UCC256403: About setting the ISNS resistance value

user5996000

Part Number: UCC256403

Hi expert,

I am designing a 2.7kW power supply using UCC256403.

When designing the resistance value connected to ISNS, there is a design method for the upper limit in the data sheet, but there is no design method for the lower limit.

How should I design the minimum voltage for ISNS?

ISNS_resistance.xlsx

over 1 year ago

0 Jonathan Wong over 1 year ago

TI__Expert 8580 points

Hello,

We are on holiday today for Good Friday and an expert will respond next week.

Regards,

Jonathan Wong

0 Mike O' over 1 year ago in reply to Jonathan Wong

TI__Guru* 85946 points

Hello,

There is an excel design tool at the following link that will calculate the ISNS resistor for your design.

https://www.ti.com/tool/download/SLUC675

Regards,

0 user5996000 over 1 year ago in reply to Mike O'

Prodigy 60 points

Hello,

This tool has the same calculations as the datasheet.

I'm asking how to design the lower limit.

How should I design the lower limit value?

I would like to know how to design the lower limit of RISNS to avoid problems due to variations in other component characteristics.

Regards,

0 Mike O' over 1 year ago in reply to user5996000

TI__Guru* 85946 points

Hello,

I think you believe there might be two different setting for VTH_H and VTH_L.

There is not it is set with one ISNS resistor value. This why the calculations for RISNS are the same in the data sheet and the excel tool.

Regards,

Power management

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UCC256403: About setting the ISNS resistance value