A switch control circuit

Abstract

The present application relates to a switch control circuit, comprising a first switch circuit, an MCU and a signal control circuit, wherein the input end of the first switch circuit is connected to the positive electrode of a battery, the output end of the first switch circuit is connected to the MCU, the signal control circuit is connected to the MCU and a load respectively, and the signal control circuit is used to control the on and off of the circuit where the load is located. The present application has the effect of extending the life of the switch.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic off-grid technology, and in particular to a switch control circuit. Background Art

[0002] Photovoltaic off-grid refers to off-grid photovoltaic power generation systems. Off-grid photovoltaic power generation systems are widely used in remote mountainous areas, areas without electricity, islands, communication base stations, street lamps and other application places, and are used to power portable electrical equipment such as hair dryers and table lamps. Off-grid photovoltaic power generation systems convert solar energy into electrical energy when there is light, and the MCU regulates and controls the electrical energy. On the one hand, the adjusted energy is sent to the load, and on the other hand, the excess energy is sent to the battery pack for storage; when there is no light, the battery supplies power to the load.

[0003] The switch of an off-grid photovoltaic power generation system is generally connected to the circuit of the load, resulting in a large current flowing through the switch. During use, a large current will be generated at the moment of closing and opening the switch, which will impact the switch and affect its service life. Summary of the invention

[0004] In order to increase the service life of a switch, the present application provides a switch control circuit.

[0005] A switch control circuit provided in this application adopts the following technical solution:

[0006] A switch control circuit comprises a first switch circuit, an MCU and a signal control circuit, wherein the input end of the first switch circuit is connected to the positive electrode of a battery, the output end of the first switch circuit is connected to the MCU, the signal control circuit is connected to the MCU and a load respectively, and the signal control circuit is used to control the on and off of a circuit where the load is located.

[0007] By adopting the above technical solution, the battery supplies power to the MCU and the stable signal control circuit through the first switch circuit. When the switch is closed, the signal control circuit controls the circuit where the load is located to be turned on, and the load works. The first switch circuit is separated from the circuit where the load is located. The MCU and the stable signal control circuit are power consumption units of the circuit where the first switch circuit is located. Since P=UI, when the voltage is constant, the current is proportional to the power. The power of the MCU and the stable signal control circuit is small, so that the current flowing through the first switch circuit is small, the heat is small, and the switch is subjected to less impact at the moment of closing and opening, thereby increasing the service life of the switch.

[0008] Optionally, the first switching circuit includes a sixth diode D6, a first switch K1, a forty-third capacitor C43, a sixty-sixth resistor R66, a thirty-third capacitor C33 and a sixty-fifth resistor R65, the anode of the sixth diode D6 is connected to the positive electrode of the battery, the cathode of the sixth diode D6 is connected to one end of the first switch K1, the other end of the first switch K1 is connected to the MCU, the positive electrode of the forty-third capacitor C43 is connected to the other end of the first switch K1, the negative electrode of the forty-third capacitor C43 is grounded, one end of the sixty-sixth resistor R66 is connected to the positive electrode of the forty-third capacitor C43, and the other end is connected to the positive electrode of the thirty-third capacitor C33, the sixty-fifth resistor R65 and the sixty-sixth resistor R66 are connected in parallel, the positive electrode of the forty-third capacitor C43 is connected to the sixty-fifth resistor R65, and the negative electrode of the forty-third capacitor C43 is grounded.

[0009] By adopting the above technical solution, the forty-third capacitor C43, the sixty-sixth resistor R66, the thirty-third capacitor C33 and the sixty-fifth resistor R65 form a filter circuit, which can improve the stability of the battery output voltage.

[0010] Optionally, the signal control circuit includes a first MOS tube Q1, a third MOS tube Q3, an eighty-third resistor R83, a fifty-second resistor R52, a fifth diode D5, a twenty-second capacitor C22 and a sixty-second resistor R62, the gate of the first MOS tube Q1 is connected to the MCU, the source of the first MOS tube Q1 is connected to the load, the drain of the first MOS tube Q1 is connected to the drain of the third MOS tube Q3, the drain of the third MOS tube Q3 is connected to one end of the eighty-third resistor R83, the other end of the eighty-third resistor R83 is connected to the load, the gate of the third MOS tube Q3 is connected to the MCU, the source of the third MOS tube Q3 is connected to one end of the fifty-second resistor R52, the other end of the fifty-second resistor R52 is grounded, the cathode of the fifth diode D5 is connected to the gates of the first MOS tube Q1 and the third MOS tube Q3, and the twenty-second capacitor C22, the sixty-second resistor R62 and the fifth diode D5 are connected in parallel.

