Laser projection device and switching circuit

Abstract

Some embodiments of the present application provide a laser projection device and a switching circuit. The laser projection device is provided with a driving switching circuit between the power supply circuit and the light source driving circuit, the driving switching circuit adopts the above-mentioned switching circuit, and includes a main switching circuit and a protection circuit. The main switching circuit can timely respond to a fault state signal meeting a second level, thereby timely cutting off the power supply to the light source driving circuit when a fault occurs. The protection circuit can switch to a locking state after receiving the fault state signal, continuously output a protection switching signal meeting the second level to the main switching circuit, and make the main switching circuit be locked in an open state, thereby realizing lock protection, avoiding the laser being frequently lit due to frequent system restart, and avoiding the laser and related devices being damaged due to continuous heating. In addition, the above-mentioned switching circuit can also be applied to other any type of electronic device, respond to a fault state signal thereof, and realize lock protection.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a laser projection device and a switching circuit. Background Technology

[0002] In recent years, with the development of laser projection display technology, laser projection devices such as laser TVs, laser micro-projectors, and art TVs have gradually entered people's work and lives. Because laser projection devices are portable and easy to carry, they can be moved to different projection locations as needed, bringing great convenience to users.

[0003] In laser projection equipment, the laser's on / off state is controlled by a drive circuit. If a short circuit occurs in the laser, the current flowing through it will increase significantly, causing the laser to operate beyond its specifications. Although the drive circuit can detect this short circuit and cut off the power supply to the laser, the fault signal indicating the short circuit disappears after the power is cut off, causing the drive circuit to restart and re-supply the laser. If the short circuit persists, the drive circuit will frequently restart, and the laser will repeatedly operate beyond its specifications, leading to heat buildup on the laser and related components, and potentially even burnout.

[0004] Therefore, it is necessary to provide a new short-circuit fault handling solution to prevent the laser of laser projection equipment from being damaged by short-circuit faults. Utility Model Content

[0005] Some embodiments of this application provide a laser projection device and a switching circuit that can more effectively deal with short-circuit faults in the laser projection device and prevent the laser from being burned out.

[0006] Some embodiments of this application provide a laser projection device, including: Laser; A light source driving circuit, coupled to the laser, is configured to output a laser power supply signal to the laser to control the light emission state of the laser; Power supply circuit; A drive switch circuit, coupled to the power supply circuit and the light source drive circuit respectively, is configured to control the power supply path of the power supply circuit to the light source drive circuit to be turned on or off. The driving switch circuit includes: Main switching circuit; the main switching circuit includes: The switch input terminal is coupled to the power supply circuit; The switch output terminal is coupled to the light source driving circuit; The control signal input terminal is configured to receive a switch control signal; wherein the switch control signal includes at least one of a fault status signal and a protection switch signal; The main switch circuit is configured such that, when the switch control signal meets a first level, the switch input terminal and the switch output terminal are connected to supply power to the light source driving circuit through the power supply circuit; and when the switch control signal meets a second level, the switch input terminal and the switch output terminal are disconnected to stop supplying power to the light source driving circuit through the power supply circuit. Protection circuit; the protection circuit includes: The fault signal input terminal is configured to receive the fault status signal; The control signal output terminal is coupled to the control signal input terminal and is configured to output the protection switch signal to the control signal input terminal to control the conduction or disconnection of the main switch circuit; The protection circuit is configured to switch and remain in a locked state when the fault status signal is received at the fault signal input terminal; wherein, in the locked state, the protection switch signal is a signal that satisfies the second level.

[0007] In the above embodiments, after receiving the above-mentioned fault status signal, the protection circuit can switch and remain in the locked state, thereby continuously outputting a protection switch signal that meets the above-mentioned second level to the main switch circuit.

[0008] In this way, the control signal input terminal of the main switch circuit can continuously receive the protection switch signal that meets the second level mentioned above, thereby keeping the switch input terminal and switch output terminal in an open state; even if the fault status signal disappears after the power supply to the laser is stopped, the main switch circuit will not be turned on again, thus avoiding frequent switching of the main switch when the short circuit fault of the laser negative electrode is always present, keeping the laser in a power-off state, and preventing the laser and related components from being burned out.

[0009] In some embodiments, the protection circuit further includes: a working voltage receiving terminal, configured to receive a preset working voltage to power on the protection circuit; The protection circuit is further configured to: in the locked state, when the working voltage receiving terminal is powered off and re-receives the preset working voltage, switch to the unlocked state; wherein, in the unlocked state, the protection switch signal is a signal that satisfies the first level.

[0010] In the above embodiments, upon receiving a fault status signal, the protection circuit switches and remains in a locked state, thereby keeping the main switch circuit in a corresponding off state. This ensures that even if the fault persists for an extended period, it will not damage the laser or related components. After the fault disappears, the protection circuit can be de-energized and then re-energized to release its locked state, i.e., switch to an unlocked state. This causes the output protection switch signal to meet the aforementioned first level, thus re-energizing the main switch circuit. The power supply circuit can then re-power the light source drive circuit, allowing the laser projection equipment to resume normal operation.

[0011] In some embodiments, the protection circuit is configured to switch to and remain in the locked state when the fault status signal is received at the fault signal input terminal and the number of receptions within a preset time reaches a preset number.

[0012] In the above embodiments, the protection circuit can switch and remain in the above-mentioned locked state only when the number of times the fault status signal is received within a preset time reaches a preset number, that is, when the fault exists for a long time, so that the main switch circuit also remains in the open state accordingly; if the number of times the fault status signal is received within the preset time does not reach the preset number, it indicates that the corresponding fault is a short-term fault, so the protection circuit does not act and remains in the unlocked state. Thus, after the corresponding fault disappears automatically, the main switch circuit can still respond normally to the enable control signal, etc., and the laser projection equipment can continue to work normally.

[0013] In some embodiments, the protection circuit includes: A counting circuit, coupled to the fault signal input terminal, is configured to generate a first electrical signal; wherein the first electrical signal is used to indicate the number of times the fault signal input terminal receives the fault status signal within the preset time period; A comparison circuit, coupled to the counting circuit, is configured to compare the first electrical signal with a preset electrical signal and output a comparison result signal; Wherein, the preset electrical signal is an electrical signal corresponding to the preset number of times, and the comparison result signal includes a first comparison result signal indicating that the number of times received is less than the preset number of times, and a second comparison result signal indicating that the number of times received is not less than the preset number of times; A signal conditioning circuit, coupled to the comparison circuit, is configured to, upon receiving the first comparison result signal, adjust the protection switch signal to a signal that satisfies the first level, and upon receiving the second comparison result signal, adjust the protection switch signal to a signal that satisfies the second level.

[0014] In the above embodiments, the counting circuit, comparison circuit, and signal conditioning circuit in the protection circuit cooperate with each other. After the number of times the fault status signal is received reaches a preset number, the output protection switch signal can be locked at the second level. That is, the protection circuit enters the locked state and will not change the level state of the protection switch signal due to the disappearance of the fault status signal. Thus, the main switch circuit is also locked in the open state and will not be turned on again after the fault status signal disappears.

[0015] In this way, even if the fault still exists, it will not damage the laser or related components of the laser projection equipment, thus ensuring the safety of the laser projection equipment and extending its service life.

[0016] In some embodiments, the counting circuit includes: A first capacitor; the first terminal of the first capacitor is coupled to the operating voltage receiving terminal of the protection circuit through a charging resistor to receive a preset operating voltage; the second terminal of the first capacitor is grounded; A charge / discharge control circuit, coupled to the fault signal input terminal, is configured to control the preset operating voltage to charge the first capacitor upon receiving the fault status signal. The voltage signal at the first terminal of the first capacitor is used as the first electrical signal.

[0017] In the above embodiments, a counting circuit is formed by the first capacitor and the corresponding charging and discharging control circuit. Each time a fault status signal is received, the first capacitor can be charged, so that the voltage of the first electrical signal, that is, the voltage of the first terminal of the first capacitor, can continuously increase as the number of fault status signals received increases. In turn, the comparison circuit can output the corresponding comparison result signal according to the voltage magnitude of the first electrical signal, so that the entire protection circuit can realize the function described in the previous embodiments.

[0018] In some embodiments, the charge / discharge control circuit includes: A first charging switch; the first terminal of the first charging switch is coupled to the working voltage receiving terminal of the protection circuit through a current-limiting resistor, the second terminal of the first charging switch is grounded, and the control terminal of the first charging switch is coupled to the fault signal input terminal. The first charging switch is turned on when it receives the fault status signal at its control terminal, and turned off when it does not receive the fault status signal. The second charging switch; the first terminal of the second charging switch is coupled to the first terminal of the first capacitor through a discharge resistor, the second terminal of the second charging switch is grounded, and the control terminal of the second charging switch is coupled to the first terminal of the first charging switch; The switching state of the second charging switch is the opposite of that of the first charging switch.

[0019] In the above embodiments, a circuit that can control the charging of the first capacitor based on the fault status signal can be formed using only a switching transistor and a resistor. The structure is simple, easy to implement, and low in cost, and can be widely used in laser projection equipment with different configurations.

[0020] In some embodiments, the comparison circuit includes: an operational amplifier; The non-inverting input of the operational amplifier is coupled to the counting circuit to receive the first electrical signal; The inverting input terminal of the operational amplifier receives the preset electrical signal; The output terminal of the operational amplifier is coupled to the signal conditioning circuit; The operational amplifier is configured to output a first comparison result signal when the first electrical signal is less than the preset electrical signal, and to output a second comparison result signal when the first electrical signal is not less than the preset electrical signal.

