| 摘要 |
PURPOSE: A source voltage detector is provided to offer a stable output by using trigger operation points of the first schmidt trigger part and the second schmidt trigger part. CONSTITUTION: A source voltage(Vcc) is divided by a resistor(R11) and a resistor(R12), and a connection point of the resistor(R11) and the resistor(R12) is connected to a non-inverting terminal of a comparator(40). A reference voltage(Vref) outputted by a reference voltage generator(50) is applied to an inverting terminal of the comparator(40). The first inverter(I1) is connected to an output terminal of the comparator(40), and an output terminal of the inverter(I1) is connected to the first schmidt trigger part(60) through a delay circuit including a resistor(R20) and a capacitor(C2). And, an output of the first schmidt trigger part(60) is connected to the second schmidt trigger part(70) through a delay circuit including a resistor(R30) and a capacitor(C3). An output terminal of the second schmidt trigger part(70) is connected to the 4th inverter(I4) and the 5th inverter(I5) in serial. A PMOS transistor(PI7) is connected between a node and the source voltage(Vcc). At this time, the node exists between the resistor(R30) and the second schmidt trigger part(70). An output terminal of the second inverter(I2) and the third inverter connected in serial each other is connected to a gate of the PMOS transistor(PI7). An input terminal of the second inverter(I2) is connected to an output terminal of the comparator(40).
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