| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit device equipped with a low-power-consumption and high-precision power source detection circuit. SOLUTION: The semiconductor integrated circuit device has a startup circuit which operates at a first supply voltage, a constant current source of self-bias type, a reference voltage generating part and a voltage comparison circuit. The constant current source of self-bias type forms a constant current corresponding to the differential voltage between threshold voltages of a first transistor and a second transistor by a first resistance element and applies it also to the first transistor through the second transistor and a current mirror circuit. The reference voltage generating part forms the reference voltage by using the constant current and supplies it to the voltage comparison circuit. The voltage comparison circuit compares the reference voltage with a second supply voltage and forms a power source detection signal. The startup circuit forms a starting voltage in such a way that the reference voltage is a voltage corresponding to the first supply voltage only until the first supply voltage reaches a specific voltage which is equal to or less than the reference voltage. COPYRIGHT: (C)2008,JPO&INPIT
|
