Patent ID: 7609498
Filing Date: 2009-10-27
Classification: H02H

Abstract:
1. An inverter circuit overcurrent protection device comprising: a plurality of switching elements, a drive circuit for driving the switching elements, a control circuit to generate a control signal to be input into the drive circuit to control a load, an overcurrent detection resistor connected to said switching elements, an overcurrent detection circuit, an external resistor; two voltage dividing resistors connected in series; and two external terminals, wherein said drive circuit, said switching elements, said voltage dividing resistors, said overcurrent detection resistor and said overcurrent detection circuit are incorporated in a single hybrid integrated circuit, wherein the voltage dividing resistors are connected in parallel to the overcurrent detection resistor and in series to one of the external terminals, wherein the overcurrent detection circuit is arranged to compare a voltage at a node between the two voltage dividing resistors with a reference voltage, the voltage at the node being input to the overcurrent detection circuit, wherein the voltage at the node between the two voltage dividing resistors is a portion of a detection voltage across the overcurrent detection resistor, wherein the external terminals are integrated as part of the single hybrid integrated circuit and connect the external resistor in series to the voltage dividing resistors, wherein the external resistor is arranged to change a voltage dividing ratio associated with the voltage dividing resistors and reduce an overcurrent protection level without changing a value of the overcurrent detection resistor and the reference voltage; and wherein the external resistor is external to the hybrid integrated circuit.