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Clarification on current sense circuit for TMDSHVMTRINSPIN

Other Parts Discussed in Thread: TMDSHVMTRINSPIN, BOOSTXL-DRV8301, DRV8301-69M-KIT

We've noticed some confusion regarding the hvkit_rev1p1 (TMDSHVMTRPFCKIT & TMDSHVMTRINSPIN) current sense circuitry that I wanted to make sure was communicated here for posterity.

We think the confusion is due to our attempt to use one HW to comprehend the case of using external OpAmp and the case of using internal PGA (on F2805x devices), as well as some legacy circuitry that remained from previous revisions. 

You'll notice the current sensing circuit uses a 1.8V reference (which was in the previous version of the design) and then a differential amp circuit to take it to 1.65 required for the reference.

If designing your own HW using the hvmtr kit as a reference there is a much better way of doing this with the correct reference of 1.65V.

 

And 1.65V references can be found in single unit pricing for as little as $0.05

Where the equation is simply: 
Vout = I * Rshunt * (20k/2k) + 1.65

The 1.65 V reference can also be done with an OPAMP as a voltage follower as done in the DRV8301-69M-KIT and  BOOSTXL-DRV8301 inverters.