Split electrical appliance anti-electric shock protection circuit

Abstract

The present invention provides a split type electrical appliance anti-electric shock protection circuit, comprising: a microprocessor U1, an NPN transistor Q3, a PNP transistor Q4, an NPN transistor Q5, an NPN transistor Q6, a PNP transistor Q7, an NPN transistor Q8, a PNP transistor Q9, an NMOS transistor Q10, a relay K1, resistors R11, R13, R14, R17, R19, R20, R21, R22, R23, R24, R25, R27, a diode D3, and a load connector P5; a current detection circuit is provided between the source and the ground of the NMOS transistor Q10; and the current detection circuit feeds back the detected current signal to the microprocessor U1. The present invention can automatically determine whether a load is connected, cut off the output when there is no load, and output the voltage supplied to the load when there is a load, thereby realizing the anti-electric shock protection function.

Description

Technical Field

[0001] The invention relates to a protection circuit, in particular to an anti-electric shock protection circuit. Background Art

[0002] At present, when split-type electrical appliances (such as steam mops, etc.) are powered on, the load and the appliance are disconnected and the load is directly replaced. The high-voltage output port of the appliance is exposed, posing a risk of electric shock. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a split-type electrical appliance anti-electric shock protection circuit, which can detect whether the load is connected, cut off the output when there is no load, and output the voltage to supply the load only when there is a load, making the split-type electrical appliance safer to use. The technical solution adopted by the present invention is:

[0004] A split type electrical appliance anti-electric shock protection circuit, comprising:

[0005] Microprocessor U1, NPN transistor Q3, PNP transistor Q4, NPN transistor Q5, NPN transistor Q6, PNP transistor Q7, NPN transistor Q8, PNP transistor Q9, NMOS transistor Q10, relay K1, resistors R11, R13, R14, R17, R19, R20, R21, R22, R23, R24, R25, R27, diode D3, load connector P5;

[0006] One end of the resistor R21 is connected to a corresponding I / O output port of the microprocessor U1, and the other end of the resistor R21 is connected to the base of the transistor Q6, one end of the resistor R20, the base of the transistor Q8 and one end of the resistor R24; the emitter of the transistor Q6 and the other end of the resistor R20 are grounded, and the emitter of the transistor Q8 and the other end of the resistor R24 ​​are grounded; the collector of the transistor Q6 is connected to one end of the resistor R14, and the other end of the resistor R14 is connected to one end of the resistor R13 and the base of the transistor Q4, and the other end of the resistor R13 is connected to the emitter of the transistor Q4. Positive voltage VCC1; the collector of transistor Q4 is connected to the anode of diode D3; the cathode of diode D3 is connected to one end of load connector P5; the collector of transistor Q8 is connected to one end of resistor R19, and the other end of resistor R19 is connected to the base of transistor Q7; the emitter of transistor Q7 is connected to one end of resistor R17, and the other end of resistor R17 is connected to the other end of load connector P5; the collector of transistor Q7 is connected to one end of resistor R25 and grounded through resistor R27, and the other end of resistor R25 is connected to a corresponding I / O input port of microprocessor U1;

[0007] One end of the resistor R11 is connected to a corresponding I / O output port of the microprocessor U1, and the other end of the resistor R11 is connected to the base of the transistor Q3, and the emitter of the transistor Q3 is grounded; the collector of the transistor Q3 is connected to one end of the coil of the relay K1, and the other end of the coil of the relay K1 is connected to the positive voltage VCC1; one end of the normally open contact of the relay K1 is connected to the voltage input end; the voltage input end is used to input the voltage Vin supplied to the load; the other end of the normally open contact of the relay K1 is connected to the other end of the load connector P5;

[0008] One end of the resistor R22 is connected to a corresponding I / O output port of the microprocessor U1, and the other end of the resistor R22 is connected to the bases of the transistors Q5 and Q9, the collector of the transistor Q5 is connected to the positive voltage VCC2, and the collector of the transistor Q9 is grounded; the emitters of the transistors Q5 and Q9 are connected to one end of the resistor R23, and the other end of the resistor R23 is connected to the gate of the NMOS transistor Q10, and the drain of the NMOS transistor Q10 is connected to the other end of the load connector P5; a current detection circuit is provided between the source of the NMOS transistor Q10 and the ground; the current detection circuit feeds back the detected current signal to the microprocessor U1.