[0021] In the above embodiments, an operational amplifier is used to compare the magnitudes of the first electrical signal and the preset electrical signal, and outputs comparison result signals with different level states. This allows the signal conditioning circuit to adjust the level state of the protection switch signal according to the level state of the comparison result signal, thereby realizing the corresponding function of the protection circuit. The structure is simple, easy to implement, and low in cost, and can be widely used in laser projection equipment with different configurations.

[0022] In some embodiments, the signal conditioning circuit includes: First regulating switch; The first terminal of the first regulating switch is coupled to the control signal output terminal; The second terminal of the first regulating switch is grounded; Second adjustment switch; The first terminal of the second regulating switch is coupled to the operating voltage receiving terminal of the protection circuit through the first regulating resistor; The second terminal of the second regulating switch is grounded through the second regulating resistor, and the second terminal of the second regulating switch is also coupled to the control terminal of the first regulating switch through the third regulating resistor; The control terminal of the second regulating switch is coupled to the comparison circuit to receive the comparison result signal; Third adjustment switch; The first terminal of the third regulating switch is coupled to the working voltage receiving terminal; The second terminal of the third regulating switch is grounded through the third regulating resistor, and the second terminal of the third regulating switch is also coupled to the control terminal of the second regulating switch; The control terminal of the third regulating switch is coupled to the first terminal of the second regulating switch; The second regulating switch is turned on when the second comparison result signal is received, and the switching states of the first regulating switch and the third regulating switch are the same as the switching state of the second regulating switch.

[0023] In the above embodiments, the signal conditioning circuit consists of multiple resistors and switching transistors. When the comparison circuit outputs a second comparison result signal, i.e., when the number of times the fault status signal is received reaches a preset number, the output signal is locked in the second level state, thereby controlling the main switching circuit to be in the open state and realizing lockout protection. Its circuit structure is simple and the implementation cost is low, and it can be widely used in laser projection equipment with different configurations.

[0024] In some embodiments, the signal conditioning circuit includes: Zener diode; The cathode of the Zener diode is coupled to the control signal output terminal; The anode of the Zener diode is grounded; The adjustable terminal of the Zener diode is coupled to the comparator circuit; Fourth adjustment switch; The first terminal of the fourth regulating switch is coupled to the working voltage receiving terminal of the protection circuit. The second terminal of the fourth regulating switch is grounded through the fourth regulating resistor; The control terminal of the fourth regulating switch is coupled to the cathode of the Zener diode; Fifth adjustment switch; The first terminal of the fifth regulating switch is coupled to the cathode of the Zener diode; The second terminal of the fifth regulating switch is grounded; The control terminal of the fifth regulating switch is coupled to the second terminal of the fourth regulating switch through the fifth regulating resistor; When the adjustable terminal of the Zener diode receives the second comparison result signal, the Zener diode is reverse-biased and the fourth and fifth adjustment switches are turned on.

[0025] In the above embodiment, when the second comparison result signal is received, the Zener diode is turned on, and the protection switch signal output by the signal conditioning circuit is pulled low; at the same time, the fourth and fifth adjustment switches are turned on and locked in the on state, so that the signal conditioning circuit enters the locked state, that is, the protection circuit enters the locked state, and the protection switch signal is continuously pulled low, thereby keeping the main switch circuit in the off state and realizing lockout protection.

[0026] Some embodiments of this application provide a switching circuit applied to an electronic device, including: Main switching circuit; the main switching circuit includes: The switch input terminal is coupled to the power supply circuit of the electronic device; The switch output terminal is coupled to the load circuit of the electronic device; The control signal input terminal is configured to receive a switch control signal; wherein the switch control signal includes at least one of a protection switch signal and a fault status signal of the electronic device; The main switch circuit is configured such that, when the switch control signal meets a first level, the switch input terminal and the switch output terminal are connected to supply power to the load circuit through the power supply circuit; and when the switch control signal meets a second level, the switch input terminal and the switch output terminal are disconnected to stop supplying power to the load circuit through the power supply circuit. Protection circuit; the protection circuit includes: The fault signal input terminal is configured to receive the fault status signal of the electronic device; The control signal output terminal is coupled to the control signal input terminal and is configured to output the protection switch signal to the control signal input terminal to control the conduction or disconnection of the main switch circuit; The protection circuit is configured to switch and remain in a locked state when the fault status signal is received at the fault signal input terminal; wherein, in the locked state, the protection switch signal is a signal that satisfies the second level.

[0027] The switching circuit provided in the above embodiments can respond to the fault status signal of the corresponding electronic device to achieve lock-up protection, that is, to ensure that the power supply path between the voltage circuit and the load circuit is kept in the disconnected state, so as to avoid the system of the corresponding electronic device being frequently restarted after the fault occurs, which would cause the relevant load to continue to heat up and be damaged. Attached Figure Description

[0028] To more clearly illustrate the implementation methods in some embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0029] Figure 1 The present application provides schematic diagrams of the structure of laser projection devices according to some embodiments. Figure 2 The present application provides schematic diagrams of the structure of laser projection devices according to some embodiments. Figure 3 The present application provides schematic diagrams of the structure of laser projection devices according to some embodiments. Figure 4 This application shows a schematic diagram of the main switching circuit in a laser projection device according to some embodiments; Figure 5 The present application shows a schematic diagram of the structure of the protection circuit in a laser projection device provided in some embodiments; Figure 6 The present application shows a schematic diagram of the structure of the protection circuit in a laser projection device provided in some embodiments; Figure 7 The present application shows a schematic diagram of the structure of the protection circuit in a laser projection device provided in some embodiments; Figure 8 The diagram shows waveforms of the voltage signals of a laser projection device provided in some embodiments of this application as a function of time when a fault occurs. Figure 9 This application shows a schematic diagram of the signal conditioning circuit in the protection circuit of a laser projection device provided in some embodiments; Figure 10 A schematic diagram of the structure of a switching circuit provided in some embodiments of this application is shown. Detailed Implementation

[0030] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0031] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0032] The terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities, and do not necessarily imply a specific order or sequence, unless otherwise specified. It should be understood that such terms are interchangeable where appropriate.

[0033] The terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device that includes a range of components is not necessarily limited to all of the components that are clearly listed, but may include other components that are not clearly listed or that are inherent to such product or device.

[0034] The application scenarios and existing problems of this application will be explained below with reference to the accompanying drawings.

[0035] In recent years, with the development of laser projection display technology, laser projection devices such as laser TVs, laser micro-projectors, and art TVs have gradually entered people's work and life, meeting diverse display needs.

[0036] Figure 1 A schematic diagram of a laser projection device provided for some embodiments. (Refer to...) Figure 1 The laser projection device 100 includes a power supply circuit 110 and multiple load circuits, with the output terminal of the power supply circuit 110 being coupled to each load circuit respectively.

[0037] The input terminal of the power supply circuit 110 can be coupled to at least one of an external power supply or a built-in power supply. The external power supply can be AC ​​power or a power bank, etc., and the built-in power supply can be the built-in battery of the laser projection device 100.

[0038] In some embodiments, the load circuit described above may include a light source circuit 120. The light source circuit 120 includes a light source driving circuit 121 and a laser light source 122. The laser light source 122 may include one or more lasers. The light source driving circuit 121 can drive each laser in the laser light source 122 according to a driving control signal to control each laser to emit light or not emit light.

[0039] The laser source 122 can be a monochromatic laser source, meaning that all lasers emit the same color laser light. When using a monochromatic laser source, the laser projection device 100 also includes a phosphor wheel and a color filter wheel. For example, the monochromatic laser source is typically a blue laser that emits blue laser light. This blue laser source sequentially illuminates three different areas of the phosphor wheel, thereby producing three colors of light. These three colors of light are then filtered sequentially by the color filter wheel to obtain higher purity primary color light.

[0040] The laser source 122 can be a three-color laser source, that is, it includes three lasers that can emit three different colors. For example, a three-color laser source typically includes a blue laser for emitting blue laser light, a red laser for emitting red laser light, and a green laser for emitting green laser light.

[0041] In some embodiments, the load circuit described above may further include Figure 1 The main control chip 130, display control circuit 140, and shown are shown. Figure 1 Fans, speakers, communication circuits, etc., not shown.

[0042] The main control chip 130 can be a system-on-a-chip (SOC). As the control center of the laser projection device 100, the main control chip 130 can uniformly control the power supply circuit 110, the light source circuit 120, the display control circuit 140, and other components within the laser projection device 100. Furthermore, the main control chip 130 can also receive audio and video data transmitted from external signal sources, or read audio and video data locally and transmit it to the display control circuit 140.

[0043] The display control circuit 140 can parse the audio and video data transmitted by the main control chip 130, generate drive signals, and transmit them to the light source circuit 120.

[0044] In some embodiments, the display control circuit 140 may include a digital light processor (DLP). The DLP uses digital light processing technology to modulate the video signal, driving the laser light source 122 to emit a beam of corresponding color and brightness, and driving a light valve imaging device, such as a digital micromirror device (DMD), to reflect the beam emitted by the laser light source 122, so that the reflected beam is projected onto the projection screen through the projection lens to form a projected image.

[0045] In some embodiments, the light source driving circuit 121 adjusts the power supply current output to the laser light source 122 according to the driving signal sent by the display control circuit 140, thereby realizing the adjustment of the luminous state of each laser in the laser light source 122 according to the image data to be displayed, such as whether to emit light, luminous brightness, luminous duration, etc.

