Automatic shutdown circuit of single chip microcomputer

Abstract

The invention relates to an automatic shutdown circuit of a single chip microcomputer. The circuit comprises an NPN triode and a PNP triode. A collector electrode of the PNP triode is connected to a power supply of the single chip microcomputer, an emitting electrode of the PNP triode is connected to a 4.5V direct current power supply and connected to a collector electrode of the NPN triode through a base electrode, a base electrode of the NPN triode is connected to a control pin of the single chip microcomputer, and an emitting electrode of the NPN triode is grounded. According to the automatic cut-off circuit of the single chip microcomputer, the single chip microcomputer can completely shut off power by itself and cannot restart automatically during shutdown, and therefore the power consumption of the single chip microcomputer is effectively saved.

Description

technical field [0001] The invention relates to a circuit, specifically an automatic shutdown circuit for a single-chip microcomputer. Background technique [0002] With the continuous development of the electronic field, the power consumption requirements of electronic products are getting higher and higher, and the power consumption requirements of single-chip microcomputer chips are also getting higher and higher. In common single-chip microcomputer application systems, the function of self-shutdown (complete shutdown) of the single-chip microcomputer is usually realized through the I / O port of the single-chip microcomputer. Generally, an I / O port of the single-chip microcomputer is used to control an electronic switch. After power on, the power is lost, so when shutting down, the level of the I / O port that realizes shutting down must be low. [0003] But the problem that often occurs is that when the electronic switch turns off the power supply, because of the existence...

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Problems solved by technology

[0003] But the problem that often occurs is that when the electronic switch turns off the power supply, because of the existence of the power filter capacitor, the voltage of the MCU system does not immediately become 0, but gradually decreases. When the voltage is low to a certain level, the MCU enters In the reset state, or the program runaway state, or the uncertain state, the I / O port controlled by the single-chip microcomputer to turn off the power may also change back to high level, which will make the electronic switch open again

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