Charge Pump Circuits
+5v Powered Charge Pump Battery
Charger February 7, 2010
The circuit below will trickle charge a four cell pack of AA or AAA NiMH
The circuit draws current from the +5v available a USB connection and pumps about 70ma
of current into the battery. This should be enough current to fully charge a pack of
2500ma-hour cells in about 36 hours. The circuit uses a single 74HC14 hex
Schmitt trigger inverter in conjunction with a voltage doubler charge pump circuit.