Electromagnetic valve driving circuit of combustible gas detector

Abstract

The utility model discloses an electromagnetic valve driving circuit of a combustible gas detector, which belongs to the field of electromagnetic valve driving and comprises a signal control module, a booster circuit module, an output control module and an output interface module, the signal control module comprises an MCU (microprogrammed control unit) chip and is used for outputting control signals, the booster circuit module is used for boosting 5V voltage to 12V voltage, and the output interface module is used for outputting control signals. The output control module controls output of the boosted voltage, and the output interface module is used for being connected with an electromagnetic valve of the combustible gas detector to drive the electromagnetic valve. According to the electromagnetic valve driving circuit of the combustible gas detector, boosting is achieved through PWM switch waveforms sent by the MCU chip of the detector, and then the effect of driving the electromagnetic valve is achieved through the MOS tube switch. The scheme is suitable for the combustible gas detector using 5V power supply, and the patent can utilize discrete components such as the MCU and the inductor of the detector to realize the boost function, and effectively replace a DCDC boost chip. The circuit is simple and low in cost.

Description

TECHNICAL FIELD

[0001] The utility model belongs to electromagnetic valve drive field, specifically a kind of electromagnetic valve drive circuit of combustible gas detector. BACKGROUND

[0002] According to the national standard requirement of combustible gas detector product, detector needs to have output interface, and for the combustible gas detector for detecting methane gas, the most external equipment matched with output interface is electromagnetic valve. When gas leakage occurs, detector output interface will output 12V voltage or 24V voltage to drive electromagnetic valve to act, to close natural gas pipeline, to prevent fire event. The electromagnetic valve of general household is driven using 12V voltage, and the load equipment of this kind of electromagnetic valve does not require high driving voltage precision, and it is pulse type electromagnetic valve, only short-time pulse voltage is needed to drive equipment. When 5V power supply is used for combustible gas detector, 5V voltage needs to be boosted to 12V to drive the electromagnetic valve matched with output interface, and boosting function is generally realized using DCDC power chip, and the cost is relatively high. SUMMARY

[0003] The utility model solves the technical problem of prior art, and provides an electromagnetic valve drive circuit of combustible gas detector, which realizes the function of boosting 5V to 12V by MCU chip, triode, inductor, diode, voltage stabilizing tube, capacitor and other discrete components used by the detector itself, and provides instantaneous large-current pulse power supply to the electromagnetic valve to drive the electromagnetic valve to act by the energy storage mode of large capacitor, without using power chip, to reduce cost.

[0004] To solve the above technical problems, the utility model adopts the following technical scheme:

[0005] An electromagnetic valve drive circuit of combustible gas detector, comprising:

[0006] A signal control module comprising an MCU chip for outputting PWM square wave signal, wherein the MCU chip has two GPIO ports for outputting control signals;

[0007] A boost circuit module connected with one of the GPIO ports of the MCU chip for boosting 5V voltage to 12V;

[0008] An output control module connected with the boost module and the other GPIO port of the MCU chip for controlling and outputting the boosted voltage;

[0009] An output interface module connected with the output control module, comprising an output interface J1 for connecting with the electromagnetic valve to drive the electromagnetic valve to act.

[0010] As a further description of the above technical solution, the voltage boosting circuit module comprises a triode Q1, an inductor L1, a diode D1, a voltage stabilizing tube D2 and a polarity capacitor C1, wherein the base of the triode Q1 is connected with a GPIO port of the MCU chip through a resistor R1, the emitter of the triode Q1 is grounded, the collector of the triode Q1 is connected with the inductor L1 and the positive electrode of the diode D1 respectively, the other end of the inductor L1 is connected with a 5V power supply, the negative electrode of the diode D1 is connected with a resistor R4, the other end of the resistor R4 is connected with an output power supply, the negative electrode of the voltage stabilizing tube D2, the positive electrode of the polarity capacitor C1 and an output control module respectively, and the positive electrode of the voltage stabilizing tube D2 and the negative electrode of the polarity capacitor C1 are both grounded.

