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 Analog-to-Digital Converter (ADC) peripherals and specialized Pulse Width Modulation (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 Technology 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 Digital Signal Processor (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 a 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 three strings of LEDs, replacing three separate analog control Integrated Circuits (ICs). Furthermore, there are resources left over for active Power Factor Correction (PFC) and digital communications.
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 Digital Signal Controller (DSC) | 10-bit, 2 MSPS | 4 Power Supply |
Multiple LED Driver Application with PFC
Digital LED Lighting Development Kit (Part Number: DM330014)
Microchip's Digital LED Lighting Development Kit (DM330014) enables you to quickly leverage the capabilities and performance of the dsPIC33 GS series of DSCs to develop LED lighting products. The dsPIC33 GS DSC and this reference design show you how to create a 100% digitally controlled ballast function while including advanced features such as dimming and color hue control. The dsPIC33 GS DSCs can support an entire system implementation for LED lighting products, including power-conversion circuits, such as Alternate Current (AC)-to- Direct Current (DC) and DC-to-DC conversion, along with functions such as PFC, which are necessary for a complete product and lower overall system cost.