I've been designing a battery charger circuit for a while. I couldn't decide how to shut down the current flowing through battery. Actually, a simple output diode helps a lot but they make ~0.5V drop and when current flows through it, it lowers down efficiency for about %2-3 percent.

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This is the second circuitry that I tried. I am using a MCU with 3.3V logic, this circuitry works well when changing load on and off. However, In my application, the load is a battery which may pump back all the current when supply is low.

I trying to find out which possible way will work the best for this application.

  • \$\begingroup\$ What kind of battery are you charging? Most batteries will require precise control of charging voltage and some kind of current limiting. \$\endgroup\$ – Elliot Alderson May 25 '18 at 11:58
  • \$\begingroup\$ @ElliotAlderson Mostly 3S-4S Li-Ion batteries, I've created constant current and constant voltage side. I won't charge batteries with this circuit, this supposed to turn on/off the current flow. \$\endgroup\$ – Şener May 25 '18 at 12:03
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    \$\begingroup\$ You need to clarify your question. You talk about designing a charging circuit and you say that "the load is the battery". Where is the battery in the schematic you provided? \$\endgroup\$ – Elliot Alderson May 25 '18 at 12:16
  • \$\begingroup\$ @ElliotAlderson As I specified in title, I am looking for an efficient cutoff circuitry. I said "the load is battery" because I couldn't find battery in simulation program. In schematic, battery must be connected to the drain terminal of PMOS. \$\endgroup\$ – Şener May 25 '18 at 12:21
  • \$\begingroup\$ charging a battery should be done with a controlled current, here you are only shorting the 12V supply to the battery. \$\endgroup\$ – matzeri May 26 '18 at 8:41

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