Alternating current detection circuit and automatic power-off circuit with zero power-off power consumption

Abstract

The invention discloses an alternating current detection circuit and an automatic power-off circuit with zero power-off power consumption. The alternating current detection circuit comprises resistors R1 and R2, a capacitor C1, a filter element C2, diodes D1 and D2, and a photoelectric tube U1, wherein a positive end of the diode D1 is connected with a negative end of the diode D2, and a connecting end is an end point X; the negative end of the diode D1 is connected with the positive end of the diode D2, and the connecting end is an end point Y; two ends of the resistor R1 are connected with the end point X and the end point Y; and the alternating current detection circuit also comprises a diode D3 or a triode P1. The automatic power-off circuit with the zero power-off power consumption is provided with the alternating current detection circuit which serves as a current detection device. By adoption of the alternating current detection circuit and the automatic power-off circuit, a current can be quite conveniently detected, a circuit structure is easy to minimize, and after electric equipment is closed, a socket can be totally disconnected from an external power supply.

Description

technical field

[0001] The invention relates to an alternating current detection circuit and an automatic power-off circuit with zero power consumption during power-off. Background technique

[0002] Common methods of current detection include the following types: series resistance detection, current transformer detection and Hall device detection. Each of these types of tests has its own advantages and disadvantages. Resistance detection is only suitable for lines with small currents. In a high-current detection circuit, if the insertion loss is large if the resistance is connected in series, the power dissipation will be several watts or even tens of watts. , especially in the case of a large load current variation range, it is difficult to take care of the dual requirements of detection sensitivity and high current tolerance by the detection method of series resistance. In this case, this method is generally not used; in the detection of large currents, the common meth...

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