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Help with using a power mosfet as a high DC voltage/current switch

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binaryninja

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I need to be able to switch between two power supplies depending on the condition. My problem is solid state and electromechanical relays get really expensive at high voltages/currents. Actually it was hard to even find any that could do it. So how else can you switch between two input voltages? I thought maybe using power mosfets, and I'm looking for some help doing this. I have already searched the forum, found some help but not enough.

One input can be anywhere from 9-60V DC @ 10A, and the other would be a 12V DC battery.

What is the best way to accomplish this at a low cost? If its power mosfets then please help me with the design variables.

THANKS!
 

Switching power from two sources can be realized with 2 P-channel power MOSFETs .. eg. IRF5303 (low Rdson) ..
Here is an article that describes this issue in a greater detail:
**broken link removed**

Another option is to employ two high current diodes - one feeds power from the battery, the other from an external power source - whichever voltage is higher passes through ..


IanP
:wink:
 

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  • MOSFET - Power Switches - 2 power sources.JPG
    MOSFET - Power Switches - 2 power sources.JPG
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gotta watch out for back feeding with this circuit if it is undersirable. the diode method is useful, but it is helpful to have some sort of historesis.

Mr.Cool
 
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