OPA2992-Q1: Current sensing question

CHO SR

Genius 3185 points

Part Number: OPA2992-Q1

Hi,

The customer wants to configure the current sensing circuit using OP AMP.

1) How do I do R1, R2, R3, R4, and Rshunt to be able to sense normal state = 20mA?

Connect Vo directly to the MCU.

2) Where should I connect V+ and V- as well?

4 months ago

0 Clemens Ladisch 4 months ago

Guru 257880 points

First, determine the largest Vshunt that you can afford (this minimizes the amplifier's error). Rshunt = Vshunt_max / Imax.

Then determine the largest output voltage (should not be too small, to minimize the ADC error). This allows you to compute the gain resistors.

V+ and V− determine the valid voltage range of the amplifier, so they usually are the same as the bus voltage.

It is usually a better idea to use an integrated current-sense amplifier.

0 Jerry Madalvanos 4 months ago in reply to Clemens Ladisch

TI__Mastermind 24931 points

Hello Cho,

Please see the following application example for how to implement high side current sensing. Please let me know if there are any questions on the following circuit.

https://www.ti.com/lit/an/sboa310a/sboa310a.pdf

Best,
Jerry

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OPA2992-Q1: Current sensing question