[0011] As a further description of the above technical solution, the base of the triode Q1 is also grounded through a resistor R2, so as to prevent the floating state of the MCU chip from causing abnormal conduction of the triode Q1 when the MCU chip is not controlled.

[0012] As a further description of the above technical solution, the emitter of the triode Q1 is connected with the ground through a resistor R3.

[0013] As a further description of the above technical solution, the output control module comprises a MOS tube Q3, the source of the MOS tube Q3 is connected with the voltage boosting module, the gate of the MOS tube Q3 is connected with the collector of a triode Q2 through a resistor R8, the base of the triode Q2 is connected with another GPIO port of the MCU chip through a resistor R7, the emitter of the triode Q2 is connected with the ground and an output interface module respectively, and the drain of the MOS tube Q3 is connected with the output interface module.

[0014] As a further description of the above technical solution, the resistor R6 is also connected in parallel between the source and the gate of the MOS tube Q3.

[0015] As a further description of the above technical solution, the resistor R9 is also connected in parallel between the base and the emitter of the triode Q2, so as to prevent the triode Q2 from being abnormally conducted due to the floating state of the MCU chip when the MCU chip is not controlled.

[0016] As a further description of the above technical solution, the positive electrode of the output interface J1 is connected with the drain of the MOS tube Q3, and the negative electrode of the output interface J1 is connected with the emitter of the triode Q2.

[0017] As a further description of the above technical solution, the diode D3 is also connected in series between the output interface J1 and the MOS tube Q3, so as to prevent external abnormal large voltage from flowing back and protect the MOS tube Q3.

[0018] The electromagnetic valve driving circuit of the application utilizes the PWM switching waveform emitted by the MCU chip of the detector itself to realize voltage boosting, and then realizes the driving of the electromagnetic valve through the switching of the MOS tube, and is suitable for the combustible gas detector powered by 5V, and the voltage boosting function can be realized by the MCU chip of the detector itself and discrete components such as inductors, effectively replacing the DCDC voltage boosting chip, and the circuit is simple, the cost is low, the voltage value can be directly adjusted through the voltage stabilizing tube, the power released instantaneously is high by using the capacitor energy storage discharge, and a large electrolytic capacitor can be connected in parallel on the polar capacitor to improve the driving capacity to the outside, facilitating the extension design. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a principle block diagram of the electromagnetic valve driving circuit of the combustible gas detector of the application. DETAILED DESCRIPTION

[0020] The application will be further described in combination with the drawings and specific embodiments.

[0021] The embodiment provides an electromagnetic valve driving circuit of a combustible gas detector, as shown in the figure, which comprises: Figure 1

[0022] The signal control module comprises an MCU chip for outputting a PWM square wave signal and a control signal, the MCU chip has a GPIO1 port and a GPIO2 port, the GPIO1 port is responsible for outputting a high-frequency PWM switching waveform to switch control the triode Q1 to realize the voltage boosting function, and the GPIO2 port controls the triode Q2 to realize the 12V voltage output control after voltage boosting.

[0023] The voltage boosting circuit module is connected with one GPIO port of the MCU chip and is used for boosting the 5V voltage to 12V, and the voltage boosting circuit module comprises a triode Q1, an inductor L1, a diode D1, a voltage stabilizing tube D2 and a polar capacitor C1, wherein the base of the triode Q1 is connected with one GPIO port of the MCU chip through a resistor R1, the base of the triode Q1 is also grounded through a resistor R2, the emitter of the triode Q1 is grounded, the resistor R3 is connected in series between the emitter of the triode Q1 and the ground, the collector of the triode Q1 is connected with the inductor L1 and the positive electrode of the diode D1 respectively, the other end of the inductor L1 is connected with a 5V power supply, the negative electrode of the diode D1 is connected with a resistor R4, the other end of the resistor R4 is connected with an output power supply, the negative electrode of the voltage stabilizing tube D2, the positive electrode of the polar capacitor C1 and an output control module respectively, and the positive electrode of the voltage stabilizing tube D2 and the negative electrode of the polar capacitor C1 are both grounded.

