flash will retrigger
approximately every 2.5s. This duty cycle is imposed due to the thermal constraints of the
white LED.
GPRS
GPRS mode is the same as TORCH mode, ie flick the toggle switch (SW2) to the left
(towards the TORCH pushbutton SW1). The factory set output voltage is 3.8V and it is
available on the orange connector (TB1) to be connected to a Power Amplifier or other
pulsed load.
Circuit Description (refer to schematics at the end of this manual)
Input Voltage
The circuit is designed to operate from an external Li ion battery (4.2V-3.3V).
Vbat is the node connected to the battery via J2.
J2 is to be connected to battery positive terminal. Pins 1 and 2 of J2 are joined.
J3 is to be connected to battery negative terminal. Pins 1 and 2 of J3 are joined.
A current limiting MOSFET (M1) is not currently installed on the PCB and as such the bypass
jumper (J15) needs to be installed.
Indicating LED
D2 is a red LED that indicates a source voltage is present.
Buck/Boost Converter
J1 needs to be jumpered for normal operation. This jumper has been included so a wire loop
can easily be inserted to measure the inductor current. By measuring the inductor current
and monitoring the voltage of pin 6 of U1 the average output current can also be determined.
All information contained herein is strictly confidential
© CAP-XX Pty Limited 2005
APPEB1007 User Manual rev1.0, 31-May-2005
page 2 of 6
The controller is an LTC3442 from Linear Technology. Its “Soft Start” and “Burst” features are
not currently utilized and as such J4 and J5 need to be jumpered to disable these features.
Inrush Current
A discharged supercapacitor presents itself as a short circuit and therefore inrush current
needs to be managed. The LTC3442 has an average input current limiting feature and this
has been set to approximately 1.5Amps by selecting R11 = 47KΩ.
FLASH MODE
For FLASH mode, Vout is factory set to 4.5V. This voltage can be reduced by turning R21 (a
100k pot) anticlockwise.
TORCH MODE
The continuous current required for TORCH is << FLASH current (typically 200mA Vs 2A).
Therefore the voltage dropped across the white LEDs will be less. To increase efficiency
(and to reduce thermal stress on the current limiting MOSFET (M4)) Vout should also be
reduced. Vout can be adjusted using R22 (a 1M pot). Vout is factory set to 3.8V. The FLASH
mode voltage needs to be adjusted prior to the TORCH mode voltage because the FLASH
setting affects the TORCH setting but not vice versa. If Jumper J12 is removed then the
TORCH / GPRS mode voltage is the same as that set in Flash Mode above and R22 has no
effect.
GPRS MODE
GPRS mode is the same as TORCH mode (factory set to 3.8V). The Vout setting (adjusted
using R22) has to satisfy both the external Power Amplifer and have enough voltage
headroom to drive the white LEDs in TORCH mode for the TORCH Mode current selected.
Current Control
FLASH MODE
The FLASH current is factory set to 2.0 Amps (shared between two white LEDs). It can be
reduced by turning R33 (10k pot) anti-clockwise. The current in a single white LED should
not exceed 1 Amp so if only one LED is to be used then the FLASH current should be
reduced to 1 Amp or less prior to driving the single LED. The FLASH current needs to be
adjusted prior to the TORCH current because the FLASH setting affects the TORCH setting
but not vice versa.
TORCH MODE
The TORCH current is factory set at 200mA. It can be reduced by turning R34 (2k pot) anticlockwise or increased by turning R34 clockwise. Care should be taken not to increase Torch
mode current > 400mA total (200mA per LED) so as not to overheat and destroy the LEDs.
GPRS MODE
The maximum average load current is determined by the average input current limit which is
set at 1.5Amps on the LTC3442 Buck/Boost controller. Assuming 85% efficiency, maximum
average load current = 1.5A x Vbat/(Vout in TORCH mode) x 85%. Providing the DC:DC
converter provides sufficient average load current, the supercapacitor will provide the peak
currents.
All information contained herein is strictly confidential
© CAP-XX Pty Limited 2005
APPEB1007 User Manual rev1.0, 31-May-2005
page 3 of 6
External FLASH LED
An External white LED (or other load) can be connected to the board across Jumper J7 (pin2
is +ve). When doing this, also remove Jumpers J8 and J9 to disconnect the on-board LEDs
(D5 & D6). Alternatively, more white LEDs (Lumileds LXCL-PWF1) can be connected in
parallel to D5 & D6 across J7 with Jumpers J8 and J9 in place.
External FLASH/TORCH/GPRS MODE Control
An external control signal (3V) connected to pin 2 of J13 will select TORCH MODE.
Flash PulseTimers/External FLASH Pulse Control
There are two on-board 555 timers. One generates the FLASH on-time and the other
generates the off-time. The FLASH trigger from these timers is connected to the Current
Control circuitry via J10. J10 is jumpered for normal operation. An external triggering circuit
can be connected by removing the jumper from J10 and connecting the external signal to pin
1 of J10. There is a 33k pull down resistor on this pin. A logic high signal on this pin will take
a FLASH. Make sure that this signal is < 100ms long and does not occur for at least another
2s otherwise the thermal limits of the white LEDs will be violated and they will be destroyed.
