www.microchip.com/lighting

LED Lighting Solutions Design Guide

13

LED Lighting Solutions

High Performance Digital Control

Devices in the PIC18F, PIC24 and dsPIC33F families offer

8-bit and 16-bit solutions for fast calculation of digital control

loops. In addition, these families have device variants with

fast ADC peripherals and specialized PWM modules that are

optimized for power control applications.

A selection of devices for digital power control is shown in

the table below. There are many other Microchip devices that

could be used, but these devices represent low-cost and

small package choices.

Devices in the PIC18F family have an 8-bit CPU with a

hardware multiplier. The PIC18 is a good choice for moderate

control loop rates (1-10 KHz). Devices in the dsPIC33F family

have a 16-bit CPU with DSP resources. This family is a good

choice if you need to execute multiple control loops at a

faster rate. Devices in the PIC24 family offer an intermediate

solution with 16-bit calculation performance.

The dsPIC33FJ06GS202 device has a Power Supply PWM

module that can generate high switching frequencies with

very fine edge resolution. This PWM module can also

generate phase shifted PWM signals for advanced power

supply applications.

The 28-pin dsPIC33FJ06GS202 device can provide a highly

integrated solution for LED lighting applications. The PWM

peripheral can drive 3 strings of LEDs, replacing 3 separate

analog control ICs. Furthermore, there are resources left

over for active power factor correction (PFC) and digital

communications

.

LED Lighting Development Kit Reference Design

The LED Lighting Development Kit demonstrates the

capabilities of Microchips “GS” series of dsPIC Digital Signal

Controllers (DSC) in High Brightness (HB) LED applications.

Web Links

www.microchip.com/smps

www.microchip.com/pic24

www.microchip.com/pic18

Multiple LED Driver Application with PFC

I1

I2

I3

Drive 2

Drive 3

Drive 1

I1

I2

I3

LED Drive 1

LED Drive 2

LED Drive 3

PFC

PFC

Drive

120

PFC Drive

dsPIC33FJ06GS202

MCP1416

Serial

Comm.

GPIO

40 MIPS DSP

10-bit

ADC

Output Compare

PWM3

PWM1

PWM2

PWM4

Selected Devices for Digital Power Control

Device

Pins

Architecture

ADC

PWM

PIC18F23K22

28

8-bit MCU

10-bit, 100 KSPS

3 Enhanced, 2 Standard

PIC24FJ16GA002

28

16-bit MCU

10-bit, 500 KSPS

5 Standard

dsPIC33FJ06GS202

28

16-bit DSC

10-bit, 2 MSPS

4 Power Supply