TPS25982: The accuracy of IMON load current monitoring under 3A

Takamaru Akita

Part Number: TPS25982

Hi team,

We are going to measure the load current by connecting AD converter with IMON pin of TPS25982.

I have some questions for IMON pin.

There are some infomations for the accuracy over 3A load current condition (datasheet p7 & p11:Figure 14) , but I couldn't find the accuracy information under 3A condition .

Q1. Would you kindly let me know the accuracy of load current monitor under 3A with IMON pin or accuracy of Current Monitor Gain (G(IMON)) ?

Q2. Would you tell me the reason why series resistance of RC filter resistance recommendation is 10kΩ or higher ?

There is a description for IMON application on datasheet p25.

"It is recommended to add a RC low pass filter on the IMON output to filter out any glitches and get a smooth
average current measurement. TI recommends a series resistance of 10 kΩ or higher."

Thanks

Best regards,

Akita

over 5 years ago

0 Praveen GD over 5 years ago

TI__Guru 57737 points

Hi Akita,

The device is designed to monitor current for load currents less than 3A. This is is the reason why the IMON accuracy is not measured and specified in the datasheet for load current < 3A.

Regrading the RC filter: If the R value is recommended to be less than 10 kohms so as to reduce the current flowing in the path of RC and reduce the IMON error induced by adding external RC.

0 Praveen GD over 5 years ago in reply to Praveen GD

TI__Guru 57737 points

Hi Akita,

Hope your query is resolved. In case you do not have any more queries, can we close this thread ?

0 Takamaru Akita over 5 years ago in reply to Praveen GD

Prodigy 140 points

Hi Praveen,

I'm sorry for the late reply.

About Q2, I 've understood and this question is resolved.

About Q1, Is it impossible to know the load current accuracy less than 3A?

I apologize for repeating this question, but I would like to estimate the accuracy less than 3A in advance if possible.

Thanks

Best regards,

Akita

0 Praveen GD over 5 years ago in reply to Takamaru Akita

TI__Guru 57737 points

Hi Akita,

The IMON accuracy has been characterized for load currents upto 1.5 A as you can see in the snapshot below from datasheet.

Unfortunately, due to reasons explained earlier this device IMON is not characterized for Load currents < 1.5 A.

0 Takamaru Akita over 5 years ago in reply to Praveen GD

Prodigy 140 points

Hi Praveen,

Thank you for your cooperation.

>this device IMON is not characterized for Load currents < 1.5 A

I understand.

I'll close this thread.

Thanks

Best regards,

Akita

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TPS25982: The accuracy of IMON load current monitoring under 3A