[0011] By adopting the above technical solution, the gate of the first MOS tube Q1, the gate of the third MOS tube Q3 and the MCU are connected, the source of the first MOS tube Q1 is connected to the load, one end of the eighty-third resistor R83 is connected to another load, and the first MOS tube Q1 and the third MOS tube Q3 are controlled to be turned on and off by the MCU. When the first MOS tube Q1 and the third MOS tube Q3 are turned off, the circuit where the load is located is disconnected, and the load stops working.

[0012] Optionally, it also includes a voltage sampling circuit and a voltage stabilization output module, wherein the voltage sampling circuit is connected to the battery and the MCU respectively, and the voltage stabilization output module is connected to the first switch circuit, the MCU, and the display module respectively.

[0013] By adopting the above technical solution, the voltage-stabilizing output module supplies power to the display module, and the voltage sampling circuit collects the output voltage of the battery. When the output voltage is lower than a predetermined value, the MCU controls the voltage-stabilizing output module to stop outputting; at the same time, the MCU controls the first MOS tube Q1 and the third MOS tube Q3 to be cut off, and the circuit where the load is located is disconnected, thereby reducing the over-discharge of the battery and extending the service life of the battery.

[0014] Optionally, the voltage-stabilized output module includes a second transistor T2, a chip U7 of model R1244N and its peripheral circuits, the base of the second transistor T2 is connected to the MCU, the collector of the second transistor T2 is connected to the CE pin of the chip U7, and the emitter of the second transistor T2 is grounded.

[0015] By adopting the above technical solution, the battery supplies power to the chip U7 through the first switch circuit, and the chip U7 outputs a stable 3.3V voltage to the display module, with stable output voltage and low cost. The second transistor T2 is connected to the CE pin of the chip U7. When the MCU controls the second transistor T2 to turn on, the CE pin of the chip U7 becomes a low level, and the chip U7 stops working, thereby realizing the control of the work of the chip U7.

[0016] Optionally, the voltage sampling circuit includes a fifty-seventh resistor R57, a fifty-eighth resistor R58 and a twenty-third capacitor C23, one end of the fifty-seventh resistor R57 is connected to the battery, the other end of the fifty-seventh resistor R57 is connected to the MCU, one end of the fifty-eighth resistor R58 is connected to the other end of the fifty-seventh resistor R57, the other end of the fifty-eighth resistor R58 is grounded, and the twenty-third capacitor C23 and the fifty-eighth resistor R58 are connected in parallel.

[0017] By adopting the above technical solution, the MCU collects the output voltage of the battery through the fifty-seventh resistor R57, and the twenty-third capacitor C23 and the fifty-eighth resistor R58 play a filtering role, making the collected voltage more stable and more accurate.

[0018] Optionally, it also includes a second switch circuit, which is connected to the positive electrode of the battery and the photovoltaic charging circuit respectively.

[0019] By adopting the above technical solution, the second switch circuit controls the on and off of the photovoltaic charging circuit. When not in use, the photovoltaic charging circuit is disconnected to prevent the photovoltaic panel from continuing to supply power to the battery, thereby reducing overcharging.

[0020] Optionally, the second switching circuit includes an eighty-first resistor R81, a second switch K2, an optocoupler U10 and a seventh diode D7, one end of the eighty-first resistor R81 is connected to the positive electrode of the battery, and the other end is connected to pin 1 of the optocoupler U10, one end of the second switch K2 is connected to pin 1 of the optocoupler U10, the other end of the second switch K2 is connected to pin 2 of the optocoupler U10, pins 2 and 3 of the optocoupler U10 are grounded, pin 4 of the optocoupler U10 is connected to the cathode of the seventh diode D7, and the anode of the seventh diode D7 is connected to the photovoltaic charging circuit.

