INA233: TPS24751 and INA233 share a single current sense resistor

BillTest BillTestAccount

Part Number: INA233
Other Parts Discussed in Thread: TPS24751, TPS24750

Dear Sir,

Our customer will use TPS24751 and INA233 share a single current sense resistor the circuit as below. Please help check have any effect about the Current and voltage Measurement Accuracy? Thanks!

over 6 years ago

0 Peter Iliya over 6 years ago

TI__Mastermind 26660 points

Hey Sam,

I think it is important that we know each part is not loading down the other. I see you have the VBUS pin connected to INA233 IN- pin and also the TPS24751 SENSE pin. The VBUS pin has an input impedance of 830kOhms. I don't know how much of an effect this might have though without true analysis.

What is the common mode voltage at the inputs of the INA233?

Sincerely,
Peter Iliya
Current Sensing Applications

0 BillTest BillTestAccount over 6 years ago in reply to Peter Iliya

Prodigy 60 points

Dear Peter,

The INA233 VBUS pin will change connect from IN- to IN+. Common mode voltage is 12V. Thanks!

Best Regards,

Sam Shyu

0 BillTest BillTestAccount over 6 years ago in reply to BillTest BillTestAccount

Prodigy 60 points

Dear Peter,

Have any concern for this circuit? Thanks!

Best Regards,

Sam Shyu

0 Peter Iliya over 6 years ago in reply to BillTest BillTestAccount

TI__Mastermind 26660 points

Hi Sam,

Our device is essentially a differential amplifier and thus it should not affect the TPS24751. I have reached out to the power switches team and they have seen their TPS24750 device share shunt resistors with other current shunt monitors without problem. It's possible that the TPS24750 may introduce some more error slightly with input bias current, but this is negligble since it is in the uA.

Overall, there are not any major concerns with the schematic you have provided.

Best regards,
Peter Iliya
Current Sensing Applications

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INA233: TPS24751 and INA233 share a single current sense resistor