In this case, rather than acting to prevent reverse polarity connections, the p-channel MOSFET is acting as a diode to prevent discharging of the battery through the solar cell during periods of darkness.
If you're going to use this circuit at greater than about 12 volts, a slight modification of the circuit is needed to prevent the MOSFET gate voltage limits being exceeded.
That's a nice modification there. The circuit I am using has 15v maximum from the solar cells, and a GS limit of +/- 20V, so I'm ok with this one for the time being. But yes, it's good to check your limits and modify accordingly.
Re: Mini-Tip: Diode Without a Voltage Drop
7 years 3 months ago #10724