Patent ID: 6927553

Claim:
A phase-locked battery charge system having a phase comparator, a current pump, a battery, and a differential amplifier, and a voltage control oscillator; wherein its battery charge method comprising the steps of: (a) detecting a battery voltage for said differential amplifier, and releasing the detected battery voltage after amplifying the detected battery voltage, and determining an appropriate voltage for the input of said voltage control oscillator; (b) oscillating a feedback frequency corresponding to the detected voltage by said voltage control oscillator, and feeding the frequency back to said phase comparator; (c) comparing the input frequency and the feedback frequency by said phase comparator and generating a phase error; (d) sending said phase error to said current pump to generate an appropriate charge current to charge the battery; thereby after going through a plurality of aforementioned cycles, the battery being charged fully to provide a steady battery charge, and automatically and successively work in said frequency tracking state, phase tracking state, and phase-locked state.