[0021] By adopting the above technical solution, the second switch K2 is disconnected, the current flows through the optocoupler U10, and the optocoupler U10 is turned on; the second switch K2 is closed, the optocoupler U10 is short-circuited, and the optocoupler U10 is turned off. The on and off of the photovoltaic charging circuit can be controlled by the on and off of the optocoupler U10. At the same time, the optocoupler U10 plays an isolating role, separating the second switch circuit from the photovoltaic charging circuit. The power of the optocoupler U10 is small, and the current passing through the second switch circuit is small, which can extend the service life of the second switch K2.

[0022] Optionally, it also includes a voltage stabilizing circuit, which includes a primary voltage stabilizing module and a secondary voltage stabilizing module, the input end of the primary voltage stabilizing module is connected to the output end of the first switching circuit, the output end of the primary voltage stabilizing module is connected to the input end of the secondary voltage stabilizing module, and the output end of the secondary voltage stabilizing module is connected to the MCU.

[0023] By adopting the above technical solution, the first switch circuit supplies power to the MCU through the voltage stabilizing circuit, and the stability of the MCU power supply voltage is improved through the segmented voltage stabilization of the primary voltage stabilizing module and the secondary voltage stabilizing module.

[0024] Optionally, the primary voltage stabilizing module includes a sixty-fourth resistor R64, a first transistor T1 and a second diode D2, one end of the sixty-fourth resistor R64 is connected to the collector of the first transistor T1, and the other end is connected to the base of the first transistor T1, the collector of the first transistor T1 is connected to the output end of the first switch circuit (1), the base of the first transistor T1 is connected to the cathode of the second diode D2, and the anode of the second diode D2 is grounded, and the secondary voltage stabilizing module includes a forty-sixth capacitor C46, ​​a ninth capacitor C9, a forty-fourth capacitor C44, and a forty-fifth capacitor C46. C45 and the voltage regulator U8, the 3rd pin of the voltage regulator U8 is connected to the emitter of the first transistor T1, the 1st pin of the voltage regulator U8 is grounded, the 2nd pin of the voltage regulator U8 is connected to the power supply end of the MCU, the primary side of the forty-sixth capacitor C46 is connected to the 3rd pin of the voltage regulator U8, the secondary side of the forty-sixth capacitor C46 is grounded, the ninth capacitor C9 and the forty-sixth capacitor C46 are connected in parallel, the primary side of the forty-fourth capacitor C44 is connected to the 3rd pin of the voltage regulator U8, the secondary side of the forty-fourth capacitor C44 is grounded, and the forty-fifth capacitor C45 and the forty-fourth capacitor C44 are connected in parallel.

[0025] By adopting the above technical solution, the first switching circuit supplies power to the first transistor T1, the first transistor T1 and the second diode D2 form a voltage stabilizing circuit, the emitter of the first transistor T1 outputs a stable voltage of 12V, the 12V voltage is applied to the voltage stabilizing tube U8, and the voltage stabilizing tube U8 provides a stable 3.3V voltage to the MCU, thereby improving the voltage stability.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] 1. The first switch circuit is separated from the circuit where the load is located. The MCU and the stable signal control circuit are power-consuming units of the circuit where the first switch circuit is located. The power of the MCU and the stable signal control circuit is relatively small, so that the current flowing through the first switch circuit is small, the heat generated is small, and the impact on the switch at the moment of closing and opening is small, thereby improving the service life of the switch.

[0028] 2. The voltage sampling circuit collects the output voltage of the battery. When the output voltage is lower than the preset value, the MCU controls the second transistor T2 to turn on, so that the voltage stabilization output module stops outputting. At the same time, the MCU controls the first MOS tube Q1 and the third MOS tube Q3 to turn off, and the circuit where the load is located is disconnected, thereby reducing the over-discharge of the battery and extending the service life of the battery.

[0029] 3. When not in use, the photovoltaic charging circuit is disconnected to prevent the photovoltaic panel from continuing to supply power to the battery, which can reduce overcharging. At the same time, the optocoupler U10 plays an isolating role, separating the second switch circuit from the photovoltaic charging circuit. The power of the optocoupler U10 is small, and the current passing through the second switch circuit is small, which can extend the service life of the second switch K2. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a structural block diagram of a switch control circuit in one embodiment of the present application;

[0031] Figure 2 This is the circuit diagram of the MCU;

[0032] Figure 3 is a circuit diagram of a first switching circuit;

[0033] Figure 4 It is the circuit diagram of the signal control circuit;

[0034] Figure 5 is a structural block diagram of a switch control circuit in another embodiment of the present application;

[0035] Figure 6 It is the circuit diagram of the voltage stabilizing circuit;

[0036] Figure 7 It is the circuit diagram of the voltage sampling circuit;

[0037] Figure 8 This is the circuit diagram of the voltage regulated output module;

[0038] Fig. 9 is a circuit diagram of the second switching circuit.

