 2015 Microchip Technology Inc.

DS50002363A-page 11

MCP1664 LED DRIVER

EVALUATION BOARD

USER’S GUIDE

Chapter 1. Product Overview

1.1

INTRODUCTION

This chapter provides an overview of the MCP1664 LED Driver Evaluation Board and

covers the following topics:

• MCP1664 Short Overview

• What is the MCP1664 LED Driver Evaluation Board?

• Contents of the MCP1664 LED Driver Evaluation Board

1.2

MCP1664 SHORT OVERVIEW

The MCP1664 is a compact, battery-operated, fixed-frequency, step-up DC-DC

converter optimized as LED constant current generator. This product provides an

easy-to-use power supply solution with a minimum number of external components for

applications powered by two-cell or three-cell alkaline, NiCd or NiMH batteries, one-cell

Li-Ion or Li-Polymer batteries.

The MCP1664 is a PWM-only device that operates at a fixed 500 kHz switching

frequency. The device has an operating input voltage range from 2.4V to 5.5V (with an

undervoltage of 2.3V to start and 1.85V to stop). The reference voltage is only 300 mV

in order to minimize the losses on the sense resistor and to increase the overall

efficiency of the application.

The LED can be turned on and off with a variable duty cycle applied to the EN pin for

applications that require current dimming. Compared to its counterpart, the MCP1663

which is designed to be a voltage source, the start-up time for the MCP1664 has been

decreased in order to obtain better performance in dimming applications.

The MCP1664 can supply up to 200 mA of current for a string of four LEDs

(considering a LED Forward Voltage of 3V) from a 3V or higher input voltage source.

More detailed information regarding the current capabilities of the MCP1664 are

available in the data sheet.

In order to provide a compact solution, the device is available in a small 5-Lead SOT-23

and an 8-Lead 2x3 TDFN package.

FIGURE 1-1:

Typical MCP1664 LED Driver in Boost Topology Schematic

GND

SW

EN

ON

OFF

4.7 - 20 µF

L

4.7 µH

0.3V

MCP1664

4.7 - 20 µF

D