Drive circuit and drive system

Abstract

The application provides a driving circuit and a driving system, comprising: a switching unit, a first end of the switching unit being used for electrical connection with a power supply, and a second end of the switching unit being used for electrical connection with a target device; a conduction control unit, a first end of the conduction control unit being electrically connected with a control end of the switching unit; a protection circuit, a first end of the protection circuit being electrically connected with the first end of the switching unit, a second end of the protection circuit being electrically connected with a third end of the switching unit, and a third end of the protection circuit being electrically connected with a second end of the conduction control unit; and a conduction synchronization unit, a control end of the conduction synchronization unit being electrically connected with a first input end of the conduction control unit. The driving circuit controls the switching conduction through the conduction control circuit, controls the switching unit to conduct when the alternating current is a positive half cycle through the conduction synchronization unit, and controls the switching unit to be disconnected when overcurrent or short circuit occurs through the protection circuit, thereby solving the problem that the driving circuit cannot realize overcurrent or short circuit protection in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of HVAC control, and in particular, to a driving circuit and a driving system. BACKGROUND

[0002] In some countries / regions, the control of HVAC equipment needs to use a unified HVAC controller. A single HVAC controller needs to be connected with multiple devices such as heating, ventilation, and refrigeration. Through a reasonable control algorithm, the HVAC system can save energy as much as possible under the premise of meeting the user's heating, ventilation, and refrigeration performance. The controller and the HVAC equipment are interconnected through long wiring in the building to drive the HVAC to work. Therefore, the driving circuit needs to consider functions such as wiring protection, energy saving effect, electromagnetic compatibility, anti-surge, and anti-static. The driving circuit of the HVAC is exposed to a complex electromagnetic environment, and its functions and reliability are different.

[0003] The existing driving circuit of the HVAC controller, the complete driving system is composed of multiple parallel driving circuits, each driving circuit is responsible for the driving of one device, and when the corresponding relay of the HVAC device is attracted, the device works; when the relay is disconnected, the device does not work. This wiring system has a simple structure, but the function is single and the reliability is not high. Most of the current emerging HVAC controllers are intelligent control systems that can match the best energy-saving algorithm according to the wiring state of the driving circuit. The existing driving circuit relay contact end is a passive system and cannot realize overcurrent or short circuit protection. When wiring errors or HVAC end faults occur, the controller driving circuit may be burned out.

[0004] Therefore, there is an urgent need for a driving circuit that can realize overcurrent or short circuit protection.

[0005] The above information disclosed in the background section is only used to enhance the understanding of the background of the technology described herein, and therefore, some information in the background may not form the prior art known in the country for those skilled in the art. SUMMARY

[0006] The main purpose of the present application is to provide a driving circuit and a driving system to solve the problem that the existing driving circuit cannot realize overcurrent or short circuit protection.

[0007] According to an aspect of an embodiment of the present application, a driving circuit is provided, which comprises a switching unit, a conduction control unit, a protection circuit and a conduction synchronization unit, wherein a first end of the switching unit is electrically connected to a power supply, a second end of the switching unit is electrically connected to a target device, a third end of the switching unit is grounded, and the switching unit is configured to control conduction or disconnection of the target device; a first end of the conduction control unit is electrically connected to a control end of the switching unit, and the conduction control unit is configured to control operation of the switching unit; a first end of the protection circuit is electrically connected to the first end of the switching unit, a second end of the protection circuit is electrically connected to the third end of the switching unit, a third end of the protection circuit is electrically connected to a second end of the conduction control unit, and the protection circuit is configured to control disconnection of the switching unit under a predetermined condition, the predetermined condition including at least one of overcurrent and short circuit; and a control end of the conduction synchronization unit is electrically connected to a first input end of the conduction control unit, and the conduction synchronization unit is configured to control the switching unit to operate in a positive half cycle of alternating current.

[0008] Optionally, the switching unit comprises a first switching device and a second switching device, wherein the first switching device comprises a first NMOS tube and a first diode, a source of the first NMOS tube is electrically connected to an anode of the first diode, a drain of the first NMOS tube is electrically connected to a cathode of the first diode, and the drain of the first NMOS tube is the first end of the switching unit; the second switching device comprises a second NMOS tube and a second diode, a source of the second NMOS tube is electrically connected to an anode of the second diode, a drain of the second NMOS tube is electrically connected to a cathode of the second diode, the drain of the second NMOS tube is the second end of the switching unit, the source of the second NMOS tube is electrically connected to the source of the first NMOS tube, a gate of the second NMOS tube is electrically connected to a gate of the first NMOS tube, and the gate of the second NMOS tube is the control end of the switching unit.

[0009] Optionally, the switching unit further comprises a third diode, an anode of the third diode is electrically connected to the source of the first NMOS tube and the source of the second NMOS tube, a cathode of the third diode is electrically connected to the second end of the protection circuit, and the anode of the third diode is the third end of the switching unit.

[0010] Optionally, the conduction control unit comprises a flip-flop circuit and a third switching device, wherein the flip-flop circuit comprises a D flip-flop and a first resistance module, a first end of the first resistance module is electrically connected with an output end of the D flip-flop, a first input end of the D flip-flop is a first input end of the conduction control unit, a second input end of the D flip-flop is a second input end of the conduction control unit, and a second end of the first resistance module is a second end of the conduction control unit; a control end of the third switching device is electrically connected with the output end of the D flip-flop, a first end of the third switching device is grounded, a second end of the third switching device is electrically connected with the control end of the switching unit, and the second end of the third switching device is a first end of the conduction control unit.

[0011] Optionally, the third switching device comprises a third NMOS tube, a second resistance module and a first transistor, wherein a gate of the third NMOS tube is electrically connected with a second end of the first resistance module, and a source of the third NMOS tube is grounded; a first end of the second resistance module is electrically connected with a drain of the third NMOS tube; a base of the first transistor is electrically connected with a second end of the second resistance module, a collector of the first transistor is electrically connected with the control end of the switching unit, an emitter of the first transistor is configured to be electrically connected with the power supply, and the collector of the first transistor is the first end of the conduction control unit.

[0012] Optionally, the third switching device further comprises a first filter circuit and a second filter circuit, wherein one end of the first filter circuit is electrically connected with the base of the first transistor and the second end of the second resistance module, and the other end of the first filter circuit is electrically connected with the emitter of the first transistor; one end of the second filter circuit is electrically connected with the collector of the first transistor, and the other end of the second filter circuit is electrically connected with the third end of the switching unit.

[0013] Optionally, the first filter circuit comprises a third resistance module and a first capacitor module, wherein a first end of the third resistance module is electrically connected with the second end of the second resistance module; a first end of the first capacitor module is electrically connected with the first end of the third resistance module, and a second end of the first capacitor module is electrically connected with a second end of the third resistance module; the second filter circuit comprises a second capacitor module and a fourth resistance module, wherein a first end of the second capacitor module is electrically connected with the third end of the switching unit, and a second end of the second capacitor module is electrically connected with the control end of the switching unit; a first end of the fourth resistance module is electrically connected with the first end of the second capacitor module, and a second end of the fourth resistance module is electrically connected with the second end of the second capacitor module.