[0046] Figure 2 A schematic diagram of the light source circuit 120 in a laser projection device 100 in some embodiments is shown. The following is in conjunction with... Figure 2 The working principle of the light source circuit 120 is explained.

[0047] Reference Figure 2 In the light source circuit 120, the laser light source 122 is represented by a laser VD602. The light source driving circuit 121 may include a driving chip 2211 and related peripheral circuits.

[0048] The driver chip 2211 has the following pins: (1) The working voltage input pin VIN is used to receive the working voltage VCC so that the driver chip 2211 can be powered on and operated; (2) The analog dimming pin ADIM is used to receive the analog dimming (ADIM) signal output by the display control circuit 140; (3) Pulse width modulation dimming pin PDIM is used to receive the pulse width modulation dimming (PDIM) signal output by the display control circuit 140; (4) Gate control pin GATE is used to output a switching control signal to the gate of the switching transistor in the peripheral circuit; (5) The current detection pin ISEN is used to collect the current of the laser VD602; (6) Ground pin GND; (7) Status signal pin STATUS is used to receive the fault status signal FLT.

[0049] The peripheral circuits associated with the aforementioned driver chip 2211 include: (1) Capacitor C601 is connected between the input terminal of the light source driving circuit 121 and ground. It can filter the power supply signal of the input light source driving circuit 121 to ensure the input voltage V Dr-in Stable and noise-free; (2) Capacitor C602 and inductor L904 can form an LC filter circuit to filter the power supply signal output from the light source driving circuit 121 to the laser. (3) Diode VD601 can provide a fast discharge path for the capacitor C602 and inductor L904 mentioned above, so as to quickly adjust the output voltage V of the light source driving circuit 121. Dr-out ; (4) Switch V601, its first end is coupled to the negative output terminal of the light source driving circuit 121, its second end is grounded through resistor R601, and its control terminal is connected to the gate control pin GATE of the driver chip 2211.

[0050] based on Figure 2 As shown in the structure, the driver chip 2211 can control the switching frequency of the switching transistor V601 according to the ADIM, PDIM and other driving signals sent by the display control circuit 140, thereby adjusting the output voltage and output current of the light source driving circuit 121, and thus realizing the dimming of the laser VD602.

[0051] In addition, the ISEN current detection pin of the driver chip 2211 is connected to the second terminal of the switching transistor V601, so that the driver chip 2211 can obtain the voltage V across the resistor R601. R601 Furthermore, considering the resistance value R of resistor R601 R601 The current I flowing through resistor R601 is calculated. R601 =V R601 / R R601 Since R601 and laser VD602 are essentially connected in series, therefore I R601It can be used to characterize the magnitude of the current flowing through the laser VD602, so that the driver chip 2211 can be adjusted according to the current I. R601 This enables feedback adjustment of the laser current, ensuring accurate dimming.

[0052] Continue to refer to Figure 2 One possible fault condition of the laser projection device 100 is that the negative terminal of the laser VD602 is short-circuited to the common ground of the device, i.e., the negative terminal of the laser VD602 is grounded, thereby causing the voltage applied to the laser VD602 to change from the aforementioned output voltage V. Dr-out The input voltage V is changed to the above. Dr-in If the input voltage V Dr-in If the current is too high, the current in the VD602 laser will be very high, which may cause the VD602 laser to burn out.

[0053] In some embodiments, when the negative terminal of laser VD602 is short-circuited to ground, driver chip 2211 can detect a significant increase in the current of laser VD602 through the current detection pin ISEN. Thus, driver chip 2211 can determine that laser VD602 has a short-circuit fault and generate a fault status signal FLT to instruct the relevant circuit to stop supplying power to laser VD602.

[0054] For example, the driver chip 2211 can output a low-level fault status signal FLT through its STATUS pin to indicate that the above-mentioned laser negative electrode short circuit fault has occurred, and output a high-level fault status signal FLT or no signal to indicate that there is no fault.

[0055] For example, the power supply circuit 110 can receive the aforementioned fault status signal FLT, and upon receiving the fault status signal FLT, its output can be turned off, which means that the input voltage V of the light source driving circuit 121 is reduced. Dr-in The output voltage V of the light source driving circuit 121 is 0, thus the output voltage V is 0. Dr-out The value is also 0, stopping the power supply to the laser VD602.

[0056] However, the input voltage V of the light source driving circuit 121 is transmitted through the power supply circuit 110, etc. Dr-in When the current is set to 0, the current on the laser VD602 also becomes 0. The current value detected by the current detection pin ISEN of the driver chip 2211 also becomes 0. As a result, the driver chip 2211 no longer outputs the above-mentioned fault status signal FLT (outputting a high-level signal indicating no fault). The power supply circuit 110 also does not receive the above-mentioned fault status signal FLT, and considers the current system to be fault-free, and restores the power supply to the light source driver circuit 121.

[0057] In this scenario, if the short-circuit fault to ground at the negative terminal of laser VD602 persists, after the power supply circuit restores power to the light source drive circuit 121, laser VD602 will again experience a large current, causing the drive chip 2211 to output the aforementioned fault status signal FLT again. This cycle repeats, with power supply circuit 110 frequently restarting and laser VD602 frequently experiencing large current surges. As the heat generated by the large current accumulates, laser VD602 and other related components, such as the equipment casing, still face the risk of being burned out.

[0058] It is evident that cutting off the power supply to the light source driving circuit 121 by using the fault status signal FLT output by the driver chip 2211 cannot prevent the laser from being burned out in the event of a negative short circuit fault.

[0059] In view of this, some embodiments of this application provide another laser projection device that can more effectively handle laser short-circuit faults and prevent the laser from being burned out.

[0060] Figure 3 This application provides a schematic diagram of the structure of a laser projection device 200 according to some embodiments. (Refer to...) Figure 3 The laser projection device 200 includes a power supply circuit 210, a light source driving circuit 221, a laser tube light source 222, a display control circuit 240, etc., and its functions can be referred to the previous embodiment, which will not be repeated here.

[0061] like Figure 3 As shown, the laser projection device 200 also includes a drive switch circuit 250, which is connected in series between the power supply circuit 210 and the light source drive circuit 221, and can turn on or off the power supply path of the power supply circuit 210 to the light source drive circuit 221.

[0062] In some embodiments, the drive switch circuit 250 may include a main switch circuit 251 and a protection circuit 252. The main switch circuit 251 has a switch input terminal IN, a switch output terminal OUT, and a control signal input terminal Cin; the switch input terminal IN is coupled to the power supply circuit 210, the switch output terminal OUT is coupled to the light source drive circuit 221, and the control signal input terminal Cin is used to receive switch control signals.

[0063] The main switch circuit 251 is configured to, when the received switch control signal meets the first level, conduct between its switch input terminal IN and switch output terminal OUT to supply power to the light source drive circuit 221 through the power supply circuit 210; and when the received switch control signal meets the second level, disconnect between its switch input terminal IN and switch output terminal OUT to stop supplying power to the light source drive circuit 221 through the power supply circuit 210.

[0064] For example, the power supply circuit 210 can apply the output voltage to the system bus of the laser projection device 200. The main switch circuit 251 can obtain a power supply signal by connecting its switch input terminal IN to the system bus. Other load circuits can also obtain this power supply signal by connecting to the system bus. (For ease of description and comparison with V...) Dr-in Distinguishing between power supply signals at different nodes, the voltage of this power supply signal can be expressed as V. bus .

[0065] In some embodiments, the display control circuit 240 can enable the drive switch circuit 250 according to the projection display requirements; based on this, the display control circuit 240 can be coupled to the control signal input terminal Cin, and the switch control signal can include the enable control signal LED-EN sent by the display control circuit 240.

[0066] The display control circuit 240 can send an enable control signal LED-EN that meets the first level as required by the projection display when the laser needs to be lit, thereby turning on the main switch circuit 251 and the power supply circuit 210 can supply power to the light source drive circuit 221, so that the laser is lit.

[0067] Conversely, according to the projection display requirements, when it is necessary to turn off the laser, the display control circuit 240 can send an enable control signal LED-EN that meets the second level mentioned above, thereby turning off the main switch circuit 251, preventing the power supply circuit 210 from supplying power to the light source drive circuit 221, and turning off the laser.

[0068] In some embodiments, such as Figure 3 As shown, the aforementioned switch control signal may include: the fault status signal FLT output by the driver chip 2211 in the light source driver circuit 221.

[0069] As described in the previous embodiment, the fault status signal FLT being low indicates a short circuit to ground fault at the negative electrode of the laser in the laser source 222. Correspondingly, the second level can be low, and the corresponding first level can be high or in a high-impedance state.

[0070] Furthermore, since the port's voltage level will be pulled down to low if any one of the signals is low when multiple signals of different voltage levels are simultaneously connected to a port, setting the second voltage level that disconnects the main switch circuit 251 to low also ensures that the main switch circuit 251 can respond to the low-level signal indicating a fault, thus ensuring equipment safety, even when multiple different switch control signals are received simultaneously at the control signal input terminal Cin (e.g., when the laser negative electrode is short-circuited, the enable control signal LED-EN remains high, while the fault status signal FLT is low).

[0071] It should be noted that the fault status signal FLT described in this application embodiment is not limited to the signal indicating a short circuit fault in the negative electrode of the laser, but may also include other fault signals that may cause abnormal power supply to the laser. Those skilled in the art can configure the fault status signals that need to be connected to the drive switch circuit 250 according to actual application requirements, which will not be listed here.

