Control circuit for converting high-voltage driving state to low-voltage holding state of electromagnetic valve

Abstract

The utility model provides a control circuit for converting a high-voltage driving state into a low-voltage holding state of an electromagnetic valve, which comprises a power supply input end, a reference negative electrode end, a boost driving chip and a microcontroller, and the boost driving chip boosts the voltage of the power supply input end to a power supply output end. An inductor and a first anti-reverse diode are connected in series between a power input end and a power output end, a pull-up resistor is connected in series between an EN end of a boost driving chip and the power input end, an MOS tube is connected in series between the EN end of the boost driving chip and a reference negative electrode end, and a control end of the MOS tube is connected in series with a voltage stabilizing diode and a capacitor and then is connected with the reference negative electrode end; and the voltage stabilizing diode and the MOS tube are used for automatically switching to a low-voltage output state after the power supply output end goes through a transient high-voltage output state. According to the utility model, the working efficiency of the electromagnetic valve is improved, the energy consumption is reduced, the safety, the stability and the applicability of the circuit are ensured through various protection and regulation functions, and a powerful guarantee is provided for the long-term and reliable operation of the electromagnetic valve and electrotherapy equipment.

Description

Technical Field

[0001] The utility model belongs to the technical field of electrotherapy equipment, and particularly relates to a control circuit for converting the high-voltage driving state of a solenoid valve to the low-voltage holding state. Background Technique

[0002] In electrotherapy equipment, using an air pump to suck negative pressure is a common method to fix an adsorbent on the human skin surface. The solenoid valve is a key component to realize the air path distribution and control of the air pump, and can realize the independent control of multiple air paths. Since a relatively high voltage and current are required at the moment of starting the solenoid valve, while the requirements for the working voltage and current are relatively small to maintain the working state of the solenoid valve, the demand for electric energy is smaller. If the high voltage and large current are still maintained to keep the solenoid valve working, it is easy to cause the solenoid valve to heat up, reduce the service life of the solenoid valve, and increase the energy consumption of the entire electrotherapy equipment. How to achieve high voltage and large current when starting the solenoid valve and low voltage and low current when maintaining the working state has become the key to restricting the energy consumption of the solenoid valve. Therefore, the present invention provides a control circuit for converting the high-voltage driving state of a solenoid valve to the low-voltage holding state, realizing the efficient control of the solenoid valve. Content of the Utility Model

[0003] Aiming at the defects and problems existing in the prior art, the utility model provides a control circuit for converting the high-voltage driving state of a solenoid valve to the low-voltage holding state, aiming to realize the efficient control and low-energy consumption operation of the solenoid valve through the automatic switching between the high-voltage driving state and the low-voltage holding state.

[0004] The solution of the utility model to solve its technical problems is: adopting a control circuit for converting the high-voltage driving state of a solenoid valve to the low-voltage holding state, including a power input terminal, a reference negative terminal, a level control terminal, a power output terminal, a true ground terminal of the power supply, a boost driving chip and a microcontroller; the boost driving chip boosts the voltage at the power input terminal to the power output terminal, and an inductor and a first reverse-preventing diode are connected in series between the power input terminal and the power output terminal; the inductor and the first reverse-preventing diode are used to step down the voltage when the boost driving chip stops working; the first reverse-preventing diode is used to prevent the current at the output terminal from flowing reversely and protect the input; a pull-up resistor is connected in series between the EN terminal of the boost driving chip and the power input terminal, and a MOS transistor is connected in series between the EN terminal of the boost driving chip and the reference negative terminal. After the control terminal (gate) of the MOS transistor is connected in series with a zener diode and a capacitor, it is connected to the reference negative terminal; the zener diode and the MOS transistor are used to automatically switch to the low-voltage state after a certain time when the circuit is started (that is, the power output terminal automatically switches to the low-voltage output state after experiencing a short high-voltage output state).

[0005] A triode is connected in series between the reference negative terminal and the true ground terminal of the power supply. The control terminal of the triode is a level control terminal; the microcontroller controls the working state of the boost driving chip through the level control terminal; when the microcontroller outputs a high level to the level control terminal, the triode conducts, enabling the reference voltage to be connected to the true ground terminal of the power supply. The EN terminal of the boost driving chip is at a high level, the boost driving chip works, and the power output terminal outputs a high voltage.