[0014] Optionally, the protection circuit comprises a fourth switching device, a control end of the fourth switching device is electrically connected with the first end of the switching unit, a second end of the fourth switching device is electrically connected with the third end of the switching unit, a first end of the fourth switching device is electrically connected with the second end of the conduction control unit, the control end of the fourth switching device is the first end of the protection circuit, the second end of the fourth switching device is the second end of the protection circuit, and the first end of the fourth switching device is the third end of the protection circuit.

[0015] Optionally, the fourth switching device comprises a fifth resistance module, a second transistor and a third transistor, a second end of the fifth resistance module is electrically connected with the first end of the switching unit, a collector of the second transistor is electrically connected with a first end of the fifth resistance module, an emitter of the second transistor is electrically connected with the second end of the conduction control unit, a collector of the third transistor is electrically connected with a base of the second transistor, an emitter of the third transistor is grounded, and a base of the third transistor is electrically connected with the collector of the second transistor.

[0016] Optionally, the conduction synchronization unit comprises a first conduction control circuit and a fifth switching device, a first end of the first conduction control circuit is used for being electrically connected with the power supply, a control end of the fifth switching device is electrically connected with a second end of the first conduction control circuit, a first end of the fifth switching device is used for being electrically connected with the first input end of the conduction control unit, a second end of the fifth switching device is grounded, and the first end of the fifth switching device is the control end of the conduction synchronization unit.

[0017] Optionally, the first conduction control circuit comprises a sixth resistance module and a fourth diode, a second end of the sixth resistance module is used for being electrically connected with the power supply, a positive electrode of the fourth diode is electrically connected with a first end of the sixth resistance module, the fifth switching device comprises a fourth transistor and a seventh resistance module, a base of the fourth transistor is electrically connected with a negative electrode of the fourth diode, a collector of the fourth transistor is electrically connected with the first input end of the conduction control unit, an emitter of the fourth transistor is grounded, the collector of the fourth transistor is the control end of the conduction synchronization unit, a first end of the seventh resistance module is electrically connected with the collector of the fourth transistor, and a second end of the seventh resistance module is used for being electrically connected with the power supply.

[0018] Optionally, the drive circuit further comprises an acceleration-off unit for accelerating the speed of the target device being turned off by the switch unit, the acceleration-off unit comprising a sixth switch device and a seventh switch device, wherein a control end of the sixth switch device is electrically connected with the second end of the conduction control unit, and a first end of the sixth switch device is grounded; a control end of the seventh switch device is electrically connected with the first end of the conduction control unit, a first end of the seventh switch device is electrically connected with a second end of the sixth switch device, and a second end of the seventh switch device is electrically connected with the third end of the switch unit.

[0019] Optionally, the sixth switch device comprises a fourth NMOS tube, an eighth resistance module, a fifth transistor, a fifth diode, and a ninth resistance module, wherein a gate of the fourth NMOS tube is electrically connected with the second end of the conduction control unit, and a source of the fourth NMOS tube is grounded; a first end of the eighth resistance module is electrically connected with a drain of the fourth NMOS tube, and a second end of the eighth resistance module is configured to be electrically connected with the power supply; a base of the fifth transistor is electrically connected with the first end of the eighth resistance module, and an emitter of the fifth transistor is grounded; a negative electrode of the fifth diode is electrically connected with a collector of the fifth transistor; a first end of the ninth resistance module is electrically connected with a positive electrode of the fifth diode; the seventh switch device comprises a sixth diode and a sixth transistor, wherein a positive electrode of the sixth diode is electrically connected with a second end of the ninth resistance module, and a negative electrode of the sixth diode is electrically connected with the first end of the conduction control unit; a base of the sixth transistor is electrically connected with the positive electrode of the sixth diode, a collector of the sixth transistor is electrically connected with the third end of the switch unit, and an emitter of the sixth transistor is electrically connected with the negative electrode of the sixth diode.

[0020] Optionally, the drive circuit further comprises a detection circuit and an isolation circuit, the detection circuit being configured to detect whether the target device is connected to the drive circuit, the detection circuit comprising a first rectifier circuit and a first voltage stabilizing circuit, wherein a first end of the first rectifier circuit is electrically connected with the second end of the switch unit; a first end of the first voltage stabilizing circuit is electrically connected with a second end of the first rectifier circuit and a first input end of the isolation circuit, and a second end of the first voltage stabilizing circuit is electrically connected with the second end of the protection circuit; the isolation circuit is configured to isolate digital signals, and an output end of the isolation circuit is electrically connected with the second input end of the conduction control unit.

[0021] Optionally, the first rectifier circuit comprises a seventh diode and a tenth resistor module, wherein the positive electrode of the seventh diode is electrically connected with the second end of the switch unit; the first end of the tenth resistor module is electrically connected with the negative electrode of the seventh diode; the first voltage stabilizing circuit comprises a third capacitor module, a first voltage stabilizer, an eleventh resistor module and a twelfth resistor module, wherein the first end of the third capacitor module is electrically connected with the second end of the tenth resistor module, and the second end of the third capacitor module is electrically connected with the second end of the protection circuit; the anode of the first voltage stabilizer is electrically connected with the second end of the protection circuit, and the cathode of the first voltage stabilizer is electrically connected with the first end of the third capacitor module; the first end of the eleventh resistor module is electrically connected with the reference end of the first voltage stabilizer, and the second end of the eleventh resistor module is electrically connected with the anode of the first voltage stabilizer; the first end of the twelfth resistor module is electrically connected with the cathode of the first voltage stabilizer, and the second end of the twelfth resistor module is electrically connected with the first end of the eleventh resistor module.

[0022] Optionally, the driving circuit further comprises a micro control unit, and an output end of the micro control unit is electrically connected with the second input end of the isolation circuit, and is used for outputting a signal for turning on or off the target device.

[0023] Optionally, the driving circuit further comprises a power supply circuit, which is used for converting alternating current into direct current, and the power supply circuit comprises a second rectifier circuit and a second voltage stabilizing circuit, wherein the first end of the second rectifier circuit is electrically connected with the first end of an alternating current power supply, the second end of the second rectifier circuit is electrically connected with the second end of the alternating current power supply; the first end of the second voltage stabilizing circuit is electrically connected with the third end of the second rectifier circuit, and the second end of the second voltage stabilizing circuit is electrically connected with the fourth end of the second rectifier circuit.