[0072] When the main switch circuit 251 receives the aforementioned fault status signal FLT, it can disconnect its switch input terminal IN and switch output terminal OUT to stop supplying power to the light source drive circuit 221 through the power supply circuit 210, thereby cutting off the laser current in a timely manner.

[0073] However, if the main switch circuit 251 is controlled to disconnect solely based on the fault status signal FLT, the problem of frequent restarts leading to laser burnout, as mentioned earlier, will still exist. Therefore, this embodiment also includes a protection circuit 252, which can output another switching control signal to the main switch circuit 251, namely the protection switch signal LED-S, to solve the above problem, as detailed below.

[0074] Continue to refer to Figure 3 The protection circuit 252 has a fault signal input terminal Fin and a control signal output terminal Cout; the fault signal input terminal Fin is configured to receive the aforementioned fault status signal FLT, and the control signal output terminal Cout is configured to output the aforementioned protection switch signal LED-S.

[0075] Meanwhile, the protection circuit 252 is configured to switch and remain in a locked state upon receiving the aforementioned fault status signal FLT; wherein, in this locked state, the protection switch signal LED-S output by the control signal output terminal Cout is a signal that satisfies the aforementioned second level. That is, after receiving the aforementioned fault status signal FLT, the protection circuit 252 can switch and remain in a locked state, thereby continuously outputting the protection switch signal LED-S that satisfies the aforementioned second level to the main switch circuit 251.

[0076] In this way, the control signal input terminal Cin of the main switch circuit 251 can continuously receive the protection switch signal LED-S that meets the second level mentioned above, thereby keeping the switch input terminal IN and the switch output terminal OUT in an open state; even if the fault status signal FLT disappears after the power supply to the laser is stopped, the main switch circuit 251 will not be turned on again, thus avoiding the frequent switching of the main switch circuit 251 when the short circuit fault of the laser negative electrode is always present, keeping the laser in a power-off state, and preventing the laser and related components from being burned out.

[0077] In some embodiments, such as Figure 4As shown, the main switch circuit 251 may include: a main switch transistor V611, an auxiliary switch transistor V612, and related auxiliary components.

[0078] The first terminal of the main switch transistor V611 is connected to the switch input terminal IN of the main switch circuit 251 to receive the bus voltage V. bus The first terminal of the main switching transistor V611 is coupled to the switching output terminal of the main switching circuit 251, and is used to provide the input voltage V to the light source driving circuit 221. Dr-in .

[0079] The control terminal of the main switch V611 is coupled to the first terminal of the auxiliary switch V612, the second terminal of the auxiliary switch V612 is grounded, and the control terminal of the auxiliary switch V612 is coupled to the control signal input terminal Cin.

[0080] To ensure the normal operation of the main switch V611 and auxiliary switch V612, the main switch circuit 251 also includes the following auxiliary components: Resistors R611 and R612 are connected in series between the control terminal of the main switch V611 and the first terminal of the auxiliary switch V612. Capacitor C611 has its two ends connected to the first terminal and the control terminal of the main switch transistor V611, respectively. Resistor R613 is connected at both ends to the first terminal of the main switch transistor V611, and between resistors R611 and R612. The diode VD611 has its anode connected between resistors R611 and R612, and its cathode connected to the control terminal of the main switch V611. Capacitor C612 is connected at its two ends to the control terminal and the second terminal of auxiliary switch V612, respectively. Resistor R614 is connected at its two ends to the control terminal and the second terminal of auxiliary switch V612, respectively.

[0081] For example, the main switch V611 can be a low-level conduction switch (such as a PMOS transistor), and the auxiliary switch V612 can be a high-level conduction switch (such as an NPN transistor). Correspondingly, Figure 4 The working principle of the main switch circuit 251 shown is as follows: When a high-level switch control signal (such as a high-level enable control signal LED-EN) is received at the control signal input terminal Cin, i.e., the control terminal of the auxiliary switch V612, the auxiliary switch V612 is turned on. This pulls down the control terminal voltage of the main switch V611, turning on the main switch V611. This establishes a connection between the switch input terminal IN and the switch output terminal OUT of the main switch circuit 251, allowing the main switch circuit 251 to output the supply voltage V. Dr-in ; When a low-level switching control signal (such as the fault status signal FLT) is received at the control signal input terminal Cin, i.e., the control terminal of the auxiliary switch V612, the auxiliary switch V612 turns off. This causes the voltage at the control terminal of the main switch V611 to rise, turning off the main switch V611. The main switching circuit 251 then stops outputting the supply voltage V. Dr-in .

[0082] In some embodiments, such as Figure 4 As shown, the control signal input terminal Cin can include two terminals, namely Cin1 and Cin2. One of the control signal input terminals Cin1 is directly coupled to the control terminal of the auxiliary switch V612 and is used to receive the fault status signal FLT. The other control signal input terminal Cin2 is coupled to the control terminal of the auxiliary switch V612 through resistor R615 and is used for the above-mentioned enable control signal LED-EN and protection switch signal LED-S.

[0083] This configuration is based on the fact that the fault status signal FLT is either absent (which can be considered a high impedance state) or low (which can be directly coupled to the control terminal of the auxiliary switch V612). However, the enable control signal LED-EN and the protection switch signal LED-S are likely to be high voltage signals and should not be directly coupled to the control terminal of the auxiliary switch V612. Therefore, current and voltage are limited by resistor R615 to prevent the auxiliary switch V612 from being damaged by overcurrent or overvoltage at the control terminal.

[0084] In some embodiments, the protection circuit 252 is further provided with a working voltage receiving terminal, which is configured to receive a preset working voltage VCC so that the protection circuit 252 is powered on and put into operation.

[0085] Based on this, the protection circuit 252 is further configured to switch to an unlocked state if its operating voltage receiving terminal is de-energized and re-receives the preset operating voltage VCC when it is in a locked state; wherein, in the unlocked state, the protection switch signal LED-S output by the control signal output terminal Cout is a signal that satisfies the first level mentioned above.

[0086] In the above embodiment, after receiving the fault status signal, the protection circuit 252 switches and remains in the locked state, thereby continuously outputting the protection switch signal LED-EN that meets the second level signal to the main switch circuit 251, so that the main switch circuit 251 remains in the off state. In this way, even if the fault exists for a long time, it will not cause damage to the laser or related devices.

[0087] After the fault disappears, the locked state of the protection circuit 252 can be released by turning off and then turning on the power again, i.e., switching to the unlocked state. This will cause the protection switch signal output by the circuit to meet the first level mentioned above, which will turn the main switch circuit 251 back on. The power supply circuit 210 can then supply power to the light source drive circuit 221 again, and the laser projection equipment can resume normal operation.

[0088] It should be noted that the power-off and power-on of the protection circuit 252 can be achieved by manual operation by the user, such as powering off and restarting the laser projection device 200; or it can be achieved by setting other detection and control circuits, such as the detection and control circuit being configured to control the power-off and restart of the protection circuit 252 if no fault status signal is received within a relatively long preset time, thereby releasing the locked state of the protection circuit 25.

[0089] In some embodiments, the protection circuit 252 may also be configured to switch to and remain in the locked state when the fault signal input terminal Fin receives the fault status signal and the number of receptions within a preset time reaches a preset number.

[0090] In real-world applications, the malfunctions of laser projection equipment 200 may be short-lived faults or anomalies that disappear automatically, or they may be long-term faults that persist for an extended period. For example, acoustic shocks can cause a momentary increase in the laser current, but this will quickly disappear.

[0091] For long-term faults, the main switch circuit 251 can be kept in the off state by the protection circuit 252, effectively preventing damage to the laser or related components. For short-term faults, since the laser has a certain capacity to withstand large currents for short periods, the power supply to the laser does not need to be cut off. After the short-term fault disappears, the entire device will naturally return to normal operation without causing the laser or related components to burn out.

[0092] If the actual fault is short-term, the protection circuit 252 will also switch to the locked state, which will affect the normal operation of the laser projection equipment. The laser projection equipment may even need to wait for the protection circuit 252 to be powered on again before it can resume normal operation.

[0093] Therefore, in this embodiment of the application, the protection circuit 252 is configured such that if the number of times a fault status signal is received within a preset time reaches a preset number, it switches and remains in the above-mentioned locked state; otherwise, if the number of times a fault status signal is received within a preset time does not reach the preset number, the protection circuit 252 does not operate and remains in the unlocked state.

[0094] In other words, the protection circuit 252 can distinguish between short-term and long-term faults based on the number of times a fault status signal is received within a preset time. The principle behind this is: Since the relevant detection circuit (such as the aforementioned driver chip 2211) will no longer generate a fault status signal after the short-term fault disappears automatically, the protection circuit 252 will only receive one or a very few fault status signals in the event of a short-term fault. In the event of a long-term fault, the relevant detection circuit will detect the fault again every time the main switch circuit 251 switches. As long as the long-term fault does not disappear, the relevant detection circuit will output the fault status signal multiple times, and the protection circuit 252 will receive the fault status signal multiple times.

[0095] Based on this, the protection circuit 252 can switch and remain in the above-mentioned locked state only when the number of times the fault status signal is received within a preset time reaches a preset number, that is, when the fault exists for a long time, so that the main switch circuit 251 also remains in the open state accordingly; if the number of times the fault status signal is received within the preset time does not reach the preset number, it indicates that the corresponding fault is a short-term fault, so the protection circuit 252 does not operate and remains in the unlocked state. Thus, after the corresponding fault disappears automatically, the main switch circuit 251 can still respond normally to the enable control signal LED-EN, etc., and the laser projection equipment 200 can continue to work normally.

