CN210954215U

CN210954215U - Alternating current detection circuit using switch leakage

Info

Publication number: CN210954215U
Application number: CN201921471151.XU
Authority: CN
Inventors: 任雪刚
Original assignee: Shanghai Xinquan Microelectronic Technology Co ltd
Current assignee: Shanghai Xinquan Microelectronic Technology Co ltd
Priority date: 2019-09-05
Filing date: 2019-09-05
Publication date: 2020-07-07
Anticipated expiration: 2029-09-05

Abstract

The utility model discloses an utilize alternating current detection circuitry of switch electric leakage, a serial communication port, include: the leakage detection module is connected to a power grid through a live wire VL, the power grid is connected with a switch S1, and a parasitic capacitor C1 is arranged inside the switch S1; the leakage detection module comprises a resistor R1, a resistor R2, a comparator and a clamping diode, wherein the positive input end of the comparator is connected to the live wire VL through the resistor R1, the negative input end of the comparator is an internal reference, the clamping diode and the resistor R2 are connected between the resistor R1 and the positive input end of the comparator, and the output end of the comparator can output high/low levels. An utilize alternating current detection circuitry of switch electric leakage, need not carry out the circuit transformation, be fit for general distribution and mode of connection, the circuit is succinct.

Description

Alternating current detection circuit using switch leakage

Technical Field

The utility model belongs to the circuit field especially relates to an utilize alternating current detection circuit of switch electric leakage.

Background

In a typical emergency system, an ac switch is connected in series with the emergency power source before the emergency power source is connected to the grid. The switch is used for controlling the AC input signal. When the switch is in an ON state, the emergency power supply can be connected to a power grid to realize normal illumination. When the switch is in an OFF state, the emergency power supply is in an OFF-grid state, and the emergency power supply system has no output. Therefore, the emergency power supply is also required to be able to be activated when the ac grid fails, regardless of whether the switch is in the ON state or the OFF state. In the existing technical scheme, a three-wire control mode is adopted. I.e. a single live line, which is directly connected to the emergency power supply without a switch control loop, as shown in fig. 1. Therefore, when the switch is turned OFF, whether the alternating current power grid is in a power failure state can still be judged through the single live wire, and whether the emergency power supply is started for the load is judged according to the power failure state.

However, this wiring is different from the ordinary wiring. The general power distribution mode is two wiring of zero line and live wire, and emergency power source's power distribution and wiring mode can't be compatible with general 2 line wiring modes, and general switch also can't use. Therefore, if a three-wire control mode is adopted, the distribution line and the switch need to be modified, the line modification is very inconvenient, and time and labor are wasted.

SUMMERY OF THE UTILITY MODEL

In view of the above problem, the utility model provides an utilize interchange detection circuitry of switch electric leakage can judge whether normal work of electric wire netting need not to draw a live wire alone, need not to reform transform general wiring mode and switch, need not to adopt control system such as controller sensor, and is convenient succinct more to accord with actual demand.

In order to achieve the above object, the utility model adopts the following technical scheme:

an alternating current detection circuit using a switch leakage, comprising: the leakage detection module is connected to a power grid through a live wire VL, the power grid is connected with a switch S1, and a parasitic capacitor C1 is arranged inside the switch S1; the leakage detection module comprises a resistor R1, a resistor R2, a comparator and a clamping diode, wherein the positive input end of the comparator is connected to the live wire VL through the resistor R1, the negative input end of the comparator is an internal reference, the clamping diode and the resistor R2 are connected between the resistor R1 and the positive input end of the comparator, and the output end of the comparator can output high/low levels.

According to the technical scheme, the clamping diode and the comparator are connected to the power grid, and whether the power grid is normally operated or not can be judged according to the output of the comparator no matter whether the power grid switch is closed or disconnected.

More preferably, the clamping diode and the resistor R2 are connected in parallel and grounded.

Preferably, the power supply further comprises a rectifier bridge BR, two alternating current input ends of the rectifier bridge BR are respectively connected with a live line VL and a null line VN of a power grid, an output positive end of the rectifier bridge BR is connected with a VBUS interface, an output negative end of the rectifier bridge BR is grounded, and a capacitor C2 is connected at the VBUS interface.

Preferably, the circuit is connected with a switch S1, a parasitic capacitor C1 is arranged in the switch S1, and the live line VL is connected with an alternating current input end of the rectifier bridge BR through a switch S1.

More preferably, the parasitic capacitor C1 is connected in parallel with the switch S1.

Compared with the prior art, the beneficial effects of the utility model are that:

1. an utilize exchange detection circuitry of switch electric leakage for need not a live wire of drawing alone when judging whether the electric wire netting has a power failure, the event need not carry out the circuit transformation, is fit for general distribution and mode of connection, has greatly made things convenient for the detection of exchange electric wire netting voltage.

