Protective circuit capable of preventing short circuit or micro-short circuit or touch-caused spark of direct-current power supply

Abstract

The invention discloses a protective circuit capable of preventing short circuit or micro-short circuit or touch-caused spark of a direct-current power supply. The V+ end and the V- end of the power supply are connected with the positive access end and the negative access end of electric equipment correspondingly; a connecting wire of the V- end and the electric equipment is connected in series with a switch tube Q1; a voltage sampling circuit and a voltage stabilizing circuit are connected between the V+ end and the V- end; the output of the voltage sampling circuit is connected with an MCU; the output of the MCU is connected with the control end of the switch tube Q1; and the voltage stabilizing circuit outputs stable voltage to supply power for the work of the MCU. The abnormal state of the short circuit or the micro-short circuit or the touch-caused spark which may occur between the VA+ and VA- points is judged by connecting a resistor R1 and a resistor R2 in series to sample waveform change of the supply voltage, inputting the waveform change of the supply voltage into the MCU and comparing with the internal datum of the MCU, on and off of the switch tube Q1 on the V- end connecting line are controlled, the power supply safety is protected timely, combustion of combustibles caused by spark is avoided, the structure is simple and the cost is low.

Description

technical field [0001] The invention relates to power supply protection technology, in particular to a protection circuit for preventing short circuit or micro short circuit of DC power supply or sparks generated by touch. Background technique [0002] As an indispensable part of electrical appliances, power supply has always been one of the important guarantees for the normal operation of electrical appliances. It is widely used in various electronic devices such as industrial control, communication office, and home consumption. However, the requirements of the power supply vary with different electronic devices, and they all have different technical specifications and indicators, especially various protection functions, including short-circuit protection, micro-short-circuit protection and touch sparks, among which short-circuit protection is the most important function More attention has been paid to micro-short circuits that can also cause instability in power supply wo...

AI Technical Summary

Problems solved by technology

In some cases, there is no short circuit at the output end of the switching power supply, but a short circuit occurs inside the power supply, and the obvious faults inside the power supply cannot be perceived through the external environment; at this time, the equipment is generally still operating normally, and the corresponding protection The circuit does not turn on the protection work, but the internal components will be short-circuited, which will cause the internal temperature to rise rapidly, exceeding the requirements of safety regulations, so that the power supply will always work at extremely high temperatures, increasing the loss of power supply components, overheating operation, and eventually cause damage to the power supply, or even cause a fire, etc.

In the above case, it is too late when the power supply is found to be faulty, and the best time for diagnosis and troubleshooting is missed

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