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Associate II
September 11, 2025
Solved

STEF01 VCC/GND in a -48V system

  • September 11, 2025
  • 1 reply
  • 1094 views

Hi Sir, 

For a system with -48V and 0V (Ground) power rails, can I use the STEF01 with the following connections?

Connect the IC's GND pin to the system -48V rail.

Connect the IC's VCC pin to the system 0V rail.

 

TIENHUA_0-1757580574111.png

 

Will the chip work correctly and safely in this configuration?

Thank you

 

Best answer by Peter BENSCH

Well, that looks better. The STEF01 only wants positive voltage at VCC against its GND pin and also the connections that are necessary for its GND pin. The way you have drawn it now, it should work.

Good luck!

Regards
/Peter

1 reply

Peter BENSCH
Technical Moderator
September 11, 2025

How do you imagine how the STEF01 should switch the output if it and the input are connected to GND, i.e. short-circuited?

For this configuration with negative voltage, you can only use it if 0V of the input is NOT connected to 0V of the output.

Hope that helps?

Regards
/Peter

TIENHUAAuthor
Associate II
September 12, 2025

Hi Peter,

Apologies for the earlier misunderstanding. When I indicated Vout = 0V, my intention was simply to illustrate that when the switch is turned on, Vout would follow Vin at 0V. I did not mean directly tying both sides to the same voltage, which would result in a short circuit. Based on the diagram below, could you please confirm that this configuration should operate correctly?

TIENHUA_0-1757644288291.png

 

Peter BENSCH
Peter BENSCHBest answer
Technical Moderator
September 12, 2025

Well, that looks better. The STEF01 only wants positive voltage at VCC against its GND pin and also the connections that are necessary for its GND pin. The way you have drawn it now, it should work.

Good luck!

Regards
/Peter