Why no remote sense details in PSUs?

[Flyback]

Hi,
Why do remote sense PSU's not give details about the remote sense circuitry inside the module?
The info is needed.
As you can see from the attached, the resistor valuss are needed, or else they may interfere with any load share resistors used.

Eg

https://www.murata.com/products/productdata/8807039270942/pqu650.pdf?1656300615000

...no details of remote sense

 

[crutschow]

The remote sense lines are connected directly to the power supply output terminals at the remote load, which is a very low impedance point, so I don't see how any remote sense current (which is likely very low) that can interfere with any "load share resistors", whatever those are.
You do not want to add any external resistor in the sense lines, as you appear to show.

 

[Flyback]

You do not want to add any external resistor in the sense lines, as you appear to show

Yes, my apologies, i should have explained that this needs the resistance in the sense line, to do load sharing....it is this resistor's action, that is "messed up", by internal resistors relating to the "remote sense" function.

 

[crutschow]

i should have explained that this needs the resistance in the sense line, to do load sharing....it is this resistor's action, that is "messed up", by internal resistors relating to the "remote sense" function.

Well, you are trying to do something with the sense lines they are not designed to do, so can't help you there.
Have you tried measuring the resistance of the sense lines?

 

[Flyback]

Thanks, AYK, using sense lines for Load sharing is a normal procedure, as on page 1 of the UCC29002 datasheet

https://www.ti.com/lit/ds/symlink/ucc29002.pdf?ts=1675636263323&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUCC29002

...Have you tried measuring the resistance of the sense lines?

Thanks, i see your point, i could measure from S+ to V+ and from V- to S-......that will tell me those two resistors...but there may be more inside....i cant see why they dont just provide the schem of the remote_sense_related circuitry.

 

[crutschow]

using sense lines for Load sharing is a normal procedure, as on page 1 of the UCC29002 datasheet

Okay, I wasn't familiar with that technique.

.i cant see why they dont just provide the schem of the remote_sense_related circuitry.

Likely because the power supply manufacturer wasn't aware of that load sharing technique, and for normal remote sensing, the impedance of the remote sense lines is not of importance.

If you want a more accurate impedance measurement of the sense line, you could connect it through an ammeter and measure the current into the sense terminals at some nominal voltage.