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 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 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 three strings of LEDs, replacing three separate analog control ICs. Furthermore, there are resources left over for active power factor correction (PFC) and digital communications.
Devices for Digital Power Control
|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|
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 Digital Signal Controllers (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 AC-to-DC and DC-to-DC conversion, along with functions such as Power Factor Correction (PFC), which are necessary for a complete product and lower overall system cost.
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