Electromagnetic valve driving circuit for flameout protection of gas stove
By employing a combination design of two sets of switching transistors and isolation chips in the solenoid valve drive circuit of the gas stove, along with a detection circuit, the safety hazards of the solenoid valve drive circuit when key components fail are resolved, thus ensuring the safe and reliable use of the gas stove.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-29
- Publication Date
- 2026-03-27
AI Technical Summary
The existing gas stove's solenoid valve drive circuit has difficulty cutting off the gas supply in time when key components fail, posing a safety hazard. Furthermore, the controller is susceptible to damage from high voltage or high current, causing the flameout protection system to malfunction.
The design employs a combination of two sets of switching transistors and two sets of isolation chips, which are connected to the controller through different wiring methods. An additional detection circuit monitors the status of the switching transistors, ensuring that the other switching transistor can safely cut off the power supply to the gas solenoid valve when one switching transistor fails, and preventing output loss of control when the controller fails.
It improves the safety and reliability of the solenoid valve drive circuit, prevents the gas solenoid valve from opening abnormally, ensures the safe use of the gas stove, and promptly detects and handles switch tube faults to avoid controller damage.
Smart Images
Figure CN224050422U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to gas -cooker technical field relates to a gas -cooker flame -out protection solenoid valve drive circuit. BACKGROUND
[0002] In daily life, gas stove is indispensable cooking equipment in the family kitchen. However, its use process has many security risks, for example: when the gas stove encounters accidental flameout, such as strong wind straight blow, cooking soup spills to pour out the flame, or ignition link failure, etc., if the gas supply cannot be cut off in time, the leaked gas is easy to accumulate in the air, once meets the open fire, instantaneously causes explosion or fire, brings catastrophic consequences to the family.
[0003] At present, the mainstream accidental flameout protection means of the market gas stove mainly has two kinds: thermocouple type flameout protection and ion induction type flameout protection. These two kinds of flameout protection means can all send control signal to control solenoid valve to close gas valve when detecting that the flame is extinguished, but the current solenoid valve drive circuit control structure is single, once the key component fails, it is difficult to realize cutting off the gas supply in time, and there is a big security risk. Moreover, these circuits and controllers lack effective isolation measures, when the switching element fails, high voltage or large current may flow into the controller circuit, causing the controller to burn out, and then making the whole flameout protection system malfunction. From this point of view, the current solenoid valve drive circuit has the problem of low safety and reliability. SUMMARY
[0004] The utility model aims at the above -mentioned problem existing in prior art, proposes a kind of solenoid valve drive circuit of gas stove flameout protection, and the technical problems it wants to solve are: how to improve the safety and reliability of solenoid valve drive circuit.
[0005] The utility model discloses a gas -cooker flame -out protection's electromagnetic valve drive circuit can be realized through the following technical scheme: a gas -cooker flame -out protection's electromagnetic valve drive circuit, including power supply VCC, the gas electromagnetic valve for cutting off gas supply and the controller for sending off the control instruction of cutting off gas according to the flame extinguishing signal received, this electromagnetic valve drive circuit still includes switch tube Q1, switch tube Q2, isolation chip U2 and isolation chip U3, the 1 foot of switch tube Q1 is connected with power supply VCC through the gas electromagnetic valve, the 2 foot of switch tube Q1 is connected with the 3 foot of isolation chip U2 through resistance R5, the 4 foot of isolation chip U2 is connected positive voltage, the 1 foot of isolation chip U2 is connected with the output end of controller through resistance R19, the 2 foot of isolation chip U2 is grounded, the 1 foot of switch tube Q2 is connected with the 3 foot of switch tube Q1, the 1 foot of switch tube Q2 is also connected with power supply VCC through resistance R66, the 2 foot of switch tube Q2 is connected with the 4 foot of isolation chip U3 through resistance R6, the 3 foot of switch tube Q2 is grounded, the 3 foot of isolation chip U3 is connected negative voltage, the 1 foot of isolation chip U3 is connected another positive voltage, the 2 foot of isolation chip U3 is connected with the output end of controller through resistance R17.