[0006] Preferably, an input terminal resistor is connected in series between the power input terminal and the capacitor. When the power input terminal charges the capacitor through the input terminal resistor to the conduction voltage of the zener diode, the zener diode conducts and the MOS transistor conducts, pulling down the EN terminal of the boost driving chip to a low level. The boost driving chip stops working, and the voltage at the power output terminal is lower than that at the power input terminal. By adjusting the values of the input terminal resistor and the capacitor, the charging time can be adjusted to meet the opening time requirements of different solenoid valves.

[0007] Preferably, a second reverse protection diode is connected between the power output terminal and the reference negative terminal, which is used to protect circuit devices from damage by high voltage and high current when the solenoid valve suddenly disconnects or is short-circuited, and to eliminate electromagnetic interference.

[0008] Preferably, a resistor group is connected in series between the power output terminal and the reference negative terminal in sequence. The FB terminal of the boost driving chip is connected to the common terminal of the series resistors. By adjusting the resistance value of the resistor group, the voltage range of the power output terminal can be adjusted to adapt to the opening voltage requirements of different solenoid valves.

[0009] Preferably, the triode is replaced by a current amplification chip such as a Darlington transistor. Or, the triode includes a first triode and a second triode. The collectors of the two triodes are connected to the reference negative terminal, and the emitter of the first triode is connected to the base of the second triode; the base of the first triode is the level control terminal; a resistor one is connected in series between the base and the collector of the first triode, and a resistor two is connected in series between the base and the collector of the second triode and then connected to the true ground terminal of the power supply.

[0010] Preferably, a light-emitting diode and a voltage-dividing resistor are connected in series between the power output terminal and the reference negative terminal. The light-emitting diode is used to indicate the high-voltage and low-voltage states. When the power output terminal is at the high voltage after boosting, the brightness of the light-emitting diode is the brightest. When the power output terminal is at the unboosted voltage, the brightness of the light-emitting diode becomes dimmer.

[0011] Preferably, a third reverse protection diode is connected in series between the power input terminal and the capacitor. The third reverse protection diode is used to discharge the charge of the capacitor to ensure that there is no residual charge when the solenoid valve is opened for the second time.

[0012] Advantages of the present utility model: The designed control circuit not only improves the working efficiency of the solenoid valve and reduces energy consumption, but also ensures the safety, stability and applicability of the circuit through various protection and regulation functions, providing a strong guarantee for the long-term reliable operation of the solenoid valve and the electrotherapy device.

[0013] 1. By providing high voltage and high current when the solenoid valve starts and low voltage and low current when maintaining the working state, this control circuit effectively reduces power consumption and the overall energy consumption of the electrotherapy device. Since the current and voltage for maintaining the working state of the solenoid valve are reduced, the heating phenomenon of the solenoid valve is reduced, thereby extending the service life of the solenoid valve and the entire electrotherapy device. The switching from the high-voltage start state to the low-voltage maintenance state is automatic, without the need for an additional control circuit or manual intervention, improving the reliability and convenience of the system. By reducing the voltage and current for maintaining the working state of the solenoid valve, the heat generation of the solenoid valve is significantly reduced, avoiding equipment failures or damages caused by overheating.

[0014] 2. This circuit is designed with various protection functions, including protecting devices from being damaged by high voltage and high current through a diode connected between the power supply and the ground, eliminating electromagnetic interference, and preventing reverse current flow at the output end, etc., ensuring the stability and safety of the circuit. By adjusting the resistance value of the resistor and the capacitance of the capacitor, it can adapt to the opening voltage and opening time requirements of different solenoid valves, increasing the applicability and flexibility of the circuit. Description of the Drawings

[0015] Figure 1 It is a control circuit for the solenoid valve to switch from the high-voltage drive state to the low-voltage holding state. Specific Embodiments

[0016] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0017] Embodiment 1: For the solenoid valve in the prior art, the driving voltage and current remain unchanged both at the moment of startup and in the maintaining state, resulting in large energy consumption and serious heating of the solenoid valve. The control circuit for the solenoid valve to switch from the high-voltage drive state to the low-voltage holding state provided in this embodiment is as Figure 1 shown. Figure 1 The control circuit in it mainly includes: the power input terminal VCC_IN, the reference negative terminal REF_GND, the level control terminal CONTROL, the power output terminal VCC_OUT, the true ground terminal GND of the power supply, the boost drive chip U1 and the microcontroller, etc. VCC_IN, REF_GND, and CONTROL on the left side of the circuit diagram are respectively the input terminal (positive polarity) of the power supply, REF_GND (reference negative terminal, not the real GND), and the level control terminal. VCC_OUT and GND on the right side of the circuit are respectively the output terminal (positive polarity) of the power supply and the GND of the power supply (real GND).