[0024] Optionally, the second rectifier circuit comprises a ninth diode, a fourth capacitor module and a twelfth diode, wherein the positive electrode of the ninth diode is configured to be electrically connected with the first end of the alternating power supply; the second end of the fourth capacitor module is electrically connected with the negative electrode of the ninth diode; the positive electrode of the twelfth diode is electrically connected with the first end of the fourth capacitor module, and the negative electrode of the twelfth diode is configured to be electrically connected with the second end of the alternating power supply; the second voltage stabilizing circuit comprises a thirteenth resistor module, a second voltage stabilizer, a fifth capacitor module, a seventh transistor, a fourteenth resistor module and a fifteenth resistor module, wherein the second end of the thirteenth resistor module is electrically connected with the second end of the fourth capacitor module; the cathode of the second voltage stabilizer is electrically connected with the first end of the thirteenth resistor module, and the anode of the second voltage stabilizer is electrically connected with the first end of the fourth capacitor module; the first end of the fifth capacitor module is electrically connected with the reference end of the second voltage stabilizer, and the second end of the fifth capacitor module is electrically connected with the first end of the thirteenth resistor module; the base of the seventh transistor is electrically connected with the second end of the fifth capacitor module, the collector of the seventh transistor is electrically connected with the second end of the thirteenth resistor module, and the emitter of the seventh transistor is configured to output direct current; the first end of the fourteenth resistor module is electrically connected with the first end of the fifth capacitor module, and the second end of the fourteenth resistor module is electrically connected with the emitter of the seventh transistor; the first end of the fifteenth resistor module is electrically connected with the anode of the second voltage stabilizer and grounded, and the second end of the fifteenth resistor module is electrically connected with the first end of the fourteenth resistor module.

[0025] According to an aspect of the embodiments of the present application, there is provided a driving system, comprising: one or more HVAC devices and one or more driving circuits, wherein one of the HVAC devices corresponds to one of the driving circuits, the HVAC device is electrically connected with the driving circuit, and the driving circuit is any of the driving circuits.

[0026] In the embodiment of the present application, the driving circuit comprises a switching unit, a conduction control unit, a protection circuit and a conduction synchronization unit, wherein the first end of the switching unit is electrically connected with a power supply, the second end of the switching unit is electrically connected with a target device, the third end of the switching unit is grounded, and the switching unit is used to control the conduction or disconnection of the target device; the first end of the conduction control unit is electrically connected with the control end of the switching unit, and is used to control the operation of the switching unit; the first end of the protection circuit is electrically connected with the first end of the switching unit, the second end of the protection circuit is electrically connected with the third end of the switching unit, the third end of the protection circuit is electrically connected with the second end of the conduction control unit, and is used to control the disconnection of the switching unit under a predetermined condition, the predetermined condition comprising at least one of overcurrent and short circuit; and the control end of the conduction synchronization unit is electrically connected with the first input end of the conduction control unit, and is used to control the conduction of the switching unit when the alternating current at the two ends of the switching unit is in a positive half cycle. The driving circuit controls the conduction of the switching unit through the conduction control circuit, controls the conduction of the switching unit when the alternating current at the two ends of the switching unit is in a positive half cycle through the conduction synchronization unit, and controls the disconnection of the switching unit when the alternating current at the two ends of the switching unit is in a positive half cycle and overcurrent or short circuit occurs in the circuit through the protection circuit, so that the target device is not connected to the circuit, thereby solving the problem that the driving circuit cannot realize overcurrent or short circuit protection in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and serve as an explanation of the present application, and do not constitute improper limitations to the present application. In the drawings:

[0028] Figure 1 A driving circuit schematic diagram of a typical embodiment of the present application is shown;

[0029] Figure 2 A power supply circuit and a plurality of driving circuits of an embodiment of the present application are shown;

[0030] Figure 3 A driving circuit schematic diagram of an embodiment of the present application is shown;

[0031] Figure 4 A driving circuit schematic diagram of another embodiment of the present application is shown;

[0032] Figure 5 A driving circuit schematic diagram of still another embodiment of the present application is shown;

[0033] Figure 6 A power supply circuit schematic diagram of an embodiment of the present application is shown.

[0034] In the above drawings, the following reference signs are used:

[0035] 10, switch unit; 20, conduction control unit; 30, protection circuit; 40, conduction synchronization unit; 11, first switch device; 12, second switch device; 101, first NMOS tube; 102, first diode; 103, second NMOS tube; 104, second diode; 105, third diode; 21, flip-flop circuit; 22, third switch device; 201, D flip-flop; 202, first resistance module; 203, third NMOS tube; 204, second resistance module; 205, first transistor; 221, first filter circuit; 222, second filter circuit; 206, third resistance module; 207, first capacitor module; 208, fourth resistance module; 209, second capacitor module; 31, fourth switch device; 301, fifth resistance module; 302, second transistor; 303, third transistor; 41, first conduction control circuit; 42, fifth switch device; 401, sixth resistance module; 402, fourth diode; 403, fourth transistor; 404, seventh resistance module; 50, acceleration opening unit; 51, sixth switch device; 52, seventh switch device; 501, fourth NMOS tube; 502, eighth resistance module; 503, fifth transistor; 504, fifth diode; 505, ninth resistance module; 506, sixth diode; 507, sixth transistor; 60, detection circuit; 61, first rectifier circuit; 62, first voltage stabilizing circuit; 601, seventh diode; 602, tenth resistance module; 603, third capacitor module; 604, first voltage stabilizer; 605, eleventh resistance module; 606, twelfth resistance module; 70, isolation circuit; 80, micro-control unit; 90, power supply circuit; 91, second rectifier circuit; 92, second voltage stabilizing circuit; 901, ninth diode; 902, fourth capacitor module; 903, twelfth diode; 904, thirteenth resistance module; 905, second voltage stabilizer; 906, fifth capacitor module; 907, seventh transistor; 908, fourteenth resistance module; 909, fifteenth resistance module. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0037] It is to be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0038] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element, or intervening elements can also be present.

[0039] As mentioned in the background, the prior art driving circuit cannot realize overcurrent or short circuit protection, in order to solve the above problems, the present application provides a driving circuit and a driving system.

[0040] In a typical embodiment of the present application, a driving circuit is provided, as shown in Figure 1 The driving circuit includes a switching unit 10, a conduction control unit 20, a protection circuit 30, and a conduction synchronization unit 40. The first end of the switching unit 10 is electrically connected to a power supply, the second end of the switching unit 10 is electrically connected to a target device, the third end of the switching unit 10 is grounded, and the switching unit 10 is used to control the conduction or disconnection of the target device. The first end of the conduction control unit 20 is electrically connected to the control end of the switching unit 10, and is used to control the operation of the switching unit 10. The first end of the protection circuit 30 is electrically connected to the first end of the switching unit 10, the second end of the protection circuit 30 is electrically connected to the third end of the switching unit 10, the third end of the protection circuit 30 is electrically connected to the second end of the conduction control unit 20, and is used to control the disconnection of the switching unit 10 under predetermined conditions, which include at least one of overcurrent and short circuit. The control end of the conduction synchronization unit 40 is electrically connected to the first input end of the conduction control unit 20, and is used to control the operation of the switching unit 10 in the positive half cycle of alternating current.

