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OPA607-Q1: The response problem of using opa607 in TIDUF17-- <High-Voltage HEV and EV HVAC eCompressor Motor Control Reference Design>

A.W
Intellectual 410 points
Part Number: OPA607-Q1
Other Parts Discussed in Thread: OPA607

Hi,

I find that it uses OPA607 for current sensing in TIDUF17 spec.

I do a simulation with the schematic as the spec shows.

However, the simulation shows this circuit has a large delay with the output with C18(47pf),the phase margin will be ok and large than 45 degree.

However,if changing C18 to 15pf, the response will be much better.

Besides, it seems that C21(47pf) has less influence with the output response.

Am I right?

Regards

Arrow

/cfs-file/__key/communityserver-discussions-components-files/14/OPA607_2D00_response.tsc

  • +1
    TI__Intellectual 1510 points

    Hi Arrow,

    Yes you are correct, the phase and hence the stability will mainly depend on C18 (capacitor at the feedback). Though you should keep both C18 and C21 same so as to match the impedance and reject common mode signal of the differential amplifier setup at higher freq.

    C18 and R29 will create a pole at freq=1/(2*pi*R29*C18) and will set the close loop BW.

    C21 and R32||R33 will set the noninverting input filter at freq = 1/(2*pi * C21*R32||R33)

    Regards

    Anant