AP3154A Evaluation Module
120mA HIGH EFFICIENCY WHITE LED DRIVER
P3154FG-EVM Rev.1 4 of 4 MARCH 2011
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Quick Start Guide
1. Insert jumper J1 to connect VIN to the AP3154A and the onboard SDI controller. Also insert a
jumper on J2 to use the onboard controller to send SDI commands to the AP3154A.
2. Connect a +2.7V~+5.5V power supply between VIN (P1) and GND (P2) terminals. Turn on the
power supply. The red power indicator LED (LED5) will be on.
3. The SDI controller will enter State 3, where SDI commands are sent to the AP3154A to set the
current levels of all four channels. All four white LEDs will be dimming from bright to dark and from
dark to bright. The following table shows the SDI controller States and associated SDI commands.
4. Press the CYCLE button to change the SDI controller state to the next state. Every time the SDI
controller enters a new state between States 3 and 10, the corresponding LED(s) will be dimming
automatically while the other LEDs will stay at the current levels set in the previous States. Adjust
VR4 to change the repetition rate at which the LEDs are auto-dimmed.
5. While in any state between State 3 and State 10, press the UP or DOWN button to stop
auto-dimming. Then use the UP button to manually increase the current level of the LED(s) and
DOWN button to decrease it. Press the CYCLE button again to resume auto-dimming.
6. Press the CYCLE button while in State 10 will bring the SDI controller to State 1, where the
AP3154A’s switching frequency can be set by using the UP and DOWN buttons. The green LED
(LED0) will flash slowly for lower switching frequency and faster for higher switching frequency.
7. Press the CYCLE button while in State 1 will advance to State 2, where the maximum LED current
can be selected by using the UP and DOWN buttons.
8. Press and hold the CYCLE button at any time will force the SDI controller to enter State 0 and
disable the AP3154A. In this state, all white LEDs (LED1-4) will be turned off. So will the green
LED (LED0). Press the CYCLE button in State 0 will move the SDI controller to State 1.
9. If an external SDI controller is to be used, remove the jumper on J2 and connect the external SDI
signal to between the pin 2 of J2 and GND.
Table: SDI Controller Machine States
SDI
Controller
State
Green
LED
(LED0)
First
SDI
Command
Other
SDI
Commands Description
0 Off - -
Reset: 1) 1.2MHz switching frequency
2)20mAMaxCurrent
3)AllChannelsturnoff
1 Flashing
18
19
20
-
Switching frequency set to 0.6MHz
Switching frequency set to 1.2MHz (default)
Switching frequency set to 1.8MHz
2 On
13
14
15
16
-
2mA Low-Current Mode
14mA Current Mode
20mA Current Mode (default)
30mA Current Mode
3 On 5 1 or 2* Set current level for all 4 Channels
4 On 6 1 or 2* Set current level for CH2, CH4
5 On 7 1 or 2* Set current level for CH1, CH2
6 On 8 1 or 2* Set current level for CH3, CH4
7 On 9 1 or 2* Set current level for CH1
8 On 10 1 or 2* Set current level for CH2
9 On 11 1 or 2* Set current level for CH3
10 On 12 1 or 2* Set current level for CH4
*Note: Use command 1 for increasing current and command 2 for reducing current.