[0041] The driving circuit comprises a switch unit, a conduction control unit, a protection circuit and a conduction synchronization unit. The first end of the switch unit is electrically connected with a power supply, the second end of the switch unit is electrically connected with a target device, the third end of the switch unit is grounded, and the switch unit is used for controlling the conduction or disconnection of the target device. The first end of the conduction control unit is electrically connected with the control end of the switch unit, and the conduction control unit is used for controlling the operation of the switch unit. The first end of the protection circuit is electrically connected with the first end of the switch unit, the second end of the protection circuit is electrically connected with the third end of the switch unit, the third end of the protection circuit is electrically connected with the second end of the conduction control unit, and the protection circuit is used for controlling the disconnection of the switch unit under a predetermined condition, wherein the predetermined condition comprises at least one of overcurrent and short circuit. The control end of the conduction synchronization unit is electrically connected with the first input end of the conduction control unit, and the conduction synchronization unit is used for controlling the switch unit to be conducted when the alternating current between the two ends of the switch unit is a positive half cycle. The driving circuit controls the conduction of the switch through the conduction control circuit, controls the switch unit to be conducted when the alternating current between the two ends of the switch unit is a positive half cycle through the conduction synchronization unit, and controls the switch unit to be disconnected when the alternating current between the two ends of the switch unit is a positive half cycle and overcurrent or short circuit occurs in the circuit through the protection circuit, so that the target device is not connected to the circuit, thereby solving the problem that the driving circuit cannot realize overcurrent or short circuit protection in the prior art.

[0042] In practical applications, one driving circuit controls one target device. There can be multiple driving circuits, such as driving circuit 1, driving circuit 2, …, and driving circuit n, as shown in FIG. 1. Figure 2 The multiple driving circuits constitute a driving system.

[0043] In an embodiment of the present application, as shown in FIG. 2, the driving circuit comprises a switch unit, a conduction control unit, a protection circuit and a conduction synchronization unit. Figure 3As shown, the switch unit includes a first switch device 11 and a second switch device 12, wherein the first switch device 11 includes a first NMOS transistor 101 and a first diode 102, the source of the first NMOS transistor 101 is electrically connected to the anode of the first diode 102, the drain of the first NMOS transistor 101 is electrically connected to the cathode of the first diode 102, and the drain of the first NMOS transistor 101 is the first end of the switch unit 10; the second switch device 12 includes a second NMOS transistor 103 and a second diode The source of the second NMOS transistor 103 is electrically connected to the anode of the second diode 104, the drain of the second NMOS transistor 103 is electrically connected to the cathode of the second diode 104, the drain of the second NMOS transistor 103 is electrically connected to the second terminal of the switch unit 10, the source of the second NMOS transistor 103 is electrically connected to the source of the first NMOS transistor 101, and the gate of the second NMOS transistor 103 is electrically connected to the gate of the first NMOS transistor 101, and serves as the control terminal of the switch unit 10. The first NMOS transistor 101 and the second NMOS transistor 103 are connected in reverse series to prevent the NMOS body diode from being mis-conducted in an AC circuit.

[0044] Specifically, the AC power supply has two terminals, R and C. Figure 3 As shown, the first end of the above-mentioned switch unit is electrically connected to the R end of the AC power supply, and the second end of the above-mentioned switch unit is electrically connected to the C end of the AC power supply through the target device. The AC power supply parameters can be a voltage of 18~30V and a frequency of 50~60Hz.

[0045] In order to prevent the current from flowing between the multiple driving circuits and avoid the bidirectional switch from malfunctioning, in another embodiment of the present application, Figure 3 As shown, the above-mentioned switching unit 10 also includes a third diode 105, the anode of the above-mentioned third diode 105 is electrically connected to the source of the above-mentioned first NMOS tube 101, and is electrically connected to the source of the above-mentioned second NMOS tube 103, the cathode of the above-mentioned third diode 105 is electrically connected to the second end of the above-mentioned protection circuit 30, and the anode of the above-mentioned third diode 105 is the third end of the above-mentioned switching unit 10.

[0046] In another embodiment of the present application, Figure 3As shown in the figure, the conduction control unit 20 includes a flip-flop circuit 21 and a third switching device 22. The flip-flop circuit 21 includes a D flip-flop 201 and a first resistance module 202. The first end of the first resistance module 202 is electrically connected to the output end of the D flip-flop 201. The first input end of the D flip-flop 201 is the first input end of the conduction control unit 20. The second input end of the D flip-flop 201 is the second input end of the conduction control unit 20. The second end of the first resistance module 202 is the second end of the conduction control unit 20. The control end of the third switching device 22 is electrically connected to the output end of the D flip-flop 201. The first end of the third switching device 22 is grounded. The second end of the third switching device 22 is electrically connected to the control end of the switching unit 10. The second end of the third switching device 22 is the first end of the conduction control unit 20. The conduction control unit includes a flip-flop circuit and a third switching device. The D flip-flop outputs a high level, so that the third switching device is turned on, thereby controlling the conduction of the bidirectional switch.

[0047] In another embodiment of the present application, as shown in the figure, Figure 3 The third switching device 22 includes a third NMOS tube 203, a second resistance module 204, and a first transistor 205. The gate of the third NMOS tube 203 is electrically connected to the second end of the first resistance module 202. The source of the third NMOS tube 203 is grounded. The first end of the second resistance module 204 is electrically connected to the drain of the third NMOS tube 203. The base of the first transistor 205 is electrically connected to the second end of the second resistance module 204. The collector of the first transistor 205 is electrically connected to the control end of the switching unit 10. The emitter of the first transistor 205 is electrically connected to the power supply. The collector of the first transistor 205 is the first end of the conduction control unit 20. The emitter of the first transistor is electrically connected to the DC power supply. When the D flip-flop outputs a high level, the third NMOS tube is turned on, the first transistor is controlled to be turned on, and the DC power supply charges the gate-source of the first NMOS tube and the second NMOS tube through the first transistor and the third diode, so that the switching unit is turned on.

[0048] In order to make the first transistor turn on smoothly, in another embodiment of the present application, as shown in the figure, Figure 3As shown in the figure, the third switch device 22 further includes a first filter circuit 221 and a second filter circuit 222. The first filter circuit 221 has one end electrically connected to the base of the first transistor 205 and the second end of the second resistance module 204, and the other end electrically connected to the emitter of the first transistor 205. The second filter circuit 222 has one end electrically connected to the collector of the first transistor 205, and the other end electrically connected to the third end of the switch unit 10.

[0049] In another embodiment of the present application, as shown in the figure, Figure 3 The first filter circuit 221 includes a third resistance module 206 and a first capacitance module 207. The first end of the third resistance module 206 is electrically connected to the second end of the second resistance module 204. The first end of the first capacitance module 207 is electrically connected to the first end of the third resistance module 206, and the second end of the first capacitance module 207 is electrically connected to the second end of the third resistance module 206. The second filter circuit 222 includes a second capacitance module 209 and a fourth resistance module 208. The first end of the second capacitance module 209 is electrically connected to the third end of the switch unit 10, and the second end of the second capacitance module 209 is electrically connected to the control end of the switch unit 10. The first end of the fourth resistance module 208 is electrically connected to the first end of the second capacitance module 209, and the second end of the fourth resistance module 208 is electrically connected to the second end of the second capacitance module 209. When the third NMOS tube is turned on, the base potential of the first transistor is pulled down by voltage division through the second resistance module and the third resistance module, so that the first transistor is turned on.

