Patent ID: 8373957
Filing Date: 2013-02-12
Classification: H03K

Abstract:
1. A load driving circuit having a high side transistor and a low side transistor that are bipolar transistors connected in series between a first fixed voltage terminal and a second fixed voltage terminal, the load driving circuit supplying a drive current, according to an ON-OFF state of the two transistors, to a load connected to an output terminal that is a connection point of the two transistors, the load driving circuit comprising: a current source which supplies base current to the high side transistor and which adjusts the values of the base currents of the high side transistor so that a desired driving current is supplied to the load; and a protection circuit configured to compares an output voltage of the output terminal with a predetermined threshold voltage, to monitor ON and OFF states of the high side transistor, and to reduce the base current of the high side transistor as to be lower than a value required to supply the desired driving current to the load when the output voltage goes below a predetermined lower limit threshold voltage while the high side transistor is on and wherein the protection circuit comprises: and wherein the base current of the high side transistor is reduced according to the control signal.