Getting started

AN2810

12/17

Doc ID 14893 Rev 1

9

Getting started

The following step-by-step instructions are provided as a guide for quick evaluation of the

performance of the LED7707 demonstration board.

9.1

Quick startup

1.

Working in an ESD-protected environment is highly recommended. Check all wrist

straps and ESD mat earth connections before handling the LED7707 board

2.

Connect the power supply to the LED7707 board and insert the A-meter as shown in

Figure 8. Connect a V-meter between VBOOST and ground to monitor the output

voltage

3.

Connect the white LEDs array to the row1-row6 and VBOOST terminals of the

LED7707 board

4.

Set the PWM signal (500 Hz, 5% duty-cycle, 3.3 V CMOS logic levels) on a signal

generator and connect it to the DIM input

5.

Set SW1 and SW2 in the “down” position (fixed frequency and MODE to AVCC). Do not

change jumpers settings when the board is powered

6.

Set the input voltage to 12 V

7.

Turn-on the PWM generator

8.

Turn-on the VIN supply. The device turns on

9.

Vary the input voltage within the range 6 V - 32 V

10.

Set the input voltage to 12 V

11. Vary the dimming duty-cycle from 1% to 100%

12. Check the shape of the row current at 10 us dimming on-time

Note:

When used for rowx current measurement, some autoranging A-meters can trigger open-

row or shorted-LED fault detection during the automatic scale selection procedure.

Caution:

Disabling the auto-ranging option on the A-meter is recommended.