A power switching circuit and a driving circuit

Abstract

The present invention relates to a power switching circuit and a driving circuit. The power switching circuit can automatically switch the corresponding processing circuit to process the DC power according to the type of DC power supply, and then output the first power supply voltage of the load circuit. Therefore, the power switching circuit can be compatible with different vehicle-mounted power supplies, has stronger applicability, is more convenient and flexible, and reduces the circuit cost and circuit loss compared to the situation where multiple vehicle-mounted power supply systems need to be set.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a power switching circuit and a driving circuit. Background Art

[0002] Due to the low luminous flux and short life of halogen tungsten filament lamps, most of the headlights of cars and trucks on the market use automotive metal halide lamps. Automotive metal halide lamps refer to high-pressure gas discharge lamps that are filled with an inert gas mixture including xenon and do not have the filament of halogen lamps (halogen lamps). They are referred to as HID (High Intensity Discharge, xenon) lamps, which can be called metal halide lamps or xenon lamps.

[0003] To drive HID lamps, the vehicle power supply is usually increased to the working voltage and current required by HID lamps. However, different car models have different vehicle power supplies, and the current processing circuit for vehicle power supply is not compatible with different vehicle power supplies, resulting in high circuit costs and high circuit loss in the vehicle power supply system. Summary of the invention

[0004] The embodiments of the present invention aim to provide a power switching circuit and a driving circuit, which are compatible with different vehicle power supply types, reduce circuit costs, and reduce circuit losses of different vehicle power supply systems.

[0005] To solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a power switching circuit, the power switching circuit comprising: a selection circuit, a first processing circuit and a second processing circuit;

[0007] The first end of the selection circuit is used to connect to the DC power supply, the second end of the selection circuit is connected to the first end of the first processing circuit, the third end of the selection circuit is connected to the first end of the second processing circuit, and the fourth end of the selection circuit is grounded. When the DC power supply is the first DC power supply, the first end of the selection circuit is connected to the second end of the selection circuit, and when the DC power supply is the second DC power supply, the first end of the selection circuit is connected to the third end of the selection circuit;

[0008] The second end of the first processing circuit is connected to the second end of the second processing circuit, the first processing circuit is used to perform voltage stabilization processing on the first DC power supply and output the first supply voltage through the second end of the first processing circuit, and the second processing circuit is used to perform voltage conversion processing on the second DC power supply and output the first supply voltage through the second end of the second processing circuit.

[0009] In a second aspect, an embodiment of the present invention provides a driving circuit, the driving circuit comprising: the power switching circuit as described above.

[0010] In some embodiments, the driving circuit further includes a boost circuit and an ignition circuit;

[0011] The power supply end of the boost circuit is connected to the second end of the first processing circuit and the second end of the second processing circuit respectively, and the power supply end of the ignition circuit is connected to the second end of the first processing circuit and the second end of the second processing circuit respectively, and the first supply voltage is used to power the boost circuit and the ignition circuit;

[0012] The first end of the boost circuit is connected to the DC power supply, the second end of the boost circuit is respectively connected to the second end of the ignition circuit and the third end of the ignition circuit, the third end of the boost circuit is connected to the first end of the ignition circuit, and the boost circuit is used to boost the voltage of the DC power supply to obtain a first high-voltage signal;

[0013] The sixth end of the boost circuit is connected to the first end or the second end of the light source, and the boost circuit is also used to detect the current of the light source;

[0014] The fourth end of the ignition circuit is connected to one end of the light source, and the other end of the light source is grounded. When the current of the light source is less than or equal to a first preset value, the boost circuit is also used to output a first drive signal to the ignition circuit, and the ignition circuit is used to convert the first high-voltage signal into a second high-voltage signal according to the first drive signal to ignite the light source.

[0015] In some embodiments, the driving circuit further includes an AC conversion circuit;

[0016] The first end of the AC conversion circuit is connected to the second end of the boost circuit, the second end of the AC conversion circuit is connected to the fourth end of the boost circuit, the third end of the AC conversion circuit is connected to the third end of the ignition circuit, the fourth end of the AC conversion circuit is connected to the first end of the light source, and the fifth end of the AC conversion circuit is grounded; when the current of the light source is greater than or equal to a second preset value, the boost circuit is also used to stop outputting the first drive signal to the ignition circuit and output a second drive signal to the AC conversion circuit, and the AC conversion circuit is used to alternately apply the first high voltage signal to the two ends of the light source according to the second drive signal, so that the light source is in an AC working state.

[0017] In various embodiments of the present invention, the power switching circuit includes a selection circuit, a first processing circuit, and a second processing circuit. When the DC power supply is the first DC power supply, the first end of the selection circuit is connected to the second end of the selection circuit, so that the first processing circuit processes the first DC power supply and outputs the first power supply voltage of the load circuit. When the DC power supply is the second DC power supply, the first end of the selection circuit is connected to the third end of the selection circuit, so that the second processing circuit processes the second DC power supply and outputs the first power supply voltage of the load circuit. The power switching circuit can automatically switch the corresponding processing circuit to process the DC power supply according to the type of the DC power supply, and then output the first power supply voltage of the load circuit. Therefore, the power switching circuit can be compatible with different vehicle-mounted power supplies, has stronger applicability, is more convenient and flexible, and compared with the situation where multiple vehicle-mounted power supply systems need to be set up, the power switching circuit reduces the circuit cost and reduces the circuit loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0019] Figure 1a is a schematic diagram of the structure of a driving circuit provided by an embodiment of the present invention;

[0020] Figure 1b is a schematic diagram of the structure of a driving circuit provided by an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of the structure of a power switching circuit provided by an embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of a circuit structure of a power switching circuit provided by an embodiment of the present invention;

[0023] Figure 4 is a schematic structural diagram of a boost circuit provided by an embodiment of the present invention;

[0024] Figure 5 is a schematic diagram of a circuit structure of a boost circuit provided in an embodiment of the present invention;

[0025] Figure 6 is a structural schematic diagram of an ignition circuit provided by an embodiment of the present invention;

[0026] Figure 7 It is a circuit structure diagram of an ignition circuit and an AC conversion circuit provided in an embodiment of the present invention;

[0027] Figure 8 is a structural schematic diagram of one of the AC conversion circuits provided in an embodiment of the present invention;

[0028] Fig. 9 is a schematic diagram of the structure of a driving circuit provided by an embodiment of the present invention;

[0029] Fig.10 It is a circuit structure diagram of one of the driving circuits provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] Metal halide lamps for automobiles refer to high-pressure gas discharge lamps that are filled with a mixture of inert gases including xenon and do not have the filaments of halogen lamps. They are referred to as HID lamps for short and can be called metal halide lamps or xenon lamps.

[0032] In the field of automotive lighting, it is also called HID gas discharge headlights. It uses high-pressure xenon wrapped in quartz to replace traditional tungsten filaments, providing higher color temperature and more concentrated lighting. Because xenon lamps are high-voltage current xenon lamps, they can significantly reduce the burden on the vehicle's power system. The color temperature of automotive xenon lamps is between 4000K and 6000K, which is much higher than the color temperature of ordinary automotive headlight bulbs. The brightness is higher, and the light color of 4300K ​​xenon lamps is white and yellow. Because of its low color temperature, the visual effect is yellowish, and the light penetration is stronger than that of high color temperature lamps, which can improve driving safety at night and in foggy days. A beam of arc light formed by xenon gas can continuously discharge and emit light between two electrodes.

[0033] However, to drive such a high-quality light source, a sufficiently high ignition voltage of 23KV must be provided to stimulate the ionization of metal halide, and a stable voltage and current of 85V400mA must be provided to maintain this working state. Therefore, the metal halide driver power supply comes in handy. The general power supply system of fuel vehicles is 12VDC or 24VDC. The purpose of the metal halide driver power supply is to upgrade the 12VDC or 24VDC power supply system of fuel vehicles to the working voltage and current environment required by metal halide gas discharge lamps.

[0034] Different vehicle models have different on-board power supply voltages. For example, the on-board power supply voltage of a gasoline vehicle is 12VDC or 24VDC, while the first power supply voltage of the load circuit in the driving power supply is generally 12VDC or 5VDC. Therefore, different processing circuits are required for different on-board power supplies to obtain the corresponding power supply voltage.

[0035] See also Figure 1a An embodiment of the present invention provides a driving circuit, wherein the driving circuit 100 includes: a power switching circuit 10, a boost circuit 20, an ignition circuit 30 and an AC conversion circuit 40.

[0036] The input end of the power switching circuit 10 is used to access the DC power supply 200 , and the output end of the power switching circuit 10 is connected to the power supply end of the boost circuit 20 and the power supply end of the ignition circuit 30 .

[0037] The first end of the boost circuit 20 is connected to the DC power supply 200, the second end of the boost circuit 20 is respectively connected to the first end of the AC conversion circuit 40 and the second end of the ignition circuit 30, the third end of the boost circuit 20 is connected to the first end of the ignition circuit 30, and the fourth end of the boost circuit 20 is connected to the second end of the AC conversion circuit 40. The output end of the power switching circuit 10 is also connected to the AC conversion circuit 40, and the power supply voltage output by the power switching circuit 10 is used to power it. The AC conversion circuit 40 can also be powered by other power supplies.

[0038] The third end of the AC conversion circuit 40 is connected to the third end of the ignition circuit 30, the fourth end of the AC conversion circuit 40 is connected to the first end of the light source 300, the fifth end of the AC conversion circuit 40 is grounded, the second end of the light source 300 is connected to the fourth end of the ignition circuit 30, and the second end of the ignition circuit 30 is respectively connected to the first end of the AC conversion circuit 40 and the second end of the boost circuit 20.

[0039] The driving circuit 100 is used to drive the light source 300, which may be a HID lamp. The driving circuit 100 is described below by taking the light source 300 as an example. As mentioned above, the driving circuit 100 needs to increase the vehicle power supply to a working voltage and current environment that meets the requirements of the metal halide gas discharge lamp.

[0040] Specifically, combined Figure 1a , the working principle of the driving circuit 100 can be described as follows:

[0041] The DC power supply 200 includes a first DC power supply and a second DC power supply, which are vehicle-mounted power supplies. The power supply switching circuit 10 performs corresponding switching according to the difference of the DC power supply 200, that is, switches the first DC power supply and the second DC power supply, and performs different processing according to different DC power supplies 200 to obtain corresponding power supply voltages, and supplies power to other circuits of the drive circuit 100, specifically, the boost circuit 20, the ignition circuit 30 and the AC conversion circuit 40, and other internal circuits of the drive circuit 100 that need power supply can also be supplied. Hereinafter, the circuits powered by the supply voltage are collectively referred to as load circuits.