[0050] In order to make the switch unit disconnected when the circuit is overcurrent or short-circuited, in another embodiment of the present application, as shown in the figure, Figure 3 The protection circuit 30 includes a fourth switch device 31. The control end of the fourth switch device 31 is electrically connected to the first end of the switch unit 10. The second end of the fourth switch device 31 is electrically connected to the third end of the switch unit 10. The first end of the fourth switch device 31 is electrically connected to the second end of the conduction control unit 20. The control end of the fourth switch device 31 is the first end of the protection circuit 30. The second end of the fourth switch device 31 is the second end of the protection circuit 30. The first end of the fourth switch device 31 is the third end of the protection circuit 30.

[0051] In another embodiment of the present application, as shown in the figure, Figure 3As shown in the figure, the fourth switch device 31 includes a fifth resistance module 301, a second transistor 302, and a third transistor 303. The second end of the fifth resistance module 301 is electrically connected with the first end of the switch unit 10. The collector of the second transistor 302 is electrically connected with the first end of the fifth resistance module 301, and the emitter of the second transistor 302 is electrically connected with the second end of the conduction control unit 20. The collector of the third transistor 303 is electrically connected with the base of the second transistor 302, the emitter of the third transistor 303 is grounded, and the base of the third transistor 303 is electrically connected with the collector of the second transistor 302. When overcurrent or short circuit occurs in the positive half cycle of the current from the R end to the C end of the alternating current, the drain-source voltage drop of the first NMOS transistor rises. When the voltage drop is greater than the base-emitter conduction threshold of the third transistor, the third transistor is turned on, and the collector potential of the third transistor is pulled down, that is, the base potential of the second transistor is pulled down, so that the second transistor is turned on, and the collector potential of the second transistor is pulled up, so that the base of the third transistor maintains a high potential. At this time, the second transistor and the third transistor are interlocked, and can be kept on, so that the target device is not connected to the circuit, until the D flip-flop output is low or the power supply is removed.

[0052] Since the above-mentioned protection circuit only protects the case where the drain voltage of the first NMOS transistor is greater than the source voltage, it is required that the current direction of the load is the positive half cycle of the alternating current from the R end to the C end at the moment of turning on the driving circuit, so as to achieve the maximum sensitivity of protection. In order to further realize the protection effect, when the current direction of the load is the negative half cycle, the switch unit can also be smoothly disconnected. In another embodiment of the present application, as shown in the figure, Figure 3 The conduction synchronization unit 40 includes a first conduction control circuit 41 and a fifth switch device 42. The first end of the first conduction control circuit 41 is electrically connected with the power supply. The control end of the fifth switch device 42 is electrically connected with the second end of the first conduction control circuit 41. The first end of the fifth switch device 42 is electrically connected with the first input end of the conduction control unit 20, and the second end of the fifth switch device 42 is grounded. The first end of the fifth switch device 42 is the control end of the conduction synchronization unit 40.

[0053] In another embodiment of the present application, as shown in the figure, Figure 3As shown in the figure, the first conduction control circuit 41 includes a sixth resistor module 401 and a fourth diode 402, wherein the second end of the sixth resistor module 401 is electrically connected with the power supply; the positive electrode of the fourth diode 402 is electrically connected with the first end of the sixth resistor module 401; the fifth switch device 42 includes a fourth transistor 403 and a seventh resistor module 404, wherein the base of the fourth transistor 403 is electrically connected with the negative electrode of the fourth diode 402, the collector of the fourth transistor 403 is electrically connected with the first input end of the conduction control unit 20, the emitter of the fourth transistor 403 is grounded, and the collector of the fourth transistor 403 is the control end of the conduction synchronization unit 40; the first end of the seventh resistor module 404 is electrically connected with the collector of the fourth transistor 403, and the second end of the seventh resistor module 404 is electrically connected with the power supply. When the power supply voltage is in the negative half cycle, the current flows through the AC power supply C end, the sixth resistor module, the fourth diode and the base-emitter of the fourth transistor, at this time the fourth transistor is turned on, and the collector of the fourth transistor outputs a low level; when the power supply voltage is in the positive half cycle, no current flows through the AC power supply C end, the sixth resistor module, the fourth diode and the base-emitter of the fourth transistor, at this time the fourth transistor is not turned on, and the collector of the fourth transistor outputs a high level, therefore, the fourth transistor outputs a rising edge at the moment when the voltage is in the negative half cycle and enters the positive half cycle, and the rising edge is output to the CLK end of the D flip-flop. When the conduction signal enters the D end of the D flip-flop second input end, the Q output end of the D flip-flop will not respond immediately, only when the rising edge of the CLK comes, the Q output end of the D flip-flop will follow the D end of the D flip-flop second input end, so that the first NMOS transistor and the second NMOS transistor are turned on. In summary, the first NMOS transistor and the first NMOS transistor can only be turned on at the voltage zero-crossing point, because the target device is all inductive load, the current phase lags behind the voltage phase by 0-90°, therefore, the target device is finally controlled to be turned on in the positive half cycle, so as to ensure that the protection circuit takes effect quickly.

[0054] In order to make the switch unit turn off as soon as possible after triggering the overcurrent or short-circuit protection, in another embodiment of the application, as shown in Figure 4 and Figure 5 shown, the drive circuit further includes an acceleration opening unit 50 for accelerating the speed of the switch unit 10 controlling the disconnection of the target device, and the acceleration opening unit 50 includes a sixth switch device 51 and a seventh switch device 52, wherein the control end of the sixth switch device 51 is electrically connected with the second end of the conduction control unit 20, and the first end of the sixth switch device 51 is grounded; the control end of the seventh switch device 52 is electrically connected with the first end of the conduction control unit 20, the first end of the seventh switch device 52 is electrically connected with the second end of the sixth switch device 51, and the second end of the seventh switch device 52 is electrically connected with the third end of the switch unit 10.

[0055] In another embodiment of the present application, Figure 4 As shown, the sixth switch device 51 includes a fourth NMOS transistor 501, an eighth resistor module 502, a fifth transistor 503, a fifth diode 504, and a ninth resistor module 505, wherein the gate of the fourth NMOS transistor 501 is electrically connected to the second end of the conduction control unit 20, and the source of the fourth NMOS transistor 501 is grounded; the first end of the eighth resistor module 502 is electrically connected to the drain of the fourth NMOS transistor 501, and the second end of the eighth resistor module 502 is used to be electrically connected to the power supply; the base of the fifth transistor 503 is electrically connected to the first end of the eighth resistor module 502, and the emitter of the fifth transistor 503 is grounded; the cathode of the fifth diode 504 is electrically connected to the first end of the eighth resistor module 502, and the emitter of the fifth transistor 503 is grounded; The first end of the ninth resistor module 505 is electrically connected to the anode of the fifth diode 504; the seventh switching device 52 includes a sixth diode 506 and a sixth transistor 507, wherein the anode of the sixth diode 506 is electrically connected to the second end of the ninth resistor module 505, and the cathode of the sixth diode 506 is electrically connected to the first end of the conduction control unit 20; the base of the sixth transistor 507 is electrically connected to the anode of the sixth diode 506, the collector of the sixth transistor 507 is electrically connected to the third end of the switching unit 10, and the emitter of the sixth transistor 507 is electrically connected to the cathode of the sixth diode 506. When the bidirectional switch needs to be turned off, the D-type flip-flop or protection circuit pulls the gate level of the fourth NMOS transistor low, causing the drain of the fourth NMOS transistor to output a high level, turning on the fifth transistor. At this time, because the voltage at the collector of the first transistor is higher than GND (ground), current flows through the emitter-base of the sixth transistor, the ninth resistor module, the fifth diode, and the collector-emitter of the fifth transistor. This current turns on the sixth transistor, and the charge stored between the second capacitor module and the gate-source of the first and second NMOS transistors is rapidly discharged through the six transistors, causing the first and second NMOS transistors to quickly turn off, providing timely protection. The sixth diode prevents high voltage from breaking down the base-emitter of the sixth transistor. The fifth diode prevents current from VCC through the eighth resistor module, the base-collector of the fifth transistor, the ninth resistor module, and the sixth diode to the gates of the first and second NMOS transistors, potentially causing mis-conduction.