[0009] Furthermore, the current detection circuit includes resistors RS1, R26, R37, and capacitor C9; one end of the resistor RS1 is grounded, and the other end is connected to the source of the NMOS tube Q10 and one end of the resistor R26; the other end of the resistor R26 is connected to one end of the resistor R37, one end of the capacitor C9, and a corresponding sampling port of the microprocessor U1; the other end of the resistor R37 and the other end of the capacitor C9 are grounded.

[0010] Furthermore, the split-type electrical appliance anti-electric shock protection circuit further includes a capacitor C6, a resistor R16, and a diode D4;

[0011] The cathode of capacitor C6 and diode D4 are connected to one end of load connector P5, the other end of capacitor C6 is connected to one end of resistor R16, and the other end of resistor R16 and anode of diode D4 are connected to the other end of load connector P5.

[0012] Furthermore, the other end of the resistor R25 is also connected to the cathode of the Zener diode ZD1 , and the anode of the Zener diode ZD1 is grounded.

[0013] Furthermore, a filter capacitor is connected between the voltage input terminal and the ground.

[0014] The advantages of the present invention are:

[0015] 1) It can automatically determine whether the load is connected. When there is no load, the output is cut off. When there is a load, the voltage to supply the load is output to achieve the anti-electric shock protection function.

[0016] 2) Circuit components are all commonly used devices with low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the electrical principle diagram of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0019] like Figure 1 As shown, the present invention provides a split-type electrical appliance anti-electric shock protection circuit, comprising:

[0020] Microprocessor U1, NPN transistor Q3, PNP transistor Q4, NPN transistor Q5, NPN transistor Q6, PNP transistor Q7, NPN transistor Q8, PNP transistor Q9, NMOS transistor Q10, relay K1, resistors R11, R13, R14, R17, R19, R20, R21, R22, R23, R24, R25, R27, diode D3, load connector P5;

[0021] One end of the resistor R21 is connected to a corresponding I / O output port of the microprocessor U1 (pin 13 of U1 in this example), and the other end of the resistor R21 is connected to the base of the transistor Q6, one end of the resistor R20, the base of the transistor Q8 and one end of the resistor R24; the emitter of the transistor Q6 and the other end of the resistor R20 are grounded, and the emitter of the transistor Q8 and the other end of the resistor R24 ​​are grounded; the collector of the transistor Q6 is connected to one end of the resistor R14, and the other end of the resistor R14 is connected to one end of the resistor R13 and the base of the transistor Q4, and the other end of the resistor R13 is connected to the emitter of the transistor Q4. Positive voltage VCC1; the collector of transistor Q4 is connected to the anode of diode D3; the cathode of diode D3 is connected to one end of load connector P5; the collector of transistor Q8 is connected to one end of resistor R19, and the other end of resistor R19 is connected to the base of transistor Q7; the emitter of transistor Q7 is connected to one end of resistor R17, and the other end of resistor R17 is connected to the other end of load connector P5; the collector of transistor Q7 is connected to one end of resistor R25 and grounded through resistor R27, and the other end of resistor R25 is connected to a corresponding I / O input port of microprocessor U1 (pin 12 of U1 in this case);

[0022] In this embodiment, the positive voltage VCC1 is +5v;

[0023] One end of the resistor R11 is connected to a corresponding I / O output port of the microprocessor U1 (pin 10 of U1 in this example), and the other end of the resistor R11 is connected to the base of the transistor Q3, and the emitter of the transistor Q3 is grounded; the collector of the transistor Q3 is connected to one end of the coil of the relay K1, and the other end of the coil of the relay K1 is connected to the positive voltage VCC1; one end of the normally open contact of the relay K1 is connected to the voltage input end; the voltage input end is used to input the voltage Vin supplied to the load; the other end of the normally open contact of the relay K1 is connected to the other end of the load connector P5;

