A triple protection device for power input

Abstract

The present invention provides a power input triple protection device, including an AC220V input power supply, a normally closed current switch, a manual start key, a reference voltage circuit, a current transformer, a comparison circuit, a control unit and a main switch circuit. The normally closed current switch and the manual start key are connected in parallel and then connected in series to the main line of the AC220V input power supply. The current transformer detects the current I on the main line of the AC220V input power supply. The AC220V input power supply outputs a reference voltage Vref after passing through the reference voltage circuit. The collected current I is compared with the reference voltage Vref through the comparison circuit and output to the control unit. The control unit outputs the voltage required by the main switch circuit. The device has leakage overcurrent electric shock protection, automatic power cut-off protection when there is no load after the electrical appliance is operated, and power output protection when power is not output in case of power outage and power restoration. It is suitable for various household appliances, outdoor mobile electronic equipment, various charging equipment, etc., and maximizes the protection of property safety.

Description

Technical Field

[0001] The invention relates to a power input triple protection device. Background Art

[0002] As diversified household appliances enter thousands of households, due to the lack of independent single-piece protection measures, appliances that are not disconnected from the power supply in time after use are left in a state of waiting for power and heating for a long time, causing frequent fires. This is particularly prominent during the charging process of electric vehicles. After the charging process is completed, the power supply is not cut off in time, and the charger repeatedly runs and heats up, causing fires, causing great losses to people's lives and property, and even harming neighbors. Summary of the invention

[0003] The technical problem to be solved by the present invention is: in order to overcome the deficiencies in the prior art, the present invention provides a power input triple protection device.

[0004] The technical solution to be adopted by the present invention to solve its technical problems is: a power input triple protection device, including an AC220V input power supply, a normally closed current switch, a manual start button, a reference voltage circuit, and a current transformer. Preferably, the current transformer adopts a current Hall sensor, a comparison circuit, a control unit and a main switch circuit. The normally closed current switch and the manual start button are connected in parallel and then in series on the main line of the AC220V input power supply. The current transformer detects the current I on the main line of the AC220V input power supply. The AC220V input power supply outputs a reference voltage Vref after passing through the reference voltage circuit. The collected current I is compared with the reference voltage Vref through the comparison circuit, and the comparison result is output to the control unit, and the control unit outputs the voltage required by the main switch circuit.

[0005] Specifically, the comparison circuit includes adjustable resistors RW1 and RW2, operational amplifiers U1 and U2, resistors R3, R4, R5, R6, R7, R8 and R9. The current I detected by the current transformer is divided into two paths through the rectifier bridge U3. One path is divided by the adjustable resistor RW1 and the resistor R4, and the common lead end of the adjustable resistor RW1 and the resistor R4 is connected to the positive input terminal of the operational amplifier U1. The other path is divided by the adjustable resistor RW2 and the resistor R5, and the common lead end of the adjustable resistor RW2 and the resistor R5 is connected to the positive input terminal of the operational amplifier U2. The reference voltage Vref is connected to the reverse input terminals of the operational amplifiers U1 and U2 after passing through resistors R8 and R7 respectively. The adjustable resistor RW1 is used to adjust the lowest current, and the adjustable resistor RW2 is used to adjust the highest current.

[0006] Specifically, the comparison circuit further includes diodes D5 and D6, wherein the diode D5 is connected in series with the output end of the operational amplifier U1 in reverse direction, and the diode D6 is connected in series with the output end of the operational amplifier U2 in reverse direction. The diode D5 is used to implement no-current protection, and the diode D6 is used to implement overvoltage protection.

[0007] Specifically, the reference voltage circuit includes a transformer PT, a rectifier bridge U4, a voltage-stabilizing power supply chip U5, and voltage-dividing resistors R12 and R13. The AC220V input power supply is connected to the transformer PT and the rectifier bridge U4 in sequence. The power signal after voltage reduction by the transformer PT and rectification by the rectifier bridge U4 is connected to the input end of the voltage-stabilizing power supply chip U5. The output end of the voltage-stabilizing power supply chip U5 outputs the power supply voltage VCC. The voltage-dividing resistors R12 and R13 are connected in series between the power supply voltage VCC and the ground GND, and the common lead end of the voltage-dividing resistors R12 and R13 outputs the reference voltage Vref.

