Digital Signal Controller for Power Supply Design

[sac1991]

Hey guys
Which is the most widely used DSC for digital power supplies. There are so many DSC, I am getting confused. MicroChip has a good portfolio of DSC for DC DC converter(dsPIC). Texas's TMS series seems too much for cost sensitive designs. What is the realistic requirement in term of MIPS, Program Size etc, say for a PFC with Full Bridge power supply or a Full bridge with Synchronous Rectification.

 

[pradhan.rachit]

Hi,

Depends on what will be the operating frequency of your Power Supply. You will need to estimate the required time to execute your control equations along with sensing. A dsPIC will be an option I'd not prefer if the switching frequency is > 25 kHz. Mainly due to the limited processing capabilites of it in terms of word size and operating frequency. That would probably be a time when I would shift to a lower variant of the TMS series (Like the TMS320F28027). Additionaly, TI has a great software support for Digital Power Applications that can be found in ControlSUITE, thus making the development time faster.

- Rachit

 

[sac1991]

But I have seen a Microchip Reference design of 200W LLC supply, with 200kHz switching frequency with a 70 MIPS dsPIC. But I have to say TI has great support.

 

[mtwieg]

Switching frequency isn't really the major constraint for DSCs. Control bandwidth and latency are more fundamental limitations, and these don't have to correlate strongly with switching frequency. For example, a 20kHz hard switched converter and a 200kHz LLC converter may require the same control bandwidth.

 

[treez]

Here is pdf on digital controlled psu's