2. An utilize alternating current detection circuit of switch electric leakage, the circuit is succinct, the method is understandable, need not intelligent control systems such as controller, sensor, realizes the judgement that alternating current electric wire netting has a power failure through the circuit.

Drawings

Fig. 1 is a circuit diagram of a power distribution scheme of a prior art three-wire emergency system.

Fig. 2 is a circuit diagram of an ac detection circuit using switch leakage according to the present invention.

The device comprises a power supply module, a power leakage detection module and a power supply module, wherein 1, the power leakage detection module; 2. a comparator; 3. a clamping diode.

Detailed Description

For a better understanding of the present invention, the contents of the present invention will be further clarified below with reference to the accompanying drawings and examples, but the present invention is not limited to the following examples.

Examples

An alternating current detection circuit using a switch leakage, comprising: the leakage detection module 1 is connected to a power grid through a live wire VL; the leakage detection module 1 comprises a resistor R1, a resistor R2, a comparator 2 and a clamp diode 3, wherein the positive input end of the comparator 2 is connected to a live wire VL through a resistor R1, the negative input end of the comparator 2 is an internal reference, the clamp diode 3 and the resistor R2 are connected between the resistor R1 and the positive input end of the comparator 2, and the clamp diode 3 and the resistor R2 are connected in parallel and grounded. The output of the comparator 2 can output a high/low level.

The circuit further comprises a rectifier bridge BR, two alternating current input ends of the rectifier bridge BR are respectively connected with a live wire VL and a zero wire VN of a power grid, the positive output end of the rectifier bridge BR is connected with a VBUS interface, the negative output end of the rectifier bridge BR is grounded, and the VBUS interface is connected with a capacitor C2. The circuit is connected with a switch S1, a parasitic capacitor C1 is arranged in the switch S1, and a parasitic capacitor C1 is connected with the switch S1 in parallel. Live line VL is connected to the ac input of rectifier bridge BR through switch S1.

And judging whether the power grid normally supplies power according to the high/low level output by the output end of the comparator 2. When the power grid is normally powered and the switch S1 is in a closed state, the input ac voltage passes through the resistor R1 and then is input to the positive input terminal of the comparator 2, and the negative input terminal of the comparator 2 is an internal reference. The input voltage of the comparator 2 is clamped to the highest internal voltage by a clamping diode 3 to ensure that the comparator 2 is not damaged by high voltage. In this state, the voltage at the positive input terminal of the comparator 2 is higher than that at the negative input terminal, so that the comparator 2 outputs a high level to determine that the power grid is normally supplied.

When the grid is normally powered and the switch S1 is in the off state, the parasitic capacitor C1 connected in parallel with the switch S1 is equivalent to a large resistor to the ac voltage of the grid, and the ac voltage of the grid can be coupled to one end of the resistor R1 through the parasitic capacitor C1 and input to the positive input terminal of the comparator 2 through the resistor R1 (the resistor R2 is much larger than the resistor R1). The voltage at the positive input terminal of the comparator 2 is the ac voltage coupled by the parasitic capacitor C1. In this state, the voltage at the positive input terminal of the comparator 2 is higher than that at the negative input terminal, so that the comparator 2 outputs a high level to determine that the power grid is normally supplied.

When the power grid stops supplying power, the power grid is in a power-off state, and the voltages of the live wire VL and the zero wire VN are in a direct-current state no matter whether the switch S1 is opened or closed. The positive input terminal of the comparator 2 is pulled down to a low level by the resistor R1, so the comparator 2 outputs a low level, and it is determined that the power grid is cut off.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. An alternating current detection circuit using a switch leakage, comprising: the leakage detection module is connected to a power grid through a live wire VL, the power grid is connected with a switch S1, and a parasitic capacitor C1 is arranged inside the switch S1; the leakage detection module comprises a resistor R1, a resistor R2, a comparator and a clamping diode, wherein the positive input end of the comparator is connected to the live wire VL through the resistor R1, the negative input end of the comparator is an internal reference, the clamping diode and the resistor R2 are connected between the resistor R1 and the positive input end of the comparator, and the output end of the comparator can output high/low levels.

2. An alternating current detection circuit using switch leakage according to claim 1, wherein the clamping diode and the resistor R2 are connected in parallel and grounded.

3. The alternating current detection circuit utilizing the switch leakage as claimed in claim 1, further comprising a rectifier bridge BR, wherein two alternating current input ends of the rectifier bridge BR are respectively connected with a live line VL and a neutral line VN of a power grid, an output positive end of the rectifier bridge BR is connected with a VBUS interface, an output negative end of the rectifier bridge BR is connected with a ground, and a capacitor C2 is connected at the VBUS interface.

4. An AC detection circuit using switch leakage as claimed in claim 3, wherein said live line VL is connected to the AC input of said rectifier bridge BR through a switch S1.

5. An AC detection circuit using switch leakage as claimed in claim 4, wherein said parasitic capacitor C1 is connected in parallel with said switch S1.