[0042] The boost circuit 20 boosts the voltage of the DC power supply 200 and obtains a first high-voltage signal at its second end. The first high-voltage signal can be used in a subsequent ignition circuit 30, so that the ignition circuit 30 converts the first high-voltage signal into a second high-voltage signal to ignite the light source 300, wherein the voltage of the second high-voltage signal is much greater than the voltage of the first high-voltage signal.

[0043] In this embodiment, the second end of the light source 300 is connected to the third end of the AC conversion circuit 40 through the fourth end of the ignition circuit 30 and the third end of the ignition circuit 30. When the first end of the AC conversion circuit 40 is connected to the third end of the AC conversion circuit 40, the second end of the light source 300 can be connected to the second end of the boost circuit 20, that is, it can receive the first high voltage signal. When the fourth end of the AC conversion circuit 40 is connected to the fifth end of the AC conversion circuit 40, the first end of the light source 300 can be grounded through the fourth end of the AC conversion circuit 40 and the fifth end of the AC conversion circuit 40. When the first end of the AC conversion circuit 40 is connected to the third end of the AC conversion circuit 40, and the fourth end of the AC conversion circuit 40 is connected to the fifth end of the AC conversion circuit 40, the second end of the boost circuit 20, the first end of the AC conversion circuit 40, the third end of the AC conversion circuit 40, the third end of the ignition circuit 30, the fourth end of the ignition circuit 30, the second end of the light source 300, the first end of the light source 300, the fourth end of the AC conversion circuit 40, and the fifth end of the AC conversion circuit 40 form a first drive circuit.

[0044] It can be understood that the third end of the ignition circuit 30 and the fourth end of the ignition circuit 30 are connected inside the ignition circuit 30 .

[0045] The sixth end of the boost circuit 20 is connected to the first end or the second end of the light source 300. The sixth end of the boost circuit 20 can detect the current of the first driving circuit, that is, the current of the light source 300, and drive the AC conversion circuit 40 and the ignition circuit 30 to work according to the current of the light source 300. Specifically, when the current of the light source 300 is less than or equal to the first preset value, the boost circuit 20 outputs the first drive signal to the ignition circuit 30 through its third end. When the current of the light source 300 is greater than or equal to the second preset value, the boost circuit 20 can output the second drive signal to drive the AC conversion circuit 40 through its fourth end.

[0046] The sixth terminal of the boost circuit 20 may be directly or indirectly connected to the first terminal or the second terminal of the light source 300 .

[0047] The ignition circuit 30 converts the first high-voltage signal into a second high-voltage signal according to the first drive signal. The second high-voltage signal acts on both ends of the HID lamp. The xenon electrons in the HID lamp are ionized, and a light source is generated between the two electrodes of the HID lamp, so that the light source generates white ultra-strong arc light, that is, the HID lamp is ignited. After the HID lamp is ignited successfully, the HID lamp is broken down, and its two ends are connected, and the voltage at both ends of the HID lamp drops rapidly. Moreover, after the ignition is successful, when the boost circuit 20 detects that the current flowing through the HID lamp is greater than or equal to the second preset value, it will stop outputting the first drive signal to the ignition circuit 30, so that the ignition circuit 30 exits the ignition state.

[0048] The AC conversion circuit 40 can alternately apply the first high-voltage signal to the two ends of the HID lamp according to the second driving signal. The first high-voltage signal can act on the second end of the HID lamp via the third end of the AC conversion circuit 40, the third end of the ignition circuit 30, and the fourth end of the ignition circuit 30 in sequence. The first end of the HID lamp can be grounded via the fourth end of the AC conversion circuit 40 and the fifth end of the AC conversion circuit 40. The fourth end of the AC conversion circuit 40 and the fifth end of the AC conversion circuit 40 are connected. The first high-voltage signal can also act on the second end of the HID lamp via the third end of the AC conversion circuit 40, the third end of the ignition circuit 30, and the fourth end of the ignition circuit 30 in sequence. The fourth end of the AC conversion circuit 40 acts on the first end of the HID lamp, and the second end of the HID lamp can be grounded through the fourth end of the ignition circuit 30, the third end of the ignition circuit 30, the third end of the AC conversion circuit 40 and the fifth end of the AC conversion circuit 40, wherein the third end of the AC conversion circuit 40 and the fifth end of the AC conversion circuit 40 are connected, so that the first high-voltage signal acts alternately on the two ends of the HID lamp to maintain the two ends of the HID lamp working in an AC state, which can extend the service life of the HID lamp electrode and ensure the working life of the HID lamp.

[0049] In some embodiments, the AC conversion circuit 40 can also be omitted. Figure 1b As shown, in this embodiment, the second end of the boost circuit 20 is connected to the second end of the ignition circuit 30 and the third end of the ignition circuit 30 respectively, the third end of the boost circuit 20 is connected to the first end of the ignition circuit 30, the sixth end of the boost circuit 20 is connected to the first end or the second end of the light source 300, the fourth end of the ignition circuit 30 is connected to the second end of the light source 300, and the first end of the light source 300 is grounded.

[0050] The boost circuit 20 boosts the voltage of the DC power supply 200 and obtains a first high-voltage signal at its second end. The first high-voltage signal directly acts on the positive electrode (second end) of the light source 300. The negative electrode of the light source 300 is grounded. At this time, the first high-voltage signal makes both ends of the light source 300 work in a DC state.

[0051] The sixth end of the boost circuit 20 detects the current of the light source 300. When the current of the light source 300 is less than or equal to a first preset value, the boost circuit 20 outputs a first drive signal to the ignition circuit 30 through its third end. The ignition circuit 30 converts the first high-voltage signal into a second high-voltage signal according to the first drive signal to ignite the light source 300.

[0052] In summary, the driving circuit 100 can provide the ignition voltage required for the light source 300 to work through the ignition circuit 30, and maintain the voltage and current for the normal operation of the light source 300 through the AC conversion circuit 40, thereby realizing the function of driving the light source 300. In addition, the driving circuit 100 is compatible with different vehicle power supplies through the power switching circuit 10, and can be applied to different vehicle models, which is more flexible and convenient.

[0053] The voltage of the DC power supply 200 may be 12 V or 24 V. The supply voltage may be 12 V or 5 V. The first high voltage signal may be between 17 V and 28 V, and the second high voltage signal may be 23 KV.

[0054] In some embodiments, see Figure 2 , Figure 2 is a schematic diagram of a power switching circuit provided by an embodiment of the present invention. Figure 2 As shown, the power switching circuit 10 includes a selection circuit 11, a first processing circuit 12 and a second processing circuit 13. The output end of the power switching circuit 10 includes a first output end, which is a port PT1, and accordingly, the power supply voltage includes a first power supply voltage.

[0055] The first end of the selection circuit 11 is used to connect to the DC power supply 200, the second end of the selection circuit 11 is connected to the first end of the first processing circuit 12, and the third end of the selection circuit 11 is connected to the first end of the second processing circuit 13. The first end of the selection circuit 11 serves as the input end of the power switching circuit 10, and the second end of the first processing circuit 12 and the second end of the second processing circuit 13 both serve as the first output end of the power switching circuit 10.

[0056] The DC power supply 200 includes a first DC power supply and a second DC power supply. When the DC power supply 200 is the first DC power supply, the first end of the selection circuit 11 is connected to the second end of the selection circuit 11, so that the first DC power supply acts on the first end of the first processing circuit 12, so that the first processing circuit 12 stabilizes the first DC power supply and outputs a first supply voltage to power the load circuit.

[0057] When the DC power supply 200 is a second DC power supply, the first end of the selection circuit 11 is connected to the third end of the selection circuit 11, so that the second DC power supply acts on the first end of the second processing circuit 13, so that the second processing circuit 13 performs voltage conversion processing on the second DC power supply and outputs a first supply voltage to power the load circuit.

[0058] The voltage conversion process may be a voltage step-up process or a voltage step-down process.

[0059] The voltage of the first DC power supply is less than the voltage of the second DC power supply. For example, if the DC power supply is a vehicle-mounted power supply, the voltage of the first DC power supply may be 12 V, and the voltage of the second DC power supply may be 24 V. In other embodiments, the voltage of the first DC power supply and the voltage of the second DC power supply may also vary according to the type of the DC power supply.

[0060] The load circuit may be any circuit module in the driving circuit that needs power supply, or may be a load module of the driving circuit, such as the light source 300 .

[0061] Therefore, the power switching circuit can automatically switch the corresponding processing circuit to process the DC power according to the type of the DC power supply, and then output the first power supply voltage of the load circuit. The power switching circuit can be compatible with different vehicle power supplies, has stronger applicability, is more convenient and flexible, and reduces circuit cost and circuit loss compared to the situation where multiple vehicle power supply systems need to be set up.

[0062] like Figure 2 As shown, the selection circuit 11 includes a first voltage stabilizing module 111 and a first switch module 112 .

[0063] A first end of the first voltage stabilizing module 111 is connected to the DC power supply 200, a second end of the first voltage stabilizing module 111 is connected to a fourth end of the first switch module 112, a first end of the first switch module 112 is connected to the DC power supply 200, a second end of the first switch module 112 is connected to a first end of the first processing circuit 12, and a third end of the first switch module 112 is connected to a first end of the second processing circuit 13.

[0064] The first end of the first voltage stabilizing module 111 and the first end of the first switch module 112 both serve as the first end of the selection circuit 11, the second end of the first switch module 112 serves as the second end of the selection circuit 11, and the third end of the first switch module 112 serves as the third end of the selection circuit 11.

[0065] When the DC power supply 200 is a second DC power supply, the first voltage stabilizing module 111 is in an on state so that the first end of the first switch module 112 is connected to the third end of the first switch module 112; when the DC power supply 200 is a first DC power supply, the first voltage stabilizing module 111 is in an off state so that the first end of the first switch module 112 is connected to the second end of the first switch module 112.

[0066] like Figure 2 As shown, the first switch module 112 includes a first switch unit 1121 , a second switch unit 1122 and a third switch unit 1123 .

[0067] A first end of the first switch unit 1121 is connected to the DC power supply 200 , a second end of the first switch unit 1121 is connected to a second end of the first voltage stabilizing module 111 , and a third end of the first switch unit 1121 is connected to a third end of the second switch unit 1122 .

[0068] A first end of the second switch unit 1122 is connected to the DC power supply 200 , and a second end of the second switch unit 1122 is connected to a first end of the first processing circuit 12 .

[0069] A first end of the third switch unit 1123 is connected to the DC power supply 200 , a second end of the third switch unit 1123 is connected to a first end of the second processing circuit 13 , and a third end of the third switch unit 1123 is connected to a fourth end of the first switch unit 1121 .

