User`s guide

MCP1630 BOOST MODE LED DRIVER

DEMO BOARD USER’S GUIDE

Chapter 1. Product Overview

1.1 INTRODUCTION

The MCP1630 Boost Mode LED Driver Demo Board is a step-up, switch-mode, dc-dc

converter used for power LED applications. The demo board provides a 350 mA or

700 mA constant current source with a jumper selection. Other output currents can be

obtained with minor modifications to the board.

The MCP1630 Boost Mode LED Driver Demo Board utilizes Microchip's MCP1630V

high-speed pulse width modulator. The 8-pin MCP1630V device contains the analog

components necessary for an analog switch-mode control loop including an error

amplifier, PWM comparator, and a high current driver pin. The switching frequency and

maximum duty cycle for the MCP1630V are determined by an external clock source.

An 8-pin PIC12F683 microcontroller is used to provide a 500 kHz switching clock for

the MCP1630. In addition, the PIC12F683 firmware supervises the circuit output

voltage and can optionally dim the LEDs when a potentiometer is attached.

In this demo application, the MCP1630V device is used for Average Current mode

control using a voltage boost circuit. A ramp generator provides a reference signal to

the MCP1630V comparator. The ramp signal and error amplifier output voltage

determine the PWM duty cycle for the voltage boost circuit. The MCP1630V device is

used because its error amplifier provides a higher output voltage range than the

MCP1630 device (2.7V vs. 0.9V).

1.2 FEATURES

The MCP1630 Boost Mode LED Driver Demo Board has the following features:

• Compact size with high output power

• High efficiency over entire operating input voltage range

• Selectable output current: 350 mA or 700 mA

• Maximum output power: 30W

• Optional software dimming control

• Factory programmed source code provided

• Switching frequency, maximum duty cycle, and MCP1630 reference voltage can

be modified in firmware

• Additional application functions can be provided in firmware

Note: MCP1630 is used throughout this document for both the MCP1630 and

MCP1630V devices.