[0039] Explanation of the accompanying drawings: 1. First switching circuit; 2. Voltage stabilizing circuit; 21. Primary voltage stabilizing module; 22. Secondary voltage stabilizing module; 23. Filter capacitor group; 3. Voltage stabilizing output module; 4. Second switching circuit; 5. Signal control circuit; 6. Voltage sampling circuit. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of this application more clear, the following Figure 1-9 It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0041] The present application embodiment discloses a switch control circuit. Figure 1 and Figure 2The switch control circuit includes a first switch circuit 1, an MCU and a signal control circuit 5. The input end of the first switch circuit 1 is connected to the positive electrode of the battery, the output end of the first switch circuit 1 is connected to the MCU, the signal control circuit 5 is connected to the MCU and the load respectively, and the signal control circuit 5 is used to control the on and off of the circuit where the load is located. Among them, the MCU adopts a chip U5 of model GD32F103RCT.

[0042] Reference Figure 1 and Figure 3 The first switch circuit 1 includes a sixth diode D6, a first switch K1, a forty-third capacitor C43, a sixty-sixth resistor R66, a thirty-third capacitor C33 and a sixty-fifth resistor R65, wherein the anode of the sixth diode D6 is connected to the positive electrode of the battery, the cathode of the sixth diode D6 is connected to one end of the first switch K1, the positive electrode of the forty-third capacitor C43 is connected to the other end of the first switch K1, the negative electrode of the forty-third capacitor C43 is grounded, one end of the sixty-sixth resistor R66 is connected to the positive electrode of the forty-third capacitor C43, and the other end is connected to the positive electrode of the thirty-third capacitor C33. One end of the sixty-fifth resistor R65 is connected to the positive electrode of the thirty-third capacitor C33, and the other end is connected to the positive electrode of the forty-third capacitor C43, and the negative electrode of the forty-third capacitor C43 is grounded.

[0043] When the first switch K1 is closed, the battery supplies power to the MCU, the MCU works, and the entire off-grid photovoltaic power generation system starts; when the first switch K1 is disconnected, the MCU does not work, and the entire off-grid photovoltaic power generation system is shut down. The power of the MCU is smaller than the power of the load, so that the current flowing through the first switch K1 becomes smaller, the heat generation is reduced, and the current impact on the first switch K1 at the moment of closing and opening becomes smaller, which can increase the service life of the first switch K1. The 43rd capacitor C43, the 66th resistor R66, the 33rd capacitor C33 and the 65th resistor R65 form a filter circuit, which can improve the stability of the battery output voltage.

[0044] Reference Figure 1 and Figure 4The signal control circuit 5 includes a first MOS transistor Q1, a third MOS transistor Q3, an eighty-third resistor R83, a fifty-second resistor R52, a fifth diode D5, a twenty-second capacitor C22 and a sixty-second resistor R62, wherein the first MOS transistor Q1 and the third MOS transistor Q3 are N-channel MOS transistors, the gate of the first MOS transistor Q1 is connected to the MCU, the source of the first MOS transistor Q1 is connected to the negative electrode of the load, the drain of the first MOS transistor Q1 is connected to the drain of the third MOS transistor Q3, the drain of the third MOS transistor Q3 is connected to one end of the eighty-third resistor R83, the other end of the eighty-third resistor R83 is connected to the negative electrode of the load, the gate of the third MOS transistor Q3 is connected to the MCU, the source of the third MOS transistor Q3 is connected to one end of the fifty-second resistor R52, the other end of the fifty-second resistor R52 is grounded, the cathode of the fifth diode D5 is connected to the gates of the first MOS transistor Q1 and the third MOS transistor Q3, and the twenty-second capacitor C22, the sixty-second resistor R62 and the fifth diode D5 are connected in parallel.