[0018] The boost drive chip U1 is used to boost the voltage of the power input terminal VCC_IN to the power output terminal VCC_OUT. An inductor L1 and a first anti-reverse diode D3 are connected in series between the power input terminal VCC_IN and the power output terminal VCC_OUT; the inductor L1 and the first anti-reverse diode D3 are used to step down the voltage when the boost drive chip U1 stops working; the first anti-reverse diode D3 is used to prevent the current at the output terminal VCC_OUT from flowing in the reverse direction and protect the input VCC_IN. Only when REF_GND is grounded can the power supply circuit be formed.

[0019] A pull-up resistor R2 is connected in series between the EN terminal of the boost drive chip U1 and the power input terminal VCC_IN. A MOS transistor Q1 is connected in series between the EN terminal of the boost drive chip U1 and the reference negative terminal REF_GND. After the control terminal (gate) of the MOS transistor Q1 is connected in series with a zener diode D2 and capacitors C4 and C5, it is connected to the reference negative terminal REF_GND; the zener diode D2 and the MOS transistor Q1 are used to automatically switch to the low voltage state after the circuit has been started for a certain period of time (that is, after the power output terminal has experienced a short high voltage output state, it automatically switches to the low voltage output state); a triode Q2 and a triode Q3 are connected in series between the reference negative terminal REF_GND and the true ground terminal GND of the power supply. The control terminals of the triodes Q2 and Q3 are level control terminals CONTROL; the microcontroller controls the working state of the boost drive chip U1 through the level control terminal CONTROL. The triodes Q2 and Q3 are replaced with current amplification chips such as Darlington tubes.

[0020] Replacement. When power is applied, first, C4 and C5 are charged, and the voltage across the zener diode D2 gradually increases (about 2 seconds). When the voltage exceeds the zener voltage of D2, D2 conducts, causing the gate voltage of the MOS transistor (Q1) to change from the original low level to the high level, and the MOS transistor conducts, changing the enable terminal EN of the boost chip U1 from the original high level to the low level, so that the boost chip U1 does not perform the boosting function.

[0021] When the microcontroller outputs a high level to the level control terminal CONTROL, the triodes Q2 and Q3 conduct, connecting the reference voltage REF_GND to the true ground terminal GND of the power supply. The EN terminal of the boost drive chip U1 is at a high level, and the boost drive chip U1 works, and the power output terminal VCC_OUT outputs a high voltage.

[0022] An input resistor R1 is connected in series between the power input terminal VCC_IN and capacitors C4 and C5. When the power input terminal VCC_IN charges capacitors C4 and C5 through the input resistor R1 to the conduction voltage of the zener diode D2, the zener diode D2 conducts and the MOS transistor Q1 conducts, pulling down the EN terminal of the boost driver chip U1 to a low level. The boost driver chip U1 stops working, and the voltage of the power output terminal VCC_OUT is lower than that of the power input terminal VCC_IN.

[0023] By adjusting the values of the input resistor R1 and capacitors C4 and C5, the charging time can be adjusted to meet the opening time requirements of different solenoid valves.

[0024] A second reverse protection diode D4 is connected between the power output terminal VCC_OUT and the reference negative terminal REF_GND, which is used to protect circuit components from damage by high voltage and high current when the solenoid valve suddenly disconnects or is short-circuited, and to eliminate electromagnetic interference.

[0025] A resistor group R8 and R7 are connected in series in sequence between the power output terminal VCC_OUT and the reference negative terminal REF_GND. The FB terminal of the boost driver chip U1 is connected to the common terminal of the series resistors. By adjusting the resistance values of the resistor group R8 and R7, the voltage range of VCC_OUT can be adjusted to adapt to the opening voltage requirements of different solenoid valves.

[0026] A light-emitting diode LED1 and a voltage-dividing resistor R9 are connected in series between the power output terminal VCC_OUT and the reference negative terminal REF_GND. The light-emitting diode LED1 is used to indicate the high-voltage and low-voltage states. When VCC_OUT is the boosted high voltage, the brightness of the light-emitting diode LED1 is the brightest. When the voltage of the power output terminal VCC_OUT is the unboosted voltage, the brightness of the light-emitting diode LED1 becomes dimmer.