[0070] When the DC power supply is the second DC power supply, the first voltage stabilizing module 111 is reversely broken down, the first switch unit 1121 is in an on state, the second switch unit 1122 is in an off state, and the third switch unit 1123 is in an on state, so that the second DC power supply is connected to the first end of the second processing circuit 12, so that the second processing circuit 12 performs voltage conversion processing on the second DC power supply and then outputs the first supply voltage.

[0071] When the DC power supply is the first DC power supply, the first voltage stabilizing module 111 is not broken down, the first switch unit 1121 is in the off state, the second switch unit 1122 is in the on state, and the third switch unit 1123 is in the off state, so that the first DC power supply is connected to the first end of the first processing circuit 13, so that the first processing circuit 13 can output the first supply voltage after voltage stabilization.

[0072] When the first voltage stabilizing module 111 is reversely broken down, the first voltage stabilizing module 111 is in a conducting state; when the first voltage stabilizing module 111 is not broken down, the first voltage stabilizing module 111 is in a cut-off state.

[0073] Multiple switch units are used to realize automatic switching of the DC power supply 200, thereby improving the reliability of the system.

[0074] like Figure 2 As shown, the first processing circuit 12 includes a second voltage stabilizing module 121 and a first unidirectional conducting module 122 .

[0075] The first end of the second voltage stabilizing module 121 is connected to the second end of the selection circuit 11 , and the second end of the second voltage stabilizing module 121 is connected to the first end of the first unidirectional conduction module 122 . The second voltage stabilizing module 121 is used to stabilize the first DC power supply.

[0076] The second end of the first unidirectional conduction module 122 serves as the second end of the first processing circuit 12 , and the first unidirectional conduction module 122 is used to prevent the first supply voltage outputted from the second end of the first unidirectional conduction module 122 from flowing back to the second voltage stabilizing module 121 .

[0077] The second voltage stabilizing module 121 can perform voltage stabilization on the first DC power supply. The first DC power supply acts on the first end of the second voltage stabilizing module 121. After voltage stabilization by the second voltage stabilizing module 121, a voltage stabilization signal is output through the second end of the second voltage stabilizing module 121. The voltage stabilization signal then outputs the first supply voltage through the second end of the first unidirectional conduction module 122. When the first supply voltage is output through the second end of the first unidirectional conduction module 122, the first unidirectional conduction module 122 can prevent the first supply voltage from flowing back to the second voltage stabilizing module 121, prevent mutual series connection, and improve power supply safety.

[0078] like Figure 2 As shown, the power switching circuit 10 also includes a third processing circuit 14. The output end of the power switching circuit 10 also includes a second output end, and accordingly, the power supply voltage includes a second power supply voltage. The first end of the third processing circuit 14 is respectively connected to the second end of the first processing circuit 12 and the second end of the second processing circuit 13, and the second end of the third processing circuit 14 serves as the second output end of the power switching circuit 10. The second output end of the power switching circuit 10 is port PT2. The third processing circuit 14 is used to perform voltage stabilization and voltage conversion processing on the first power supply voltage to obtain a second power supply voltage, and output the second power supply voltage at port PT2.

[0079] See also Figure 3 , Figure 3 FIG. 1 is a schematic diagram of a circuit structure of a power switching circuit provided by an embodiment of the present invention. Figure 3 As shown, the first voltage stabilizing module 111 includes a voltage stabilizing diode ZD1 and a voltage stabilizing diode ZD2, the first switch unit 1121 includes a transistor Q1, a transistor Q2, a transistor Q3, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7, the second switch unit 1122 includes a transistor Q4 and a resistor R8, and the third switch unit 1123 includes a transistor Q5 and a resistor R9.

[0080] Specifically, the anode of the voltage regulator tube ZD1 is connected to the cathode of the voltage regulator tube ZD2, and the anode of the voltage regulator tube ZD2 is respectively connected to one end of the resistor R2, one end of the resistor R1, and one end of the resistor R4. The other end of the resistor R2 is connected to the base of the transistor Q1, and the other end of the resistor R4 is connected to the base of the transistor Q2. The collector of the transistor Q1 is respectively connected to one end of the resistor R3 and one end of the resistor R6, and the other end of the resistor R6 is connected to the base of the transistor Q3. The collector of the transistor Q2 is respectively connected to one end of the resistor R5 and one end of the resistor R9, and the other end of the resistor R9 is connected to the base of the transistor Q5. The collector of the transistor Q3 is respectively connected to one end of the resistor R7 and one end of the resistor R8, and the other end of the resistor R8 is connected to the base of the transistor Q4. The collector of the transistor Q4 is connected to the first end of the first processing circuit 12, and the collector of the transistor Q5 is connected to the first end of the second processing circuit 13.

[0081] The cathode of the voltage regulator ZD1, the other end of the resistor R3, the other end of the resistor R5, the other end of the resistor R7, the emitter of the transistor Q4 and the emitter of the transistor Q5 are commonly connected to the DC power supply 200. The other end of the resistor R1, the emitter of the transistor Q1, the emitter of the transistor Q2 and the emitter of the transistor Q3 are commonly grounded.

[0082] The first end of the first voltage stabilizing module 111 is the cathode of the voltage stabilizing tube ZD1, and the second end of the first voltage stabilizing module 111 is the anode of the voltage stabilizing tube ZD2. The first end of the first switch unit 1121 is the common connection end of the resistor R3, the resistor R5 and the resistor R7, the second end of the first switch unit 1121 is the common connection end of the resistor R2 and the voltage stabilizing tube ZD2, the third end of the first switch unit 1121 is the collector of the transistor Q3, and the fourth end of the first switch unit 1121 is the collector of the transistor Q2.

[0083] The on-state of the first voltage stabilizing module 111 means that both the voltage stabilizing tubes ZD1 and ZD2 are reversely broken down, the off-state of the first voltage stabilizing module 111 means that both the voltage stabilizing tubes ZD1 and ZD2 are not reversely broken down, the on-state of the first switch unit 1121 means that both the transistors Q1 and Q2 are turned on, and the transistor Q3 is turned off, and the off-state of the first switch unit 1121 means that both the transistors Q1 and Q2 are turned off, and the transistor Q3 is turned on. The on-state of the second switch unit 1122 means that the transistor Q4 is turned on, and the off-state of the second switch unit 1122 means that the transistor Q4 is turned off. The on-state of the third switch unit 1123 means that the transistor Q5 is turned on, and the off-state of the third switch unit 1123 means that the transistor Q5 is turned off.

[0084] In the embodiment of the present invention, the voltage of the DC power supply 200 is different, and the working states of the voltage regulator tube ZD1 and the voltage regulator tube ZD2 are different, thereby controlling the conduction and closing of the corresponding transistors. The conduction and closing of the transistors form different paths, so that the DC power supply 200 acts on the first end of the first processing circuit 12 or the first end of the second processing circuit 13, so that the first processing circuit 12 or the second processing circuit 13 performs corresponding processing.

[0085] The voltage stabilization values ​​of the voltage regulator tube ZD1 and the voltage regulator tube ZD2 can be selected according to the voltage of the first DC power supply and the second DC power supply. The use of two voltage regulator tubes can improve the reliability of the power supply.

[0086] In the embodiment of the present invention, transistors Q1, Q2 and Q3 are all NPN transistors, transistors Q4 and Q5 are all PNP transistors. The model of the NPN transistor may be FMMT493, and the model of the PNP transistor may be FMMT593.

[0087] like Figure 3 As shown, the second voltage stabilizing module 121 includes a resistor R10 and a voltage stabilizing chip U1 , and the first unidirectional conducting module 122 includes a diode D1 .

[0088] One end of the resistor R10 is connected to the second end of the selection circuit 11, the other end of the resistor R10 is connected to the input end of the voltage stabilizing chip U1, the output end of the voltage stabilizing chip U1 is connected to the anode of the diode D1, and the ground end of the voltage stabilizing chip U1 is grounded.

[0089] One end of the resistor R11 is connected to the DC power supply 200, and the other end of the resistor R11 and the cathode of the diode D1 serve together as the second end of the first unidirectional conduction module 122. One end of the resistor R10 serves as the first end of the second voltage regulator module 121, the output end of the voltage regulator chip U1 serves as the second end of the second voltage regulator module 121, and the anode of the diode D1 serves as the first end of the first unidirectional conduction module 122.

[0090] In the embodiment of the present invention, the model of the voltage stabilizing chip U1 may be MC7812, which is a three-terminal voltage stabilizing integrated circuit IC chip and may be packaged in T0252. The model of the diode D1 may be US1J.

[0091] The second voltage stabilizing module 121 may also include a plurality of filter capacitors, which may be configured at the input and output ends of the voltage stabilizing chip U1 to filter the voltage of the first DC power supply and the first supply voltage. Specifically, the second voltage stabilizing module 121 also includes a filter capacitor C1, a filter capacitor C2, a filter capacitor C3, and a filter capacitor C4, one end of the filter capacitor C1 and one end of the filter capacitor C2 are connected to the input end of the voltage stabilizing chip U1, the other end of the filter capacitor C1 and the other end of the filter capacitor C2 are connected to the ground, one end of the filter capacitor C3 and one end of the filter capacitor C4 are connected to the output end of the voltage stabilizing chip U1, and the other end of the filter capacitor C3 and the other end of the filter capacitor C4 are connected to the ground. The filter capacitor C1 and the filter capacitor C2 jointly filter the voltage signal of the first DC power supply, and the filter capacitor C3 and the filter capacitor C4 jointly filter the voltage signal of the first supply voltage.

[0092] like Figure 3 As shown, the second processing circuit includes a switching power supply chip U2, a resistor R12, a diode D2, a diode D3, a diode D4, a diode D5, an inductor L1, a voltage regulator ZD3, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14 and a capacitor C15.

[0093] A first end of the switching power chip U2 is connected to a third end of the selection circuit, a second end of the switching power chip U2 is respectively connected to a cathode of a diode D5, one end of a capacitor C11, one end of a capacitor C12, and one end of a capacitor C13, a third end of the switching power chip U2 is respectively connected to one end of a resistor R12 and the other end of a capacitor C11, and a fourth end of the switching power chip U2 is respectively connected to a cathode of a diode D2 and the other end of a capacitor C12.

[0094] The other end of the resistor R12 is connected to the anode of the Zener diode ZD3, the cathode of the Zener diode ZD3 is respectively connected to the anode of the diode D2, the cathode of the diode D3 and the other end of the capacitor C13, the anode of the diode D3 is connected to the anode of the diode D4, the cathode of the diode D4 serves as the second end of the second processing circuit, one end of the inductor L1 is respectively connected to the cathode of the diode D5 and to the cathode of the diode D3 through the capacitor C13, the other end of the inductor L1 is respectively connected to the anode of the diode D3, the anode of the diode D4, one end of the capacitor C14 and one end of the capacitor C15, the anode of the diode D5, the other end of the capacitor C14 and the other end of the capacitor C15 are commonly grounded.

