EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: newtekuser on December 25, 2024, 03:13:54 am
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I am working on a simple 12V power source switching circuit using a P-channel mosfet and LTC4412 IC. The idea is to automatically switch to 12V battery backup if the primary power is out. I'm prioritizing the primary by adding a schottky diode to create a small voltage drop on the backup. Can someone please chime in if I messed something up in the wiring? Schematic attached.
Thanks in advance!
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Just before I have my lovely lunch.....
Your schematic shows the MOSFET is shorted out?
It should look like this:[attachimg=1]
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Just before I have my lovely lunch.....
Your schematic shows the MOSFET is shorted out?
It should look like this: (Attachment Link)
Oops, I very much misunderstood the operation of the IC. Corrected.
So, the VIN of the IC is connected to the backup source and not the primary source, or is that depending on whether I want to monitor when the backup goes offline instead of the main power?
Also, for "prioritization" of main power over battery (to prevent battery from being used when main is active), is the use of a schottky diode to create a voltage drop the right approach?
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Wrong again. D1 polarity is wrong, and cathode of D8 should be connected to D of MOSFET
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Wrong again. D1 polarity is wrong, and cathode of D8 should be connected to D of MOSFET
Thank you! It's 5am but 3rd time's a charm ::)
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Now it looks correct