AATIAN107 Datasheet, PDF (3/8 Pages) SiGe Semiconductor, Inc. – S2Cwire Controlled, Serial LED Boost Driver

AHK1421 EVAL :
EVALUATION BOARD DATASHEET
EV-184
S²Cwire Controlled, Serial LED Boost Driver
Getting Started
Setup (Figure 3)
1. Connect an input power source (to supply between 2.7V and 5.5V) to the board by placing the jumper, J1 on the
left (Connects DC+ power to AHK1421).
2. Connect the DC+ power to the microcontroller VDD by using the jumper V_MCU.
3. Connect the EN/SET jumper to connect the microcontroller GPIOs to the AHK1421 EN/SET pins.
4. After all jumpers are in the correct position, apply power between 2.7V and 5.5V to the DC+ and DC- terminals to
power on the AHK1421 (U1) and microcontroller (U2). The red LED (LED1) will illuminate when the microcontroller
is powered. The green LED (LED2) will flicker when the three buttons to transfer S²C wire data for AHK1421 are
operated.
5. Use the UP, DOWN and CYCLE buttons to vary the brightness of the 6 white LEDs using the EN/SET serial data
S²Cwire interface
Figure 3: AHK1421 Evaluation Board Measurement Configuration
S²Cwire Control
Short the EN/SET jumper to receive S²Cwire data generated by the microcontroller according to the status of the three
buttons. The AHK1421 records the number of rising edges which control output current in EN/SET pin and change the
value of output current from 20mA to 0.4mA when RFB is 12.5Ω
•• UP button: The UP button increments the number of EN/SET rise edges from 1 to 32 each time this button is pushed.
By holding down the button for more than 0.6 seconds, the microcontroller enters auto-increment mode. The LED
will dim and wrap back after S²C wire data reaches 32.
•• DOWN button: The DOWN button decrements the number of EN/SET rise edges from 32 to 1 each time this button
is pushed. By holding down the button for more than 0.6 seconds, the microcontroller enters auto-decrement mode.
The LED will brighten and wrap back after S²Cwire data reaches 1.
•• CYCLE button: The button increments or decrements the number of EN/SET edges automatically and cyclically after
a single push according to the previous EN edges up or down event.
•• UP+DOWN+CYCLE button: EN/SET is set to 0V and the AHK1421 is shut down. All white LEDs are turned off.
EV-184.2011.05.1.0
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