| 摘要 |
PURPOSE: A power on reset circuit is provided to detect the level of the source for stabilizing the operation regardless of the ascending slope of the source voltage, and operating the circuit normally when the source voltage is decreased below a predetermined level. CONSTITUTION: The circuit includes a source voltage detector(300) and a delay output(400). The source voltage detector receives the source voltage from outside and generate a voltage detects signal(VSO1). The delay output(400) receives the source voltage(VCC) and the ground voltage from outside and delay one of the source voltage and the ground voltage selectively to generate a reset signal with response to the source voltage detect signal(VSO1). The source voltage detector(300) further includes a reference voltage generator(10), a voltage divider(20), and a differential amplifier(30). The reference voltage generator generates a reference voltage of a predetermined level(VNEG). The voltage divider receives the VCC from outside and divides the VCC into a predetermined level to generate a division voltage(VPOS). The differential amplifier(30) receives VCC from outside, the VNEG and VPOS, compares VNEG with VPOS to generate VSO1. The delay output includes a switch(40), a charger(50) and an inverter(60). The switch(40) is turned on with response to VSO1. The charger(50) delays one of the VCC or ground voltage with response to the on/off state of the switch to generates a charge signal(VPD). The inverter(60) receives and inverts the VPD.
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