• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 49 subscribers
  • Views 650 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

OPA2374: How important is the buffer in this circuit?

Lucas Schulte9
Expert 6955 points
Part Number: OPA2374
Other Parts Discussed in Thread: BOOSTXL-DRV8301, LM7705

This is the external current sense circuit from the BOOSTXL-DRV8301. How important is the buffer for the 1.5V coming off of the voltage divider? Mainly I would like to see if a single channel op amp could be used rather than the dual channel.

  • 0
    TI__Expert 6955 points

    Correction : 1.65V from the voltage divider.

  • 0 in reply to Lucas Schulte9
    Guru 47485 points

    If you look at the divider from that DC output, it is probably trying to hold the output of the diff stage above ground as no op amp can swing to ground completley - if so, your other option is to use the LM7705 as a negative supply (can be shared among multiple channels) and get rid of the DC level shift positive through that buffer. 

  • Former Member
    0 Former Member in reply to Lucas Schulte9

    Hello Lucas,

    The buffer prevents the input non-inverting input of the amplifier from seeing the equivalent resistance of the voltage divider.  The voltage divider and buffer look to be setting the DC offset.

    Also, 2.2uF at the output of the buffer is quite significant.  Given that their is no stability compensation here, this may very well cause stability issues for the buffer.

    Regards,

    Daniel