Digital switching in power supplies

[ShubhamSharma]

hello everyone
1. Is it possible to use digital methods for switching in power supplies?

2. If yes, then what could be the advantage gained by this?

3. Is it possible to solve right half zero problem by using digital methods of switching?

 

[d123]

Hi,

I can't find the right pdf to tell you the name of it, sorry. Look for Microchip (DSPIC-related) digital control application note(s), they should have some documentation to help with those questions, at least provide an overview and further links.

 

[asdf44]

hello everyone
1. Is it possible to use digital methods for switching in power supplies?

2. If yes, then what could be the advantage gained by this?

3. Is it possible to solve right half zero problem by using digital methods of switching?

You mean digital control? I design digitally controlled amplifiers and the #1 reason is the flexibility it offers in terms of tuning the modulation scheme, control scheme, control loop parameters, fault handling etc.

The downside of 'flexibility' however is that flexibility translates into time tuning and developing the control code. Also digital control has challenges with timing resolution and accuracy is limited by the ADC's and/or DACs which translate to/from the digital domain.

Microcontroller and DSP solutions can be quite cost effective if the included ADC's and/or DACs are good enough (generally not true for my applications, hence we use FPGA's with custom ADC circuitry). TI in particular with the Piccolo and Delfino line of DSP's has good parts for digital control with extra bells and whistles like high resolution PWM outputs and comparators that are integrated with the PWMs and ADC for what's basically a hybrid analog/digital integrated solution (capable of current mode control).

On the low end I was recently eying Microchip's 8-bit micros which can have 8 comparators, 4 opamps, 4 programmable logic/FF cells, a 10-bit dac, 10-bit adc and a programmable analog ramp generator. That's a neat package that can do an entire modulation/control loop all in analog and could use the dac and adc for additional monitoring/control.


For question 3 the answer is yes but that's not particularly special. Analog control can deal with right half zero's as well and digital solutions can handle them the same way (digital control techniques are analogous to their analog counterparts). Though yes, there may be smarter ways to handle it specifically in the digital world if it was absolutely necessary to push performance to the limits.