[0024] ​The output control module is connected with the voltage boosting module and another GPIO port of the MCU chip, and is used for controlling and outputting the voltage after boosting; the output control module comprises a MOS tube Q3, the source of the MOS tube Q3 is connected with the voltage boosting module, the gate of the MOS tube Q3 is connected with the collector of a triode Q2 through a resistor R8, the source and the gate of the MOS tube Q3 are further connected with a resistor R6 in parallel, the base of the triode Q2 is connected with another GPIO port of the MCU chip through a resistor R7, the emitter of the triode Q2 is connected with the ground and an output interface module respectively, the base and the emitter of the triode Q2 are further connected with a resistor R9 in parallel, and the drain of the MOS tube Q3 is connected with the output interface module.

[0025] The output interface module is connected with the output control module, and comprises an output interface J1, which is used for being connected with an external electromagnetic valve and driving the external electromagnetic valve to act; the positive pole of the output interface J1 is connected with the negative pole of a diode D3, the positive pole of the diode D3 is connected with the drain of the MOS tube Q3, and the negative pole of the output interface J1 is connected with the emitter of the triode Q2.

[0026] The working principle is as follows:

[0027] The combustible gas detector is in a normal working state: the MCU chip is generally powered by 3.3V, a high-frequency PWM wave signal is output from the GPIO1 port of the MCU chip, the amplitude of the PWM wave is 3.3V, and the triode Q1 is switched controlled. When the MCU chip outputs a high level, the high level provides a driving current to the triode Q1 through the resistor R1, the triode Q1 is turned on, the 5V power supply forms a path through the inductor L1, the triode Q1 and the resistor R3, at this time, the inductor L1 will store energy, and the resistor R2 is pulled down to the ground, which prevents the triode Q1 from being abnormally turned on due to the floating state of the MCU chip when the MCU chip is not controlled. When the MCU chip outputs a low level, the triode Q1 is cut off, because the inductor current cannot change suddenly, the induced electromotive force generated by the inductor itself charges the capacitor C1 through the diode D1 and the resistor R4, and the diode D1 prevents the voltage from flowing back to the front end, thereby ensuring the stability of the voltage. After a plurality of switching periods, the capacitor C1 will be fully charged, and the voltage in the full state is determined by the stabilizing tube D2. When the product is in normal working state, the GPIO1 port will always output the PWM wave, so as to ensure that the voltage of the capacitor C1 is in the full state, in this state, the GPIO2 port of the MCU chip is low, the triode Q2 is in the cut-off state, and therefore the MOS tube Q3 is also in the closed state, the electric energy stored in the capacitor C1 will not be released, and the resistor R9 has the same effect as the resistor R2, which prevents the triode Q2 from being abnormally turned on due to the floating of the MCU chip when the MCU chip is not controlled.

[0028] The working state of the combustible gas detector alarm: the GPIO1 port of the MCU chip keeps the PWM control waveform, and continuously charges the capacitor C1, when the combustible gas detector identifies the gas leakage, the GPIO2 port of the MCU chip will output a 1 second or shorter time pulse high level, during the pulse high level, the transistor Q2 will be turned on, the 12V voltage on the capacitor C1 will pass through the resistor R6, R8 and the transistor Q2 to form a path, because the voltage division of the resistor R6 and the resistor R8 makes the VGS of the MOS tube Q3 less than VGS(th), at this time, the MOS tube Q3 will be in the conductive state. The electrical energy stored in the capacitor C1 will be released externally, and the external electromagnetic valve will be driven through the output interface J1 to act, generally the driving time of the electromagnetic valve is less than 1 second. Diode D3 is used to prevent external abnormal large voltage from flowing back, and to protect the MOS tube Q3. After the GPIO2 port outputs the pulse high level, it will output low level again, at this time, the transistor Q2 is in the cut-off state again, and the boost circuit module will charge the capacitor C1 again, so that the capacitor C1 is full when the combustible gas detector receives the alarm signal next time, and the external electromagnetic valve can be driven again.