[0095] like Figure 3 As shown, the third processing circuit 14 includes a voltage stabilizing chip U3, and the input end of the voltage stabilizing chip U3 is respectively connected to the second end of the first processing circuit 12 and the second end of the second processing circuit 13, that is, the input end of the voltage stabilizing chip U3 serves as the first end of the third processing circuit 14, and the output end of the voltage stabilizing chip U3 serves as the second end of the third processing circuit 14.

[0096] The first end of the switching power supply chip U2 serves as the first end of the second processing circuit.

[0097] The input end of the voltage stabilizing chip U3 is connected to the first power supply voltage output by the first processing circuit 12 and the second processing circuit 13. The voltage stabilizing chip U3 steps down and stabilizes the first power supply voltage, and outputs a second power supply voltage at its output end after processing.

[0098] In the embodiment of the present invention, the first power supply voltage is +12V, the second power supply voltage is +5V, and the model of the voltage regulator chip U3 is 78M05.

[0099] The third processing circuit 14 may further include a plurality of filter capacitors, which may be configured at the input and output ends of the voltage stabilizing chip U3 to filter the first power supply voltage or the second power supply voltage.

[0100] Combination Figure 3 , the working principle of the power switching circuit 10 can be described as follows:

[0101] When the DC power supply 200 is the first DC power supply, the VCC terminal is the first DC power supply, the Zener diodes ZD1 and ZD2 are cut off, the transistors Q1 and Q2 are cut off due to the low base level, and the first DC power supply acts on the bases of the transistors Q3 and Q5. Therefore, the transistor Q3 is turned on, and the base level of the transistor Q4 is pulled down, so that the transistor Q4 is turned on, and the transistor Q5 is cut off due to the high base level. The first DC power supply acts on the input end of the voltage regulator chip U1 through the emitter and collector of the transistor Q4. After being stabilized by the voltage regulator chip U1, the first supply voltage is output. After the first supply voltage is stabilized and stepped down by the voltage regulator chip U3, the second supply voltage is output.

[0102] When the DC power supply 200 is the second DC power supply, the VCC terminal is the second DC power supply, the Zener diodes ZD1 and ZD2 are reversely broken down and turned on, the transistors Q1 and Q2 are turned on because the bases are at a high level, the transistor Q1 is turned on, and the base level of the transistor Q3 is pulled down, so that the transistor Q3 is turned off, the second DC power supply acts on the base of the transistor Q4, so that the transistor Q4 is turned off, and the conduction of the transistor Q2 pulls down the base level of the transistor Q5, and the transistor Q5 is turned on due to the low base level, the second DC power supply acts on the input end of the switching power supply chip U2 through the emitter and collector of the transistor Q5, and after being stepped down by the switching power supply chip U2, the first power supply voltage is output, and the first power supply voltage is further stepped down and stabilized by the voltage regulator chip U3 to output the second power supply voltage.

[0103] In summary, the power switching circuit can automatically switch the corresponding processing circuit to process the DC power according to the type of DC power supply, and then output the first power supply voltage of the load circuit. Therefore, the power switching circuit can be compatible with different vehicle power supplies, has stronger applicability, is more convenient and flexible, and reduces circuit cost and circuit loss compared to the situation where multiple vehicle power supply systems need to be set up.

[0104] The boost circuit 20 is used to convert the voltage of the vehicle power supply into a first high voltage signal to maintain the normal operation of the light source 300, or to supplement the voltage signal to the light source 300 when it is just started. If a higher first high voltage signal is to be achieved, the number of turns of the first transformer of the conventional boost circuit 20 is large, which increases the circuit cost. At the same time, when the voltage signal is supplemented to the light source 300, it is easy to have a lack of energy.

[0105] See also Figure 4 , Figure 4 is a schematic diagram of a boost circuit provided by an embodiment of the present invention. Figure 4 As shown, the boost circuit 20 includes a control module 201 , a second switch module 202 , a voltage conversion module 203 and a first energy storage circuit 204 .

[0106] The first end of the second switch module 202 is connected to the port PT1 for accessing the first power supply voltage, the second end of the second switch module 202 is connected to the first end of the control module 201 , and the third end of the second switch module 202 is connected to the first end of the voltage conversion module 203 .

[0107] The second end of the voltage conversion module 203 is connected to the DC power supply 200 , and the third end of the voltage conversion module 203 is connected to the first end of the first energy storage circuit 204 and the port PT3 respectively.

[0108] The control module 201 outputs a first control signal to the second switch module 202 through its first end, and acts on the second end of the second switch module 202, so that the second switch module 202 performs signal conversion on the first control signal to obtain a second control signal. The second control signal acts on the first end of the voltage conversion module 203, so that the voltage conversion module 203 performs boost and rectification processing on the DC power supply 200 in sequence according to the second control signal, and stores the energy obtained after the processing in the first energy storage circuit 204, and the first energy storage circuit 204 stores the energy to output a first high-voltage signal at the first end of the first energy storage circuit 204, and the first high-voltage signal acts on the light source 300 and the ignition circuit 30 to ignite the light source 300 and maintain the normal operation of the light source 300.

[0109] The boost circuit can control the voltage conversion module 203 to boost and rectify the DC power supply 200 through the first control signal output by the control module 201, so that the voltage conversion module 203 stores the processed energy in the first energy storage circuit 204, and then the first energy storage circuit 204 outputs a first high-voltage signal, thereby achieving a boost conversion from a lower voltage signal to a higher voltage signal and doubling the voltage.

[0110] The first control signal output by the control module 201 is a PWM wave, and the voltage of the first high-voltage signal can be adjusted by adjusting the frequency of the PWM wave. The second control signal is a signal with a state opposite to the first control signal, and the second control signal is a PWM wave with the same frequency as the first control signal. Specifically, when the first control signal is a high-level signal, the second switch module 202 is in an on state, and the second control signal is a low-level signal. When the first control signal is a low-level signal, the second switch module 202 is in an off state, and the second control signal is a high-level signal. The frequency of the PWM wave can be set as needed. In the embodiment of the present invention, it is 66KHz.

[0111] At the same time, if Figure 4As shown, the third end of the control module 201 is connected to the port PT5 for outputting the first driving signal of the ignition circuit 30 , and the fourth end of the control module 201 is connected to the port PT4 for outputting the second driving signal of the AC conversion circuit 40 .

[0112] The control module 201 is a central processing unit composed of one or a few large-scale integrated circuits. These circuits perform the functions of the control unit and the arithmetic logic unit. The control module 201 can complete operations such as fetching instructions, executing instructions, and exchanging information with external memory and logic units. It is the operation control part of the microcomputer and can form a microcomputer with the memory and peripheral circuit chips.

[0113] In some embodiments, Figure 4 As shown, the boost circuit 20 further includes an absorption circuit 205. One end of the absorption circuit 205 is connected to the DC power supply 200 and the second end of the voltage conversion module 203 respectively, and the other end of the absorption circuit 205 is connected to the fourth end of the voltage conversion module 203. When the second switch module 202 is in the on state, the absorption circuit 205 is used to clamp the voltage of the fourth end of the voltage conversion module 203.

[0114] When the second switch module 202 is in the on state, the second control signal is in the low level state, the third terminal in the voltage conversion module 203 is in the low level state, and at the same time, the fourth terminal in the voltage conversion module 203 is in the high level state. The high level state of the fourth terminal in the voltage conversion module 203 may damage the voltage conversion module 203, so the absorption circuit can clamp the voltage of the fourth terminal of the voltage conversion module 203 to protect the voltage conversion module 203.

[0115] In some embodiments, Figure 4 As shown, the boost circuit 20 further includes a first voltage detection circuit 206 and a second voltage detection circuit 207 .

[0116] A first end of the first voltage detection circuit 206 is connected to the DC power supply 200 , a second end of the first voltage detection circuit 206 is connected to a fifth end of the control module 201 , and the first voltage detection circuit 206 is used to detect the voltage of the DC power supply 200 .

[0117] The first end of the second voltage detection circuit 207 is connected to the first end of the first energy storage circuit 204. Specifically, the first end of the second voltage detection circuit 207 is connected to port PT3, and the second end of the second voltage detection circuit is connected to the second end of the control module 201. The second voltage detection circuit is used to detect the voltage of the first end of the first energy storage circuit 204.

[0118] When the circuit works normally, the voltage at the first end of the first energy storage circuit 204 is the voltage value corresponding to the first high voltage signal, that is, the voltage at which the light source 30 enters a normal working state after ignition is completed.

[0119] In an embodiment of the present invention, the voltage at the first end of the first energy storage circuit 204 is the voltage acting on the light source 30 through the AC conversion circuit 40 or the voltage directly acting on the light source 30. If the DC power supply 200 is a vehicle-mounted power supply, the first voltage detection circuit 206 detects the voltage of the vehicle-mounted power supply, and the second voltage detection circuit 207 samples the voltage of the light source 30.

[0120] In some embodiments, the boost circuit 20 also includes a third detection circuit 208, which is connected to the first end or the second end of the light source 300 and to the sixth end of the control module 201 through port PT6. The third detection circuit 208 is used to detect the current of the light source 300 and transmit the sampled current of the light source 300 to the sixth end of the control module 201 for the control module 201 to receive and analyze, thereby obtaining the current value of the light source 300.

[0121] When the second voltage detection circuit 207 detects the first high voltage signal, but the third detection circuit 208 does not detect the current of the light source 300, it indicates that the light source 300 is not in a working state. The control module 201 determines that the current of the light source 300 is less than or equal to the first preset value, and then sends a first drive signal through its fourth terminal to drive the ignition circuit 30 to work, so as to perform high voltage ignition on the light source.

[0122] After ignition is successful, the third detection circuit 208 can detect the current of the light source 300. When the current of the light source 300 is greater than or equal to the second preset value, the control module 201 stops sending the first drive signal, so that the ignition circuit 30 exits ignition. The first drive signal is a pulse signal.

[0123] The third detection circuit 208 can also be connected to the first end or the second end of the light source 300 through the AC conversion circuit 40. Specifically, the third detection circuit 208 can also be connected to the first end or the second end of the light source 300 through the sixth end of the AC conversion circuit 40 to detect the current of the light source 300.

[0124] When the control module 201 stops outputting the first driving signal, the control module 201 outputs the second driving signal to the AC conversion circuit 40 through port PT4, so that the AC conversion circuit 40 alternately applies the first high voltage signal to the two ends of the light source 300 according to the second driving signal, so that the light source 300 is in an AC working state.

[0125] See also Figure 5 , Figure 5is a schematic diagram of a circuit structure of a boost circuit provided by an embodiment of the present invention, such as Figure 5 As shown, the voltage conversion module 203 includes a first transformer T1, a MOS transistor Q8 and a diode D8.