[0006] The gas -cooker flame -out protection's electromagnetic valve drive circuit adopts two groups of switch tubes and two groups of isolation chips to control the disconnection and conduction of the gas electromagnetic valve, can have another switch tube to safely cut off the power supply VCC of the gas electromagnetic valve when one switch tube fails, two groups of switch tubes and two groups of isolation chips are connected with the controller in different wiring modes, when controlling, the two output ends of the controller send different level signals to control the corresponding isolation chips and switch tubes to conduct simultaneously or cut off simultaneously, prevent the controller from being dead or burning out all high level signals or all low level signals due to the controller fault, cause the output to be out of control, the electromagnetic valve is abnormally opened, effectively improve the safety and reliability of the electromagnetic valve drive circuit.
[0007] In the above-mentioned gas -cooker flame -out protection's electromagnetic valve drive circuit, the electromagnetic valve drive circuit still includes the first detection circuit for detecting the switch condition of switch tube Q1 and the second detection circuit for detecting the switch condition of switch tube Q2, one end of the first detection circuit is connected with the 1 foot of switch tube Q1, one end of the second detection circuit is connected with the 1 foot of switch tube Q2, the other end of the first detection circuit and the other end of the second detection circuit are connected with the input end of the controller. Through the setting of the first detection circuit and the second detection circuit, the switch tube can be found in time when the switch tube fails, improve the safety and reliability of the circuit.
[0008] In the electromagnetic valve drive circuit for gas stove flameout protection, the first detection circuit comprises the resistor R9, the resistor R10 and the voltage stabilizing tube U7, one end of the resistor R9 is connected with the pin 1 of the switch tube Q1 through the resistor R10, one end of the resistor R9 is connected with the negative electrode of the voltage stabilizing tube U7, the other end of the resistor R9 is connected with the positive electrode of the voltage stabilizing tube U7, and the negative electrode of the voltage stabilizing tube U7 is connected with the input end of the controller. The first detection circuit detects the state of the switch tube Q1 through voltage division by the resistor and the characteristics of the voltage stabilizing tube, and the circuit structure is simple, low in cost and easy to realize. When the switch tube Q1 fails to be turned on or is continuously turned on, the first detection circuit outputs a signal different from the normal state, so that the controller can timely perceive and take corresponding measures, such as alarm.
[0009] In the electromagnetic valve drive circuit for gas stove flameout protection, the second detection circuit comprises the resistor R12, the resistor R11 and the voltage stabilizing tube U8, one end of the resistor R12 is connected with the pin 1 of the switch tube Q1 through the resistor R11, one end of the resistor R12 is connected with the negative electrode of the voltage stabilizing tube U8, the other end of the resistor R12 is connected with the positive electrode of the voltage stabilizing tube U8, and the negative electrode of the voltage stabilizing tube U8 is connected with the input end of the controller. When the switch tube Q2 fails to be turned on or is continuously turned on, the second detection circuit outputs a signal different from the normal state, so that the controller can timely perceive and take corresponding measures, such as alarm, and the staff can timely replace the components, thereby improving the safety and reliability of the electromagnetic valve drive circuit.
[0010] In the electromagnetic valve drive circuit for gas stove flameout protection, the electromagnetic valve drive circuit further comprises the switch tube Q3 and the isolation chip U4, the pin 1 of the switch tube Q3 is connected with the pin 3 of the switch tube Q2, the pin 1 of the switch tube Q3 is further connected with the power supply VCC through the resistor R67, the pin 2 of the switch tube Q3 is connected with the pin 3 of the isolation chip U4 through the resistor R7, the pin 4 of the isolation chip U4 is connected with the positive voltage, the pin 1 of the isolation chip U4 is connected with the output end of the controller through the resistor R18, the pin 2 of the isolation chip U4 is grounded, and the resistor R47 is further connected between the pin 1 and the pin 2 of the isolation chip U4. The design of the switch tube Q3 and the isolation chip U4 can further improve the reliability of the control of the gas electromagnetic valve.
