| 摘要 |
PURPOSE:To prevent the inflow of dark currents to a protective circuit, and to reduce power consumption by mounting a first switching means, in which the positive side of a power supply is connected to a first electrode and load to a second electrode respectively, and an overheat protective circuit to the same semiconductor substrate and supplying the protective circuit with the power supply by a second switching means. CONSTITUTION:A MOS transistor 11 is turned ON by control voltage Vin from a control input terminal 13, but large currents are made to flow through the transistor 11 and a junction temperature is elevated When the trouble of a short circuit is generated in load RL under the state. Consequently, the temperature of a substrate is also raised, the forward voltage of a plurality of diodes constituting a heatsensitive element 14 is lowered, potential difference at both ends of a resistor 12b is increased, a MOS transistor 16 for control is turned ON, and the MOS transistor 11 for controlling load is turned OFF forcibly. Accordingly, no current flows through the load RL, and the transistor 11 is damaged. The device is suitable for an automobile, etc., and is useful of prevent the run-down a battery. |