[0126] The first transformer T1 includes a first primary winding and a first secondary winding, the first end of the first primary winding is connected to the DC power supply 200 (VCC end), the second end of the first primary winding is respectively connected to the drain of the MOS tube Q8 and the first end of the first secondary winding, the second end of the first secondary winding is connected to the anode of the diode D8, the cathode of the diode D8 is respectively connected to the first end of the first energy storage circuit 204 and the port PT3, the gate of the MOS tube Q8 is connected to the third end of the second switch module 202, and the source of the MOS tube Q8 is grounded.

[0127] The MOS tube Q8 is an NMOS tube, and the model may be UTC50N100.

[0128] The gate of the MOS tube Q8 is the first end of the voltage conversion module 203, the first end of the first primary winding is the second end of the voltage conversion module 203, the cathode of the diode D8 is the third end of the voltage conversion module 203, and the drain of the MOS tube, the second end of the first primary winding and the first end of the first secondary winding together serve as the fourth end of the voltage conversion module 203.

[0129] In the embodiment of the present invention, the first end of the first secondary winding of the first transformer T1 is connected to the second end of the first primary winding to form an auto-coupling connection mode. Compared with the conventional first transformer T1 connection mode in which the first end of the first secondary winding is grounded, the connection mode of the first transformer T1 can output a higher voltage under the same winding turns ratio, and requires fewer coil turns under the same output voltage.

[0130] Therefore, the auto-coupling connection mode of the first transformer T1 in the embodiment of the present invention can reduce circuit cost and output a higher voltage.

[0131] At the same time, since the first transformer T1 is connected in an auto-coupling manner, part of the electric energy can be directly obtained from the vehicle power supply to provide to the light source 300, providing part of the energy required for the metal halide to accelerate the separation after being broken down by high voltage, and directly obtaining electric energy from the vehicle power supply, so that the supplementary energy is sufficient, and the light source 300 will not be short of energy, thereby ensuring the stable and normal operation of the light source 300, thereby improving the working efficiency of the light source 300. The traditional connection method of the first transformer T1 can only provide the energy required for the accelerated separation of the metal halide to the light source 300 through the first energy storage circuit 204, and the amount of supplementary energy depends on the energy stored in the first energy storage circuit 204, and there may be insufficient supplementation, causing the light source 300 to be short of energy.

[0132] like Figure 5 As shown, the first energy storage circuit 204 includes a resistor R13, a diode D6 and a capacitor C5.

[0133] One end of the resistor R13 is connected to the cathode of the diode D8 and the cathode of the diode D6 respectively, and the other end of the resistor R13 is connected to the anode of the diode D6 and one end of the capacitor C5 respectively, and the other end of the capacitor C5 is grounded.

[0134] One end of the resistor R13 and the cathode of the diode D6 serve as a first end of the first energy storage circuit 204 , and the other end of the capacitor C5 serves as a second end of the first energy storage circuit 204 .

[0135] The DC power supply 200 is boosted by coupling the first primary winding of the first transformer T1 with the first secondary winding, and the boosted signal is rectified by the diode D8. The energy obtained after rectification is charged and stored in the capacitor C5 through the resistor R13. The capacitor C5 then outputs the first high-voltage signal to release to the AC conversion circuit 40 and the ignition circuit 30, so that the ignition circuit 30 converts the first high-voltage signal into the second high-voltage signal according to the first driving signal to ignite the light source 300, and the AC conversion circuit 30 alternately acts the first high-voltage signal on the two ends of the light source 300 according to the second driving signal, so that the light source 300 is in an AC working state.

[0136] In the embodiment of the present invention, the energy required for accelerating the separation of the internal metal halide can also be provided to the light source 300 through the capacitor C5, but this method is generally used when the second DC power supply 200 (higher power supply voltage) is powered. When the light source 300 is broken down by the high voltage, the voltage across the light source 300 is between 17V and 28V. At this time, the energy stored in the capacitor C5 is provided to the light source 300 through the diode D6 and the AC conversion circuit 40, completing the energy required for accelerating the separation of the metal halide inside the light source.

[0137] like Figure 5As shown, the second switch module 202 includes a resistor R14, a resistor R15, a resistor R16, a transistor Q6 and a transistor Q7.

[0138] One end of the resistor R14 is connected to the first end of the control module 201, and the other end of the resistor R14 is respectively connected to the base of the transistor Q6 and the transistor Q7, the emitter of the transistor Q6 is grounded, the collector of the transistor Q6 is respectively connected to the collector of the transistor Q7 and one end of the resistor R15, and the emitter of the transistor Q7 is connected to the port PT1 for accessing the first power supply voltage. The other end of the resistor R15 is respectively connected to one end of the resistor R16 and the gate of the MOS tube Q8, and the other end of the resistor R16 is grounded.

[0139] The transistor Q6 is an NPN transistor, and its model may be 8050. The transistor Q7 may be a PNP transistor, and its model may be 8550.

[0140] The emitter of the transistor Q7 serves as the first end of the second switch module 202 , one end of the resistor R14 serves as the second end of the second switch module 202 , and the other end of the resistor R15 and one end of the resistor R16 serve together as the third end of the second switch module 202 .

[0141] The on state of the second switch module 202 means that the transistor Q6 is on and the transistor Q7 is off, and the off state of the second switch module 202 means that the transistor Q6 is off and the transistor Q7 is on.

[0142] In some embodiments, the control module 201 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), an ARM (Advanced RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components; it can also be any traditional processor, controller, microcontroller or state machine; it can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0143] In the embodiment of the present invention, the control module 201 includes a single-chip microcomputer U4, a pin 1 of the single-chip microcomputer U4 is connected to the resistor R14 for outputting a first control signal, a pin 2 of the single-chip microcomputer U4 is connected to the second voltage detection circuit 207 for obtaining the voltage of the light source 300, a pin 3 of the single-chip microcomputer U4 is connected to the AC conversion circuit 40 for outputting a second drive signal of the AC conversion circuit 40, a pin 4 of the single-chip microcomputer U4 is connected to the ignition circuit 30 for outputting a first drive signal of the ignition circuit 30, and a pin 5 of the single-chip microcomputer U4 is connected to the first voltage detection circuit 206 for obtaining the voltage of the DC power supply 200. A pin 6 of the single-chip microcomputer U4 is used to obtain the current of the light source 300. The power supply voltage of the single-chip microcomputer U4 is +5V, which can be obtained from the second end of the third processing circuit 14.

[0144] like Figure 5 As shown, the absorption circuit 205 includes a capacitor C6, a diode D7 and a resistor R17.

[0145] One end of capacitor C6 is respectively connected to one end of resistor R17 and the first end of the first primary winding, the other end of capacitor C6 is respectively connected to the other end of resistor R17 and the cathode of diode D7, and the anode of diode D7 is respectively connected to the second end of the first primary winding and the first end of the first secondary winding.

[0146] The model of diode D7 may be 1N4148.

[0147] One end of the capacitor C6 and one end of the resistor R17 serve together as a first end of the absorption circuit 205 , and an anode of the diode D7 serves as a second end of the absorption circuit 205 .

[0148] like Figure 5 As shown, the first voltage detection circuit 206 includes a resistor R18, a resistor R19, a resistor R20 and a capacitor C7, and the second voltage detection circuit 207 includes a resistor R21, a resistor R22, a resistor R23 and a capacitor C8.

[0149] One end of the resistor R18 is connected to the DC power supply 200, the other end of the resistor R18 is respectively connected to one end of the resistor R19 and one end of the resistor R20, the other end of the resistor R19 and one end of the capacitor C7 are grounded together, and the other end of the capacitor C7 and the other end of the resistor R20 are connected to the fifth end of the control module 201.

[0150] One end of the resistor R21 is connected to the port PT3, the other end of the resistor R21 is respectively connected to one end of the resistor R23 and one end of the resistor R22, the other end of the resistor R22 and one end of the capacitor C8 are grounded together, and the other end of the capacitor C8 and the other end of the resistor R23 are connected to the second end of the control module 201.

[0151] One end of the resistor R18 serves as a first end of the first voltage detection circuit 206 , and the other end of the capacitor C7 and the other end of the resistor R20 serve together as a second end of the first voltage detection circuit 206 .

[0152] One end of the resistor R21 serves as a first end of the second voltage detection circuit 207 , and the other end of the capacitor C8 and the other end of the resistor R23 serve together as a second end of the second voltage detection circuit 207 .

[0153] Combination Figure 5 , the working principle of the boost circuit 20 can be described as follows:

[0154] The single-chip microcomputer U4 outputs the first control signal of the second switch module 202 through its 1 pin. When the first control signal is at a low level, the transistor Q6 is turned off, the transistor Q7 is turned on, and then the MOS tube Q8 is turned on, the DC power supply 200 forms a loop with the first primary winding, the current and magnetic flux of the first primary winding increase, the first transformer T1 stores energy, the voltage induced at the second end of the first secondary winding is a negative voltage, and the diode D8 is turned off. The capacitor C5 outputs the first high-voltage signal through the diode D6 to discharge the stored electric energy to the light source 300.

[0155] When the first control signal is at a high level, transistor Q6 is turned on, transistor Q7 is turned off, and then MOS tube Q8 is turned off, the DC power supply 200 and the first primary winding do not form a closed loop, the current and magnetic flux of the first primary winding are reduced, the voltage induced at the second end of the first secondary winding is a positive voltage, the diode D8 is turned on, and the first transformer T1 releases the stored energy to the capacitor C5, and can also be released to the subsequent circuit (ignition circuit 30 and AC conversion circuit 40).

[0156] When the first control signal is at a low level or a high level, the capacitor C5 can output the first high voltage signal to the subsequent circuit to ensure the normal operation of the subsequent circuit.

[0157] It should be noted that the circuit structure of the boost circuit 20 of the present application can ensure that the voltage output by the port PT3 is the voltage corresponding to the first high voltage signal.

[0158] When the light source 300 is not started, the light source 300 needs to be ignited with high voltage. In the conventional ignition circuit 30, a discharge tube is used to realize ignition, which belongs to passive ignition. The discharge tube is generally a bidirectional voltage regulator diode, which has a dark effect. In a dark environment, the voltage at both ends is high voltage, and in a bright environment, the voltage at both ends is low voltage. The voltage at both ends varies with the ambient light intensity, which will cause the voltage at both ends of the light source 300 to be unstable.

[0159] See also Figure 6 , Figure 6 is a schematic diagram of the structure of an ignition circuit provided by an embodiment of the present invention, such as Figure 6 As shown, the ignition circuit 30 includes a second transformer 301 , a second energy storage circuit 302 and a first switch circuit 303 .

