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TPS92691-Q1: If TPS92691-Q1 's switch current limit lead high power consumption ?

Henry Li78
Prodigy 205 points
Part Number: TPS92691-Q1
Other Parts Discussed in Thread: TPS92692

Hi TI Team:

  I have a question about our current limit function ,our thresh hold of IS Pin is 525mV ,does it means if I want to limit my current to 3A ,there will be a 3*0.525=1.575W power consumption?

If my caculate is wrong ,please help to tell me how to caculate the power consumption.

  • 0
    TI__Mastermind 28655 points
    Hello,

    You also have to take into account duty cycle and current ripple. If the duty cycle is high and the current ripple small it can be over one watt.

    Regards,
  • 0 in reply to Irwin Nederbragt
    Prodigy 205 points
    Hi Irwin:
    Is there any solution to low down the consumption?
  • 0 in reply to Henry Li78
    TI__Mastermind 28655 points

    Hello Henry,

    There are several things that can be done.  Since this is regulating current via CSN and CSP you can limit the operating range and use a smaller Peak CS resistor value.  Then it should never get near the 0.525V peak threshold.  You can also prevent the peak currents from getting too high by using UVLO disable to prevent it from running at very low input voltage (depending on the topology you are using).  You could also fold back the current via Iadj when the input voltage gets lower.

    Another option is to look at the TPS92692, peak current threshold is 0.25V instead of 0.525.

    And if you don't mind the cost you could look at using a current sense transformer if it is that much of a concern.

    Regards,