TMS320F280039C: TIDM-02000 Peak current mode control without load

fakir A

Part Number: TMS320F280039C
Other Parts Discussed in Thread: PMP23126, C2000WARE

Hello everyone,

I have a question regarding PCMC control mode.
If our DCDC is with very low load. As a result, the input current is also very low, how the PCMC regulation behaves. Should we use another control mode when we have a very low load ?

over 2 years ago

0 Shamim Choudhury over 2 years ago

TI__Genius 12225 points

At very low load you can reduce the PWM frequency and still do PCMC. This way the power stage will transfer less power and hence regulate the output volt.

0 fakir A over 2 years ago in reply to Shamim Choudhury

Prodigy 30 points

hello Shamim,

Thanks a lot for your answer. Currently the PWM frequency is 100khz. how to determine the right frequency to apply?

Thank you for the support.

0 Shamim Choudhury over 2 years ago

TI__Genius 12225 points

Slowly reduce the frequency until it regulates the output. Check the Frequency Folding technique implemented in PMP23126. This is under close loop control. Freq is gradually reduces for light load regulation. This is a released design in C2000Ware DP SDK

0 Shamim Choudhury over 2 years ago in reply to Shamim Choudhury

TI__Genius 12225 points

Typo

Frequency is gradually reduced for light load regulation

0 fakir A over 2 years ago in reply to Shamim Choudhury

Prodigy 30 points

Ok thanks.

Can we used the VMC at low load and we switch to the PCMC when load > 50A for example ? If yes do you have one example please

0 Shamim Choudhury over 2 years ago in reply to fakir A

TI__Genius 12225 points

Yes, you can try that. But VMC requires DC blocking caps in your power stage to prevent volt-sec unbalance.

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TMS320F280039C: TIDM-02000 Peak current mode control without load