Author Topic: Phase Correct PWM Generator Chip  (Read 1384 times)

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Offline CM800Topic starter

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Phase Correct PWM Generator Chip
« on: September 13, 2015, 07:05:44 pm »
I am currently working on a full bridge controller to drive high power high frequency transformers, I have a bit of trouble trying to pick out the heart of it.

Ideally I want to have:

15-35kHz (possibly up to 60kHz) Variable frequency control
I want to vary the pulse width for power control between 0 and 50% and a form of variable current limiting.
Looking to have some form of controllable deadtime to help deal with the use of large IGBTs and opto-isolated gate drive.

Originally I was just going to use an Arduino, however I found that I cannot vary the frequency to any useful degree.

Does anyone have any recommendation of a chip I could use?

While I am aware I could make a triangle wave generator and use op-amps and other circuit components to make a complete analog circuit the time required to do so and the exponential raise of mess and things that could go wrong, I don't think it is worth it.
 

Offline ajb

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Re: Phase Correct PWM Generator Chip
« Reply #1 on: September 13, 2015, 08:18:12 pm »
A lot of the more powerful mcus have much more advanced PWM capabilities than the rudimentary counters in the Arduino's ATMega provide.  If you prefer to stick with 8-bit, Atmel's XMega parts have much more powerful timer/counter modules, and most of the major mcu makers also do several chips specifically designed for controlling power stages, such as Atmel's AT90PWM series.  There are more options in the ARM realm as well, for instance I know Atmel's SAMD21 (Cortex M0+) series have what they call "Timer Counter for Control" modules with programmable fault inputs and things.  I haven't used them for anything but basic PWM to date, but they seem reasonably powerful from the datasheet.  I'm sure other ARM integrators have parts with similar if not superior features.  Probably best to browse a few catalogs and skim the datasheets of the most likely parts to see which best suit your application.
 

Offline CM800Topic starter

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Re: Phase Correct PWM Generator Chip
« Reply #2 on: September 13, 2015, 09:17:14 pm »
That certainly has merit, I would rather like to stay within the Atmel Range as I already brought the ATMEL-ICE programmer.  Seems I may have to be spinning my own board.

Does anyone else have any suggestions?
 


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