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TLV9061-Q1: Output is not correct about the low side current value

Sam Sun
Intellectual 785 points
Part Number: TLV9061-Q1
Other Parts Discussed in Thread: TLV9061

The current output is not accurate, the maximum deviation is 1A, and the peak input current is 30A

Could you please help check the schmetic?

  • 0
    TI__Mastermind 27526 points

    Hello Sam,

    You are likely running into a stability issue.

    I've simulated your circuit and you have 4.75 degrees of phase margin. The main cause of this is the capacitance that is present on the inverting terminal of the TLV9061.

    To keep your input filters at the same frequency, you can split resistors R102/R106 in half and double the value of C90, C94, C89. Configuring the circuit this way has 110 degrees of phase margin.

    Best,
    Jerry

  • 0 in reply to Jerry Madalvanos
    Intellectual 785 points

    I've tested one device and the situation has improved, but this method doesn't seem to be universal, and the other boards don't work well.

    Could you please give some advice? and why  the value of C90,C94,C89 can influce the phase margin?

  • 0 in reply to Sam Sun
    TI__Mastermind 27526 points

    Hello Sam,

    Do you have an input/output waveform from an oscilloscope?

    Capacitance on IN- introduces phase lag in the feedback loop. This reduces the phase margin of your feedback loop and can make your amplifier unstable. C94, C90 are the main components that introduce phase lag. Moving C89 just keeps the inputs symmetrical, and should not impact stability.

    Best,
    Jerry