[0011] In the electromagnetic valve driving circuit for the gas stove flameout protection, the electromagnetic valve driving circuit further comprises a third detection circuit for detecting the switching condition of the switching tube Q3, the third detection circuit comprises the resistor R14, the resistor R13 and the voltage stabilizing tube U9, one end of the resistor R14 is connected with the pin 1 of the switching tube Q3 through the resistor R13, one end of the resistor R14 is connected with the negative electrode of the voltage stabilizing tube U9, the other end of the resistor R14 is connected with the positive electrode of the voltage stabilizing tube U9, and the negative electrode of the voltage stabilizing tube U9 is connected with the input end of the controller. Through the third detection circuit, the failure of the switching tube Q3 can be found in time, and the safety and reliability of the circuit are improved.
[0012] In the electromagnetic valve driving circuit for the gas stove flameout protection, the electromagnetic valve driving circuit further comprises the switching tube Q4 and the isolation chip U5, the pin 1 of the switching tube Q4 is connected with the pin 3 of the switching tube Q3, the pin 1 of the switching tube Q4 is further connected with the power supply VCC through the resistor R68, the pin 2 of the switching tube Q4 is connected with the pin 4 of the isolation chip U5 through the resistor R8, the pin 3 of the isolation chip U5 is connected with the negative voltage, the pin 1 of the isolation chip U5 is connected with the positive voltage, the pin 2 of the isolation chip U5 is connected with the output end of the controller through the resistor R20, and the resistor R48 is further connected between the pin 1 and the pin 2 of the isolation chip U5. The switching tube Q4 and the isolation chip U5 are added, and the reliability of the control of the gas electromagnetic valve is further improved.
[0013] In the electromagnetic valve driving circuit for the gas stove flameout protection, the electromagnetic valve driving circuit further comprises a fourth detection circuit for detecting the switching condition of the switching tube Q4, the fourth detection circuit comprises the resistor R15, the resistor R16 and the voltage stabilizing tube U10, one end of the resistor R15 is connected with the pin 1 of the switching tube Q4 through the resistor R16, one end of the resistor R15 is connected with the negative electrode of the voltage stabilizing tube U10, the other end of the resistor R15 is connected with the positive electrode of the voltage stabilizing tube U10, and the negative electrode of the voltage stabilizing tube U10 is connected with the input end of the controller. Through the fourth detection circuit, the failure of the switching tube Q4 can be found in time, and the safety and reliability of the circuit are further improved.
[0014] In the electromagnetic valve drive circuit for gas stove flameout protection, the electromagnetic valve drive circuit further comprises a resistor R64, a resistor R65, a capacitor C26 and a voltage stabilizing tube U33, the switch tube Q4 is connected with the ground through the resistor R64, the switch tube Q4 is connected with one end of the capacitor C26, the negative electrode of the voltage stabilizing tube U33 and the input end of the controller through the resistor R65, and the other end of the capacitor C26 and the positive electrode of the voltage stabilizing tube U33 are grounded.
[0015] In the electromagnetic valve drive circuit for gas stove flameout protection, the electromagnetic valve drive circuit further comprises a diode D4, the negative electrode of the diode D4 is connected with the power supply VCC, and the positive electrode of the diode D4 is connected with the pin 1 of the switch tube Q1.
[0016] Compared with the prior art, the electromagnetic valve drive circuit for gas stove flameout protection has the following advantages:
[0017] 1. The plurality of switch tubes are used for controlling the gas electromagnetic valve, so that when the switch tube fails, other effective switch tube can be used to realize safe cut-off of the power supply of the gas electromagnetic valve when abnormal flameout occurs, and the safety and reliability of the gas stove are ensured.
