AN2754

Description of the board

13/20

4

Description of the board

The evaluation board is configured as constant current supply. Current regulation is

accomplished by regulating the voltage across a current sense resistor

4.1

Input/output connection

The following table describes the input/output connections.

Table 2.

Input/output connections

Reference

designator

Name

Description

J1

LED cathode

Output to cathode of LED

J2

LED anode

Output to anode of LED

J3

Supply/sync

VIN_SW: Power input supply voltage to be tied to VIN_A. (VIN_SW max=18 V)

VIN_A: Analog input supply voltage to be tied to VIN_SW. (VIN_ A max=18 V)

SYNC: Synchronization and frequency select. Connect SYNC to GND for 900 kHz

switching frequency or connect to an external clock from 400 kHz to 1.2 MHz.

J4

Enable

Use this connector to enable and disable DC-DC converter. Connect a jumper

between the ON pin and the center pin to enable the supply. Connect a jumper

between the OFF pin and the center pin to disable the supply. If this pin is left open,

the EVM does not operate correctly. This pin is also used for PWM dimming control

of the LED current.