MCP1664 LED Driver Evaluation Board User’s Guide

DS50002363A-page 12

 2015 Microchip Technology Inc.

1.3

WHAT IS THE MCP1664 LED DRIVER EVALUATION BOARD?

The MCP1664 LED Driver Evaluation Board is used to evaluate and demonstrate

Microchip Technology’s MCP1664 product. This board demonstrates the MCP1664 in

a boost-converter application supplied from an external voltage source, which drives a

string of LEDs with three selectable currents. The MCP1664 LED Driver Evaluation

Board was developed to help engineers reduce the product design cycle time.

LEDs can be dimmed in two ways:

• Analog dimming: changes LED light output by simply adjusting the value of the

sense resistor and, by doing so, modifying the DC current in the LED string.

• Pulse-width modulation (PWM) dimming: achieves the same effect as analog

dimming by varying the duty cycle of a constant current in the string to effectively

change the average current in the string.

For analog dimming, three output currents can be selected: 90 mA,180 mA and

270 mA. The output current can be changed with a dual switch that changes the

external LED current sense equivalent resistance.

For PWM dimming, a small triangular wave generator was added to the board along

with a variable resistor that sets the duty cycle for the EN pin.

1.4

CONTENTS OF THE MCP1664 LED DRIVER EVALUATION BOARD

This MCP1664 LED Driver Evaluation Board kit includes:

• One MCP1664 LED Driver Evaluation Board unit (ADM00641)

• Important Information Sheet