Abstract: The inventive subject matter provides a circuit and a method for efficiently charging a battery. In one aspect of the invention, the circuit includes a constant current circuit configured to provide a direct current through the battery. The circuit also includes a pulsing current circuit that works with the constant current circuit and configured to simultaneously provide a series of pulsed current to the battery. In some embodiments, the series of current pulses includes constructive resonant ringing that is constructive with respect to the charging of the battery.

Abstract: The inventive subject matter provides a circuit and a method for efficiently charging a battery. In one aspect of the invention, the circuit includes an oscillator that generates a series of current pulses at a frequency that corresponds to a resonant frequency of the battery. Each pulse in the series includes ringing oscillations that includes a main pulse and a group of ringing decaying pulses. The group of ringing decaying pulses includes pulses with gradually smaller amplitudes over time until the pulses completely die out.