[0160] The second transformer 301 includes a second primary winding and a second secondary winding which are coupled to each other.

[0161] The first end of the second energy storage circuit 302 is connected to port PT3 for receiving the first high-voltage signal. The second end of the second energy storage circuit 302 is connected to the first end of the second primary winding. The second energy storage circuit 302 is used to store the first high-voltage signal output by the boost circuit 20 and provide a discharge voltage to the second primary winding based on the first high-voltage signal.

[0162] The first end of the first switch circuit 303 is connected to the port PT5 for receiving the first drive signal, the second end of the first switch circuit 303 is connected to the second end of the second primary winding, and the first switch circuit 303 is used to operate in the on state according to the first drive signal.

[0163] The first end of the second secondary winding is connected to the second end of the light source 300, the first end of the light source 300 is directly grounded or grounded through the fourth end of the AC conversion circuit 40 and the fifth end of the AC conversion circuit 40, wherein the fifth end of the AC conversion circuit 40 is grounded, the fourth end of the AC conversion circuit 40 is connected to the fifth end of the AC conversion circuit 40, the second end of the second secondary winding is connected to the port PT7, and is connected to the second end of the boost circuit 20 through the third end of the AC conversion circuit 40 and the first end of the AC conversion circuit 40, wherein the third end of the AC conversion circuit 40 and the first end of the AC conversion circuit are connected, so that the second end of the second secondary winding can be connected to the first high voltage signal. The second transformer 301 is used to convert the discharge voltage into the second high voltage signal when the first switch circuit 303 is in the on state, so as to ignite the light source 300.

[0164] The first end of the second energy storage circuit 302 serves as the second end of the ignition circuit, the first end of the first switch circuit 303 serves as the first end of the ignition circuit, the first end of the second secondary winding serves as the fourth end of the ignition circuit, and the second end of the second secondary winding serves as the third end of the ignition circuit.

[0165] When the boost circuit 20 outputs the first high voltage signal, the first high voltage signal is stored by the second energy storage circuit 302 .

[0166] When it is necessary to perform high-voltage ignition on the light source 300, the control module 201 outputs a first drive signal through port PT5 to drive the first switch circuit 303 to be in a conducting state, so that the second energy storage circuit 302, the second primary winding and the first switch circuit 303 form a closed loop, and the electric energy stored in the second energy storage circuit 302 is discharged through the second primary winding of the second transformer 301 and the first switch circuit 303, and a discharge voltage is provided to the second primary winding, so that the second primary winding couples the discharge voltage to the second secondary winding, and a second high-voltage signal is formed at the second secondary winding. The voltage of the second high-voltage signal is the ignition voltage, and the metal halide of the light source 300 breaks down under the action of the second high-voltage signal and enters arc discharge. After the ignition is successful, the control module 201 stops driving the first switch circuit 303, and the first switch circuit 303 is in a cut-off state, so that the ignition circuit 30 exits the ignition, thereby completing the ignition process of the light source 300.

[0167] In the embodiment of the present invention, the control module 201 controls the working state of the first switch circuit 303 to control the ignition process of the light source 300. When the first switch circuit 303 is in the on state, the voltage at both ends of the first switch circuit 303 is stable and is not affected by the ambient light. Therefore, the voltage at the second primary winding of the second transformer 301 is stable, and then the second high-voltage signal at the second secondary winding is stable, and the voltage at both ends of the light source 300 is also stable. Compared with the traditional ignition circuit 30, the ignition circuit 30 in the embodiment of the present invention can ensure that the light source 300 is stably ignited, thereby increasing the probability of successful ignition.

[0168] See also Figure 7 , Figure 7 is a schematic diagram of the structure of an ignition circuit provided by an embodiment of the present invention, such as Figure 7 As shown, the second energy storage circuit 302 includes a resistor R24, a resistor R25, a resistor R26 and a capacitor C9. In the embodiment of the present invention, the second transformer 301 is represented by an ignition transformer T2.

[0169] One end of resistor R24 ​​is connected to port PT3, the other end of resistor R24 ​​is respectively connected to one end of resistor R25, one end of capacitor C9 and the first end of the second primary winding, the other end of resistor R25 is connected to one end of resistor R26, and the other end of resistor R26 and the other end of capacitor C9 are grounded together.

[0170] One end of the resistor R24 ​​serves as a first end of the second energy storage circuit 302 , and one end of the resistor R25 and one end of the capacitor C9 serve as a second end of the second energy storage circuit 302 .

[0171] like Figure 7As shown, the first switch circuit 303 includes a MOS transistor Q9, a gate of the MOS transistor Q9 is connected to the port PT5, a source of the MOS transistor Q9 is grounded, and a drain of the MOS transistor Q9 is connected to the second end of the second primary winding.

[0172] The drain of the MOS transistor Q9 serves as the second end of the first switch circuit 303, and the gate of the MOS transistor Q9 serves as the first end of the first switch circuit 303. The conduction state of the first switch circuit 303 means that the MOS transistor Q9 is turned on.

[0173] In the embodiment of the present invention, the capacitor C9 can be 474J680V, ​​the MOS tube Q9 is an NMOS tube, and the second secondary winding of the ignition transformer T2 has a larger number of turns than the second primary winding to obtain a second high voltage signal with a higher voltage. The resistor R25 and the resistor R26 are discharge resistors.

[0174] Combination Figure 7 , the working principle of the ignition circuit 30 is described as follows:

[0175] When the boost circuit 20 outputs a first high voltage signal, the voltage of the first high voltage signal is 400 VDC. The first high voltage signal charges the capacitor C9 via the resistor R24, and the capacitor C9 stores electrical energy.

[0176] When high-voltage ignition of the light source 300 is required, the control module 201 outputs a first drive signal through port PT5. The first drive signal is a high-level signal. The high-level signal acts on the gate of the MOS tube Q9, so that the MOS tube Q9 is turned on. At this time, the electric energy stored in the capacitor C9 is discharged to the ground through the second primary winding of the ignition transformer T2 and the source and drain of the MOS tube Q9, providing a discharge voltage for the second primary winding.

[0177] The discharge voltage is coupled to the second secondary winding via the second primary winding, generating a second high voltage signal at the second secondary winding. The voltage of the second high voltage signal is 23KV. The second high voltage signal serves as an ignition high voltage to break down the metal halide of the light source 300, causing the light source 300 to enter arc discharge.

[0178] After successful ignition, the voltage across the light source 300 drops rapidly to between 17V and 28V. At this time, the control module 201 detects the current of the light source 300 and stops outputting the first drive signal, so that the MOS tube Q9 is turned off and the ignition circuit 30 exits ignition, thereby completing the ignition process of the light source 300.

[0179] When the light source 300 works normally, it can be driven directly by a DC signal, for example, the first high-voltage signal is directly applied to both ends of the light source 300, or it can be driven by an AC signal, for example, the first high-voltage signal is alternately applied to both ends of the light source 300. The AC signal can make the two electrodes of the light source 300 work in an AC state, thereby extending the service life of the lamp electrodes and ensuring the working life of the lamp.

[0180] Specifically, see Figure 8 , Figure 8 is a schematic diagram of the structure of an AC conversion circuit provided by an embodiment of the present invention, such as Figure 8 As shown, the AC conversion circuit 40 includes an H-bridge circuit 401 , a second switch circuit 402 and a third switch circuit 403 .

[0181] The first end of the H-bridge circuit 401 is connected to the first end of the second switch circuit 402, the second end of the H-bridge circuit 401 is connected to the port PT3, the third end of the H-bridge circuit 401 is connected to the port PT7 and the third end of the second switch circuit 402 respectively. The fourth end of the H-bridge circuit 401 is connected to the second end of the second switch circuit 402, the fifth end of the H-bridge circuit 401 is grounded, the sixth end of the H-bridge circuit 401 is connected to the first end of the third switch circuit 403, the seventh end of the H-bridge circuit 401 is connected to the second end of the third switch circuit 403 and the first end of the light source 300 respectively, the eighth end of the H-bridge circuit 401 is connected to the third end of the third switch circuit 403, the ninth end of the H-bridge circuit 401 is connected to the sixth end of the boost circuit 20, and the second end of the light source 300 is connected to the fourth end of the ignition circuit 30. The sixth end of the boost circuit 20 is connected to the first end or the second end of the light source 300 through the ninth end of the H-bridge circuit 401.

[0182] The second end of the second switch circuit 402 is also connected to the fourth end of the third switch circuit 403, and the fourth end of the second switch circuit 402 is connected to the port PT4. The fourth end of the second switch circuit 402 is used to access the second drive signal. The second drive signal is a periodic signal, and one period of the second drive signal includes a first level signal and a second level signal.

[0183] The second switch circuit 402 and the third switch circuit 403 are used to control the second end of the H-bridge circuit 401 to be connected to the third end of the H-bridge circuit 401, and the fifth end of the H-bridge circuit 401 to be connected to the seventh end of the H-bridge circuit 401 when the second driving signal is at the first level signal. The H-bridge circuit 401 applies the first high voltage signal to the second end of the light source 300.

[0184] The second switch circuit 402 and the third switch circuit 403 are also used for controlling the second end of the H-bridge circuit 401 to be connected to the seventh end of the H-bridge circuit 401, and the fifth end of the H-bridge circuit 401 to be connected to the third end of the H-bridge circuit 401 when the second driving signal is at a second level signal. The H-bridge circuit 401 applies the first high voltage signal to the first end of the light source 300.

[0185] The second end of the H-bridge circuit 401 serves as the first end of the AC conversion circuit 40, the fourth end of the second switch circuit 402 serves as the second end of the AC conversion circuit 40, the third end of the H-bridge circuit 401 serves as the third end of the AC conversion circuit 40, the seventh end of the H-bridge circuit 401 serves as the fourth end of the AC conversion circuit 40, the fifth end of the H-bridge circuit 401 serves as the fifth end of the AC conversion circuit 40, and the ninth end of the H-bridge circuit 401 serves as the sixth end of the AC conversion circuit 40.

[0186] For details, please refer to Figure 7 The H-bridge circuit 401 includes: a MOS transistor Q10, a MOS transistor Q11, a MOS transistor Q12 and a MOS transistor Q13.

[0187] The gate of the MOS tube Q10 is connected to the first end of the second switch circuit 402, the drain of the MOS tube Q10 is respectively connected to the second end of the boost circuit 20 and the drain of the MOS tube Q12, and are commonly connected to the port PT3, the source of the MOS tube Q10 is respectively connected to the third end of the ignition circuit 30, the third end of the second switch circuit 402 and the drain of the MOS tube Q11, the gate of the MOS tube Q11 is connected to the second end of the second switch circuit 402, the source of the MOS tube Q11 and the source of the MOS tube Q13 are commonly grounded, the gate of the MOS tube Q12 is connected to the first end of the third switch circuit 403, the source of the MOS tube Q12 is respectively connected to the second end of the third switch circuit 403, the first end of the light source 300 and the drain of the MOS tube Q13, and the gate of the MOS tube Q13 is connected to the third end of the third switch circuit 403.