[0018] 2. The combination of the plurality of switch tubes and the isolation chip is connected with the controller in different wiring modes, so that the single-chip microcomputer death or the fault of burning all high-level or all low-level signals caused by the controller failure can be prevented, the situation that the gas electromagnetic valve is opened due to uncontrolled output can be effectively avoided, and the safety is further improved.
[0019] 3. The detection circuit is further arranged, the switching conditions of each switch tube are monitored, the fault condition of the switch tube can be detected in time, and measures are taken, so that the gas electromagnetic valve can be turned on or turned off more safely and reliably. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 It is a circuit structure schematic view of the utility model.
[0021] In the figure, 1, controller;2, gas electromagnetic valve;3, first detection circuit;4, second detection circuit;5, third detection circuit;6, fourth detection circuit. DETAILED DESCRIPTION
[0022] In order to make the purpose, technical scheme and advantages of the utility model more clear, the utility model implementation mode will be further described in combination with the drawings below. The following description of at least one exemplary embodiment is actually only illustrative, but never as any limitation on the utility model and its application or use. Based on the examples in the utility model, all other examples obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.
[0023] As Figure 1As shown, the electromagnetic valve driving circuit of the gas stove flameout protection includes a power supply VCC, a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, an isolation chip U2, an isolation chip U3, an isolation chip U4, an isolation chip U5, a diode D4, a gas electromagnetic valve 2 for cutting off the gas supply, and a controller 1 for issuing a gas cutting control instruction according to the received flameout signal. The 1 pin of the switch tube Q1 is connected with the power supply VCC through the gas electromagnetic valve 2, the negative electrode of the diode D4 is connected with the power supply VCC, the positive electrode of the diode D4 is connected with the 1 pin of the switch tube Q1, the 2 pin and the 3 pin of the switch tube Q1 are further connected with a resistor R1, the 2 pin of the switch tube Q1 is connected with the 3 pin of the isolation chip U2 through a resistor R5, the 4 pin of the isolation chip U2 is connected with a positive voltage, the 1 pin of the isolation chip U2 is connected with the output end of the controller 1 through a resistor R19, the 2 pin of the isolation chip U2 is grounded, and the 1 pin and the 2 pin of the isolation chip U2 are further connected with a resistor R50; the 1 pin of the switch tube Q2 is connected with the 3 pin of the switch tube Q1, the 1 pin of the switch tube Q2 is further connected with the power supply VCC through a resistor R66, the 1 pin and the 2 pin of the switch tube Q2 are further connected with a resistor R2, the 2 pin of the switch tube Q2 is connected with the 4 pin of the isolation chip U3 through a resistor R6, the 3 pin of the isolation chip U3 is connected with a negative voltage, the 1 pin of the isolation chip U3 is connected with another positive voltage, the 2 pin of the isolation chip U3 is connected with the output end of the controller 1 through a resistor R17, and the 1 pin and the 2 pin of the isolation chip U3 are further connected with a resistor R49; the 1 pin of the switch tube Q3 is connected with the 3 pin of the switch tube Q2, the 1 pin of the switch tube Q3 is further connected with the power supply VCC through a resistor R67, the 2 pin and the 3 pin of the switch tube Q3 are further connected with a resistor R3, the 2 pin of the switch tube Q3 is connected with the 3 pin of the isolation chip U4 through a resistor R7, the 4 pin of the isolation chip U4 is connected with a positive voltage, the 1 pin of the isolation chip U4 is connected with the output end of the controller 1 through a resistor R18, the 2 pin of the isolation chip U4 is grounded, and the 1 pin and the 2 pin of the isolation chip U4 are further connected with a resistor R47; the 1 pin of the switch tube Q4 is connected with the 3 pin of the switch tube Q3, the 1 pin of the switch tube Q4 is further connected with the power supply VCC through a resistor R68, the 1 pin and the 2 pin of the switch tube Q4 are further connected with a resistor R4, the 2 pin of the switch tube Q4 is connected with the 4 pin of the isolation chip U5 through a resistor R8, the 3 pin of the isolation chip U5 is connected with a negative voltage, the 1 pin of the isolation chip U5 is connected with a positive voltage, the 2 pin of the isolation chip U5 is connected with the output end of the controller 1 through a resistor R20, and the 1 pin and the 2 pin of the isolation chip U5 are further connected with a resistor R48.The switch tube Q4 is also connected with the resistance R64, the resistance R65, the capacitor C26 and the voltage stabilizing tube U33. The switch tube Q4 is connected with the ground through the resistance R64. The 3-pin of the switch tube Q4 is also connected with the resistance R65. The other end of the resistance R65 is also connected with one end of the capacitor C26, the negative pole of the voltage stabilizing tube U33 and the input end of the controller. The other end of the capacitor C26 and the positive pole of the voltage stabilizing tube U33 are grounded.
