• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 32 subscribers
  • Views 271 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

DRV8662: Single-ended DC operation

DRV8662: Can I directly drive VIN without cap couple by AC signal?

Allen Huang
Prodigy 140 points

Part Number: DRV8662

Tool/software:

DRV8662.TSCrefer to attched file that is TINA schemaic. Is it OK?

  • 0
    TI__Genius 10305 points

    Hey Allen, 

    Expect a response from our expert asap. They are currently unavailable.

    Regards,
    Ore.

  • 0
    TI__Expert 5280 points

    The coupling caps before input are essentially DC blocking capacitors so that the amplifier is only amplifying the AC signals. These are used in the circuit to provide better amplifier performance (CMRR, PSRR, VOUTerror, etc...) as well as lower power consumed by the DRV8662. If your signal possibly include the DC signals, it is recommended to add the coupling cap.

    Your schematic looks good to me. 

    Best,

    Hailong 

  • 0 in reply to Hailong Chen
    Prodigy 140 points

    Because input signal frequency=1~60Hz, coupling cap will cause signal distorted.
    Input signals are from MCU output. They are complementary PWM signals. Vp-p=6V, Vp+=3V, Vp-=-3V

    __  __   3V

    |  |  |

    |  |_|      -3V

  • 0 in reply to Allen Huang
    TI__Expert 5280 points

    You can try using larger capacitors to minimize the impact on the 1-60 Hz PWM input. 

    The DRV8662 sets the DC operating point for the input and may not be 0 volts. So not having the capacitor there gives concern that an input voltage not centered around the same DC voltage won't have the gain properly applied or could get offset on the output. So it is recommended to have the cap there.