[0096] In some embodiments, reference is made to Figure 5 The protection circuit 252 may include a counting circuit 2521, a comparison circuit 2522, and a signal conditioning circuit 2523.

[0097] The counting circuit 2521 is coupled to the fault signal input terminal Fin and the comparison circuit 2522 respectively, and is configured to record the number of times the fault signal input terminal Fin receives the fault status signal FLT, and generate the corresponding first electrical signal.

[0098] The first electrical signal can represent the number of times the fault signal input terminal Fin receives the fault status signal FLT within the preset time period. For example, the first electrical signal can be a voltage signal, and the higher the voltage value, the more times the fault signal input terminal Fin receives the fault status signal FLT, and the two are positively correlated.

[0099] For example, when the counting circuit 2521 receives a fault status signal once, the first electrical signal is 1V. When the counting circuit 2521 receives two fault status signals in a row, the first electrical signal rises to 2V. When the counting circuit 2521 receives three fault status signals in a row, the first electrical signal rises to 3V.

[0100] The comparison circuit 2522 is coupled to the counting circuit 2521 and the signal conditioning circuit 2523 respectively, and is configured to compare the first electrical signal output by the counting circuit 2521 with a preset electrical signal, and output the comparison result signal to the signal conditioning circuit 2523.

[0101] The aforementioned preset electrical signal is an electrical signal corresponding to a preset number of times. The aforementioned comparison result signal includes a first comparison result signal and a second comparison result signal; the first comparison result signal indicates that the first electrical signal is less than the preset electrical signal, that is, it indicates that the number of times the counting circuit 2521 receives the fault status signal is less than the preset number of times; the second comparison result signal indicates that the first electrical signal is not less than the preset electrical signal, that is, it indicates that the number of times the counting circuit 2521 receives the fault status signal is not less than the preset number of times.

[0102] The aforementioned signal conditioning circuit 2523 is coupled to the comparator circuit 2522 and the control signal output terminal Cout, respectively, and is configured as follows: Upon receiving the first comparison result signal output by the comparator circuit 2522, the protection switch signal LED-S output by the control signal output terminal Cout is adjusted to a signal that satisfies the first level mentioned above, so that the main switch circuit 251 can be in the on state or can respond to other control signals, such as the enable control signal LED_EN. Upon receiving the second comparison result signal output by the comparison circuit 2522, the protection switch signal LED-S output by the control signal output terminal Cout is adjusted to meet the above-mentioned second level and locked, so that the main switch circuit 251 is locked in the off state accordingly.

[0103] The working principle of the protection circuit 252 described above is further illustrated below with examples.

[0104] For example, suppose that the laser can withstand a maximum of three high-current surges within a preset time, based on its capacity. If more than three surges are observed, the laser may overheat and be damaged. Based on the relationship between the first electrical signal and the number of surges, the preset electrical signal can be set as a reference voltage signal VREF, and its voltage value can be any value between 2V and 3V.

[0105] In this way, after the counting circuit 2521 receives three consecutive fault status signals, the first electrical signal reaches 3V, which is greater than the voltage value of the preset electrical signal. Then, the comparison circuit 2522 outputs the second comparison result signal, and the signal conditioning circuit 2523 adjusts and locks the output protection switch signal LED-S at the second level, so that the main switch circuit 251 is locked in the off state.

[0106] In the above embodiment, the counting circuit 2521, the comparison circuit 2522, and the signal conditioning circuit 2523 in the protection circuit 252 cooperate with each other. After the number of times the fault status signal is received reaches a preset number, the output protection switch signal LED-S can be locked at the second level. That is, the protection circuit 252 enters the locked state and will not change the level state of the protection switch signal LED-S due to the disappearance of the fault status signal. As a result, the main switch circuit 251 is also locked in the open state and will not be turned on again after the fault status signal disappears.

[0107] In this way, even if the fault still exists, it will not damage the laser or related components of the laser projection equipment 200, thereby ensuring the safety of the laser projection equipment and extending its service life.

[0108] In some embodiments, the counting circuit 2521 described above can be implemented by a digital circuit, i.e., a timer, that has the function of accumulating the number of input pulses.

[0109] In some embodiments, to reduce costs, the counting circuit 2521 described above can be employed as follows: Figure 6 The circuit structure is shown. (Refer to...) Figure 6 The counting circuit 2521 may include a first capacitor C622 and a corresponding charge / discharge control circuit 25211.

[0110] The first terminal of the first capacitor C622 is coupled to the working voltage receiving terminal of the protection circuit 252 through the charging resistor R622 to receive the preset working voltage VCC; the second terminal of the first capacitor C622 is grounded.

[0111] The charge / discharge control circuit 25211, coupled to the fault signal input terminal Fin, is configured to control the preset operating voltage VCC to charge the first capacitor C622 when the fault status signal FLT is received.

[0112] For example, such as Figure 6 As shown, the charge / discharge control circuit 25211 can be a switching circuit with a first capacitor C622 connected in parallel, which has at least one built-in electronic switch.

[0113] Based on this, the aforementioned fault status signal serves as the switching signal for the charge / discharge control circuit 25211. That is, when no fault status signal is received, the charge / discharge control circuit 25211 is turned on, thereby short-circuiting the first capacitor C622. The first capacitor C622 discharges through the charge / discharge control circuit 25211, and the voltage at the first terminal of the first capacitor C622 decreases. When a fault status signal is received, the charge / discharge control circuit 25211 is turned off, so that the preset operating voltage VCC can charge the first capacitor C622, causing the voltage at the first terminal of the first capacitor C622 to increase.

[0114] Since the charging and discharging control circuit 25211 controls the preset operating voltage VCC to charge the first capacitor C622 every time the above-mentioned fault status signal FLT is received, the voltage at the first terminal of the first capacitor C622 will increase. Therefore, as the number of times the above-mentioned fault status signal FLT is received increases, the voltage at the first terminal of the first capacitor C622 will also continuously increase.

[0115] It can be seen that the voltage at the first terminal of the first capacitor C622 will increase as the number of times the charging and discharging control circuit 25211 receives the above-mentioned fault status signal FLT increases. Therefore, the voltage signal at the first terminal of the first capacitor C622 can be used as the above-mentioned first electrical signal, so that the entire protection circuit 252 can adjust and lock the output protection switch signal to the second level when the number of times the fault status signal is received reaches a preset number, and lock the main switch circuit 251 in the open state.

[0116] In the above embodiments, a counting circuit 2521 is formed by the first capacitor C622 and the corresponding charging and discharging control circuit 25211. Each time a fault status signal FLT is received, the first capacitor C622 can be charged. As a result, the voltage of the first electrical signal, that is, the voltage of the first terminal of the first capacitor C622, can continuously increase as the number of times the fault status signal FLT is received increases. This allows the comparison circuit 2522 to output a corresponding comparison result signal based on the magnitude of the voltage of the first electrical signal, so that the entire protection circuit 252 can achieve the function described in the previous embodiments.

[0117] In some embodiments, reference is made to Figure 7 The aforementioned charging and discharging control circuit 25211 may specifically include: a first charging switch V621 and a second charging switch V627.

[0118] The first terminal of the first charging switch V621 is coupled to the working voltage receiving terminal of the protection circuit 252 through the current limiting resistor R632 to receive the preset working voltage VCC; the second terminal of the first charging switch V621 is grounded, and the control terminal of the first charging switch V621 is coupled to the fault signal input terminal Fin.

[0119] The first terminal of the second charging switch V627 is coupled to the first terminal of the first capacitor C622 through the discharge resistor R621. The second terminal of the second charging switch V627 is grounded. The control terminal of the second charging switch V627 is coupled to the first terminal of the first charging switch V621.

[0120] In addition, a resistor R630 is connected in series between the control terminal of the first charging switch V621 and the fault signal input terminal Fin to prevent overcurrent and overvoltage at the control terminal of the first charging switch V621; the fault signal input terminal Fin is also coupled to the above-mentioned working voltage receiving terminal through the resistor R631, so that the signal input to the fault signal input terminal Fin can be normally represented as the corresponding level.

[0121] For example, Figure 7 The first charging switch V621 uses a low-level conducting switching transistor, while the second charging switch V627 uses a high-level conducting switching transistor; correspondingly, the working principle of the above-mentioned charging and discharging control circuit 25211 is as follows: If the aforementioned fault status signal FLT is not received, the control terminal of the first charging switch V621 is in a high-impedance state, and the first charging switch V621 is turned off. Subsequently, when the first charging switch V621 is turned off, the control terminal of the second charging switch V627 receives the preset operating voltage VCC through resistor R632, so its control terminal is at a high level, and the second charging switch V627 is turned on, thereby short-circuiting the first capacitor C622. The first capacitor C622 discharges through the second charging switch V627, and the voltage at the first terminal of the first capacitor C622 decreases, which also reduces the voltage of the first electrical signal.

[0122] When a low-level fault status signal FLT is received, the control terminal of the first charging switch V621 becomes low, thus turning on the first charging switch V621. Subsequently, with the first charging switch V621 on, the control terminal of the second charging switch V627 is grounded and becomes low, turning off the second charging switch V627. The first capacitor C622 is no longer short-circuited, so it can be charged by the preset operating voltage VCC. The voltage at the first terminal of the first capacitor C622 increases, which also increases the voltage of the first electrical signal.