[0008] Specifically, the main switch circuit includes a resistor R11, a main switch Q1 and a current excitation coil KA. The main switch Q1 adopts a field effect transistor. The output ends of the operational amplifiers U1 and U2 are connected to the gate of the field effect transistor Q1 through the resistor R11. The current excitation coil KA is connected in series between the power supply voltage VCC and the drain of the field effect transistor Q1, and the diode D7 is reversely connected in parallel at both ends of the current excitation coil KA. The source of the field effect transistor Q1 is grounded GND.

[0009] The beneficial effects of the present invention are as follows: the present invention provides a triple protection device for power input, which has leakage and overcurrent electric shock protection, automatic power cut-off protection when there is no load after the electrical appliance is operated, and no power output protection when there is a power outage or power restoration. The device is suitable for various household appliances, outdoor mobile electronic equipment, various charging equipment, etc., and can maximize the protection of property safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0011] Figure 1 It is a schematic diagram of the principle of the best embodiment of the present invention.

[0012] Figure 2 It is a schematic diagram of the working principle of the present invention. DETAILED DESCRIPTION

[0013] The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present invention in a schematic manner, and therefore only shows the components related to the present invention.

[0014] like Figure 1As shown, a power input triple protection device of the present invention includes an AC220V input power supply, a normally closed current switch, a manual start key, a reference voltage circuit, a current transformer L, a comparison circuit, a control unit and a main switch circuit. The normally closed current switch and the manual start key are connected in parallel and then connected in series to the main line of the AC220V input power supply. The current transformer detects the current I on the main line of the AC220V input power supply. The AC220V input power supply outputs a reference voltage Vref after passing through the reference voltage circuit. The collected current I is compared with the reference voltage Vref through the comparison circuit, and the comparison result is output to the control unit, and the control unit outputs the voltage required by the main switch circuit. The current transformer L preferably adopts a current Hall sensor of model NC150, and the main control chip of the main control board of the control unit adopts TLP358H.

[0015] like Figure 2 As shown in the figure, the normally closed current switch KB and the manual start key KW are connected in parallel and then in series on the AC220V main power supply line. In the figure, KN is the excitation coil of the manual start key KW. The resistor R1 is connected in parallel to the output end of the current transformer to prevent the current transformer from being open when the line fails, so that a very high voltage is generated in the current transformer L, causing internal insulation breakdown. The output current of the current transformer L is rectified by the rectifier bridge U3, and the resistor R2 and the capacitor C1 are connected in parallel at the output end of the rectifier bridge U3 to play a current limiting protection role.

[0016] The comparison circuit includes adjustable resistors RW1 and RW2, operational amplifiers U1 and U2, resistors R3, R4, R5, R6, R7, R8 and R9. The current I detected by the current transformer is divided into two paths through the rectifier bridge U3. One path is divided by the adjustable resistor RW1 and the resistor R4, and the common lead end of the adjustable resistor RW1 and the resistor R4 is connected to the positive input end of the operational amplifier U1. The other path is divided by the adjustable resistor RW2 and the resistor R5, and the common lead end of the adjustable resistor RW2 and the resistor R5 is connected to the positive input end of the operational amplifier U2. The reference voltage Vref is connected to the reverse input ends of the operational amplifiers U1 and U2 after passing through resistors R8 and R7 respectively. The adjustable resistor RW1 is used to adjust the lowest current, and the adjustable resistor RW2 is used to adjust the highest current.

[0017] Specifically, the comparison circuit further includes diodes D5 and D6, wherein the diode D5 is connected in series with the output end of the operational amplifier U1 in reverse direction, and the diode D6 is connected in series with the output end of the operational amplifier U2 in reverse direction. The diode D5 is used to implement no-current protection, and the diode D6 is used to implement overvoltage protection.

[0018] Specifically, the reference voltage circuit includes a transformer PT, a rectifier bridge U4, a voltage-stabilized power supply chip U5, and voltage-dividing resistors R12 and R13. The AC220V input power supply is connected to the transformer PT and the rectifier bridge U4 in sequence. The power signal after voltage reduction by the transformer PT and rectification by the rectifier bridge U4 is connected to the input end of the voltage-stabilized power supply chip U5. The output end of the voltage-stabilized power supply chip U5 outputs the power supply voltage VCC. The voltage-dividing resistors R12 and R13 are connected in series between the power supply voltage VCC and the ground GND, and the common lead-out end of the voltage-dividing resistors R12 and R13 outputs the reference voltage Vref. In this embodiment, the voltage-stabilized power supply chip U5 adopts 74LS7812, the output power supply voltage VCC is 12V, and the output voltage of the transformer PT is 15V.

