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Original question:

TLV6001-Q1: Diff.Amp Available Questions

TLV6001-Q1: Operation error

CHO SR
Genius 3415 points
Part Number: TLV6001-Q1
Other Parts Discussed in Thread: TLV9001, , TLV9001-Q1, INA180-Q1

Hi, 

The customer experienced a problem with the operation after configuring the circuit.

The circuit increased R101 (Rshunt) from 0.1 ohm to 1.4 ohm, but it does not work.

Is it the same problem as offset error?

It seems to work only when it is increased to approximately 5 ohms or more.

Are there any circuit problems?

The circuit shows the difference when changing as shown below.

R106 = R107

R108 = R109

The behavior depends on the R106 (=R107) Value.

Please advise what kind of difference there is depending on the value of R106(=R107).

And, customer changed it to TLV9001 and tested it, but it was not resolved.

  • 0
    Guru 318200 points

    What are the voltages at pins 1 and 3 of the opamp? Anything above 5.2 V would not work; the TLV6001-Q1 or TLV9001-Q1 do not allow input voltages above their own supply.

    The INA180-Q1 would be a better idea for this application.

  • 0 in reply to Clemens Ladisch
    TI__Mastermind 33493 points

    Hey Cho,

    For the above table, the below table shows what would be your ideal values for your output.

    Current 20mA 525mA
    Gain 30 600mV 15.75V
    60 1.2V 31.5V
    60 1.2V 31.5V

    The op amp will not output a voltage above the supply rail, so you will have to lower your gain to have a full swing on your output. If the max current is 525mA, the maximum gain you can have for a linear response is 9.33.

    You can switch to a dedicated current sense amplifier, but that device is just an integrated version of the above circuit. You can input a voltage above the supply rail as long as the current is limited to below 10mA.

    Best,
    Jerry