[0123] In the above embodiments, a circuit that can control the charging of the first capacitor C622 based on the fault status signal can be formed using only a switching transistor and a resistor. The structure is simple, easy to implement, and low in cost, and can be widely used in laser projection equipment with different configurations.

[0124] In some embodiments, reference continues to be made to Figure 7 The aforementioned comparator circuit 2522 may include an operational amplifier N621B.

[0125] The positive power supply terminal of the aforementioned operational amplifier N621B is coupled to the working voltage receiving terminal of the protection circuit 252, and the negative power supply terminal is grounded. That is, the preset working voltage VCC is used as the working voltage of the operational amplifier N621B, so that it can be powered on and operated.

[0126] The non-inverting input of the operational amplifier N621B is coupled to the counting circuit 2521 to receive the first electrical signal output by the counting circuit 2521. Its inverting input receives the reference voltage VREF, and its output is coupled to the signal conditioning circuit 2523 to output the comparison result signal.

[0127] For example, refer to Figure 7 The non-inverting input of the operational amplifier N621B is coupled to the first terminal of the first capacitor C622. Therefore, the voltage signal at the first terminal of the first capacitor C622, i.e. the first electrical signal mentioned above, can be denoted as V3.

[0128] For example, refer to Figure 7 The inverting input of the operational amplifier N621B receives the reference voltage VREF through resistor R623 and is grounded through resistor R624; the voltage signal received by the inverting input is the aforementioned preset electrical signal, and its voltage can be denoted as V4.

[0129] The aforementioned operational amplifier N621B is configured to output the first comparison result signal when the first electrical signal is less than a preset electrical signal, i.e., V3 is less than V4; and to output the second comparison result signal when the first electrical signal is not less than the preset electrical signal, i.e., V3 is not less than V4.

[0130] For example, when V3 is less than V4, the output of operational amplifier N621B is low, that is, the first comparison result signal is a low level signal; when V3 rises to V4, the output level of operational amplifier N621B changes to a high level signal, that is, the second comparison result signal.

[0131] In the above embodiments, the magnitudes of the first electrical signal and the preset electrical signal are compared by an operational amplifier, and the comparison result signals with different level states are output accordingly. The signal conditioning circuit 2523 can adjust the level state of the protection switch signal LED-S according to the level state of the comparison result signal, so as to realize the corresponding function of the protection circuit 252. The structure is simple, easy to implement, and low in cost, and can be widely used in laser projection equipment with different configurations.

[0132] In some embodiments, reference continues to be made to Figure 7 The signal conditioning circuit 2523 may include: a first conditioning switch V623, a second conditioning switch V622 and a third conditioning switch V626.

[0133] The first terminal of the first regulating switch V623 is coupled to the control signal output terminal Cout, and outputs the protection switch signal LED-S; the second terminal of the first regulating switch V623 is grounded.

[0134] The first terminal of the second regulating switch V622 is coupled to the working voltage receiving terminal of the protection circuit 252 through the first regulating resistor R625 to receive the preset working voltage VCC and ensure that the second regulating switch V622 is powered on and working; the second terminal of the second regulating switch V622 is grounded through the second regulating resistor R628, and the second terminal of the second regulating switch V622 is also coupled to the control terminal of the first regulating switch V623 through the third regulating resistor R629.

[0135] The first terminal of the third regulating switch V626 is also coupled to the aforementioned working voltage receiving terminal to ensure that the third regulating switch V626 is powered on and working; the second terminal of the third regulating switch V626 is grounded through the third regulating resistor R627, and the second terminal of the third regulating switch V626 is also coupled to the control terminal of the second regulating switch V622; the third regulating switch V626 is coupled to the first terminal of the second regulating switch V622.

[0136] Specifically, the second regulating switch V622 is turned on when it receives the second comparison result signal, and the switching states of the first regulating switch V623 and the third regulating switch V626 are the same as the switching state of the second regulating switch V622.

[0137] For example, such as Figure 7 As shown, the first regulating switch V623 and the second regulating switch V622 can be high-level conducting switching transistors, and the third regulating switch V626 can be a low-level conducting switching transistor; based on this, the working principle of the above signal conditioning circuit 2523 is as follows: When the comparison circuit 2522 outputs a low-level first comparison result signal, the signal received by the control terminal of the second adjustment switch V622, namely V5, is low-level. Therefore, the second adjustment switch V622 is turned off. Correspondingly, the first adjustment switch V623 and the third adjustment switch V626 are both turned off. The first terminal of the first adjustment switch V623 is essentially floating, that is, the protection switch signal LED-S is in a high-impedance state, which has no effect on the state of the main switch circuit 251. The entire system of the laser projection device 200 works normally. When the comparator circuit 2522 outputs a high-level second comparison result signal, the signal received by the control terminal of the second regulating switch V622, namely V5, is at a high level. Therefore, the control terminal of the second regulating switch V622 is turned on, and correspondingly, the first regulating switch V623 is turned on, thereby making the protection switch signal LED-S low level. At the same time, the third regulating switch V626 is also turned on, which can keep the voltage of the control terminal of the second regulating switch V622, namely V5, at a high level, thus locking the protection switch signal LED-S in a low level state, namely the aforementioned second level state, and locking the main switch circuit 251 in the off state.

[0138] In the above embodiments, the signal conditioning circuit 2523 consists of multiple resistors and switching transistors. When the comparison circuit 2522 outputs a second comparison result signal, that is, when the number of times the fault status signal is received reaches a preset number, the output signal is locked in the second level state, thereby controlling the main switch circuit 251 to be in the open state and realizing lockout protection. Its circuit structure is simple and the implementation cost is low, and it can be widely used in laser projection equipment with different configurations.

[0139] In the above embodiments, by adjusting the values ​​of the discharge resistor R621, the charging resistor R622, the first capacitor C622, and V4 in the protection circuit 252, the preset number of times described in the previous embodiments can be adjusted, that is, the number of times the main switch circuit 251 is allowed to disconnect and reconnect when a fault occurs.

[0140] Figure 8 It shows Figure 7 The signal waveform diagram related to the protection circuit 252. Among them, V... cin This indicates the voltage at the control signal input terminal of the main switch circuit 251, that is... Figure 4 The control terminal voltage of the auxiliary switching transistor V612; by Figure 4 As can be seen from the circuit structure, when at least one of the three signals LED-EN, LED-S, and FLT is low, V cin This is a low level.

[0141] The following is combined with Figure 3 , Figure 4 , Figure 7 and Figure 8 Taking a preset number of times of 3 as an example, the working principle of the drive switch circuit 250 in this application embodiment will be further explained.

[0142] like Figure 8 During the time period t0 to t1 shown, after the laser projection device 200 is turned on and the system is powered on, the display control circuit 240 outputs a high-level LED-EN, causing the control terminal voltage V of the auxiliary switching transistor V612 to... cin When the voltage is high, the main switch circuit 251 is turned on, and the input voltage V of the light source drive circuit 221 is increased. Dr-in The signal level is high; at the same time, the display control circuit 240 outputs signals such as ADIM and PDIM, the light source drive circuit 221 works normally, and the laser VD602 in the laser light source 222 is lit.

[0143] Since the laser projection device 200 is working normally, the fault status signal FLT output by the driver chip 2211 is in a high-impedance state. Correspondingly, in the counting circuit 2521 of the protection circuit 252, the first charging switch V621 is turned off and the second charging switch V627 is turned on. The first capacitor C622 discharges through the discharge resistor R621 and the second charging switch V627, thereby causing the voltage V3 at the non-inverting input terminal of the operational amplifier N621B to be lower than the voltage V4 at the inverting input terminal. The output signal of the operational amplifier N621B is low (i.e., the first comparison result), and the voltage V5 is low. The second adjustment switch V622 in the signal conditioning circuit 2523 is turned off, and the first adjustment switch V623 and the third adjustment switch V626 are also turned off. The protection switch signal LED-S output by the protection circuit 252 is in a high-impedance state, which does not affect the control terminal voltage V of the auxiliary switch transistor V612. cin .

[0144] like Figure 8 During the time period t1 to t2 shown, the negative terminal of laser VD602 is short-circuited to ground, the fault status signal FLT goes low, and the control terminal voltage V of auxiliary switch V612 decreases. cin When the voltage drops to a low level, the auxiliary switch V612 turns off, which in turn turns off the main switch V611, disconnecting the main switch circuit 251 and reducing the input voltage V of the light source drive circuit 221. Dr-in When the voltage drops, laser VD602 is turned off. Simultaneously, during the period from t1 to t2, protection circuit 252 also receives the low-level FLT signal. The first charging switch V621 is turned on and the second charging switch V627 is turned off, causing the preset operating voltage VCC to charge the first capacitor C622 through the charging resistor R622. V3 begins to rise, but does not reach V4, so V5 remains low. The third adjustment switch V626 remains off, and the protection switch signal LED-S output by protection circuit 252 remains in a high-impedance state.

[0145] like Figure 8 During the time period from t2 to t3, the FLT signal returns to a high-impedance state, and the control terminal voltage V of the auxiliary switch V612... cin When the voltage level changes to high, auxiliary switch V612 turns on, and main switch V621 turns on. Dr-in When the high level is restored, the driver chip 2211 restarts, and the laser is lit again. At the same time, the first charging switch V621 in the protection circuit 252 is turned off, the second charging switch V627 is turned on, the first capacitor C622 discharges through the discharge resistor R621 and the second charging switch V627, V3 decreases, V5 remains at a low level, and the protection switch signal LED-S output by the protection circuit 252 remains in a high impedance state.

