Datasheet

EVAL-ADP1655
Rev. 0 | Page 7 of 20
EN1 and EN2 Enabled Flash
Note that it is recommended to use an external power supply
for this operation because fixed Flash current values are set to
320 mA and 500 mA for two and one LED(s), respectively.
Otherwise, the USB current sourcing limitation of 500 mA
will be exceeded. Use the I2C_EN, EN1, and EN2 buttons in
Section 7.
1. Set I2C_EN low (button becomes gray).
2. Set EN1 high (green). The red indicator LED (D4) should
light up on the ADP1655 evaluation board.
3. Set EN2 high (green) to initiate Flash.
ENABLING UP TO 500 MA LED CURRENTS
The ADP1655 limits LED output current to 400 mA by default
if two LEDs are used. In one-LED operation, currents of up to
500 mA are automatically allowed.
In I
2
C interface mode, it is possible for you to enable up to
500 mA of output currents in two-LED operation.
1. Set I2C_EN in Section 7 of the user registers window.
2. Disable the amount of LED detection by selecting 0 - LED
Amount OFF in Section 3.
3. Click the Program 0x03 button.
4. Click the Program 0’s to 0x05… button in Section 6. This
allows you to use any Flash current setting from 200 mA
to 500 mA.
SOFTWARE OR HARDWARE TORCH
I
2
C Logic Mode
1. Set I2C_EN high (green) in Section 7 of the user registers
window.
2. In Section 2, set Output Mode to External Torch, set
1 - Torch Mode ON.
3. Click the Program 0x04 button.
The torch current level can be programmed by setting the
desired value under Assist Light Current in Section 3. To light
up the LEDs, click the Torch button in Section 7. In addition,
the TORCH hardware button on the motherboard can be used
by clicking torch button in Section 8.
2-Bit Logic Mode
1. Set I2C_EN low (button becomes gray).
2. Click the Torch button in Section 7 (input controls) to
light up the LEDs in torch mode, or use the TORCH
hardware button on the motherboard, which must first be
enabled via the torch button in Section 8 of the user
registers window.
TIMEOUT DURATION PROGRAMMING
Timeout is hardware limited to a maximum of 850 ms. Desired
Flash timeouts can be set by changing the setting under the
S/W Flash Timer box in Section 5 and clicking the Program
0x02 button.
FAULT DETECTION STATUS
Faults in Section 4 is used to read back the fault detection
status from the ADP1655. Click Read 0x05 to view information
about the fault. I2C_EN must be high (green) to be in read
mode. Overvoltage fault occurs when the output voltage is
greater than 9.5 V (typical). A timeout fault occurs when the
STROBE button on the evaluation board is pressed longer than
the programmed timeout duration in strobe level-sensitive
mode. A thermal fault occurs when the device junction
temperature is greater than 150°C. A short-circuit fault occurs
if the LED_OUT pin remains grounded during startup.
LED AMOUNT DETECTION
The amount of LEDs is detected by the ADP1655 and the
detection is enabled from 1 - LED Amount ON in Section 3.
The amount of LEDs is measured during the start of either
Flash or torch, and the default level for whether one or two
LEDs are connected to the output is set at 4.3 V (typical).
Detection level can be changed to 4.3 V plus V
REF
offset using
the Vref Offset box.
HISTORY
Whenever you issue a command (both read and write), it is
recorded in the History tab, shown in Figure 12. To display the
History dialog box, click the History tab on the evaluation
software GUI. You can copy and paste the history into a file for
future evaluation purposes.