Patent ID: 7379285
Filing Date: 2008-05-27
Classification: H03K

Abstract:
1. An apparatus for driving an inductive load according to a control signal supplied from an external controller, comprising: a pair of power supply circuits for complementarily supplying power to the inductive load in response to said control signal; a first heat protection circuit that monitors an operating temperature of the pair of power supply circuits, detects an overheat condition of the power supply circuits based on the monitored operating temperature, and produces, depending on the detection of the overheat condition, first data showing whether or not the power supply circuits are in the overheat condition, the first data including given data commanding heat protection to be performed on the power supply circuits; a data holder that holds the first data produced by the first heat protection circuit; a driver that is connected to the external controller to drive the external controller; a second heat protection circuit, thermally decoupled from the power supply circuits, that monitors an operating temperature of the driver, detects an overheat condition of the driver based on the detected operating temperature of the driver, and produces second data commanding heat protection to be performed on the driver when the overheat condition of the driver is detected, the first and second data produced by the first and second heat protection circuits being reflected in the control signal; and a gate that allows the driver to send the first data held in the data holder to the external controller provided that the second heat protection circuit detects no overheat condition of the line driver, and allows the driver to send the second data to the external controller when the second heat protection circuit detects the overheat condition of the line driver.