[0027] A third reverse protection diode D1 is connected in series between the power input terminal VCC_IN and capacitors C4 and C5. The third reverse protection diode D1 is used to discharge the charges of capacitors C4 and C5 to ensure that there is no residual charge when the solenoid valve is opened for the second time.

[0028] Figure 1Among them, U1 is a boost drive chip. As long as it has the function of enabling the boost or not, it can be used. The specific input voltage and output voltage of the boost can be flexibly selected according to the usage requirements. For example, HM3342, ZCC9428, LYF63303, etc. The voltage of VCC_IN is lower than that of VCC_OUT. The voltage of VCC_IN is boosted by the boost chip to obtain VCC_OUT. By controlling the level of the EN terminal of the boost drive chip, the switching between the boost and non-boost states can be achieved. When the EN terminal of the boost drive chip U1 is at a high level, the boost drive chip U1 works, and the boosted voltage VCC_OUT is higher than VCC_IN. When the EN terminal of the boost drive chip U1 is at a low level, the boost drive chip U1 does not work, and the voltage at the VCC_IN terminal is stepped down by the inductor L1 and D3 to obtain VCC_OUT, and its VCC_OUT is slightly lower than the voltage at the VCC_IN terminal. Accordingly, the boost and non-boost states can be respectively used for the high-voltage start-up and low-voltage maintenance states required at the moment when the solenoid valve is energized, thereby reducing the power consumption when the solenoid valve state is maintained.

[0029] When the microcontroller outputs a low level to the control terminal CONTROL, Figure 1 the circuit does not work. The reason is that although there is an input terminal (positive polarity) of the power supply, REF_GND (reference negative terminal, not the real GND) is not connected to the real power ground, and a loop cannot be formed. Therefore, Figure 1 the circuits shown do not work. When the microcontroller outputs a high level to the control terminal CONTROL, the controlled triodes Q2 and Q3 are turned on, and the reference voltage REF_GND is connected to the real ground (GND). At this time, the EN terminal of the boost drive chip U1 is at a high level, and the boost drive chip U1 boosts the voltage, and VCC_OUT outputs a high voltage to provide the high voltage required for the start-up of the solenoid valve. At the moment when the control terminal CONTROL is at a high level, VCC_IN charges the capacitors C4 and C5 through the resistor R1. After a period of time t, the voltage on the capacitors C4 and C5 reaches the conduction voltage of the zener diode D2, D2 conducts, the gate of the MOS transistor Q1 changes from a low voltage to a high voltage, the MOS transistor Q1 conducts, pulls down the EN terminal of the boost drive chip U1 to a low level, the boost drive chip U1 stops working and no longer performs the boost function, and the voltage of VCC_OUT is lower than the voltage of VCC_IN, meeting the low-voltage requirement for maintaining the solenoid valve state.

[0030] Figure 1Among them, R2 is a pull-up resistor that plays a role in limiting current. Capacitors C6, C7, and C8 are filter capacitors that eliminate high-frequency interference in the circuit. LED1 is used to indicate the high-voltage and low-voltage states. When VCC_OUT is the high voltage after boosting, the brightness of LED1 is the brightest (at the moment of startup). When VCC_OUT is the voltage without boosting, the brightness of LED1 becomes dimmer (during maintenance). D4 is a diode connected between the power supply and the ground, which plays a role in protecting the components in the circuit from being damaged and eliminating electromagnetic interference in the circuit. When the solenoid valve (inductive load) in the circuit suddenly disconnects or shorts, high voltage and high current will be generated, which may cause damage to components such as transistors and integrated circuits in the circuit. The diode connected between the power supply and the ground can play a protective role in this case, guiding the voltage and current to the ground, thus avoiding damage to the circuit components. In the circuit, if there is line inductance between the DC power supply and the ground, it may cause the reference point of the DC power supply to change, resulting in electromagnetic interference. The diode connected between the power supply and the ground can eliminate this electromagnetic interference and maintain the stability of the DC power supply (VCC_OUT). The function of D1 is to discharge the charges of C4 and C5 to ensure that there is no residual charge in C4 and C5 when the solenoid valve is turned on for the second time, and to ensure that the voltage regulator diode D2 conducts only after sufficient charging time. D3 is used to prevent the current at the output end (VCC_OUT) from flowing in the reverse direction and damaging the input VCC_IN. By adjusting the resistance values of R8 and R7, the voltage range of VCC_OUT can be adjusted to meet the requirements of the opening voltage values of different solenoid valves. By adjusting the values of R1 and C4, C5, the charging time can be adjusted to meet the requirements of different solenoid valves for the opening time.