[0146] like Figure 8During the time period t3 to t4, the laser was lit in the previous period, causing the driver chip 2211 to detect the short circuit fault again. The FLT signal switched to a low level again, and the control terminal voltage V of the auxiliary switch V612 decreased. cin When the voltage drops to low, the state of the relevant circuit components is as follows: during the period from t1 to t2, V3 increases further by charging the first capacitor C622. However, V4 is still not reached at time t2, so V5 remains low. The protection switch signal LED-S output by the protection circuit 252 remains in a high-impedance state.

[0147] like Figure 8 During the t4 to t5 period shown, the driver chip 2211 restarts again, the FLT signal returns to a high impedance state, and the control terminal voltage V of the auxiliary switch V612... cin When the voltage level changes to high, referring to the time period from t2 to t3 mentioned above, the first capacitor C622 discharges, V3 decreases, V5 remains at a low level, and the protection switch signal LED-S output by the protection circuit 252 remains in a high-impedance state.

[0148] like Figure 8 During the period from t5 to t6, the driver chip 2211 detected the short circuit fault again, and the FLT signal switched to low level for the third time. The control terminal voltage V of the auxiliary switch V612... cin V becomes low level Dr-in As the voltage decreases, the first capacitor C622 begins to charge again, and V3 increases further.

[0149] Starting from time t6, V3 reaches V4, the output level of operational amplifier N621B changes, and V5 correspondingly changes from low to high, turning on the second regulating switch V622. This, in turn, turns on the first regulating switch V623, causing the protection switch signal LED-S output by protection circuit 252 to go low. The third regulating switch V626 also turns on, thus maintaining V5 at a high level, no longer affected by the output signal of operational amplifier N621B. This keeps the second regulating switch V622 and the first regulating switch V623 in the conducting state, and protection circuit 252 continuously outputs the low-level protection switch signal LED-S (i.e., protection circuit 252 enters a locked state). The control terminal voltage V of auxiliary switch transistor V612... cin The voltage remains low, so even if the FLT signal returns to a high impedance state, the auxiliary switch V612 will not turn on, and the main switch V611 will remain off, continuously pulling down the input voltage V of the light source driver circuit 221. Dr-in .

[0150] Therefore, at time t5, the FLT signal transitions to a low level for the third time. After the main switch circuit 251 shuts off the protection for the third time, the protection circuit 252 also receives a low-level FLT signal three times consecutively. The voltage V3 of the first capacitor C622 continues to accumulate. Starting from time t6, V3 reaches V4, meaning the first electrical signal reaches the preset electrical signal. The protection circuit 252 switches and remains in the locked state, continuously outputting a low-level protection switch signal LED-S, continuously pulling down the level of the control signal input terminal of the main switch circuit 251 (i.e., V). cin The main switch circuit 251 is locked in the open state, and the input voltage V of the light source drive circuit 221 is... Dr-in Even if the driver chip 2211 restarts itself, the short circuit fault between the negative terminal and ground of the laser VD602 will still exist, but the laser will not be lit, thus preventing the laser VD602 from overheating and burning out.

[0151] As can be seen from the above analysis, the drive switch circuit 250 provided in the above embodiment can automatically protect and restart when the laser projection device 200 experiences a short-term fault, and can also lock and protect in the open state when a long-term fault occurs, so as to avoid the laser from being continuously heated and burned out due to frequent system restarts.

[0152] In some embodiments, the signal conditioning circuit 2523 described above may also employ... Figure 9 The structure shown.

[0153] Reference Figure 9 The signal conditioning circuit 2523 may include a Zener diode N402, a fourth conditioning switch V402 and a fifth conditioning switch V401.

[0154] The cathode of the Zener diode N402 is coupled to the control signal output terminal Cout of the protection circuit 252, which can output a switching signal to the main switching circuit 251. The anode of the Zener diode N402 is grounded. The Zener diode N402 also has an adjustable terminal, which is coupled to the comparator circuit 2522, that is, coupled to the output terminal of the comparator circuit 2522.

[0155] The first terminal of the fourth regulating switch V402 is coupled to the operating voltage receiving terminal of the protection circuit 252, receiving the preset operating voltage VCC to power on the signal conditioning circuit 2523. The second terminal of the fourth regulating switch V402 is grounded through the fourth regulating resistor R408. The control terminal of the fourth regulating switch V402 is coupled to the cathode of the Zener diode N402.

[0156] The first terminal of the fifth regulating switch V401 is coupled to the cathode of the Zener diode N402, the second terminal of the fifth regulating switch V401 is grounded, and the control terminal of the fifth regulating switch V401 is coupled to the second terminal of the fourth regulating switch V402 through the fifth regulating resistor R407.

[0157] For example, the fourth regulating switch V402 can be a low-level conducting switch, and the fifth regulating switch V401 can be a high-level conducting switch. Based on this, for Figure 9 The working principle of the signal conditioning circuit 2523 shown is explained.

[0158] Based on the conduction characteristics of a Zener diode with an adjustable terminal, it can be known that when the voltage at its adjustable terminal reaches the preset reference voltage V... adj When the diode is in reverse conduction, the voltage between its cathode and anode stabilizes at the diode's regulated voltage V. Z This achieves a voltage stabilizing effect.

[0159] Therefore, in the above embodiment, when the comparator circuit 2522 outputs a high-level second comparison result signal, the adjustable terminal voltage of the Zener diode N402 can reach its reference voltage V. adj This causes the Zener diode N402 to conduct in reverse.

[0160] When the Zener diode N402 is reverse-biased, the protection switch signal LED-S output from the signal conditioning circuit 2523 is pulled low, and the control signal input level of the main switch circuit 251 (such as V) is reduced. cin () was lowered.

[0161] Simultaneously, when the Zener diode N402 is reverse-biased, the voltage at the control terminal of the fourth regulating switch V402 is pulled low, thus satisfying its conduction condition, and the fourth regulating switch V402 is turned on. With the fourth regulating switch V402 turned on, the voltage at the control terminal of the fifth regulating switch V401 is pulled high by the resistor R408, thus turning on the fifth regulating switch V401.

[0162] After the fifth regulating switch V401 is turned on, the voltage at the control terminal of the fourth regulating switch V402 will be continuously pulled down. Even if the output signal level of the comparison circuit 2522 changes, the fourth regulating switch V402 will not be turned off, thereby locking the fourth regulating switch V402 and the fifth regulating switch V401 in the on state. That is, the protection circuit 252 is switched to the locked state, so that the output protection switch signal LED-S is continuously pulled down, and the level at the control signal input terminal of the main switch circuit 251 is also continuously pulled down, so that the entire drive switch circuit 250 achieves lock-up protection.

[0163] In some embodiments, an emitter resistor R409 is connected in series between the first terminal of the fourth regulating switch V402 and the operating voltage receiving terminal. This resistor can share power consumption, prevent the fourth regulating switch V402 from being damaged by overcurrent, and stabilize its operating point.

[0164] In some embodiments, the first terminal of the fifth regulating switch V401 is also coupled to the working voltage receiving terminal through the collector resistor R406, which can prevent the fifth regulating switch V401 from being damaged by overcurrent, stabilize the voltage of the first terminal of the fifth regulating switch V401, and ensure that the control terminal voltage of the fourth regulating switch V402 can be continuously pulled low and locked in the on state.

[0165] In the above embodiment, upon receiving the second comparison result signal, the Zener diode N402 is turned on, and the protection switch signal LED-S output from the output terminal of the signal conditioning circuit 2523 is pulled low; simultaneously, the fourth adjustment switch V402 and the fifth adjustment switch V401 are successively turned on and locked in the on state, causing the signal conditioning circuit 2523 to enter the locked state, that is, the protection circuit 252 enters the locked state, and the protection switch signal LED-S is continuously pulled low, thereby keeping the main switch circuit 251 in the off state and realizing lockout protection.

[0166] Only after the preset working voltage VCC received at the first terminal of the fourth regulating switch V402 is de-energized and re-energized can the fourth regulating switch V402 and the fifth regulating switch V401 be turned off, the locked state be released, and the signal conditioning circuit 2523 and the protection circuit 252 be restored to the unlocked state.

[0167] As can be seen, the laser projection device 200 provided in the above embodiment, by setting a drive switch circuit 250 between the power supply circuit 210 and the light source driving circuit 221, the drive switch circuit 250 includes a main switch circuit 251 and a protection circuit 252. The main switch circuit 251 can respond to fault status signals in a timely manner, thereby cutting off the power supply to the light source driving circuit 221 in a short-term fault. The protection circuit 252 can record the number of times the fault status signal is received, and when the preset number is reached, it switches to a locked state and continuously outputs a protection switch signal that meets the second level to the main switch circuit 251, so that the main switch circuit 251 is locked in the open state. This achieves lockout protection in the event of a long-term fault, avoids the laser from being frequently lit due to frequent system restarts, and avoids the laser and related components from being damaged by continuous overheating.

[0168] Some embodiments of this application also provide a switching circuit that can be applied to various electronic devices, such as mobile phones, tablet computers, laptops, in-vehicle displays, LCD TVs, laser TVs, laser micro-projectors, etc.

