TPS2660: programmable Ilim

Frank H

Part Number: TPS2660
Other Parts Discussed in Thread: TPL1401,

Tool/software:

I would like to implement a programmable current limit. Can I do this with a digital potentiometer between Ilim and RTN?

Also, would a buffered output potentiometer like the TPL1401 (https://www.ti.com/product/TPL1401) work also.

RTN is separated from GND by the reverse polarity circuit. What happens in case of a reverse polarity voltage on Vin (i.e. -24V) to the RTN pin? What voltages can be expected there?

I worry about this as the potentiometer will be powered by 3.3V and GND.

Do you have other recommendations or maybe even an app note on how to implement this?

Thanks!

Frank

4 months ago

0 Amrit Jit 4 months ago

TI__Mastermind 30801 points

Hello Frank,

I will check on this and get back.

There is TI design which implements variable RILIM. You can check this out if helpful.

TIDA-01081 reference design | TI.com

0 Frank H 4 months ago in reply to Amrit Jit

TI__Intellectual 2670 points

Hello Amrit,

thanks for TIDA. It shows an implementation with a voltage DAC output driving the RLIM resistor. As you have tested this, it seems to be working.

As the RLIM now is not connected anymore to RTN of the TPS2660, but through the Vout of the DAC buffer has a path to GND, will this do anything to the functionality (like reverse blocking) of the TPS2660?

I guess RTN and GND are kept separate in TPS2660 for a good reason.

Thanks!

Frank

0 Amrit Jit 4 months ago in reply to Frank H

TI__Mastermind 30801 points

Hello Frank,

RTN and GND are separated for reverse polarity protection.

All other pins are connected to RTN. DAC output requires ground reference.

Do you need reverse polarity protection for your application?

Thanks
Amrit

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TPS2660: programmable Ilim