Patent ID: 6144187
Filing Date: 2000-11-07
Classification: H02J,Y02B

Abstract:
A battery charger circuit for an electronic device operated by a battery, the circuit comprising:a voltage control loop adapted to couple to the battery to control a voltage level of the battery to a selected voltage level;a current control loop adapted to couple to the battery to control current delivered to the battery at a selected current magnitude;a power control loop adapted to couple to the battery and the electronic device to control the power drawn by the charger circuit to a selected power level; anda combine circuit configured to combine outputs of the voltage control loop, current control loop and power control loop,wherein, the power control loop comprises:a current sense circuit having first and second input terminals adapted to couple across a current sense resistor,a voltage input terminal configured to monitor an input supply voltage, anda multiplier circuit having a first input coupled to an output of the current sense circuit, a second input coupled to the voltage input terminal, and an output, the multiplier circuit being configured to generate at its output a signal representative of the power draw from the charger circuit.