I'd like to build a battery-powered DC power supply that will accept a single-cell battery in either polarity (i.e. it doesn't matter which way you put the battery in). I'm thinking of using the circuit below to rectify the voltage.
Are there any gotchas? Is there a better design for my constraints (listed below)?
You'll notice that
Q2 are N-channel MOSFETs.
Q4 are P-channel. Let's assume they all support positive and negative gate voltages of more than the battery voltage.
The resistor labeled
LOAD stands in the place of the rest of the power supply and everything powered by it.
My design constraints for the rectifier include:
- Very low power loss (less than 1uA quiescent current; less than 1Ohm resistance)
- Support small loads (average of 130uA, peak 20mA, minimum 5uA)
- Support single cell Li-ion (3.7 - 4.2V)
- Support battery in both polarities
Perhaps importantly, I won't be supporting the case where the battery is inserted one way and then quickly inserted the other way. In other words, I don't need to rectify square waves. For that matter I don't need to rectify AC of any kind.