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DRV401: On improving driving output capability Application problem

Part Number: DRV401
Other Parts Discussed in Thread: TIPD184, DRV411, DRV421EVM, INA240, DRV421, DRV8837C

When using DRV401, in the EXTERNAL COMPENSATION COIL DRIVER of the data sheet, it is introduced that the driver capability can be improved by adding buffers, but how to implement it is not described in detail. Can you provide the recommended application circuit and the recommended chip of buffers? What should be noted in the process of using this circuit? Thank you!

  • Hello user5854835,

    Thanks for using the forum.  You can use the circuit in TIPD184 which has the similar output amplifier to drive the compensation coil.  Please be aware that you need to have the transistors able to drive the current you require and can possibly dissipate a large amount of power.

  • The operational amplifier schematic of TIPD184 is dual power supply, and it is for DRV411, but I need a single power supply to improve the DRV401 recommended schematic, I do not know if there is any reference in this regard, thank you!
  • Currently there is no reference design for this.  You will lose the capability of measuring current in both directions if you use the current circuit with a single supply.  It seems that this question has come up more than once.  I will look into it to see if there is another alternative.

  • Thank you for your reply. I look forward to finding a solution as soon as possible. Thank you!

  • Hello user5854835,

    I came up with a circuit that could work on a single supply.  I did verify functionality using the DRV421EVM and core I have.  It does function but there is some noise issues and I did not completely  verify the accuracy as I did not have time to do more analysis and I wanted to give you something to look over.  You may need to add some logic or delay from the ICOMP pins and the input to the DRV8837C.  Please note the bias point of the DRV8837C is not at mid-supply like that of the DRV401 or DRV421.  Also the output can have large VCM changes on Rshunt and you would need a current shunt monitor like the INA240 to remove those high frequency common mode changes.