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TMS320F280025C: A simple reference design/code for Pulse Frequency Modulation (PFM).

Duman Demir
Prodigy 132 points
Part Number: TMS320F280025C
Other Parts Discussed in Thread: C2000WARE

I have to regulate a simple series resonant converter using PFM (constant duty cycle with varying frequency) via feedback control. The frequency of the PWM waveform is to be changed according to change in output voltage using PID control. I have found a reference design on TI website TIDM-1001, but the software for this design is too complicated for a beginner to understand and I find myself lost even after spending too much time on this code. I want a simple reference code that can read output voltage of the converter through ADC, compare it with a reference, generate an error and update the PWM frequency according to that error.  I have gone through ePWM module in technical reference manual and have got a basic understanding of the PWM generation mechanism. If anyone knows about such a reference please share with me or if you have some good advice on how to start, please share.

Thank you!

  • 0
    TI__Expert 6965 points

    Hi,

    To change frequency of PWM output and keep fixed duty cycle, you will need to change TBPRD (period in cycles) and CMPA (on time in cycles) accordingly.

    For example of ADC PWM setting example, please refer to driverlib examples in C2000ware, and you can find basic PID example code in digital control library (DCL) examples in C2000ware. Thanks.

    Han