LMV796: LMV796 application

Eric Shen42

Part Number: LMV796

Dear Team:
I asked a question on another post, Ron Michallick help relay to me, a circuit and a formula were provided.

I want to know how this formula works? In my opinion, VF1(out)= (Rp+R5)/R5 * (IG1)*Rs, Rp=R6*R7/(R6+R7). I don't know what 0.1V means? And I just know Rp/R5=48.47, why not (Rp+R5)/R5?

Is this a non-inverting amplifier circuit？

Thanks!

over 5 years ago

0 Tim Claycomb over 5 years ago

TI__Genius 15410 points

Hi Eric,

The complete transfer function of the circuit is VF1 = IG1 * Rs * (R2//R3) / (R3+R4) * (R5+R6//R7) / R5.

Assuming R4=R5 and R2=R6 and R3=R7 the equation can simplify to VF1 = IG1 * Rs * (R6//R7) / R4.

I recommend taking a look at "Low-side, bidirectional current sensing circuit" for another low side current sensing document.

Thank you,

Tim Claycomb

0 Ron Michallick over 5 years ago in reply to Tim Claycomb

TI__Guru*** 148336 points

Eric,

Tim answered the gain part. I'll answer the offset part.

The DC offset is R3/(R3+R2)*Vs= 316k/(316k+10,000k)*3.3V = 0.1011V

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LMV796: LMV796 application