[0024] In the embodiment, the switch tube Q1 and the switch tube Q3 are N-channel field effect tubes. The switch tube Q2 and the switch tube Q4 are P-channel field effect tubes. The isolation chip U2, the isolation chip U3, the isolation chip U4 and the isolation chip U5 are all optical couplers. The controller 1 is a single-chip microcomputer.
[0025] In the embodiment, the electromagnetic valve driving circuit further comprises a first detection circuit 3 for detecting the switching state of the switch tube Q1, a second detection circuit 4 for detecting the switching state of the switch tube Q2, a third detection circuit 5 for detecting the switching state of the switch tube Q3 and a fourth detection circuit 6 for detecting the switching state of the switch tube Q4. The first detection circuit 3 comprises the resistance R9, the resistance R10 and the voltage stabilizing tube U7. One end of the resistance R9 is connected with the 1-pin of the switch tube Q1 through the resistance R10. One end of the resistance R9 is connected with the negative pole of the voltage stabilizing tube U7. The other end of the resistance R9 is connected with the positive pole of the voltage stabilizing tube U7. The negative pole of the voltage stabilizing tube U7 is connected with the input end of the controller 1. The second detection circuit 4 comprises the resistance R12, the resistance R11 and the voltage stabilizing tube U8. One end of the resistance R12 is connected with the 1-pin of the switch tube Q1 through the resistance R11. One end of the resistance R12 is connected with the negative pole of the voltage stabilizing tube U8. The other end of the resistance R12 is connected with the positive pole of the voltage stabilizing tube U8. The negative pole of the voltage stabilizing tube U8 is connected with the input end of the controller 1. The third detection circuit 5 comprises the resistance R14, the resistance R13 and the voltage stabilizing tube U9. One end of the resistance R14 is connected with the 1-pin of the switch tube Q3 through the resistance R13. One end of the resistance R14 is connected with the negative pole of the voltage stabilizing tube U9. The other end of the resistance R14 is connected with the positive pole of the voltage stabilizing tube U9. The negative pole of the voltage stabilizing tube U9 is connected with the input end of the controller 1. The fourth detection circuit 6 comprises the resistance R15, the resistance R16 and the voltage stabilizing tube U10. One end of the resistance R15 is connected with the 1-pin of the switch tube Q4 through the resistance R16. One end of the resistance R15 is connected with the negative pole of the voltage stabilizing tube U10. The other end of the resistance R15 is connected with the positive pole of the voltage stabilizing tube U10. The negative pole of the voltage stabilizing tube U10 is connected with the input end of the controller 1.