[0029] According to the above schematic diagram parameters, if the frequency of the PWM switch waveform output by the GPIO1 port of the MCU chip is set to 10K, and the duty cycle is 50%, the 12V voltage full charging time is about 12 seconds, the charging time requirement can be adjusted according to the duty cycle and the corresponding component parameters.

[0030] The above examples are only used to illustrate the technical solutions of the present application, but not to limit them; those skilled in the art should understand that the technical solutions recorded in the above examples can be modified, or some technical features can be replaced equivalently; and these modifications or replacements will not change the essence of the corresponding technical solutions out of the protection scope of the present application.

Claims

1. An electromagnetic valve drive circuit for a combustible gas detector, characterized by The utility model relates to a signal control module, a boost circuit module, an output control module and an output interface module. The signal control module comprises an MCU chip for outputting a PWM square wave signal, and the MCU chip has two GPIO ports for outputting control signals. The boost circuit module is connected with one of the GPIO ports of the MCU chip and is used for boosting 5V voltage to 12V. The output control module is connected with the boost module and the other GPIO port of the MCU chip and is used for controlling output of the boosted voltage. The output interface module is connected with the output control module and comprises an output interface J1 for being connected with a solenoid valve to drive the solenoid valve to act.

2. The solenoid valve drive circuit of a combustible gas detector according to claim 1, characterized in that: The boost circuit module comprises a transistor Q1, an inductor L1, a diode D1, a voltage stabilizing tube D2 and a polarity capacitor C1, wherein the base of the transistor Q1 is connected with one of the GPIO ports of the MCU chip through a resistor R1, the emitter of the transistor Q1 is grounded, the collector of the transistor Q1 is connected with the inductor L1 and the positive electrode of the diode D1 respectively, the other end of the inductor L1 is connected with a 5V power supply, the negative electrode of the diode D1 is connected with a resistor R4, the other end of the resistor R4 is connected with an output power supply, the negative electrode of the voltage stabilizing tube D2, the positive electrode of the polarity capacitor C1 and the output control module respectively, and the positive electrode of the voltage stabilizing tube D2 and the negative electrode of the polarity capacitor C1 are grounded.

3. The solenoid valve drive circuit of a combustible gas detector according to claim 2, characterized in that: The base of the transistor Q1 is also grounded through a resistor R2.

4. A solenoid drive circuit for a combustible gas detector as defined in claim 2 or 3, characterized in that: The resistor R3 is connected in series between the emitter of the transistor Q1 and the ground.

5. The solenoid valve drive circuit of a combustible gas detector according to claim 1, wherein: The output control module comprises a MOS tube Q3, the source of the MOS tube Q3 is connected with the boost module, the gate of the MOS tube Q3 is connected with the collector of a transistor Q2 through a resistor R8, the base of the transistor Q2 is connected with the other GPIO port of the MCU chip through a resistor R7, the emitter of the transistor Q2 is connected with the ground and the output interface module respectively, and the drain of the MOS tube Q3 is connected with the output interface module.

6. The solenoid valve drive circuit of a combustible gas detector according to claim 5, characterized in that: The resistor R6 is also connected in parallel between the source and the gate of the MOS tube Q3.

7. An electromagnetic valve drive circuit for a combustible gas detector as defined in claim 5 or 6, characterized in that: The resistor R9 is also connected in parallel between the base and the emitter of the transistor Q2.

8. The solenoid valve drive circuit of a combustible gas detector according to claim 1, wherein: The positive electrode of the output interface J1 is connected with the drain of the MOS tube Q3, and the negative electrode of the output interface J1 is connected with the emitter of the transistor Q2.

9. The solenoid valve drive circuit of a combustible gas detector according to claim 8, characterized in that: The diode D3 is also connected in series between the output interface J1 and the MOS tube Q3.

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