[0045] The gate of the first MOS tube Q1 and the gate of the third MOS tube Q3 are at a high level, the gate of the first MOS tube Q1 and the third MOS tube Q3 are turned on, the circuit where the load is located is turned on, and the load is working. The gate of the first MOS tube Q1 and the gate of the third MOS tube Q3 are at a low level, the gate of the first MOS tube Q1 and the third MOS tube Q3 are turned off, the negative electrode of the load and the grounding terminal are disconnected, the circuit where the load is located is disconnected, and the load stops working. The MCU controls the on and off of the first MOS tube Q1 and the third MOS tube Q3, and then controls whether the load is working. Through the isolation effect of the signal control circuit 5, the current of the load does not pass through the first switch K1.

[0046] Optional, see Figure 5 The switch control circuit also includes a voltage stabilizing circuit 2, a voltage sampling circuit 6, a voltage stabilizing output module 3 and a second switch circuit 4.

[0047] Reference Figure 3 and Figure 6 , the voltage stabilizing circuit 2 includes a primary voltage stabilizing module 21, a secondary voltage stabilizing module 22 and a filter capacitor group 23. Among them, the primary voltage stabilizing module 21 includes a sixty-fourth resistor R64, a first transistor T1 and a second diode D2, wherein the first transistor T1 is an NPN transistor. One end of the sixty-fourth resistor R64 is connected to the collector of the first transistor T1, and the other end is connected to the base of the first transistor T1. The collector of the first transistor T1 is connected to the first switch K1, the base of the first transistor T1 is connected to the cathode of the second diode D2, and the anode of the second diode D2 is grounded.

[0048] The secondary voltage stabilization module 22 includes a 46th capacitor C46, ​​a 9th capacitor C9, a 44th capacitor C44, a 45th capacitor C45 and a voltage regulator U8. The model of the voltage regulator U8 is CX7533, the 3rd pin of the voltage regulator U8 is connected to the emitter of the first transistor T1, the 1st pin of the voltage regulator U8 is grounded, and the 2nd pin of the voltage regulator U8 is connected to the power supply terminal of the MCU. The primary side of the 46th capacitor C46 is connected to the 3rd pin of the voltage regulator U8, the secondary side of the 46th capacitor C46 is grounded, the 9th capacitor C9 is connected in parallel with the 46th capacitor C46, ​​the primary side of the 44th capacitor C44 is connected to the 3rd pin of the voltage regulator U8, the secondary side of the 44th capacitor C44 is grounded, and the 45th capacitor C45 is connected in parallel with the 44th capacitor C44.

[0049] The filter capacitor group 23 and the forty-fifth capacitor C45 are connected in parallel. The filter capacitor group 23 includes a second capacitor C2, a third capacitor C3, a tenth capacitor C10, an eleventh capacitor C11, a fourth capacitor C4, a twenty-fifth capacitor C25 and a twenty-sixth capacitor C26 which are connected in parallel in sequence.

[0050] The first transistor T1 and the second diode D2 form a voltage stabilizing circuit 2. The emitter of the first transistor T1 outputs a 12V voltage, which is applied to the voltage stabilizing tube U8. The voltage stabilizing tube U8 then provides a 3.3V working voltage to the MCU, and the filter capacitor group 23 plays a filtering role. By segmented voltage stabilization, the stability of the MCU power supply voltage can be improved.

[0051] Reference Figure 5 and Figure 7 , the voltage sampling circuit 6 is connected to the battery and the MCU respectively, and the voltage stabilizing output module 3 is connected to the first switch circuit 1, the MCU, and the display module. The voltage sampling circuit 6 includes a fifty-seventh resistor R57, a fifty-eighth resistor R58, and a twenty-third capacitor C23. One end of the fifty-seventh resistor R57 is connected to the battery, the other end of the fifty-seventh resistor R57 is connected to the MCU, one end of the fifty-eighth resistor R58 is connected to the other end of the fifty-seventh resistor R57, the other end of the fifty-eighth resistor R58 is grounded, and the twenty-third capacitor C23 is connected in parallel with the fifty-eighth resistor R58.

[0052] The MCU collects the output voltage of the battery through the fifty-seventh resistor R57, and the twenty-third capacitor C23 and the fifty-eighth resistor R58 act as filters to make the collected voltage more stable and more accurate.