[0188] like Figure 7 As shown, the second switch circuit 402 includes a transistor Q14, a transistor Q15, and a MOS transistor Q16, and the third switch circuit 403 includes a transistor Q17, a transistor Q18, and a MOS transistor Q19.

[0189] The base of the transistor Q14 is respectively connected to the fourth end of the boost circuit 20 and the base of the transistor Q15, and are commonly connected to the port PT4. The emitter of the transistor Q14 is grounded, the collector of the transistor Q14 is connected to the gate of the MOS transistor Q16, the source of the MOS transistor Q16 is grounded, the drain of the MOS transistor Q16 is connected to the gate of the MOS transistor Q10, and the collector of the transistor Q14 is also connected to the first power supply voltage.

[0190] The emitter of the transistor Q15 is grounded, the collector of the transistor Q15 is connected to the gate of the MOS transistor Q11, the base of the transistor Q17 and the base of the transistor Q18 respectively, the emitter of the transistor Q17 is grounded, the collector of the transistor Q17 is connected to the gate of the MOS transistor Q13, the emitter of the transistor Q18 is grounded, the collector of the transistor Q18 is connected to the gate of the MOS transistor Q19, the source of the MOS transistor Q19 is grounded, the drain of the MOS transistor Q19 is connected to the gate of the MOS transistor Q12, and the collectors of the transistor Q15, the collectors of the transistor Q17 and the collectors of the transistor Q18 are also connected to the first power supply voltage respectively.

[0191] In the embodiment of the present invention, the transistors Q14 , Q15 , Q17 and Q18 are all NPN transistors, and the MOS transistors Q10 to Q19 are all NMOS transistors.

[0192] In the embodiment of the present invention, the H-bridge circuit 401 also includes a resistor R27, the third detection circuit 208 includes a resistor R28 and a capacitor C10, one end of the resistor R27 is respectively connected to one end of the resistor R28, the source of the MOS tube Q10 and the source of the MOS tube Q11, the other end of the resistor R27 is grounded, the other end of the resistor R28 is respectively connected to one end of the capacitor C10 and the sixth end of the boost circuit 20 through the port PT6, and the other end of the capacitor C10 is grounded.

[0193] The boost circuit 20 obtains the voltage on the resistor R28 through the port PT6 to obtain the current of the light source 300 and implement the sampling of the current of the light source 300. The resistor R28 and the capacitor C10 form a filter circuit to filter out the sharp signal in the current of the light source 300 to protect the sixth terminal of the boost circuit 20.

[0194] In some embodiments, the AC conversion circuit 40 may also be provided with some diodes as needed to prevent power supply series connection, and may also be provided with some voltage regulators to protect the gates of the corresponding MOS tubes. The MOS tubes Q16 and Q19 may also improve the floating ground drive problem of the corresponding MOS tubes.

[0195] Specifically, the second switch circuit 402 also includes a diode D6, a voltage regulator tube ZD4, a capacitor C11, a resistor R29 and a resistor R30. The anode of the diode D6 is connected to one end of the resistor R29, and the other end of the resistor R29 is respectively connected to the collector of the transistor Q15 and the gate of the MOS tube Q11. The cathode of the diode D6 is respectively connected to one end of the resistor R30 and one end of the capacitor C11. The other end of the resistor R30 is respectively connected to the drain of the MOS tube Q16, the gate of the MOS tube Q10 and the cathode of the voltage regulator tube ZD4. The other end of the capacitor C11 is respectively connected to the anode of the voltage regulator tube ZD4, the source of the MOS tube Q10 and the drain of the MOS tube Q11.

[0196] The third switch circuit 403 also includes a diode D7, a voltage regulator tube ZD5, a capacitor C12, a resistor R31 and a resistor R32. The anode of the diode D7 is connected to one end of the resistor R32, and the other end of the resistor R32 is respectively connected to the collector of the transistor Q17 and the gate of the MOS tube Q13. The cathode of the diode D7 is respectively connected to one end of the resistor R31 and one end of the capacitor C12. The other end of the resistor R31 is respectively connected to the drain of the MOS tube Q19, the gate of the MOS tube Q12 and the cathode of the voltage regulator tube ZD5. The other end of the capacitor C12 is respectively connected to the anode of the voltage regulator tube ZD5, the source of the MOS tube Q12 and the drain of the MOS tube Q13.

[0197] The gate of the MOS transistor Q10 serves as the first end of the H-bridge circuit 401, the drain of the MOS transistor Q10 serves as the second end of the H-bridge circuit, the source of the MOS transistor Q10 and the drain of the MOS transistor Q11 serve together as the third end of the H-bridge circuit, the gate of the MOS transistor Q11 serves as the fourth end of the H-bridge circuit, the source of the MOS transistor Q11 and the source of the MOS transistor Q13 serve together as the fifth end of the H-bridge circuit, the gate of the MOS transistor Q13 serves as the sixth end of the H-bridge circuit, the drain of the MOS transistor Q13 and the source of the MOS transistor Q12 serve together as the seventh end of the H-bridge circuit, the gate of the MOS transistor Q12 serves as the eighth end of the H-bridge circuit, and the source of the MOS transistor Q11 and the source of the MOS transistor Q13 also serve together as the ninth end of the H-bridge circuit.

[0198] The drain of the transistor Q16 and the cathode of the voltage regulator ZD4 serve together as the first end of the second switch circuit 402, the collector of the transistor Q15 and the base of the transistor Q18 serve together as the second end of the second switch circuit 402, the anode of the voltage regulator ZD4 serves as the third end of the second switch circuit 402, and the base of the transistor Q14 and the base of the transistor Q15 serve together as the fourth end of the second switch circuit 402.

[0199] The collector of the transistor Q17 serves as the first end of the third switch circuit 403, the anode of the voltage regulator tube ZD5 serves as the second end of the third switch circuit 403, the cathode of the voltage regulator tube ZD5 and the drain of the MOS tube Q19 serve as the third end of the third switch circuit 403, and the base of the transistor Q17 and the base of the transistor Q18 serve as the fourth end of the third switch circuit 403.

[0200] The first on-state of the second switch circuit 402 means that the transistors Q14 and Q15 are on, and the MOS transistor Q16 is off, and the off-state of the second switch circuit 402 means that the transistors Q14 and Q15 are off, and the MOS transistor Q16 is on. The second on-state of the third switch circuit 403 means that the transistors Q17 and Q18 are off, and the MOS transistor Q19 is on, and the off-state of the third switch circuit 403 means that the transistors Q17 and Q18 are on, and the MOS transistor Q19 is off.

[0201] Combination Figure 7 , the working principle of the AC conversion circuit 40 can be described as follows:

[0202] The fourth terminal of the boost circuit 20 outputs a second driving signal, which is a square wave signal. When the square wave signal is at a first level signal, the first level signal is a high level signal, the transistor Q14 and the transistor Q15 are turned on, the gate of the MOS transistor Q16 is at a low level and is cut off, and the +12V power supply voltage is loaded on the MOS transistor Q10 through the diode D6 and the resistor R30 to turn it on, and the MOS transistor Q11 is turned off because the gate level of the MOS transistor Q11 is pulled down by the conduction of the transistor Q15.

[0203] The transistor Q17 and the transistor Q18 are turned off because their base levels are pulled down by the conduction of the transistor Q15. The 12V power supply voltage acts on the gate level of the MOS transistor Q13 to turn it on. The 12V power supply voltage acts on the gate of the MOS transistor Q19 to turn it on, pulling down the gate level of the MOS transistor Q12 to turn it off. In this way, the MOS transistors Q10 and Q13 in the H-bridge circuit 401 are turned on, and the MOS transistors Q11 and Q12 are turned off.

[0204] When the square wave signal is in the second level signal, the second level signal is a low level signal, the transistor Q14 and the transistor Q15 are turned off, the 12V power supply voltage acts on the gate of the MOS transistor Q16 to turn it on, the MOS transistor Q16 is turned on to lower the gate level of the MOS transistor Q10, so that the MOS transistor Q10 is turned off, and because the transistor Q15 is turned off, the 12V power supply voltage acts on the gate of the MOS transistor Q11, so that the MOS transistor Q11 is turned on.

[0205] Due to the cut-off of the transistor Q15, the 12V power supply voltage also acts on the bases of the transistors Q17 and Q18, so that the transistors Q17 and Q18 are turned on. The transistor Q17 is turned on to pull down the gate of the MOS transistor Q13, so that the MOS transistor Q13 is turned off. The transistor Q18 is turned on to pull down the level of the gate of the MOS transistor Q19, so that the MOS transistor Q19 is turned off. The cut-off of the MOS transistor Q19 causes the 12V power supply voltage to act on the gate of the MOS transistor Q12 via the diode D7 and the resistor 32, so that the MOS transistor Q12 is turned on. In this way, the MOS transistors Q10 and Q13 in the H-bridge circuit 401 are turned off, and the MOS transistors Q11 and Q12 are turned on.

[0206] The high level of the square wave signal may be 5V, and the low level may be 0V. The 12V power supply voltage may be provided by the first power supply voltage output by the power switching circuit 10 .

[0207] Meanwhile, when the ignition circuit 30 performs high voltage ignition on the light source 300 , the MOS transistors Q10 and Q13 are in the on state, and the MOS transistors Q12 and Q11 are in the off state.

[0208] In summary, the MOS tube Q10, the MOS tube Q13, the MOS tube Q11 and the MOS tube Q12 are continuously turned on and off in rotation, thereby ensuring that the two electrodes of the light source 300 work in an AC state, thereby extending the service life of the lamp electrodes and ensuring the working life of the lamp. At the same time, the AC conversion circuit controls the MOS tubes in the H-bridge circuit to be turned on and off in rotation through the second switch circuit and the third switch circuit. If the fourth end of the boost circuit is the IO port of the single-chip microcomputer, the AC conversion circuit in the present invention can use only one IO port to output a square wave signal to realize the function of AC conversion. Compared with the method of using all software control, the use of IO ports can be saved and the circuit cost can be reduced.

[0209] See also Fig. 9 , Fig. 9 is a schematic diagram of a structure of a driving circuit provided by an embodiment of the present invention, such as Fig. 9 As shown, the driving circuit includes a protection circuit 50 in addition to the above-mentioned power switching circuit, boost circuit, ignition circuit and AC conversion circuit.

