TPS25944L: The problem with the current ADC

Blaz Jakob

Part Number: TPS25944L

Hello. I using a TPS25644L with current limit 5A. I set under voltage to 10V and over voltage protection to 15V. I have R(LIM) set to 18k so the max current will be 4.94A. For R(IMON) I set the same value of resistor like in datasheet which is the 19.1k. That will give me the ratio of 1V/1A. But when I load with 1A I got the 1.5V on R(IMON) pin.

Please advice.

Blaz J.

over 6 years ago

0 Rakesh over 6 years ago

TI__Guru* 96061 points

Hi Blaz ,

The voltage at R(IMON) pin depends only on load current and R(IMON) value. Are you testing on EVM or you made your own board?
where else the R(IMON) pin is interfaced?
Can you please share your complete system schematic.

Regards,
Rakesh

0 Blaz Jakob over 6 years ago in reply to Rakesh

Prodigy 60 points

I develop my own board. I use steps in the datasheet.

0 Blaz Jakob over 6 years ago in reply to Blaz Jakob

Prodigy 60 points

The FuseCurrent 1 line go directly to analog processor pin.

0 Blaz Jakob over 6 years ago in reply to Blaz Jakob

Prodigy 60 points

Yes, I figured out. The problem si diode D2. The diode has his own voltage drop so at 0.5A I measure 0.72 so 0.22V offsets. I measure voltage in cathode pin of a diode, but instead, i must measure on anode pin of a diode. Thank you for support.

0 Rakesh over 6 years ago in reply to Blaz Jakob

TI__Guru* 96061 points

Hi Blaz ,

Nice.
What is your end equipment and where exactly you are using TPS25644L in your system and for which purpose/protection?
Let me know if you need any support.

Regards,
Rakesh

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TPS25944L: The problem with the current ADC