LM25066A: Power management forum

Oliver Ou

Part Number: LM25066A
Other Parts Discussed in Thread: LM25066, , TPS24770

Hi,

LM25066 has 25mV minimum current sensor threshold, for larger than 100A current application, the power loss on shunt resistor is too high.

Customer wants to add an amplifier to increase the current sense amplitude and use smaller shunt resistor, the idea is shown in below:

Is it workable for LM25066A?

Thanks.

Oliver Ou

over 5 years ago

0 Praveen GD over 5 years ago

TI__Guru 57737 points

Hi Oliver,

We haven't analysed the performance of LM25066 using this circuit as of now. Let us look into it get back to you by tomorrow.

Meanwhile, one issue I can see is that for rapidly increasing loads or short circuit condition the circuit breaker response time can be delayed due to the bandwidth of the amplifier.

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

TI__Guru 57737 points

Hi Oliver,

We do not see any other issue in using this circuit other than the circuit breaker response time delay due to the bandwidth of the amplifier.

As we have not tested this circuit completely, please ask customer to evaluate the circuit performance before using it in their system.

By the way, why don't you introduce TPS24770 to customer. This part has 10mV current limit threshold and solve the customer issue of power loss in sense resistor. Do they require PMBUS telemetry ?

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

TI__Intellectual 2845 points

Hi Praveen,

Thanks a lot for your comments. Yes, customer needs PMBUS telemetry. We also considered the analogy controller with digital current sensor.

Do we have new generation PMBUS controller to support higher current application now?

Thanks.

Oliver Ou

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

TI__Guru 57737 points

Hi Oliver,

LM25066 can support higher current applications. We have seen customers using LM25066 for greater than 200A applications.

In your case, you wanted to reduce the power dissipation in the sense resistor otherwise LM25066 is aptly suitable for high current applications.

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

TI__Guru 57737 points

Hi Oliver,

Do you have any other questions ? If not, can we close this thread ?

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

TI__Intellectual 2845 points

Yes, we can close it. Thanks.