[0056] In actual applications, when an overcurrent or short circuit occurs in the positive half cycle of the current at the R terminal relative to the C terminal of the AC power, the second transistor and the third transistor in the above protection circuit continue to be turned on, and the third NMOS transistor and the fourth NMOS transistor can also be turned off, accelerating the disconnection of the switch unit.

[0057] In order to detect whether the target device is connected to the driving circuit, and in order to isolate the digital signal, enhance the ESD, EFT, surge and EMC performance, in another embodiment of the present application, as shown in Figure 4 and Figure 5 The driving circuit further comprises a detection circuit 60 and an isolation circuit 70. The detection circuit 60 is used to detect whether the target device is connected to the driving circuit. The detection circuit 60 comprises a first rectifier circuit 61 and a first voltage stabilizing circuit 62. The first end of the first rectifier circuit 61 is electrically connected to the second end of the switch unit 10. The first end of the first voltage stabilizing circuit 62 is electrically connected to the second end of the first rectifier circuit 61 and the first input end of the isolation circuit 70. The second end of the first voltage stabilizing circuit 62 is electrically connected to the second end of the protection circuit 30. The isolation circuit 70 is used for digital signal isolation. The output end of the isolation circuit 70 is electrically connected to the second input end of the conduction control unit 20. The conduction signal of the isolation circuit enters the second input end of the D flip-flop.

[0058] In practical applications, the isolation circuit can be realized by general methods such as integrated digital isolator, optocoupler, transformer, etc. Those skilled in the art can select according to actual needs.

[0059] In another embodiment of the present application, as shown in Figure 4As shown in the figure, the first rectifier circuit 61 includes a seventh diode 601 and a tenth resistor module 602, wherein the positive electrode of the seventh diode 601 is electrically connected to the second end of the switch unit 10; the first end of the tenth resistor module 602 is electrically connected to the negative electrode of the seventh diode 601; the first voltage stabilizing circuit 62 includes a third capacitor module 603, a first voltage stabilizer 604, an eleventh resistor module 605, and a twelfth resistor module 606, wherein the first end of the third capacitor module 603 is electrically connected to the second end of the tenth resistor module 602, and the second end of the third capacitor module 603 is electrically connected to the second end of the protection circuit 30; the anode of the first voltage stabilizer 604 is electrically connected to the second end of the protection circuit 30, and the cathode of the first voltage stabilizer 604 is electrically connected to the first end of the third capacitor module 603; the first end of the eleventh resistor module 605 is electrically connected to the reference end of the first voltage stabilizer 604, and the second end of the eleventh resistor module 605 is electrically connected to the anode of the first voltage stabilizer 604; the first end of the twelfth resistor module 606 is electrically connected to the cathode of the first voltage stabilizer 604, and the second end of the twelfth resistor module 606 is electrically connected to the first end of the eleventh resistor module 605. When there is no target device connected, the second end of the switch unit has no voltage load, and the level output to the isolation circuit is consistent with GND, that is, low level; when there is a target device connected, the current flows from the seventh diode and the eleventh resistor module to the third capacitor module, wherein the first voltage stabilizer is an adjustable parallel voltage stabilizer, the voltage value at both ends is set through the eleventh resistor module and the twelfth resistor module, and the first voltage stabilizer functions to maintain the voltage at both ends of the third capacitor module as a constant value, that is, the third capacitor module can continuously output high level. The seventh diode functions to prevent the current from flowing from the third transistor and the first voltage stabilizer to the second end of the switch unit, causing the bidirectional switch to be misdirected, and the eleventh resistor module functions to limit the current flowing to the detection circuit. The output signal of the detection circuit is connected to the isolation circuit.

[0060] In order to be able to represent the turn-on or turn-off of the target device, in another embodiment of the present application, as shown in the figure, Figure 5 the driving circuit further includes a micro control unit 80, and the output end of the micro control unit 80 is electrically connected to the second input end of the isolation circuit 70, for outputting a signal for turning on or turning off the target device. The GPIO output of the micro control unit is high level or low level, which respectively represents that the target device is turned on or turned off, and the output signal of the detection circuit is connected to the isolation circuit, which can be detected by the micro control unit through the isolation circuit.

[0061] In order to form a direct current power supply, in another embodiment of the present application, as shown in the figure, Figure 2 and Figure 6As shown in the figure, the driving circuit further comprises a power supply circuit 90 for converting alternating current into direct current, the power supply circuit 90 comprising a second rectifier circuit 91 and a second voltage stabilizing circuit 92, wherein the first end of the second rectifier circuit 91 is electrically connected to the first end of the alternating current power supply, the second end of the second rectifier circuit 91 is electrically connected to the second end of the alternating current power supply; the first end of the second voltage stabilizing circuit 92 is electrically connected to the third end of the second rectifier circuit 91, and the second end of the second voltage stabilizing circuit 92 is electrically connected to the fourth end of the second rectifier circuit 91.

[0062] In practical application, the power supply circuit has a simple structure, and multiple driving circuits can share one power supply circuit, thereby effectively reducing the cost.

