AMC1200-Q1: Sense resistor current & value

abhishek deshmukh

Prodigy 220 points

Part Number: AMC1200-Q1
Other Parts Discussed in Thread: AMC1200, AMC3301

Hello,

I am using AMC1200-Q1 for isolated voltage sensing.

The sense resistor across AMC1200-Q1 is 673 ohm & max drop across it is 246mV.

But, the current through it is 375uA, because of high series resistor values (1M + 1M ohm).

Is OK to have such low current through R3 in below snap.

Will it induce noise at the output of AMC1200?

Regards,

Abhishek D.

over 2 years ago

+1 Alexander Smith over 2 years ago

TI__Guru 50551 points

Hi Abhishek,

This is fine and how you have the device configured is correct. The noise from the resistive divider should couple equally to both VINP and VINN and be cancelled by the common-mode rejection ratio of the device.

Can you please share some information about the application?

How do you plan to generate the high side supply?

We have devices, such as AMC3301 with an integrated DC/DC converter that greatly simplifies the design: https://e2e.ti.com/blogs_/b/analogwire/posts/simplify-your-isolated-current-and-voltage-sensing-designs-with-single-supply-isolated-amplifiers-and-adcs

0 abhishek deshmukh over 2 years ago in reply to Alexander Smith

Prodigy 220 points

Thank you, Alexander.

I will check AMC3301.

I am working on 11kW Onboard charger.

Regards,

Abhishek D.

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AMC1200-Q1: Sense resistor current & value