[0024] When the load is a motor, the split-type electrical appliance anti-electric shock protection circuit also includes a capacitor C6, a resistor R16, and a diode D4; the cathode of the capacitor C6 and the diode D4 are connected to one end of the load connector P5, the other end of the capacitor C6 is connected to one end of the resistor R16, and the other end of the resistor R16 and the anode of the diode D4 are connected to the other end of the load connector P5; this part of the circuit can protect the inductive load;

[0025] One end of the resistor R22 is connected to a corresponding I / O output port of the microprocessor U1 (pin 11 of U1 in this example), and the other end of the resistor R22 is connected to the bases of transistors Q5 and Q9, the collector of transistor Q5 is connected to the positive voltage VCC2, and the collector of transistor Q9 is grounded; the emitters of transistors Q5 and Q9 are connected to one end of the resistor R23, and the other end of the resistor R23 is connected to the gate of the NMOS transistor Q10, and the drain of the NMOS transistor Q10 is connected to the other end of the load connector P5; a current detection circuit 100 is provided between the source of the NMOS transistor Q10 and the ground;

[0026] In this embodiment, the positive voltage VCC2 is +12v;

[0027] The current detection circuit 100 includes resistors RS1, R26, R37, and capacitor C9; one end of the resistor RS1 is grounded, and the other end is connected to the source of the NMOS tube Q10 and one end of the resistor R26; the other end of the resistor R26 is connected to one end of the resistor R37, one end of the capacitor C9, and a corresponding sampling port of the microprocessor U1 (pin 9 of U1 in this example); the other end of the resistor R37 and the other end of the capacitor C9 are grounded;

[0028] In some preferred embodiments, the other end of the resistor R25 is also connected to the cathode of the voltage zener diode ZD1, and the anode of the voltage zener diode ZD1 is grounded, which can protect the corresponding I / O input port of the microprocessor U1 (pin 12 of U1 in this example);

[0029] In some preferred embodiments, filter capacitors C7 and C8 are also connected between the voltage input terminal and the ground;

[0030] Microprocessor U1 sampling microcontroller;

[0031] When the power is turned on, the 10th pin of the microprocessor U1 outputs a low level by default, the relay K1 is de-energized, and its normally open contact is disconnected; thus, the power supply to the load connector P5 is cut off;

[0032] Then the microprocessor U1 pin 13 outputs a high level. Figure 1 The signal S01 is high level, Q4, Q6 are turned on, and Q7, Q8 are turned on. If the load connector P5 is connected to a load, then Figure 1The signal S02 at the right end of the middle resistor R25 is high level, and the microprocessor U1 detects the high level signal at the 13th pin. If the load connector P5 is not connected to the load at this time, the microprocessor U1 detects the low level signal at the 13th pin, thereby realizing the detection of whether the load is connected;

[0033] When it is confirmed that the load is detected, the 13th pin of the microprocessor U1 outputs a low level, turning off the detection-related circuit. Then the 10th pin of the microprocessor U1 outputs a high level, and the 11th pin outputs a high level. Figure 1 In the middle, signals S03 and S04 are both high, the normally open contact of relay K1 is closed, Q10 is turned on, and the voltage Vin is applied to the load;

[0034] The current sampling circuit 100 works and feeds back a signal S05 to the microprocessor U1. When the voltage detected by the 9th pin of the microprocessor U1 is lower than the set threshold, it indicates that the load has been unplugged from the load connector P5. The 10th pin of the microprocessor U1 outputs a low level, the relay K1 is de-energized, and its normally open contact is disconnected, cutting off the power supply to the load connector P5.