[0210] The input end of the protection circuit 50 is connected to the DC power supply 200, and the output end is respectively connected to the input end of the power switching circuit 10 and the first end of the boost circuit 20. The protection circuit 50 is used to prevent the DC power supply 200 from being reversely connected.

[0211] Specifically, see Fig.10 , Fig.10 is a schematic diagram of a circuit structure of a driving circuit provided by an embodiment of the present invention, such as Fig.10As shown, the protection circuit 50 includes a MOS transistor Q20, a MOS transistor Q21 and a voltage regulator ZD6. The gate of the MOS transistor Q20 and the gate of the MOS transistor Q21 are commonly connected to the cathode of the voltage regulator ZD6 and the first end of the DC power supply 200. The source of the MOS transistor Q20 is connected to the second end of the DC power supply 200. The drain of the MOS transistor Q20 and the drain of the MOS transistor Q21 are commonly connected. The source of the MOS transistor Q21 is grounded, and the anode of the voltage regulator ZD6 is grounded.

[0212] Only when the first end of the DC power supply 200 is the positive electrode and the second end is the negative electrode, the voltage regulator ZD6 breaks down in the reverse direction to obtain a positive voltage regulator voltage of 12V, which acts on the gate of the MOS tube Q20 and the gate of the MOS tube Q21, so that the MOS tube Q20 and the MOS tube Q21 are turned on, the DC power supply 200 outputs normally, and the output end of the protection circuit 50 outputs the voltage of the DC power supply 200.

[0213] If the DC power supply 200 is in reverse connection, the first end of the DC power supply 200 is the negative pole, the second end of the DC power supply 200 is the positive pole, the cathode of the voltage regulator tube ZD6 obtains a reverse voltage, the MOS tube Q20 and the MOS tube Q21 are both cut off, and the two ends of the DC power supply 200 cannot form a loop to protect the subsequent circuit.

[0214] The protection circuit 50 uses two MOS tubes to prevent the power supply from being reversely connected, which can prevent the MOS tube from being turned off continuously, thereby improving the circuit reliability and further improving the circuit safety.

[0215] The working principles of other circuits of the driving circuit in the embodiment of the present invention are the same as those of the above-mentioned power switching circuit, boost circuit, ignition circuit and AC conversion circuit, and will not be repeated here.

[0216] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A power switching circuit, characterized in that: The power switching circuit includes: a selection circuit, a first processing circuit and a second processing circuit; The first end of the selection circuit is used to connect to the DC power supply, the second end of the selection circuit is connected to the first end of the first processing circuit, and the third end of the selection circuit is connected to the first end of the second processing circuit. When the DC power supply is the first DC power supply, the first end of the selection circuit is connected to the second end of the selection circuit, and when the DC power supply is the second DC power supply, the first end of the selection circuit is connected to the third end of the selection circuit; The second end of the first processing circuit is connected to the second end of the second processing circuit, the first processing circuit is used to perform voltage stabilization processing on the first DC power supply and output the first supply voltage through the second end of the first processing circuit, and the second processing circuit is used to perform voltage conversion processing on the second DC power supply and output the first supply voltage through the second end of the second processing circuit; The selection circuit includes a first voltage stabilizing module and a first switch module; The first end of the voltage stabilizing module is connected to the DC power supply, and the second end of the voltage stabilizing module is connected to the fourth end of the first switch module; The first end of the first switch module is connected to the DC power supply, the second end of the first switch module is connected to the first end of the first processing circuit, and the third end of the first switch module is connected to the first end of the second processing circuit. When the DC power supply is the second DC power supply, the voltage stabilizing module is in an on state so that the first end of the first switch module is connected to the third end of the first switch module. When the DC power supply is the first DC power supply, the voltage stabilizing module is in an off state so that the first end of the first switch module is connected to the second end of the first switch module. The first switch module includes a first switch unit, a second switch unit and a third switch unit; The first end of the first switch unit is connected to the DC power supply, the second end of the first switch unit is connected to the second end of the first voltage stabilizing module, and the third end of the first switch unit is connected to the third end of the second switch unit; A first end of the second switch unit is connected to the DC power supply, and a second end of the second switch unit is connected to a first end of the first processing circuit; A first end of the third switch unit is connected to the DC power supply, a second end of the third switch unit is connected to a first end of the second processing circuit, and a third end of the third switch unit is connected to a fourth end of the first switch unit; When the DC power supply is the first DC power supply, the first switch unit and the third switch unit are both in an off state, and the second switch unit is in an on state; When the DC power supply is the second DC power supply, the first switch unit and the third switch unit are both in an on state, and the second switch unit is in an off state; The voltage stabilizing module includes a voltage stabilizing tube ZD1 and a voltage stabilizing tube ZD2, the first switch unit includes a transistor Q1, a transistor Q2, a transistor Q3, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6 and a resistor R7, the second switch unit includes a transistor Q4 and a resistor R8, and the third switch unit includes a transistor Q5 and a resistor R9; The anode of the voltage regulator tube ZD1 is connected to the cathode of the voltage regulator tube ZD2, and the anode of the voltage regulator tube ZD2 is respectively connected to one end of the resistor R2, one end of the resistor R1, and one end of the resistor R4; The other end of the resistor R2 is connected to the base of the transistor Q1, and the other end of the resistor R4 is connected to the base of the transistor Q2; The collector of the transistor Q1 is connected to one end of the resistor R3 and one end of the resistor R6 respectively, and the other end of the resistor R6 is connected to the base of the transistor Q3; The collector of the transistor Q2 is connected to one end of the resistor R5 and one end of the resistor R9 respectively, and the other end of the resistor R9 is connected to the base of the transistor Q5; The collector of the transistor Q3 is connected to one end of the resistor R7 and one end of the resistor R8 respectively, and the other end of the resistor R8 is connected to the base of the transistor Q4; The collector of the transistor Q4 is connected to the first end of the first processing circuit, and the collector of the transistor Q5 is connected to the first end of the second processing circuit; The cathode of the voltage regulator tube ZD1, the other end of the resistor R3, the other end of the resistor R5, the other end of the resistor R7, the emitter of the transistor Q4 and the emitter of the transistor Q5 are commonly connected to the DC power supply; The other end of the resistor R1 , the emitter of the transistor Q1 , the emitter of the transistor Q2 , and the emitter of the transistor Q3 are grounded in common.

2. The power switching circuit according to claim 1, characterized in that: The first processing circuit includes a second voltage stabilizing module and a first unidirectional conducting module; The first end of the second voltage stabilizing module is connected to the second end of the selection circuit, the second end of the second voltage stabilizing module is connected to the first end of the first unidirectional conducting module, and the second voltage stabilizing module is used to stabilize the voltage of the first DC power supply; The second end of the first unidirectional conduction module serves as the second end of the first processing circuit, and the first unidirectional conduction module is used to prevent the first power supply voltage outputted from the second end of the first unidirectional conduction module from flowing back to the second voltage stabilizing module.

3. The power switching circuit according to claim 2, characterized in that: The second voltage stabilizing module includes a resistor R10 and a voltage stabilizing chip U1, and the first unidirectional conducting module includes a diode D1; One end of the resistor R10 is connected to the second end of the selection circuit, the other end of the resistor R10 is connected to the input end of the voltage stabilizing chip U1, the output end of the voltage stabilizing chip U1 is connected to the anode of the diode D1, and the ground end of the voltage stabilizing chip U1 is grounded; The cathode of the diode D1 serves as the second end of the first unidirectional conduction module.

4. The power switching circuit according to claim 1, characterized in that: The second processing circuit includes a switching power supply chip U2, a resistor R12, a diode D2, a diode D3, a diode D4, a diode D5, an inductor L1 and a voltage regulator ZD3; The input end of the switching power chip U2 is connected to the third end of the selection circuit, the soft start end of the switching power chip U2 is connected to the cathode of the diode D5, the feedback end of the switching power chip U2 is connected to one end of the resistor R12, and the output end of the switching power chip U2 is connected to the cathode of the diode D2; The anode of the diode D5 is grounded, the other end of the resistor R12 is connected to the anode of the voltage regulator ZD3, the cathode of the voltage regulator ZD3 is respectively connected to the anode of the diode D2 and the cathode of the diode D3, the anode of the diode D3 is connected to the anode of the diode D4, the cathode of the diode D4 serves as the second end of the second processing circuit, one end of the inductor L1 is respectively connected to the cathode of the diode D5 and the cathode of the diode D3, and the other end of the inductor L1 is respectively connected to the anode of the diode D3 and the anode of the diode D4.

5. The power switching circuit according to claim 1, characterized in that: The power switching circuit also includes a third processing circuit; The first end of the third processing circuit is connected to the second end of the first processing circuit and the second end of the second processing circuit respectively, and the third processing circuit is used to stabilize and convert the first supply voltage to obtain a second supply voltage, and output the second supply voltage at the second end of the third processing circuit.

6. A driving circuit, characterized in that: The driving circuit comprises a power switching circuit as described in any one of claims 1-5.

7. The driving circuit according to claim 6, characterized in that: The driving circuit also includes a boost circuit and an ignition circuit; The power supply end of the boost circuit is connected to the second end of the first processing circuit and the second end of the second processing circuit respectively, and the power supply end of the ignition circuit is connected to the second end of the first processing circuit and the second end of the second processing circuit respectively, and the first supply voltage is used to power the boost circuit and the ignition circuit; The first end of the boost circuit is connected to the DC power supply, the second end of the boost circuit is respectively connected to the second end of the ignition circuit and the third end of the ignition circuit, the third end of the boost circuit is connected to the first end of the ignition circuit, and the boost circuit is used to boost the voltage of the DC power supply to obtain a first high-voltage signal; The sixth end of the boost circuit is connected to the first end or the second end of the light source, and the boost circuit is also used to detect the current of the light source; The fourth end of the ignition circuit is connected to the second end of the light source, and the first end of the light source is grounded. When the current of the light source is less than or equal to a first preset value, the boost circuit is also used to output a first drive signal to the ignition circuit, and the ignition circuit is used to convert the first high-voltage signal into a second high-voltage signal according to the first drive signal to ignite the light source.

8. The driving circuit according to claim 7, characterized in that: The driving circuit also includes an AC conversion circuit; The first end of the AC conversion circuit is connected to the second end of the boost circuit, the second end of the AC conversion circuit is connected to the fourth end of the boost circuit, the third end of the AC conversion circuit is connected to the third end of the ignition circuit, the fourth end of the AC conversion circuit is connected to the first end of the light source, and the fifth end of the AC conversion circuit is grounded; when the current of the light source is greater than or equal to a second preset value, the boost circuit is also used to stop outputting the first drive signal to the ignition circuit and output a second drive signal to the AC conversion circuit, and the AC conversion circuit is used to alternately apply the first high voltage signal to the two ends of the light source according to the second drive signal, so that the light source is in an AC working state.

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