Adding Intelligence to Lighting Applications

HB-LED - Advanced Digital Solution

Devices in the PIC18F and dsPIC30F 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 of 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 kHz - 10 kHz).

Devices in the dsPIC30F family have a 16-bit CPU with DSP resources. The dsPIC30F family is a good choice if you need to execute multiple control loops at a faster rate.

All devices shown in the table have advanced PWM modules with two output pins per PWM channel. All of these devices can generate complementary PWM output signals with dead time for driving half-bridge and H-bridge power circuits.

The dsPIC30F1010 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 dsPIC30F1010 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.

A multiple LED driver application with PFC.

Literature on the Web

PIC18F1230/1330 Device Data Sheet, DS39758

dsPIC30F2010 Device Data Sheet, DS70118

dsPIC30F1010/202X Device Data Sheet, DS70178

AN937- Implementing a PIC Controller using a PIC18 MCU, DS00937

Selected Devices for Digital Power Control