[0026] The electromagnetic valve driving circuit of the gas stove flameout protection, when applied, when the controller 1 receives the ignition signal, the outputs of the controller 1 respectively send high level signals to the isolation chip U2 and the isolation chip U4, send low level signals to the isolation chip U3 and the isolation chip U5, so that the isolation chip U2, the isolation chip U3, the isolation chip U4 and the isolation chip U5 are all turned on, so that the switching tubes Q1, Q2, Q3 and Q4 connected with the corresponding isolation chips are all turned on, and then the power supply VCC and the coil of the gas electromagnetic valve 2 form a loop with the ground, so that the gas electromagnetic valve 2 is turned on. When the controller 1 receives the flameout signal, the outputs of the controller 1 output opposite level signals, control the isolation chip U2, the isolation chip U3, the isolation chip U4 and the isolation chip U5 to be disconnected, so as to control the corresponding connected switching tubes Q1, Q2, Q3 and Q4 to be disconnected, so as to control the gas electromagnetic valve 2 to be disconnected, so as to cut off the gas supply. In the control process, as long as one of the switching tubes can be normally disconnected, the gas electromagnetic valve 2 can be normally disconnected, which ensures that the gas can be cut off in time when the flame is abnormally extinguished, and avoids gas leakage. In addition, the electromagnetic valve driving circuit is also provided with detection circuits for detecting the switching tubes, which can discover and handle in time when the working state of the switching tubes is inconsistent with the actual state, so as to ensure safety.
[0027] The specific embodiments described herein are merely illustrative of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the spirit of the present application or exceed the scope defined by the appended claims.
Claims
1. An electromagnetic valve drive circuit for gas stove flame failure protection, comprising a power supply VCC, a gas electromagnetic valve (2) for cutting off the gas supply and a controller (1) for issuing a cut-off gas control command in response to a received flame failure signal, characterized in that, The electromagnetic valve drive circuit further comprises a switch tube Q1, a switch tube Q2, an isolation chip U2 and an isolation chip U3, the 1 pin of the switch tube Q1 is connected with the power supply VCC through the gas electromagnetic valve (2), the 2 pin of the switch tube Q1 is connected with the 3 pin of the isolation chip U2 through the resistor R5, the 4 pin of the isolation chip U2 is connected with the positive voltage, the 1 pin of the isolation chip U2 is connected with the output end of the controller (1) through the resistor R19, the 2 pin of the isolation chip U2 is grounded, the 1 pin of the switch tube Q2 is connected with the 3 pin of the switch tube Q1, the 1 pin of the switch tube Q2 is also connected with the power supply VCC through the resistor R66, the 2 pin of the switch tube Q2 is connected with the 4 pin of the isolation chip U3 through the resistor R6, the 3 pin of the switch tube Q2 is grounded, the 3 pin of the isolation chip U3 is connected with the negative voltage, the 1 pin of the isolation chip U3 is connected with another positive voltage, the 2 pin of the isolation chip U3 is connected with the output end of the controller (1) through the resistor R17.
2. The solenoid valve drive circuit for flame failure protection of a gas hob according to claim 1, characterized in that The electromagnetic valve drive circuit further comprises a first detection circuit (3) for detecting the switching condition of the switch tube Q1 and a second detection circuit (4) for detecting the switching condition of the switch tube Q2, one end of the first detection circuit (3) is connected with the 1 pin of the switch tube Q1, one end of the second detection circuit (4) is connected with the 1 pin of the switch tube Q2, the other end of the first detection circuit (3) and the other end of the second detection circuit (4) are connected with the input end of the controller (1).
3. The solenoid valve drive circuit for flame failure protection of a gas hob according to claim 2, characterized in that The first detection circuit (3) comprises a resistor R9, a resistor R10 and a voltage stabilizing tube U7, one end of the resistor R9 is connected with the 1 pin of the switch tube Q1 through the resistor R10, one end of the resistor R9 is connected with the negative electrode of the voltage stabilizing tube U7, the other end of the resistor R9 is connected with the positive electrode of the voltage stabilizing tube U7, and the negative electrode of the voltage stabilizing tube U7 is connected with the input end of the controller (1).
4. The solenoid valve drive circuit for flame failure protection of a gas hob according to claim 2 or 3, characterized in that The second detection circuit (4) comprises a resistor R12, a resistor R11 and a voltage stabilizing tube U8, one end of the resistor R12 is connected with the 1 pin of the switch tube Q1 through the resistor R11, one end of the resistor R12 is connected with the negative electrode of the voltage stabilizing tube U8, the other end of the resistor R12 is connected with the positive electrode of the voltage stabilizing tube U8, and the negative electrode of the voltage stabilizing tube U8 is connected with the input end of the controller (1).