Auto Flash
If J14 is jumpered then the two 555 timers will be continuously triggered to generate an 80ms
flash pulse every 2.5s. Jumpering J14 has the same effect as pressing SW3 continuously.
Further Information
CAP-XX will be pleased to provide further information on the applications described here,
and on the use of supercapacitors in any application. Please use the contact details on the
header page, or visit the CAP-XX web site.
All information contained herein is strictly confidential
© CAP-XX Pty Limited 2005
APPEB1007 User Manual rev1.0, 31-May-2005
page 4 of 6
Schematics
J15
2
1
FET Bypass
8
7
6
5
805
R1
Vbat
J2
1
1
2
3
22m
2
C4
4u7
805
Vbattery
C5
4u7
805
C6
4u7
805
R5
4
J3
1
2
805
47n
GND
R16
C17
56n
805
1
U3
LM4041
3
6
1k8
805
D2
D3
LSR976
805
LYR976
805
R13
470
805
7
+
Vbat
U4
1
2
3
TS1852
R15=R19/(1.22/I/22m-1)
5
4
C20
100n
805
C19
4u7
805
LM4041
3
1
2
C21
4u7
805
L1
Inductor Current
1
2
1
J4
C14
4u7
805
C15
?
805
R11
?
805
Vout
SW1
SW2
Vin
Vout
*SHDN/SS FB
Rlim
VC
Rt
Burst
Sgnd
Pgnd
R12
?
805
R4
300k
805
805
R8
DNP
R2
DNP
805
C7
DNP
805
C2
4u7
805
C3
4u7
805
R3
22k
805
C8
DNP
805
R14
110k
805
Vout
Vout
1 J5
Vin
J6
1
Burst DIS
R20
805
M3
?
2
Burst EN
R25
805
33k
All information contained herein is strictly confidential
APPEB1007 User Manual rev1.0, 31-May-2005
R17
805
33k
2
R18
?
805
CAP-XX
R6
22k
805
C16 805 ?
C18
?
805
C1
R21
3 100k
T93YB
2
1
FDV301N
SOT23
page 5 of 6
M2
FDV302P
SOT23
3
R23
330k
1
805
2
D1
6
8
12
11
7
5
CON1
GPRS
1
LTC3442
U1
4
9
1
10
2
3
R7
?
805
MBRO520LT1
SOD123
J1
heat
C12
4u7
805
2
C11
4u7
805
SS DIS
C10
4u7
805
1
C9
100u
TPSC
2
4u7
IHLP
13
Vin
1V2
U5
Vbat
2 D4
BZX84C
SOT23
© CAP-XX Pty Limited 2005
R26
33k
805
1
R10
1k
805
3V
Vin
Vout
GND
*Shdn Bypass
TC1185
SOT23-A
R24
10k
805
3
R9
1k
805
C13
OUT
5
R19
33k
805
M1
IRF7433
SO8
33k
805
-
22
805
Vout
2
Vin
U2B
R15
Vin
R22
1M
2 T93YB
Torch Vout
3V
C24
10u
805
R36
220k
805
R40
C28
47n
805
150k
805
C26
100n
805
U6
1
2
3
4
5
6
7
3V
R38
33k
805
LEDpulse
C25
100n
805
C29
100n
805
DIS
TH
CON
RES
OUT
TRIG
GND
VCC
DIS
TH
CON
RES
OUT
TRIG
14
13
12
11
10
9
8
R37
680k
805
3V
C27
100n
805
Vout
TLC556CD
SOIC
3V
Offtime Trigger
D5
D7
D6
LumiLED
?
3
LumiLED
?
2
SW3
J8
Flash
J9
3V
3V
3
+
3V
Offtime Trigger
3
M5
R33
10k
2 T93YB
3
2
Pulse
1
Pulse EN
1
M6
Vdd
C23
R31
220p
603
1V2
1M5
805
Torch
B3SN
J11
1
2
M7
GND
Torch Vout
FDV301N
3V
SW2
Flash Torch
ET01MD1CBE
2
R42
3k3
805
M8
Torch/*Flash
J12
Torch Voltage
1
FDV301N
J13
1
2
EXT Mode
M9
FDV301N
R45
33k
805
All information contained herein is strictly confidential
© CAP-XX Pty Limited 2005
APPEB1007 User Manual rev1.0, 31-May-2005
ZXM64NO2X
MSOP8
R30
R047
805
1
FDV301N
SW1
R39
33k FDV301N
805
4
3k3
805
R34
2k
2 T93YB
M4
150
805
R35
J10
LEDpulse
1
4
-
TS1852
SO
R32
33k
805
1
R29
OUT
2
R28
33k
805
U2A
1
2
3
33k
805
5
6
7
8
R27
100k
805
R44
3V
8
2
Auto Flash
Vcc
J14
1
C22
100n
805
page 6 of 6
LED Current
1
LED Current
1V2
R43
3k3
805
B3SN
J7
LED Bypass
1
R41
33k
805
BAT754
SOT23
2
2
1
2
3V