[0019] Specifically, the main switch circuit includes a resistor R11, a main switch Q1 and a current excitation coil KA. The main switch Q1 adopts a field effect transistor. The output ends of the operational amplifiers U1 and U2 are connected to the gate of the field effect transistor Q1 through the resistor R11. The current excitation coil KA is connected in series between the power supply voltage VCC and the drain of the field effect transistor Q1, and the diode D7 is reversely connected in parallel at both ends of the current excitation coil KA. The source of the field effect transistor Q1 is grounded GND.

[0020] Working principle:

[0021] Connect the power supply AC220V, start the manual start button KA, power output, current detection component current transformer L, the main control board of the control unit enters the working state, the main control board outputs the voltage required for the excitation coil KA of the main switch Q1, the main switch Q1 is closed, and the connected electrical equipment can start to run. The main control board receives the signal output by the current detection component, and keeps the main switch Q1 closed according to the set maximum current value and minimum current value. If the maximum current value is exceeded or lower than the minimum current value, the main control board stops the excitation coil KA voltage output, and the main switch Q1 is disconnected, thereby playing the role of leakage protection and automatic disconnection after the electrical equipment ends. If you need to re-run the power output, you need to manually start the manual start button KA.

[0022] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the scope of the present invention through the above description. The technical scope of this invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A power input triple protection device, characterized in that: It includes an AC220V input power supply, a normally open current switch, a manual start key, a reference voltage circuit, a current transformer, a comparison circuit, a control unit and a main switch circuit. The normally open current switch and the manual start key are connected in parallel and then in series on the main line of the AC220V input power supply. The current transformer detects the current I on the main line of the AC220V input power supply. The AC220V input power supply outputs a reference voltage Vref after passing through the reference voltage circuit. The collected current I is compared with the reference voltage Vref through the comparison circuit, and the comparison result is output to the control unit. The control unit outputs the voltage required by the main switch circuit. The comparison circuit includes adjustable resistors RW1 and RW2, operational amplifiers U1 and U2, resistors R3, R4, R5, R6, R7, R8 and R9. The current I detected by the current transformer is divided into two paths through the rectifier bridge U3. One path is divided by the adjustable resistor RW1 and the resistor R4, and the common lead end of the adjustable resistor RW1 and the resistor R4 is connected to the positive input terminal of the operational amplifier U1. The other path is divided by the adjustable resistor RW2 and the resistor R5, and the common lead end of the adjustable resistor RW2 and the resistor R5 is connected to the positive input terminal of the operational amplifier U2. The reference voltage Vref is connected to the reverse input terminals of the operational amplifiers U1 and U2 after passing through the resistors R8 and R7 respectively. The main switch circuit includes a resistor R11, a main switch Q1 and an excitation coil KA. The main switch Q1 adopts a field effect transistor. The output ends of the operational amplifiers U1 and U2 are connected to the gate of the field effect transistor Q1 through the resistor R11. The excitation coil KA is connected in series between the power supply voltage VCC and the drain of the field effect transistor Q1, and the diode D7 is reversely connected in parallel at both ends of the excitation coil KA. The source of the field effect transistor Q1 is grounded GND.

2. The power input triple protection device according to claim 1, characterized in that: The comparison circuit further includes diodes D5 and D6. The diode D5 is connected in series with the output end of the operational amplifier U1 in reverse direction, and the diode D6 is connected in series with the output end of the operational amplifier U2 in reverse direction.

3. The power input triple protection device according to claim 1, characterized in that: The reference voltage circuit includes a transformer PT, a rectifier bridge U4, a voltage-stabilizing power supply chip U5, and voltage-dividing resistors R12 and R13. The AC220V input power supply is connected to the transformer PT and the rectifier bridge U4 in sequence. The power signal after voltage reduction by the transformer PT and rectification by the rectifier bridge U4 is connected to the input end of the voltage-stabilizing power supply chip U5. The output end of the voltage-stabilizing power supply chip U5 outputs the power supply voltage VCC. The voltage-dividing resistors R12 and R13 are connected in series between the power supply voltage VCC and the ground GND, and the common lead end of the voltage-dividing resistors R12 and R13 outputs the reference voltage Vref.

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