Patent ID: 6998818
Filing Date: 2006-02-14
Classification: H02J

Abstract:
1. A battery charging circuit, comprising: a. input terminals for receiving an input voltage and an input current; b. an overvoltage protection circuit; c. a voltage regulation circuit having an output voltage; d. a current regulation circuit; e. a means for sensing current flowing through the charging circuit, wherein the means for sensing current comprises a resistor; f. battery terminals for coupling to a rechargeable battery cell; and g. a microprocessor having a plurality of inputs and outputs; wherein by way of the plurality of inputs, the microprocessor is capable of sensing: wherein the microprocessor calculates a circuit current by dividing the voltage across the means for sensing current by an impedance value of the resistor; wherein the microprocessor calculates the power dissipation across the voltage regulation circuit by multiplying the voltage across the voltage regulation circuit by the circuit current; and wherein when the power dissipation across the voltage regulation circuit exceeds a predetermined maximum voltage regulation power threshold, the microprocessor actuates a first output coupled to the current regulation circuit, causing the circuit current to decrement by a predetermined amount.