[0053] Reference Figure 3 and Figure 8, the voltage-stabilized output module 33 includes a second triode T2, a chip U7 of model R1244N and its peripheral circuit. Among them, the peripheral circuit includes a 24th capacitor C24, a 29th capacitor C29, a 26th resistor R26, a 30th capacitor C30, a 43rd resistor R43, a 25th resistor R25, a 27th capacitor C27, a 4th diode D4, a 31st capacitor C31, a 30th resistor R30, a second inductor L2, a 32nd capacitor C32 and a 42nd capacitor C42, the VIN pin of the chip U7 is connected to the first switch K1, the primary side of the 24th capacitor C24 is connected to the VIN pin of the chip U7, and the secondary side of the 24th capacitor C24 is grounded. The primary side of the 29th capacitor C29 is connected to the VIN pin of the chip U7, and the secondary side of the 29th capacitor C29 is grounded. One end of the 26th resistor R26 is connected to the primary side of the 24th capacitor C24, and the other end is connected to the CE pin of the chip U7. The primary side of the 30th capacitor C30 is connected to the CE pin of U7, the secondary side of the 30th capacitor C30 is grounded, and the GND pin of the chip U7 is grounded. One end of the 25th resistor R25 is connected to the BST pin of the chip U7, and the other end is connected to the primary side of the 27th capacitor C27, and the secondary side of the 27th capacitor C27 is connected to the LX pin of the chip U7. The cathode of the fourth diode D4 is connected to the LX pin of the chip U7, and the anode of the fourth diode D4 is grounded. One end of the 43rd resistor R43 is connected to the VFB pin of the chip U7, and the other end is grounded. One end of the second inductor L2 is connected to the LX pin of the chip U7, and the other end is connected to the VCC port, which is used to power the display module. One end of the 30th resistor R30 is connected to the BST pin of the chip U7, and the other end is connected to the VCC port. The 31st capacitor C31 and the 30th resistor R30 are connected in parallel. The primary side of the thirty-second capacitor C32 is connected to the VCC port, the secondary side of the thirty-second capacitor C32 is grounded, and the forty-second capacitor C42 and the thirty-second capacitor C32 are connected in parallel.

[0054] When the battery supplies power to chip U7, it first charges capacitor C30, and then applies it to the CE pin of chip U7 relatively slowly, which serves the purpose of delayed start, reduces the impact of instantaneous voltage on the circuit and chip U7, and improves the stability of the circuit. Chip U7 supplies power to the display module, which displays the status information of the off-grid photovoltaic power generation system.

[0055] The second transistor T2 is an NPN transistor, the base of the second transistor T2 is connected to the MCU, the collector of the second transistor T2 is connected to the CE pin of the chip U7, and the emitter of the second transistor T2 is grounded.

[0056] The second transistor T2 is turned off, the potential of the CE pin of the chip U7 is high, the chip U7 is working, and the LX pin of the chip U7 outputs 3.3V. When the sampling voltage is less than the preset value, the enable end of the MCU sends a signal to the base of the second transistor T2, so that the second transistor T2 is turned on, the potential of the CE pin of the chip U7 changes from high level to low level, and the chip U7 stops working. At the same time, the MCU controls the first MOS tube Q1 and the third MOS tube Q3 to be turned off, and the circuit where the load is located is disconnected, thereby reducing the over-discharge of the battery and extending the service life of the battery.

[0057] Reference Fig. 9 The second switch circuit 4 includes an eighty-first resistor R81, a second switch K2, an optocoupler U10 and a seventh diode D7, one end of the eighty-first resistor R81 is connected to the positive electrode of the battery, and the other end is connected to pin 1 of the optocoupler U10, one end of the second switch K2 is connected to pin 1 of the optocoupler U10, the other end of the second switch K2 is connected to pin 2 of the optocoupler U10, pins 2 and 3 of the optocoupler U10 are grounded, pin 4 of the optocoupler U10 is connected to the cathode of the seventh diode D7, and the anode of the seventh diode D7 is connected to the photovoltaic charging circuit.

[0058] When the second switch K2 is disconnected, the optocoupler U10 is turned on; when the second switch K2 is closed, the optocoupler U10 is short-circuited and the optocoupler U10 is turned off. The on and off of the photovoltaic charging circuit can be controlled by the on and off of the optocoupler U10. When not in use, the photovoltaic charging circuit is disconnected to prevent the photovoltaic panel from being unable to continue to supply power to the battery, thereby reducing overcharging. At the same time, the optocoupler U10 plays an isolating role, separating the second switch circuit 4 from the photovoltaic charging circuit. The current of the photovoltaic charging circuit does not pass through the second switch K2, the power of the optocoupler U10 is small, and the current flowing through the second switch circuit 4 is small, which can extend the service life of the second switch K2.

