Patent ID: 6958591

Claim:
A safety circuit for protecting a battery against an over-voltage condition associated with a voltage at an output terminal of a charging circuit, comprising: a coupling circuit wherein the coupling circuit is coupled between the output terminal of the charging circuit and an input terminal of the battery, and wherein the coupling circuit is configured to produce an IR drop in response to the over-voltage condition such that the voltage at the output terminal of the charging circuit is increased; a control transistor wherein a source of the control transistor is coupled to the output terminal of the charging circuit, wherein the control transistor has an associated gate-to-source voltage (VGS), and wherein the control transistor is configured to provide a first activation signal when the increased voltage at the output terminal of the charging circuit increases the magnitude of the control transistor VGS beyond a conduction threshold of the control transistor; and a regulator wherein the regulator is coupled to the output terminal of the charging circuit, wherein the regulator is activated in response to the first activation signal such that the voltage at the output terminal of the charging circuit is lowered.