[0031] Advantages of this circuit: (1) This circuit can provide high voltage at the moment when the solenoid valve starts, and use low voltage to maintain the state of the solenoid valve. The automatic switching from the high-voltage state to the low-voltage state does not require additional control. (2) This circuit effectively combines voltage conversion (high-voltage to low-voltage switching) and current amplification (the circuit inside the box), ensuring that the high voltage and large current at the moment when the solenoid valve starts can start smoothly. (3) It also has other protection functions listed above.

[0032] The above specific embodiments of the present invention are only used for exemplary illustration or explanation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention.

Claims

1. A control circuit for converting a solenoid valve from a high-pressure driving state to a low-pressure holding state, characterized in that: The invention comprises a power input terminal (VCC_IN), a reference negative terminal (REF_GND), a level control terminal (CONTROL), a power output terminal (VCC_OUT), a power ground terminal (GND), a boost driver chip (U1) and a microcontroller; the boost driver chip (U1) boosts the voltage of the power input terminal (VCC_IN) to the power output terminal (VCC_OUT), and an inductor (L1) and a first anti-reverse diode (D3) are connected in series between the power input terminal (VCC_IN) and the power output terminal (VCC_OUT); an EN terminal of the boost driver chip (U1) and the power input terminal (VCC_IN) are connected to the power supply terminal (VCC_OUT); a first anti-reverse diode (D3) is connected in series between the EN terminal of the boost driver chip (U1) and the power input terminal (VCC_IN); ), a pull-up resistor (R2) is connected in series between the EN terminal of the boost driver chip (U1) and the reference negative terminal (REF_GND), a MOS tube (Q1) is connected in series between the EN terminal of the boost driver chip (U1) and the reference negative terminal (REF_GND), a voltage stabilizing diode (D2) and a capacitor (C4, C5) are connected in series to the control terminal of the MOS tube (Q1), and then connected to the reference negative terminal (REF_GND); a transistor (Q2, Q3) is connected in series between the reference negative terminal (REF_GND) and the true ground terminal (GND) of the power supply, and the control terminal of the transistor (Q2, Q3) is a level control terminal (CONTROL); the microcontroller controls the working state of the boost driver chip (U1) through the level control terminal (CONTROL).

2. The control circuit according to claim 1, characterized in that: An input resistor (R1) is connected in series between the power input terminal (VCC_IN) and the capacitors (C4, C5).

3. The control circuit according to claim 1, characterized in that: A second anti-reverse diode (D4) is connected between the power supply output terminal (VCC_OUT) and the reference negative terminal (REF_GND).

4. The control circuit according to claim 1, characterized in that: A resistor group (R8, R7) is connected in series between the power output terminal (VCC_OUT) and the reference negative terminal (REF_GND), and the FB terminal of the boost driver chip (U1) is connected to the common end of the series resistors.

5. The control circuit according to claim 1, characterized in that: The transistors (Q2, Q3) are replaced by Darlington transistors.

6. The control circuit according to claim 1, characterized in that: The transistors include transistor 1 (Q2) and transistor 2 (Q3), the collectors of the two transistors are connected to the reference negative terminal (REF_GND), the emitter of transistor 1 (Q2) is connected to the base of transistor 2 (Q3); the base of transistor 1 (Q2) is the level control terminal (CONTROL); a resistor 1 (R11) is connected in series between the base and collector of transistor 1 (Q2), and a resistor 2 (R12) is connected in series between the base and collector of transistor 2 (Q3) and then connected to the true ground terminal (GND) of the power supply.

7. The control circuit according to claim 1, characterized in that: A light emitting diode (LED1) and a voltage dividing resistor (R9) are connected in series between the power supply output terminal (VCC_OUT) and the reference negative terminal (REF_GND).

8. The control circuit according to claim 1, characterized in that: A third anti-reverse diode (D1) is connected in series between the power input terminal (VCC_IN) and the capacitors (C4, C5).

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