5. The solenoid valve driving circuit for flame failure protection of gas hobs according to claim 1 or 2 or 3, characterized in that, The electromagnetic valve drive circuit further comprises a switch tube Q3 and an isolation chip U4, the 1 pin of the switch tube Q3 is connected with the 3 pin of the switch tube Q2, the 1 pin of the switch tube Q3 is also connected with the power supply VCC through the resistor R67, the 2 pin of the switch tube Q3 is connected with the 3 pin of the isolation chip U4 through the resistor R7, the 4 pin of the isolation chip U4 is connected with the positive voltage, the 1 pin of the isolation chip U4 is connected with the output end of the controller (1) through the resistor R18, the 2 pin of the isolation chip U4 is grounded, and the resistor R47 is further connected between the 1 pin and the 2 pin of the isolation chip U4.
6. The solenoid valve drive circuit for flame failure protection of a gas hob according to claim 5, characterized in that The solenoid valve drive circuit also includes a third detection circuit (5) for detecting the switching status of the switching transistor Q3. The third detection circuit (5) includes a resistor R14, a resistor R13 and a Zener diode U9. One end of the resistor R14 is connected to pin 1 of the switching transistor Q3 through the resistor R13. One end of the resistor R14 is connected to the negative terminal of the Zener diode U9. The other end of the resistor R14 is connected to the positive terminal of the Zener diode U9. The negative terminal of the Zener diode U9 is connected to the input terminal of the controller (1).
7. The solenoid valve drive circuit for flame failure protection of a gas hob according to claim 5, characterized in that The solenoid valve drive circuit also includes a switching transistor Q4 and an isolation chip U5. Pin 1 of the switching transistor Q4 is connected to pin 3 of the switching transistor Q3. Pin 1 of the switching transistor Q4 is also connected to the power supply VCC through resistor R68. Pin 2 of the switching transistor Q4 is connected to pin 4 of the isolation chip U5 through resistor R8. Pin 3 of the isolation chip U5 is connected to a negative voltage, and pin 1 of the isolation chip U5 is connected to another positive voltage. Pin 2 of the isolation chip U5 is connected to the output terminal of the controller (1) through resistor R20. Resistor R48 is also connected between pin 1 and pin 2 of the isolation chip U5.
8. The solenoid valve drive circuit for flame failure protection of a gas hob according to claim 7, characterized in that The solenoid valve drive circuit also includes a fourth detection circuit (6) for detecting the switching status of the switching transistor Q4. The fourth detection circuit (6) includes a resistor R15, a resistor R16 and a Zener diode U10. One end of the resistor R15 is connected to pin 1 of the switching transistor Q4 through the resistor R16. One end of the resistor R15 is connected to the negative terminal of the Zener diode U10. The other end of the resistor R15 is connected to the positive terminal of the Zener diode U10. The negative terminal of the Zener diode U10 is connected to the input terminal of the controller (1).
9. The solenoid valve drive circuit for flame failure protection of a gas hob according to claim 7, characterized in that The solenoid valve drive circuit also includes resistors R64 and R65, capacitor C26 and Zener diode U33. The switching transistor Q4 is connected to ground through resistor R64. The switching transistor Q4 is connected to one end of capacitor C26, the negative terminal of Zener diode U33 and the input terminal of the controller through resistor R65. The other end of capacitor C26 and the positive terminal of Zener diode U33 are both grounded.
10. The solenoid valve driving circuit for flame failure protection of gas hobs according to claim 1 or 2 or 3, characterized in that, The solenoid valve drive circuit also includes a diode D4, the negative terminal of which is connected to the power supply VCC, and the positive terminal of which is connected to pin 1 of the switching transistor Q1.