[0063] In another embodiment of the present application, as Figure 6As shown in the figure, the second rectifier circuit 91 includes a ninth diode 901, a fourth capacitor module 902, and a twelfth diode 903. The positive pole of the ninth diode 901 is electrically connected to the first end of the AC power supply. The second end of the fourth capacitor module 902 is electrically connected to the negative pole of the ninth diode 901. The positive pole of the twelfth diode 903 is electrically connected to the first end of the fourth capacitor module 902, and the negative pole of the twelfth diode 903 is electrically connected to the second end of the AC power supply. The second voltage stabilizing circuit 92 includes a thirteenth resistor module 904, a second voltage stabilizer 905, a fifth capacitor module 906, a seventh transistor 907, a fourteenth resistor module 908, and a fifteenth resistor module 909. The second end of the thirteenth resistor module 904 is electrically connected to the second end of the fourth capacitor module 902. The cathode of the second voltage stabilizer 905 is electrically connected to the first end of the thirteenth resistor module 904, and the anode of the second voltage stabilizer 905 is electrically connected to the first end of the fourth capacitor module 902. The first end of the fifth capacitor module 906 is electrically connected to the reference end of the second voltage stabilizer 905, and the second end of the fifth capacitor module 906 is electrically connected to the first end of the thirteenth resistor module 904. The base of the seventh transistor 907 is electrically connected to the second end of the fifth capacitor module 906, the collector of the seventh transistor 907 is electrically connected to the second end of the thirteenth resistor module 904, and the emitter of the seventh transistor 907 is used to output DC power. The first end of the fourteenth resistor module 908 is electrically connected to the first end of the fifth capacitor module 906, and the second end of the fourteenth resistor module 908 is electrically connected to the emitter of the seventh transistor 907. The first end of the fifteenth resistor module 909 is electrically connected to the anode of the second voltage stabilizer 905 and grounded, and the second end of the fifteenth resistor module 909 is electrically connected to the first end of the fourteenth resistor module 908. The R end and the C end of the AC power supply are charged to the fourth capacitor module through the ninth diode and the twelfth diode to form a DC power supply. The second voltage stabilizer is an adjustable parallel voltage stabilizer. The voltage value of VCC is set by the fourteenth resistor module and the fifteenth resistor module, and the VCC voltage can be maintained as a constant value. Multiple drive circuits can share the power supply circuit, but the R end and the C end cannot be reversed or a bridge rectifier is used instead, otherwise the bidirectional switch will be misdirected.

[0064] In another exemplary embodiment of the present application, a drive system is provided, including one or more HVAC devices and one or more drive circuits. One of the HVAC devices corresponds to one of the drive circuits. The HVAC device is electrically connected to the drive circuit. The drive circuit is any of the drive circuits described above.

[0065] The driving system comprises the driving circuit, the driving circuit controls the switch to be turned on through the turn-on control circuit, controls the switch unit to be turned on when the alternating current at both ends of the light unit is a positive half cycle through the turn-on synchronization unit, and controls the switch unit to be turned off when the alternating current at both ends of the switch unit is a positive half cycle and overcurrent or short circuit occurs in the circuit through the protection circuit, so that the target device is not connected to the circuit, and the problem that the driving circuit cannot realize overcurrent or short circuit protection in the prior art is solved.

[0066] From the above description, it can be seen that the above-mentioned embodiments of the application achieve the following technical effects:

[0067] 1) The driving circuit of the application comprises a switch unit, a turn-on control unit, a protection circuit and a turn-on synchronization unit, wherein the first end of the switch unit is used for being electrically connected with a power supply, the second end of the switch unit is used for being electrically connected with a target device, the third end of the switch unit is grounded, and the switch unit is used for controlling the turn-on or turn-off of the target device; the first end of the turn-on control unit is electrically connected with the control end of the switch unit, and is used for controlling the operation of the switch unit; the first end of the protection circuit is electrically connected with the first end of the switch unit, the second end of the protection circuit is electrically connected with the third end of the switch unit, the third end of the protection circuit is electrically connected with the second end of the turn-on control unit, and is used for controlling the switch unit to be turned off under a predetermined condition, the predetermined condition comprising at least one of overcurrent and short circuit; and the control end of the turn-on synchronization unit is electrically connected with the first input end of the turn-on control unit, and is used for controlling the switch unit to work in a positive half cycle of alternating current. The driving circuit controls the switch to be turned on through the turn-on control circuit, controls the switch unit to be turned on when the alternating current at both ends of the light unit is a positive half cycle through the turn-on synchronization unit, and controls the switch unit to be turned off when the alternating current at both ends of the switch unit is a positive half cycle and overcurrent or short circuit occurs in the circuit through the protection circuit, so that the target device is not connected to the circuit, and the problem that the driving circuit cannot realize overcurrent or short circuit protection in the prior art is solved.

[0068] 2) The driving system of the application comprises the driving circuit, the driving circuit controls the switch to be turned on through the turn-on control circuit, controls the switch unit to be turned on when the alternating current at both ends of the light unit is a positive half cycle through the turn-on synchronization unit, and controls the switch unit to be turned off when the alternating current at both ends of the switch unit is a positive half cycle and overcurrent or short circuit occurs in the circuit through the protection circuit, so that the target device is not connected to the circuit, and the problem that the driving circuit cannot realize overcurrent or short circuit protection in the prior art is solved.

[0069] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A drive circuit characterized by comprising: The drive circuit comprises: a switch unit, a first end of the switch unit is electrically connected with a power supply, a second end of the switch unit is electrically connected with a target device, a third end of the switch unit is grounded, and the switch unit is used for controlling the conduction or disconnection of the target device; a conduction control unit, a first end of the conduction control unit is electrically connected with a control end of the switch unit, and the conduction control unit is used for controlling the operation of the switch unit; a protection circuit, a first end of the protection circuit is electrically connected with the first end of the switch unit, a second end of the protection circuit is electrically connected with the third end of the switch unit, and a third end of the protection circuit is electrically connected with a second end of the conduction control unit, and the protection circuit is used for controlling the switch unit to be disconnected under a predetermined condition, the predetermined condition including at least one of overcurrent and short circuit; a conduction synchronization unit, a control end of the conduction synchronization unit is electrically connected with a first input end of the conduction control unit, and the conduction synchronization unit is used for controlling the switch unit to work in an AC positive half cycle; wherein, the conduction control unit comprises: a flip-flop circuit comprising a D flip-flop and a first resistance module, a first end of the first resistance module is electrically connected with an output end of the D flip-flop, a first input end of the D flip-flop is a first input end of the conduction control unit, a second input end of the D flip-flop is a second input end of the conduction control unit, and a second end of the first resistance module is a second end of the conduction control unit; a third switch device, a control end of the third switch device is electrically connected with an output end of the D flip-flop, a first end of the third switch device is grounded, a second end of the third switch device is electrically connected with a control end of the switch unit, and the second end of the third switch device is a first end of the conduction control unit.

2. The drive circuit according to claim 1, characterized in that, The switch unit comprises: a first switch device comprising a first NMOS tube and a first diode, a source of the first NMOS tube is electrically connected with a positive electrode of the first diode, a drain of the first NMOS tube is electrically connected with a negative electrode of the first diode, and the drain of the first NMOS tube is a first end of the switch unit; a second switch device comprising a second NMOS tube and a second diode, a source of the second NMOS tube is electrically connected with a positive electrode of the second diode, a drain of the second NMOS tube is electrically connected with a negative electrode of the second diode, the drain of the second NMOS tube is a second end of the switch unit, the source of the second NMOS tube is electrically connected with the source of the first NMOS tube, a gate of the second NMOS tube is electrically connected with a gate of the first NMOS tube, and the gate of the second NMOS tube is a control end of the switch unit.

3. The drive circuit according to claim 2, characterized in that, The switch unit further comprises: a third diode, a positive electrode of the third diode is electrically connected with the source of the first NMOS tube and the source of the second NMOS tube, a negative electrode of the third diode is electrically connected with a second end of the protection circuit, and the positive electrode of the third diode is a third end of the switch unit.

