| 摘要 |
An overheat protection circuit 1 of a semiconductor integrated circuit device of the invention has filter means for removing a high frequency component from a power supply voltage Vcc. Specifically, the overheat protection circuit 1 has: a band gap power supply portion BG and resistors R1 and R2 that produce a reference voltage Vref; a transistor N1 for temperature detection; resistors R3 and R4 that generate, from the power supply voltage Vcc, a control signal Sctrl according to the on/off state of the transistor N1; a transistor P1 that is turned on/off according to the control signal Sctrl; and a transistor N2 and resistors R5 and R6 that generate an overheat protection signal Stsd according to the on/off state of the transistor P1. In addition, the overheat protection circuit 1 has, as the filter means, a resistor R7 and a capacitor C1 that are respectively connected to the emitter and the collector of the transistor P1. This makes it possible to perform a high-accuracy overheat protection operation despite variations in power supply voltage (superimposition of pulse).
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