I/O interface

AN2810

8/17

Doc ID 14893 Rev 1

5

I/O interface

The LED7707 demonstration board is equipped with the test points described in Table 3.

6

Recommended equipment

●

4.5 V to 32 V, 2 A capable power supply

●

Digital multi-meters

●

20 MHz oscilloscope

●

Signal generators for PWM dimming and synchronization clock (optional)

7

Configuration

The LED7707 demonstration board allows the user to choose the desired mode of operation

using the SW1 and SW2 selectors (refer to the configuration description in the following

paragraphs). A red LED is connected to the FAULT pin to easily monitor its status; if this

option is not required, the monitor LED can be disconnected opening the J2 jumper.

7.1

SW1 fixed or adjustable switching frequency (FSW pin)

The SW1 selector is used to choose between the fixed switching frequency (660 kHz) and a

user-defined switching frequency in the range 250 kHz to 1 MHz (see Figure 5). When

placed in the “down” position, the fixed switching frequency is selected.

Table 3.

LED7707 demonstration board test points description

Test point

Description

VIN+

Input voltage, positive terminal

VIN-

Input voltage, negative terminal

GND

Reference ground

ROW1 to ROW6

Current generator output

VBOOST

Boost regulator output voltage

DIM

PWM dimming input

EN

Enable input (active high)

SYNC

Synchronization output

FSW

Synchronization input

FAULT

Fault signal, active low