[0059] The implementation principle of a switch control circuit in an embodiment of the present application is as follows: the first switch K1 is closed, the battery supplies power to the chip U7 and the MCU, the MCU is started, the first MOS tube Q1 and the third MOS tube Q3 are turned on, the load works, and the working current of the load does not pass through the first switch K1. The power of the MCU is smaller than the power of the load, so that the current flowing through the first switch K1 becomes smaller, and the current impact received by the first switch K1 at the moment of closing and disconnecting becomes smaller. The on and off of the photovoltaic charging circuit can be controlled by the conduction and cutoff of the optical coupler U10. When not in use, by disconnecting the photovoltaic charging circuit, the optical coupler U10 plays an isolating role, so that the second switch circuit 4 is separated from the photovoltaic charging circuit, and the current of the photovoltaic charging circuit does not pass through the second switch K2. The power of the optical coupler U10 is small, and the current flowing through the second switch circuit 4 is small. The current impact received by the second switch K2 at the moment of closing and disconnecting becomes smaller, which prolongs the service life of the first switch K1 and the second switch K2.

[0060] The working current of the load and the current of the charging circuit can generally reach several amperes. In the present application, the current passing through the first switch K1 and the second switch K2 is 30 mA, which effectively reduces the current flowing through the first switch K1 and the second switch K2.

[0061] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Any feature disclosed in this specification (including the abstract and drawings), unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

Claims

1. A switch control circuit, characterized in that: The device comprises a first switch circuit (1), an MCU and a signal control circuit (5), wherein the input end of the first switch circuit (1) is connected to the positive electrode of a battery, the output end of the first switch circuit (1) is connected to the MCU, the signal control circuit (5) is connected to the MCU and a load respectively, and the signal control circuit (5) is used to control the on / off of a circuit in which the load is located; The switch control circuit further comprises a second switch circuit (4), and the second switch circuit (4) is respectively connected to the positive electrode of the battery and the photovoltaic charging circuit; The second switch circuit (4) comprises an eighty-first resistor R81, a second switch K2, an optocoupler U10 and a seventh diode D7, one end of the eighty-first resistor R81 is connected to the positive electrode of the battery, and the other end is connected to pin 1 of the optocoupler U10, one end of the second switch K2 is connected to pin 1 of the optocoupler U10, the other end of the second switch K2 is connected to pin 2 of the optocoupler U10, pins 2 and 3 of the optocoupler U10 are grounded, pin 4 of the optocoupler U10 is connected to the cathode of the seventh diode D7, and the anode of the seventh diode D7 is connected to the photovoltaic charging circuit.

2. A switch control circuit according to claim 1, characterized in that: The first switch circuit (1) comprises a sixth diode D6, a first switch K1, a forty-third capacitor C43, a sixty-sixth resistor R66, a thirty-third capacitor C33 and a sixty-fifth resistor R65, wherein an anode of the sixth diode D6 is connected to a positive electrode of a battery, a cathode of the sixth diode D6 is connected to one end of the first switch K1, the other end of the first switch K1 is connected to an MCU, a positive electrode of the forty-third capacitor C43 is connected to the other end of the first switch K1, a negative electrode of the forty-third capacitor C43 is grounded, one end of the sixty-sixth resistor R66 is connected to a positive electrode of the forty-third capacitor C43, and the other end is connected to a positive electrode of the thirty-third capacitor C33, the sixty-fifth resistor R65 and the sixty-sixth resistor R66 are connected in parallel, a positive electrode of the forty-third capacitor C43 is connected to the sixty-fifth resistor R65, and a negative electrode of the forty-third capacitor C43 is grounded.

