WO2024056015A1 - 投影设备及其激光光源的驱动方法 - Google Patents

投影设备及其激光光源的驱动方法 Download PDF

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Publication number
WO2024056015A1
WO2024056015A1 PCT/CN2023/118739 CN2023118739W WO2024056015A1 WO 2024056015 A1 WO2024056015 A1 WO 2024056015A1 CN 2023118739 W CN2023118739 W CN 2023118739W WO 2024056015 A1 WO2024056015 A1 WO 2024056015A1
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WIPO (PCT)
Prior art keywords
circuit
laser
driving
light
current
Prior art date
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PCT/CN2023/118739
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English (en)
French (fr)
Inventor
陈许
吴超
李有贵
Original Assignee
青岛海信激光显示股份有限公司
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Priority claimed from CN202211128274.XA external-priority patent/CN115437203B/zh
Application filed by 青岛海信激光显示股份有限公司 filed Critical 青岛海信激光显示股份有限公司
Publication of WO2024056015A1 publication Critical patent/WO2024056015A1/zh

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source

Definitions

  • the present disclosure relates to the technical field of projection display, and in particular to a projection device and a driving method of its laser light source.
  • Projection equipment such as laser projection equipment, uses digital light processing technology (Digital Light Processing, DLP) to digitally process the image signal, and then projects it through a laser beam.
  • DLP Digital Light Processing
  • Laser projection equipment has bright colors, high brightness, and flexible screen size. characteristics and have been widely used.
  • the present disclosure provides a projection device and a driving method for its light source, which can solve the problem in the related art that the electromagnetic waves radiated by the projection device affect the working status and performance of its internal devices and other electronic devices.
  • the technical solutions are as follows:
  • a projection device including a power circuit, a display control circuit, a laser light source and at least one light drive circuit, where the laser light source includes at least one laser;
  • the power circuit is respectively connected to the display control circuit and the at least one light driving circuit, and is used to supply power to the display control circuit and the at least one light driving circuit;
  • the display control circuit is connected to the at least one light driving circuit and is used to provide a dimming signal to the at least one light driving circuit;
  • the light driving circuit and the laser are connected one by one, and the light driving circuit and the anode of the laser are connected, and the cathodes of the at least one laser are interconnected;
  • the light driving circuit is used to provide a driving current to a connected laser based on the dimming signal, and the laser is used to emit light driven by the driving current.
  • a projection device characterized by a power supply circuit, a display control circuit, a laser light source and at least one light drive circuit, the laser light source including at least one laser;
  • the power circuit and the at least one optical drive circuit are arranged on different boards, and the optical drive board where the at least one optical drive circuit is located is close to the laser light source;
  • the power circuit is connected to the display control circuit and used to supply power to the display control circuit;
  • the display control circuit is connected to the at least one light driving circuit and is used to provide a dimming signal to the at least one light driving circuit;
  • the light driving circuit is connected to the laser one by one, and is used to provide a driving current to the connected laser based on the dimming signal, and the laser is used to emit light driven by the driving current.
  • a method for driving a laser light source is provided, applied to the projection equipment described in the first and second aspects, and the method includes:
  • the power circuit supplies power to the display control circuit and the at least one light driving circuit
  • the display control circuit provides a dimming signal to the at least one light driving circuit
  • the optical driving circuit provides driving current to the connected laser based on the dimming signal
  • the laser emits light driven by the driving current.
  • the cathode since the anode of the laser is connected to the light driving circuit, the cathode is connected together, for example, the The cathode can be connected to ground.
  • the transmission line through which the driving current flows can be effectively shortened, thereby reducing the current loop area of the driving current.
  • the electromagnetic waves radiated by the projection equipment affect the components inside the projection equipment and the The impact on the performance and working status of other electronic equipment around the projection equipment is also reduced.
  • the cathode of the laser can be connected to the line between the power circuit and the optical drive circuit, so that the voltage V d at both ends of the laser is the power supply output voltage V out output by the optical drive circuit and the power supply input by the optical drive circuit.
  • the difference between the input voltage V in .
  • the amount of voltage raised by the optical drive circuit is not affected by the input V in . Therefore, the power supply input voltage V in output by the power circuit is not limited by the rated drive voltage of the laser.
  • the selected V in of the power circuit is neither likely to cause the components to burn out due to excessive input current nor to damage the components due to excessive input voltage.
  • Figure 1 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure
  • Figure 2 is a circuit schematic diagram of a projection device in the related art
  • Figure 3 is a schematic diagram of a transmission line of a driving current for driving a laser to emit light provided by an embodiment of the present disclosure
  • Figure 4 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 5 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 6 is a schematic diagram of a transmission line of a driving current for driving a laser to emit light provided by an embodiment of the present disclosure
  • Figure 7 is a schematic diagram of a transmission line of a driving current for driving a laser to emit light provided by an embodiment of the present disclosure
  • Figure 8 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 9 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 10 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 11 is a circuit schematic diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 12 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 13 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 14 is a circuit schematic diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 15 is a schematic diagram of the changes over time of the Adim signal, Pwm signal, Drv signal and drive current provided by the embodiment of the present disclosure
  • Figure 16 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • Figure 17 is a schematic diagram of the radio disturbance limit corresponding to the frequency of a driving current provided by an embodiment of the present application.
