UCC29002: UCC29002 Sense Resistors

Richard Elmquist

Part Number: UCC29002
Other Parts Discussed in Thread: UCC39002

I have a customer asking the following questions about the UCC29002:

I am designing a set of load sharing power converters and would like to use the UCC29002. I also want to use remote sensing in this design. I think I want to include a resistance between the Sense + to Vout + terminals. I also think I want resistance between the Sense – to Ground terminals so both the high and return current path conductors are isolated from the sense lines.

I understand the calculations shown on the data sheet and application note sluu166a. Although a low side resistor is not shown on figure 6 I am assuming that one could go there. My question is; Does isolating the ground of the UCC29002 circuit from the supply ground through a low side sense resistor cause any performance problems with the UCC29002?

Should the customer use a low-side sense resistor? Or is this something that is not needed? I pointed out that I did not see these on any of our designs, but I thought you might be able to explain in detail whether he should use them or not.

Thanks for your help with this!

Richard Elmquist

over 8 years ago

0 Wangxin Huang over 8 years ago

TI__Intellectual 1550 points

Hi Richard,

UCC29002 can be used for both high-side and low side current sense. The low-side current sense case is shown at the bottom on page 1 of the datasheet

Regards,

Wangxin.

0 Richard Elmquist over 8 years ago in reply to Wangxin Huang

TI__Mastermind 45250 points

Wangxin,

I believe that customer was asking if they could use both at the same time. I believe that they need to choose either high-side or low-side, but I wanted to confirm this with you. It seems to me that they need to use one of the configurations and not use Rshunt in the high-side and low-side in the same application. Please confirm if I am correct.

Thanks for your help with this!

Richard Elmquist

0 Wangxin Huang over 8 years ago in reply to Richard Elmquist

TI__Intellectual 1550 points

Richard,

While it has rarely been used that way, I don't see any issue with it. The typical application diagram below shows that S- terminal which is tied to the GND pin of the UCC39002 is grounded. As long as V- terminal is not grounded, UCC39002 should work fine. But note that UCC39002 has only one current sense amplifier so you will need to choose either high-side or low-side current sense signal to feed into the UCC39002.

Regards,
Wangxin

0 Richard Elmquist over 8 years ago in reply to Wangxin Huang

TI__Mastermind 45250 points

Wangxin,

Thanks for your quick response!

I will let you know if the customer has any further questions.

Thanks for all your help!

Richard Elmquist

Power management

Power management forum

UCC29002: UCC29002 Sense Resistors