Faster Real-Time Control for Power Designs

The digital control of power supplies has led to many benefits, including more efficient operation and higher power density through its enabling of complex power conversion topologies, such as resonant and quasi-resonant converters. It also provides better management of power and makes the power supply easier to monitor and protect. To implement digital power designs requires a complex processor. Since their launch around a decade ago, Microchip’s dsPIC devices have proven a to be a favourite component for power designers wishing to implement digital designs. The components combine the features of a microcontroller, to take care of management and housekeeping tasks, and DSP functionality for real-time control of the circuit.

The original dsPIC device families were built with 16-bit architecture, but as time has progressed, control tasks are becoming more complex. Circuits that switched at tens of kilohertz, now can be switched at speeds of a megahertz or more. New materials, such as gallium arsenide and silicon carbide, need tighter control and more complex protection while switching at those faster rates.

To help with these solutions, and other faster real-time applications that have emerged, Microchip has launched the dsPIC33A range, which increases the architecture to 32-bit and adds a double-precision floating-point unit and enhanced DSP engine for faster real-time control

Commenting on the launch, Joe Thomsen, corporate vice president of Microchip’s digital signal controller business unit said, “We are totally focused on real time control - sense the state of a machine, make a decision based on that, and adjust the machine as quickly as possible. The dsPIC33A is a natural extension of that philosophy. We have increased the data paths, the ALU and the instruction set from 16-bits to 32-bit. And, because we went to a new process generation, we doubled the operating frequency, doubling the performance. Previous dsPIC devices could only process fixed-point math, but to model a system in MATLAB for code generation, everything has to be converted to fixed-point. We added a double precision floating-point unit to the dsPIC33A for 64-bit floating-point calculation to allow easier automated code generation. The Instruction Set Architecture (ISA) of the DSC also assists in the adoption of software code generated by model-based designs. We also increased the size of the accumulators from 40 to 72, the working registers moved from 16- to 32-bit and we added a lot more shadow registers for contact saving”.

For the fastest control loop response possible, the performance of integrated peripherals is very important. In that respect, Microchip has increased the performance of the 12-bit ADCs from 5 Msample/s, to 40 Msample/s. There are up to five of these ADCs in parallel for simultaneous sampling. Automated oversampling of the ADC is also included. Other analog features include improved high-speed comparators and op-amps for better signal chain response. The Flash memory in the dsPiC33A family has additional security capabilities that include Immutable Root of Trust, secure debugging and restricted memory access. Microchip has also included Core Independent Peripherals (CIPs), which enable interaction among the peripherals without the need for CPU involvement, allowing a single controller to manage multiple tasks. In other applications, CIPs save power by operating while the CPU is in sleep mode. In power and motor control designs where the device is almost always operating, CIPs provide improved real-time control while reserving the CPU bandwidth for software stacks, functional safety diagnostics and security functions. A PWM with 78 ps resolution is also integrated.

The first family of dsPIC33AK128MC1xx DSCs to be made available includes 128 KB Flash and an extensive peripheral set, offered in various packages, including SSOP, VQFN and TQFP options ranging from 28 to 64 pins, with package dimensions as small as at 4 × 4 mm. Future dsPIC33A families with additional memory, peripherals and larger pin counts will be added in the future.

The dsPIC33A family is supported by the MPLAB XC-DSC Compiler, MPLAB Code Configurator (MCC) and the dsPIC33A Curiosity Development Board (EV74H48A). The dsPIC33A Curiosity Development Board supports feature expansion by providing mikroBUS and Xplained Pro interfaces that enable connection to Built-in Self Text Xplained Pro (BIST XPRO) extension kits, sensors and various Click boards. Separate dual In-line modules are available to support development for motor control, digital power conversion and general-purpose embedded applications.

https://www.microchip.com/en-us/products/microcontrollers-and-microprocessors/dspic-dscs