Patent ID: 8907635

Claim:
A charging circuit electrically connected between a battery charger and a battery, comprising: a transistor comprising an emitter, a base and a collector, the emitter electrically connected to the battery charger; a current regulating resistor electrically connected to the base of the transistor; a field effect transistor comprising a source, a gate and a drain, the source electrically connected to the collector of the transistor, the drain electrically connected to the battery; and a main controller that electrically connects the collector of the transistor to receive electrical energy, the main controller comprising: a current control unit that electrically connects the base of the transistor through the current regulating resistor; a charge control unit that electrically connects the gate of the field effect transistor; and a voltage detection unit that electrically connects the charge control unit, the drain of the field effect transistor and the battery, wherein the current control unit transmits current signals to the base of the transistor to turn on the transistor and regulate the current values of the collector, the voltage detection unit detects the voltage of the battery to controls the charge control unit accordingly, and the charge control unit sends a command signal to the gate to switch the field effect transistor on or off.