TMS320F280049C: CMPSS input conditioning circuit

Shengnan Li

Part Number: TMS320F280049C

A2/B6 pin is used as comparator in Peak current mode control (as in demo TIDMDCDCbuck), the current sensing amplifier is INA290A2, between the current amplifier output and the A2/B6 pin, is it necessary to put RC circuit?

Thanks!

over 4 years ago

0 Frank Ankapong over 4 years ago

TI__Mastermind 28275 points

Hi Shengnan,

Are you also sampling A2/B6 with the ADC?

0 Shengnan Li over 4 years ago in reply to Frank Ankapong

Expert 1010 points

No, it is only used as comparator.

0 Frank Ankapong over 4 years ago in reply to Shengnan Li

TI__Mastermind 28275 points

Ok. The comparator input is high impedance and so it is easy to drive. I'm guessing you are adding the RC for noise reasons. Can you confirm?

0 Shengnan Li over 4 years ago in reply to Frank Ankapong

Expert 1010 points

This is first time i design this, actually my question is does it need RC circuit in between?

+1 Frank Ankapong over 4 years ago in reply to Shengnan Li

TI__Mastermind 28275 points

It depends on your system like i mentioned in the previous reply. The effect of the RC will be to LPF the signal to remove high frequency noise but it also slows down the signal. If you are not having any issues with noise, you don't need an RC. The CMPSS has hysteresis and filters to reduce the impact of noise.

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TMS320F280049C: CMPSS input conditioning circuit