4. The driving circuit according to claim 1, wherein: The third switch device comprises: A third NMOS transistor, a gate of the third NMOS transistor being electrically connected with a second end of the first resistance module, and a source of the third NMOS transistor being grounded; A second resistance module, a first end of the second resistance module being electrically connected with a drain of the third NMOS transistor; A first transistor, a base of the first transistor being electrically connected with a second end of the second resistance module, a collector of the first transistor being electrically connected with a control end of the switch unit, an emitter of the first transistor being configured to be electrically connected with the power supply, and the collector of the first transistor being a first end of the conduction control unit.

5. The drive circuit according to claim 4, characterized in that, The third switch device further comprises: A first filter circuit, one end of the first filter circuit being electrically connected with the base of the first transistor and the second end of the second resistance module, and the other end of the first filter circuit being electrically connected with the emitter of the first transistor; A second filter circuit, one end of the second filter circuit being electrically connected with the collector of the first transistor, and the other end of the second filter circuit being electrically connected with a third end of the switch unit.

6. The drive circuit of claim 1, wherein The protection circuit comprises: A fourth switch device, a control end of the fourth switch device being electrically connected with the first end of the switch unit, a second end of the fourth switch device being electrically connected with the third end of the switch unit, a first end of the fourth switch device being electrically connected with a second end of the conduction control unit, the control end of the fourth switch device being a first end of the protection circuit, the second end of the fourth switch device being a second end of the protection circuit, and the first end of the fourth switch device being a third end of the protection circuit.

7. The drive circuit according to claim 6, characterized in that, The fourth switch device comprises: A fifth resistance module, a second end of the fifth resistance module being electrically connected with the first end of the switch unit; A second transistor, a collector of the second transistor being electrically connected with a first end of the fifth resistance module, and an emitter of the second transistor being electrically connected with the second end of the conduction control unit; A third transistor, a collector of the third transistor being electrically connected with a base of the second transistor, an emitter of the third transistor being grounded, and the base of the third transistor being electrically connected with the collector of the second transistor.

8. The drive circuit of claim 1, wherein, The conduction synchronization unit comprises: A first conduction control circuit, a first end of the first conduction control circuit being configured to be electrically connected with the power supply; A fifth switch device, a control end of the fifth switch device being electrically connected with a second end of the first conduction control circuit, a first end of the fifth switch device being configured to be electrically connected with a first input end of the conduction control unit, a second end of the fifth switch device being grounded, and the first end of the fifth switch device being a control end of the conduction synchronization unit.

9. The driving circuit according to claim 8, wherein The first conduction control circuit comprises: A sixth resistance module, a second end of the sixth resistance module being configured to be electrically connected with the power supply; A fourth diode, a positive electrode of the fourth diode being electrically connected with a first end of the sixth resistance module; The fifth switch device comprises: a fourth transistor, a base of the fourth transistor is electrically connected with a negative electrode of the fourth diode, a collector of the fourth transistor is electrically connected with a first input end of the conduction control unit, an emitter of the fourth transistor is grounded, and the collector of the fourth transistor is a control end of the conduction synchronization unit; a seventh resistance module, a first end of the seventh resistance module is electrically connected with the collector of the fourth transistor, and a second end of the seventh resistance module is configured to be electrically connected with the power supply.

10. The drive circuit of claim 1, wherein, The driving circuit further comprises an acceleration disconnecting unit configured to accelerate a speed of disconnecting the target device controlled by the switching unit, and the acceleration disconnecting unit comprises: a sixth switch device, a control end of the sixth switch device is electrically connected with a second end of the conduction control unit, and a first end of the sixth switch device is grounded; a seventh switch device, a control end of the seventh switch device is electrically connected with a first end of the conduction control unit, a first end of the seventh switch device is electrically connected with a second end of the sixth switch device, and a second end of the seventh switch device is electrically connected with a third end of the switching unit.

11. The driving circuit of claim 10, wherein the sixth switch device comprises: a fourth NMOS tube, a gate of the fourth NMOS tube is electrically connected with the second end of the conduction control unit, and a source of the fourth NMOS tube is grounded; an eighth resistance module, a first end of the eighth resistance module is electrically connected with a drain of the fourth NMOS tube, and a second end of the eighth resistance module is configured to be electrically connected with the power supply; a fifth transistor, a base of the fifth transistor is electrically connected with the first end of the eighth resistance module, and an emitter of the fifth transistor is grounded; a fifth diode, a negative electrode of the fifth diode is electrically connected with a collector of the fifth transistor; a ninth resistance module, a first end of the ninth resistance module is electrically connected with a positive electrode of the fifth diode; the seventh switch device comprises: a sixth diode, a positive electrode of the sixth diode is electrically connected with a second end of the ninth resistance module, and a negative electrode of the sixth diode is electrically connected with the first end of the conduction control unit; a sixth transistor, a base of the sixth transistor is electrically connected with the positive electrode of the sixth diode, a collector of the sixth transistor is electrically connected with the third end of the switching unit, and an emitter of the sixth transistor is electrically connected with the negative electrode of the sixth diode.

12. The drive circuit of claim 1, wherein, The driving circuit further comprises a detection circuit and an isolation circuit, the detection circuit is configured to detect whether the target device is connected to the driving circuit, the detection circuit comprises: a first rectifier circuit, a first end of the first rectifier circuit is electrically connected with the second end of the switching unit; a first voltage stabilizing circuit, a first end of the first voltage stabilizing circuit is electrically connected with a second end of the first rectifier circuit, and is electrically connected with a first input end of the isolation circuit, and a second end of the first voltage stabilizing circuit is electrically connected with the second end of the protection circuit; the isolation circuit is configured to isolate a digital signal, and an output end of the isolation circuit is electrically connected with a second input end of the conduction control unit.

13. The driving circuit of claim 12, wherein the first rectifier circuit comprises: a seventh diode, a positive electrode of the seventh diode being electrically connected with the second end of the switch unit; a tenth resistance module, a first end of the tenth resistance module being electrically connected with a negative electrode of the seventh diode; the first voltage stabilizing circuit comprises: a third capacitance module, a first end of the third capacitance module being electrically connected with a second end of the tenth resistance module, a second end of the third capacitance module being electrically connected with the second end of the protection circuit; a first voltage stabilizer, an anode of the first voltage stabilizer being electrically connected with the second end of the protection circuit, a cathode of the first voltage stabilizer being electrically connected with the first end of the third capacitance module; an eleventh resistance module, a first end of the eleventh resistance module being electrically connected with a reference end of the first voltage stabilizer, a second end of the eleventh resistance module being electrically connected with the anode of the first voltage stabilizer; a twelfth resistance module, a first end of the twelfth resistance module being electrically connected with the cathode of the first voltage stabilizer, a second end of the twelfth resistance module being electrically connected with the first end of the eleventh resistance module. comprises:

14. A drive system characterized by, one or more HVAC devices and one or more driving circuits, wherein one of the HVAC devices corresponds to one of the driving circuits, the HVAC device is electrically connected with the driving circuit, and the driving circuit is the driving circuit of any one of claims 1 to 13. ​

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