Tiny, Fast and Powerful DSCs for Digital Power Application

Wolfgang Patelay, Freelance Journalist at Bodo's Power Systems

Microchip introduced the 14 new members of its Digital Signal Controller family (DSC) dsPIC33EP “GS” at a press conference to the power market. According to Tom Spohrer, Marketing Manager of Microchips MCU16 Divison, delivers this family the high performance needed to implement more sophisticated non-linear, predictive and adaptive control algorithms at higher switching frequencies. These advanced algorithms enable power-supply designs that are more energy efficient over widely varying load conditions and have improved dynamic response to transient conditions as well as better power supply specifications. Higher switching frequencies enable the development of physically smaller power supplies by smaller inductors and capacitors that offer higher densities and lower costs. Compared with the previous generation of DSCs, the new dsPIC33EP “GS” devices provide less than half the latency, when used in a three-pole three-zero compensator, and consume up to 80% less power in nearly any application.

This new DSC family includes advanced features such as Live Update Flash capability, which is especially helpful for high-availability or “always-on” systems. Live Update can be used to change the firmware of an operating power supply, including the active compensator calculation code, while maintaining continuous regulation. It is realized by dual Flash partitions with a switchover of < 300ns and fits transparently between compensator updates to PWM. Variants from this new digital-power-optimised DSC family are available in the industry’s smallest, 4x4mm UQFN package for space-constrained designs. 

Other key features of this family include up to five 12-bit ADCs with as many as 22 ADC inputs, providing total throughput of 16 Mega samples per second (Msps) total with five ADCs and 300ns ADC latency. An early interrupt minimizes ISR overhead. Autonomous digital comparators offload the CPU for higher performance and compare results against thresholds and interrupt if over, under, out-of-range etc. The hardware oversampling increases ADC precision by using more time. The devices include 12-bit DACs for each of the four analogue comparators, for higher-precision designs. The two on-chip programmable gain amplifiers can be used for current sensing and other precision measurements. Including these advanced analogue amplifiers on the device reduces the number of external components required, thereby saving cost and board space. 

Figure 1: The new DSC family feature higher performance, more integration, lower power and smaller footprints

These features, combined with the overall high performance of the new DSC family, make it well suited to a wide range of applications including: computing & telecoms AC/DC and DC/DC power supplies; industrial solar inverters, LED lighting, HID lighting, battery chargers, projectors and welders; and automotive LED and HID headlights and DC/DC converters; among others.

The dsPIC33EP “GS” family is supported by Microchip’s MPLAB Starter Kit for Digital Power which is priced at $129.99 and allows customers to explore using the new dsPIC33EP “GS” family in popular digital power-conversion topologies. Furthermore the new Digital Compensator Design Tool helps engineers to calculate the optimum compensator coefficients required to maximise the performance of their designs. It is a plug-in to MPLAB X IDE and accepts input plant details in poly nominal and pole/zero form as well as imported data tables from simulation or network analyzers. Response and stability calculations of the five compensator types digital 2P2Z, digital 3P3Z, PID, analogue type II & III can be performed and generates header files with compensator coefficients. This free tool, combined with Microchip’s compensator software libraries and many royalty-free dsPIC33 reference designs, make it easier than ever to design digital power-conversion applications.

Figure 2: MPLAB Starter Kit for Digital Power allows exploring the new dsPIC33EP “GS” family used in popular digital power-conversion topologies 

Microchip also partnered with Biricha Digital to offer in-depth digital-power design workshops that help analogue power-supply designers, as well as embedded system programmers, to leverage the capabilities of full digital control in their designs. The 14 dsPIC33EP “GS” family members are available in various packages, from 28 to 64 pins. All of these new DSCs are available today for sampling and volume production.

More information: Microchip Technology    Source: Bodo's Power Systems, July 2015