3. A switch control circuit according to claim 1, characterized in that: The signal control circuit (5) comprises a first MOS transistor Q1, a third MOS transistor Q3, an eighty-third resistor R83, a fifty-second resistor R52, a fifth diode D5, a twenty-second capacitor C22 and a sixty-second resistor R62, wherein the gate of the first MOS transistor Q1 is connected to the MCU, the source of the first MOS transistor Q1 is connected to the load, the drain of the first MOS transistor Q1 is connected to the drain of the third MOS transistor Q3, the drain of the third MOS transistor Q3 is connected to one end of the eighty-third resistor R83, the other end of the eighty-third resistor R83 is connected to the load, the gate of the third MOS transistor Q3 is connected to the MCU, the source of the third MOS transistor Q3 is connected to one end of the fifty-second resistor R52, the other end of the fifty-second resistor R52 is grounded, the cathode of the fifth diode D5 is connected to the gates of the first MOS transistor Q1 and the third MOS transistor Q3, and the twenty-second capacitor C22, the sixty-second resistor R62 and the fifth diode D5 are connected in parallel.

4. A switch control circuit according to claim 3, characterized in that: It also comprises a voltage sampling circuit (6) and a voltage stabilization output module (3), wherein the voltage sampling circuit (6) is connected to the storage battery and the MCU respectively, and the voltage stabilization output module (3) is connected to the first switch circuit (1), the MCU and the display module respectively.

5. A switch control circuit according to claim 4, characterized in that: The voltage-stabilizing output module (3) comprises a second transistor T2, a chip U7 of model R1244N and its peripheral circuits, the base of the second transistor T2 is connected to the MCU, the collector of the second transistor T2 is connected to the CE pin of the chip U7, and the emitter of the second transistor T2 is grounded.

6. A switch control circuit according to claim 4, characterized in that: The voltage sampling circuit (6) comprises a fifty-seventh resistor R57, a fifty-eighth resistor R58 and a twenty-third capacitor C23, one end of the fifty-seventh resistor R57 is connected to the battery, the other end of the fifty-seventh resistor R57 is connected to the MCU, one end of the fifty-eighth resistor R58 is connected to the other end of the fifty-seventh resistor R57, the other end of the fifty-eighth resistor R58 is grounded, and the twenty-third capacitor C23 and the fifty-eighth resistor R58 are connected in parallel.

7. A switch control circuit according to claim 1, characterized in that: The invention also comprises a voltage stabilizing circuit (2), wherein the voltage stabilizing circuit (2) comprises a primary voltage stabilizing module (21) and a secondary voltage stabilizing module (22), wherein the input end of the primary voltage stabilizing module (21) is connected to the output end of the first switch circuit (1), the output end of the primary voltage stabilizing module (21) is connected to the input end of the secondary voltage stabilizing module (22), and the output end of the secondary voltage stabilizing module (22) is connected to the MCU.

8. A switch control circuit according to claim 7, characterized in that: The primary voltage stabilizing module (21) comprises a sixty-fourth resistor R64, a first transistor T1 and a second diode D2, one end of the sixty-fourth resistor R64 is connected to the collector of the first transistor T1, and the other end is connected to the base of the first transistor T1, the collector of the first transistor T1 is connected to the output end of the first switch circuit (1), the base of the first transistor T1 is connected to the cathode of the second diode D2, and the anode of the second diode D2 is grounded, and the secondary voltage stabilizing module (22) comprises a forty-sixth capacitor C46, ​​a ninth capacitor C9, a forty-fourth capacitor C44, a forty-fifth capacitor C46, ​​a ninth capacitor C9, a forty-fourth capacitor C44, a forty-fifth capacitor C46, ​​a ninth capacitor C9, a forty-fifth capacitor C44, a forty-fifth capacitor C46, ​​a ninth capacitor C9, a forty-fifth capacitor C44, a forty-fifth capacitor C44, a ninth capacitor C9, a forty-fifth capacitor C44, a ninth capacitor C9, a first ... Capacitor C45 and Zener diode U8, pin 3 of the Zener diode U8 is connected to the emitter of the first transistor T1, pin 1 of the Zener diode U8 is grounded, pin 2 of the Zener diode U8 is connected to the power supply end of the MCU, the primary side of the forty-sixth capacitor C46 is connected to pin 3 of the Zener diode U8, the secondary side of the forty-sixth capacitor C46 is grounded, the ninth capacitor C9 and the forty-sixth capacitor C46 are connected in parallel, the primary side of the forty-fourth capacitor C44 is connected to pin 3 of the Zener diode U8, the secondary side of the forty-fourth capacitor C44 is grounded, and the forty-fifth capacitor C45 and the forty-fourth capacitor C44 are connected in parallel.

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