Power module will be damaged by added Overcurrent limit circuit?

[Flyback]

Hi,

We are doing a 48V 7A5 PSU with TUNS500F ACDC power module.

We want it to limit current if a 10A load is connected, so the contractors made the attached overcurrent circuit as shown. Do you think it will damage the TUNS500F “TRIM” pin, due to >5V experienced on that pin? (>5V on TRIM pin when overcurrent happens)

Attached is a representative LTspice sim of the added overcurrent circuit, and a PDF schem of it

TUNS500F datasheet (page 8...)
https://en.cosel.co.jp/tool/tag/pdf/SFE_TU.pdf

Page “TUNS-27” of the below, says TRIM pin should not have >5V applied to it….
https://en.cosel.co.jp/tool/tag/pdf/CME_TU.pdf

 

[alec_t]

Do you think it will damage the TUNS500F “TRIM” pin, due to >5V experienced on that pin? (>5V on TRIM pin when overcurrent happens)

Quite likely. It's unwise to exceed module ratings. Your sim shows ~10V spikes on that pin.
I may be misunderstanding the circuit, but why is the over-current protection being applied to the VTRIM pin rather thn the ITRIM pin?

 

[Flyback]

why is the over-current protection being applied to the VTRIM pin rather thn the ITRIM pin?

Thanks, sorry i am not aware of an "ITRIM" pin on the TUNS500F module?

 

[Pommie]

I'm confused. There isn't a 48V 7A5 version. There is a 6A5 and 10A5 version.

Mike.

 

[Flyback]

Thanks, yes, our max load is 7A5....but we want to limit it when currents of 10A or more are drawn...which may happen sometimes

 

[Pommie]

Silly suggestion, add a load that will always take 3A (10.5-7.5) and the automatic current limiting will kick in.

Can you reduce your current requirements to 6.5A and use a TUNS300F?

Mike.

 

[alec_t]

i am not aware of an "ITRIM" pin on the TUNS500F module?

Mea culpa. I was looking at the wrong module.

Edit:
A ~12k resistor between D2 and the pot wiper seems to tame the 10V spikes and bring them down to 5V.

 

[noman113]

Hi,

We are doing a 48V 7A5 PSU with TUNS500F ACDC power module.

We want it to limit current if a 10A load is connected, so the contractors made the attached overcurrent circuit as shown. Do you think it will damage the TUNS500F “TRIM” pin, due to >5V experienced on that pin? (>5V on TRIM pin when overcurrent happens)

Attached is a representative LTspice sim of the added overcurrent circuit, and a PDF schem of it

TUNS500F datasheet (page 8...)
https://en.cosel.co.jp/tool/tag/pdf/SFE_TU.pdf

Page “TUNS-27” of the below, says TRIM pin should not have >5V applied to it….
https://en.cosel.co.jp/tool/tag/pdf/CME_TU.pdf

It's confusing to me. I don't see a 48V 7A5 version. There are 6A5 and 10A5 versions.

 

[alec_t]

our max load is 7A5....but we want to limit it when currents of 10A or more are drawn.

The module has a built-in current limit of 10.5A. Won't that suffice?