No.
A MOSFET conducts equally well in both directions when turned on, so both M1 and M2 are on at the same time when Q1 is on.
No.
When Q3 is on, it turns Q1 off, which allows R1 to pull the gate-source voltage of M1 and M2 to zero, turning them off.

All make sense?

Yes that makes sense, thank you! So M2 is turned on when Q1 is on because of R1 connected to the gate of M2.

 

I agree with BobTPH in post #18. All you need is a 12 volt relay.

 

So M2 is turned on when Q1 is on because of R1 connected to the gate of M2.

No.
R1 is to turn M1 and M2 off (Vgs=0), when Q1 is off.
It has no effect when Q1 is on.

 

Would the DC2866A board from Analog devices work for this application? I know V2 on the board is listed as 24V but the data sheet says V2 can operate at 9V - 36V.

If not, would any of these other boards from Analog Devices work?

• DC1741B
• DC1329A
• DC1926A
• DC2314A
• DC2969A
• DC3001A-A

While it is unlikely both power sources will be on at the same time, I just want to make sure in the case that they are that the power sources and computer will not be damaged and only one power source will be providing power.

Thank you!

 

Hi everyone,

I am looking to switch between two 12V DC power supplies without having an actual “switch”. I’d like for 1st power supply to switch to the 2nd one when the 2nd one is turned on. I believe the current rating for the system is 12A. I’ve read about using ORing controllers, diodes, MOSFET, etc. Is there a sort of all in one chip or component that can do this instead of creating my own circuit?

Thanks!
S

Current rating for the system is actuall 8A

 

Welcome to AAC.

A module like this one might do the job for you. Unfortunately, it is rated for only 8A—but you might be able to swap out the MOSFETs on the board and add some heatsinks to increase that.

View attachment 313612​

Hi Ya’akov,

Thanks for sharing this module! I found out that the system actually operates at 8A

Welcome to AAC.

A module like this one might do the job for you. Unfortunately, it is rated for only 8A—but you might be able to swap out the MOSFETs on the board and add some heatsinks to increase that.

View attachment 313612​

Thank you for sharing this module! I’ve found out that the system actually runs at 8A, so this could be a solution. I don’t necessarily need the power sources to switch, I just need to have both connected at the same time and in the case both happen to be on (which will be unlikely) to ensure that neither the power sources or load will be damaged.

I can’t purchase from Aliexpress, do you know of any similar modules from other manufactures?

I’ve found some on analog devices that may have similar function but I’m not sure if they will work

• DC1741B
• DC1329A
• DC1926A
• DC2314A
• DC2969A
• DC3001A-A