[0035] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A split-type electrical appliance anti-electric shock protection circuit, characterized in that: include: Microprocessor U1, NPN transistor Q3, PNP transistor Q4, NPN transistor Q5, NPN transistor Q6, PNP transistor Q7, NPN transistor Q8, PNP transistor Q9, NMOS transistor Q10, relay K1, resistors R11, R13, R14, R17, R19, R20, R21, R22, R23, R24, R25, R27, diode D3, load connector P5; One end of the resistor R21 is connected to a corresponding I / O output port of the microprocessor U1, and the other end of the resistor R21 is connected to the base of the transistor Q6, one end of the resistor R20, the base of the transistor Q8 and one end of the resistor R24; the emitter of the transistor Q6 and the other end of the resistor R20 are grounded, and the emitter of the transistor Q8 and the other end of the resistor R24 ​​are grounded; the collector of the transistor Q6 is connected to one end of the resistor R14, and the other end of the resistor R14 is connected to one end of the resistor R13 and the base of the transistor Q4, and the other end of the resistor R13 is connected to the emitter of the transistor Q4. Positive voltage VCC1; the collector of transistor Q4 is connected to the anode of diode D3; the cathode of diode D3 is connected to one end of load connector P5; the collector of transistor Q8 is connected to one end of resistor R19, and the other end of resistor R19 is connected to the base of transistor Q7; the emitter of transistor Q7 is connected to one end of resistor R17, and the other end of resistor R17 is connected to the other end of load connector P5; the collector of transistor Q7 is connected to one end of resistor R25 and grounded through resistor R27, and the other end of resistor R25 is connected to a corresponding I / O input port of microprocessor U1; One end of the resistor R11 is connected to a corresponding I / O output port of the microprocessor U1, and the other end of the resistor R11 is connected to the base of the transistor Q3, and the emitter of the transistor Q3 is grounded; the collector of the transistor Q3 is connected to one end of the coil of the relay K1, and the other end of the coil of the relay K1 is connected to the positive voltage VCC1; one end of the normally open contact of the relay K1 is connected to the voltage input end; the voltage input end is used to input the voltage Vin supplied to the load; the other end of the normally open contact of the relay K1 is connected to the other end of the load connector P5; One end of the resistor R22 is connected to a corresponding I / O output port of the microprocessor U1, and the other end of the resistor R22 is connected to the bases of the transistors Q5 and Q9, the collector of the transistor Q5 is connected to the positive voltage VCC2, and the collector of the transistor Q9 is grounded; the emitters of the transistors Q5 and Q9 are connected to one end of the resistor R23, and the other end of the resistor R23 is connected to the gate of the NMOS transistor Q10, and the drain of the NMOS transistor Q10 is connected to the other end of the load connector P5; a current detection circuit is provided between the source of the NMOS transistor Q10 and the ground; the current detection circuit feeds back the detected current signal to the microprocessor U1.

2. The split-type electrical appliance anti-electric shock protection circuit as claimed in claim 1, characterized in that: The current detection circuit includes resistors RS1, R26, R37, and capacitor C9; one end of the resistor RS1 is grounded, and the other end is connected to the source of the NMOS tube Q10 and one end of the resistor R26; the other end of the resistor R26 is connected to one end of the resistor R37, one end of the capacitor C9, and a corresponding sampling port of the microprocessor U1; the other end of the resistor R37 and the other end of the capacitor C9 are grounded.

3. The split-type electrical appliance anti-electric shock protection circuit according to claim 1 or 2, characterized in that: It also includes capacitor C6, resistor R16, and diode D4; The cathode of capacitor C6 and diode D4 are connected to one end of load connector P5, the other end of capacitor C6 is connected to one end of resistor R16, and the other end of resistor R16 and anode of diode D4 are connected to the other end of load connector P5.

4. The split-type electrical appliance anti-electric shock protection circuit according to claim 1 or 2, characterized in that: The other end of the resistor R25 is also connected to the cathode of the Zener diode ZD1, and the anode of the Zener diode ZD1 is grounded.

5. The split-type electrical appliance anti-electric shock protection circuit according to claim 1 or 2, characterized in that: A filter capacitor is also connected between the voltage input terminal and the ground.

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