[0169] Reference Figure 10The switching circuit 300 provided in some embodiments of this application may include a main switching circuit 301 and a protection circuit 302. The main switching circuit 301 includes: The switch input terminal IN is coupled to the power supply circuit 400 of the corresponding electronic device; The switch output terminal OUT is coupled to the load circuit 500 of the corresponding electronic device; The control signal input terminal Cin is configured to receive a switch control signal; wherein the switch control signal includes at least one of a protection switch signal RS and a fault status signal FLT of the corresponding electronic device; The aforementioned main switch circuit 301 is configured such that, when the switch control signal meets the first level, the switch input terminal IN and the switch output terminal OUT are connected to supply power to the load circuit 500 through the power supply circuit 400; and when the switch control signal meets the second level, the switch input terminal IN and the switch output terminal OUT are disconnected to stop supplying power to the load circuit 500 through the power supply circuit 400.

[0170] The aforementioned protection circuit 302 includes: The fault signal input terminal Fin is configured to receive fault status signals from the corresponding electronic equipment; The control signal output terminal Cout is coupled to the control signal input terminal Cin of the main switch circuit 301 and is configured to output the aforementioned protection switch signal to the control signal input terminal Cin to control the main switch circuit 301 to turn on or off. The protection circuit 302 is configured to switch and remain in a locked state when the fault status signal is received at the fault signal input terminal Fin; wherein, in the locked state, the protection switch signal is a signal that satisfies the second level.

[0171] It should be noted that the specific structure and working principle of the above-mentioned switch circuit 300 can be referred to the drive switch circuit 250 in the previous embodiment, and the repeated parts will not be described again.

[0172] The switching circuit provided in the above embodiments can respond to the fault status signal of the corresponding electronic device to achieve lock-up protection, that is, to ensure that the power supply path between the voltage circuit and the load circuit is kept in the disconnected state, so as to avoid the system of the corresponding electronic device being frequently restarted after the fault occurs, which would cause the relevant load to continue to heat up and be damaged.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0174] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. A laser projection device, characterized in that, include: Laser; A light source driving circuit, coupled to the laser, is configured to output a laser power supply signal to the laser to control the light emission state of the laser; Power supply circuit; A drive switch circuit, coupled to the power supply circuit and the light source drive circuit respectively, is configured to control the power supply path of the power supply circuit to the light source drive circuit to be turned on or off. The driving switch circuit includes: Main switching circuit; the main switching circuit includes: The switch input terminal is coupled to the power supply circuit; The switch output terminal is coupled to the light source driving circuit; The control signal input terminal is configured to receive a switch control signal; wherein the switch control signal includes at least one of a fault status signal and a protection switch signal; The main switch circuit is configured such that, when the switch control signal meets a first level, the switch input terminal and the switch output terminal are connected to supply power to the light source driving circuit through the power supply circuit; and when the switch control signal meets a second level, the switch input terminal and the switch output terminal are disconnected to stop supplying power to the light source driving circuit through the power supply circuit. Protection circuit; the protection circuit includes: The fault signal input terminal is configured to receive the fault status signal; The control signal output terminal is coupled to the control signal input terminal and is configured to output the protection switch signal to the control signal input terminal to control the conduction or disconnection of the main switch circuit; The protection circuit is configured to switch and remain in a locked state when the fault status signal is received at the fault signal input terminal; wherein, in the locked state, the protection switch signal is a signal that satisfies the second level.

2. The laser projection device according to claim 1, characterized in that, The protection circuit further includes: a working voltage receiving terminal, configured to receive a preset working voltage to power on the protection circuit; The protection circuit is further configured to: in the locked state, when the working voltage receiving terminal is powered off and re-receives the preset working voltage, switch to the unlocked state; wherein, in the unlocked state, the protection switch signal is a signal that satisfies the first level.

3. The laser projection device according to claim 1, characterized in that, The protection circuit is configured to switch to and remain in the locked state when the fault status signal is received at the fault signal input terminal and the number of receptions within a preset time reaches a preset number.

4. The laser projection device according to claim 3, characterized in that, The protection circuit includes: A counting circuit, coupled to the fault signal input terminal, is configured to generate a first electrical signal; wherein the first electrical signal is used to indicate the number of times the fault signal input terminal receives the fault status signal within the preset time period; A comparison circuit, coupled to the counting circuit, is configured to compare the first electrical signal with a preset electrical signal and output a comparison result signal; Wherein, the preset electrical signal is an electrical signal corresponding to the preset number of times, and the comparison result signal includes a first comparison result signal indicating that the number of times received is less than the preset number of times, and a second comparison result signal indicating that the number of times received is not less than the preset number of times; A signal conditioning circuit, coupled to the comparison circuit, is configured to, upon receiving the first comparison result signal, adjust the protection switch signal to a signal that satisfies the first level, and upon receiving the second comparison result signal, adjust the protection switch signal to a signal that satisfies the second level.

5. The laser projection device according to claim 4, characterized in that, The counting circuit includes: A first capacitor; the first terminal of the first capacitor is coupled to the operating voltage receiving terminal of the protection circuit through a charging resistor to receive a preset operating voltage; the second terminal of the first capacitor is grounded; A charge / discharge control circuit, coupled to the fault signal input terminal, is configured to control the preset operating voltage to charge the first capacitor upon receiving the fault status signal. The voltage signal at the first terminal of the first capacitor is used as the first electrical signal.

6. The laser projection device according to claim 5, characterized in that, The charge / discharge control circuit includes: A first charging switch; the first terminal of the first charging switch is coupled to the working voltage receiving terminal of the protection circuit through a current-limiting resistor, the second terminal of the first charging switch is grounded, and the control terminal of the first charging switch is coupled to the fault signal input terminal. The first charging switch is turned on when it receives the fault status signal at its control terminal, and turned off when it does not receive the fault status signal. The second charging switch; the first terminal of the second charging switch is coupled to the first terminal of the first capacitor through a discharge resistor, the second terminal of the second charging switch is grounded, and the control terminal of the second charging switch is coupled to the first terminal of the first charging switch; The switching state of the second charging switch is the opposite of that of the first charging switch.

7. The laser projection device according to claim 4, characterized in that, The comparator circuit includes: an operational amplifier; The non-inverting input of the operational amplifier is coupled to the counting circuit to receive the first electrical signal; The inverting input terminal of the operational amplifier receives the preset electrical signal; The output terminal of the operational amplifier is coupled to the signal conditioning circuit; The operational amplifier is configured to output a first comparison result signal when the first electrical signal is less than the preset electrical signal, and to output a second comparison result signal when the first electrical signal is not less than the preset electrical signal.

8. The laser projection device according to claim 4, characterized in that, The signal conditioning circuit includes: First regulating switch; The first terminal of the first regulating switch is coupled to the control signal output terminal; The second terminal of the first regulating switch is grounded; Second adjustment switch; The first terminal of the second regulating switch is coupled to the operating voltage receiving terminal of the protection circuit through the first regulating resistor; The second terminal of the second regulating switch is grounded through the second regulating resistor, and the second terminal of the second regulating switch is also coupled to the control terminal of the first regulating switch through the third regulating resistor; The control terminal of the second regulating switch is coupled to the comparison circuit to receive the comparison result signal; Third adjustment switch; The first terminal of the third regulating switch is coupled to the working voltage receiving terminal; The second terminal of the third regulating switch is grounded through the third regulating resistor, and the second terminal of the third regulating switch is also coupled to the control terminal of the second regulating switch; The control terminal of the third regulating switch is coupled to the first terminal of the second regulating switch; The second regulating switch is turned on when the second comparison result signal is received, and the switching states of the first regulating switch and the third regulating switch are the same as the switching state of the second regulating switch.

9. The laser projection device according to claim 4, characterized in that, The signal conditioning circuit includes: Zener diode; The cathode of the Zener diode is coupled to the control signal output terminal; The anode of the Zener diode is grounded; The adjustable terminal of the Zener diode is coupled to the comparator circuit; Fourth adjustment switch; The first terminal of the fourth regulating switch is coupled to the working voltage receiving terminal of the protection circuit. The second terminal of the fourth regulating switch is grounded through the fourth regulating resistor; The control terminal of the fourth regulating switch is coupled to the cathode of the Zener diode; Fifth adjustment switch; The first terminal of the fifth regulating switch is coupled to the cathode of the Zener diode; The second terminal of the fifth regulating switch is grounded; The control terminal of the fifth regulating switch is coupled to the second terminal of the fourth regulating switch through the fifth regulating resistor; When the adjustable terminal of the Zener diode receives the second comparison result signal, the Zener diode is reverse-biased and the fourth and fifth adjustment switches are turned on.

10. A switching circuit, characterized in that, Applied to electronic devices, including: Main switching circuit; the main switching circuit includes: The switch input terminal is coupled to the power supply circuit of the electronic device; The switch output terminal is coupled to the load circuit of the electronic device; The control signal input terminal is configured to receive a switch control signal; wherein the switch control signal includes at least one of a protection switch signal and a fault status signal of the electronic device; The main switch circuit is configured such that, when the switch control signal meets a first level, the switch input terminal and the switch output terminal are connected to supply power to the load circuit through the power supply circuit; and when the switch control signal meets a second level, the switch input terminal and the switch output terminal are disconnected to stop supplying power to the load circuit through the power supply circuit. Protection circuit; the protection circuit includes: The fault signal input terminal is configured to receive the fault status signal of the electronic device; The control signal output terminal is coupled to the control signal input terminal and is configured to output the protection switch signal to the control signal input terminal to control the conduction or disconnection of the main switch circuit; The protection circuit is configured to switch and remain in a locked state when the fault status signal is received at the fault signal input terminal; wherein, in the locked state, the protection switch signal is a signal that satisfies the second level.

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