  • Figure 18 is a schematic diagram of a transmission line of a driving current for driving a laser to emit light provided by an embodiment of the present disclosure
  • Figure 19 is a schematic flowchart of a driving method provided by an embodiment of the present application.
  • Figure 20 is a schematic flowchart of a driving method provided by an embodiment of the present application.
  • Figure 21 is a schematic diagram of the hardware structure of the electronic device provided by this application.
  • FIG. 1 is a schematic circuit diagram of a projection device provided by an embodiment of the present disclosure.
  • the projection device includes a power circuit 10 , a multimedia processing circuit 20 , a display control circuit 30 , a light drive circuit 40 , a laser light source 50 , an optical-mechanical component 60 and a projection lens 70 .
  • the power circuit 10 can output a DC voltage.
  • the power circuit 10 can output a DC voltage of 12 volts (V) or 24V to the light driving circuit 40 .
  • the power supply circuit 10 can receive commercial power, filter and transform the commercial power, and then supply it to the light driving circuit 40 Provides DC power supply input voltage Vin.
  • the power circuit 10 may include a bridge rectifier circuit 11 and a power conversion circuit 12 , wherein the power conversion circuit 12 may include a power factor correction (power factor correction, PFC) circuit 121 and an LLC circuit 122 .
  • the rectifier bridge circuit 11 receives the mains power, rectifies and filters the mains power, and then outputs it to the PFC circuit 121 and the LLC circuit 122.
  • the power is converted through the PFC circuit 121 and the LLC circuit 122 to supply power to the load, such as to the light driving circuit 40. Outputs the DC supply input voltage V in .
  • the rectifier bridge circuit is the most widely used rectifier circuit in power supply circuits. It consists of four diodes and a transformer in the same direction. Rectification is the process of converting alternating current into direct current. Using devices with unidirectional conductive characteristics, alternating current that changes in direction and magnitude can be converted into direct current.
  • the PFC circuit uses the inductance compensation method to adjust the input current waveform to make it as similar as possible to the input voltage waveform so that the power factor correction value approaches 100%.
  • power factor refers to the relationship between effective power and total power consumption (apparent power), that is, the ratio of effective power divided by total power consumption (apparent power).
  • the LLC circuit is a resonant circuit that achieves constant output voltage by controlling the switching frequency (frequency adjustment).
  • the circuit contains a single-port network of inductors, capacitors and resistors. At certain operating frequencies, when the port voltage and current waveform phases are the same, the circuit is said to resonate, and a circuit that can resonate is called a resonant circuit. .
  • the power circuit 10 is electrically connected to the multimedia processing circuit 20 , the display control circuit 30 , the light driving circuit 40 , the laser light source 50 , the optomechanical component 60 and the projection lens 70 to provide power to these loads.
  • the power circuit 10 can also provide power to other functional modules and circuits in the projection equipment, such as eye protection modules, fans, and WIFI modules, to ensure the normal operation of all parts of the projection equipment.
  • the multimedia processing circuit 20 may also be called a field programmable gate array (field programmable gate array, FPGA) circuit.
  • FPGA field programmable gate array
  • the multimedia processing circuit 20 is used to receive video signals sent by the TV board.
  • the multimedia processing circuit 20 can receive video signals through various communication interfaces, such as a universal serial bus (USB) interface. Video signal transmitted by TV board.
  • USB universal serial bus
  • the TV board can be equipped with a system on chip (SoC), which can decode data in different data formats into a normalized format, and convert the data in the normalized format through a connector (connector). called video signal), transmitted to the multimedia processing circuit 20.
  • SoC system on chip
  • the multimedia processing circuit 20 can perform some processing on the video signal, such as motion estimation and motion compensation (MEMC) frequency doubling processing, image correction processing, image brightness processing, image processing, etc. clarity processing, and image color processing, etc.
  • MEMC motion estimation and motion compensation
  • the multimedia processing circuit 20 is connected to the display control circuit 30 to transmit the processed video signal to the display control circuit 30 .
  • the multimedia processing circuit 20 usually exists as an enhanced function circuit. In some low-cost solutions, this circuit part may not be provided, but the display control circuit 30 receives the video signal output by the TV board.
  • the display control circuit 30 can decode and format-convert the video signal, further process the video signal (eg, perform geometric correction processing), and generate a dimming signal based on the processed video signal.
  • the display control circuit 30 is connected to the light driving circuit 40 , so the display control circuit 30 can transmit the dimming signal to the light driving circuit 40 .
  • the dimming signal may include an analog dimming (Adim) signal and a pulse width modulation (Pulse width modulation, Pwm) signal.
  • Adim analog dimming
  • Pwm pulse width modulation
  • the Pwm signal is used to control the presence or absence of the driving current transmitted to the laser light source 50
  • the Adim signal in the dimming signal is used to control the current value of the driving current.
  • the optical drive circuit 40 may also be called a laser drive circuit, specifically a DC-DC conversion circuit, specifically a boost circuit or a buck circuit.
  • the light driving circuit 40 is used to receive the dimming signal and the power supply input voltage of the power supply circuit 10 , and based on the dimming signal, convert the input power supply input voltage into a power supply output voltage, and output a driving current to the laser light source 50 .
  • the laser light source 50 emits light driven by a driving current and transmits the light to the opto-mechanical component 60 .
  • the laser light source 50 may include at least one laser 51, and the colors of the light beams emitted by the at least one laser 51 may be the same or different.
  • each laser 51 may include a plurality of light-emitting diodes (LEDs) 511 connected in series.
  • LEDs light-emitting diodes
  • the laser light source 50 may include a monochromatic laser, or may include a multi-color laser, such as a two-color laser including a red laser and a blue laser, or as shown in FIG. 1 , a three-color laser including a red laser, a blue laser and a green laser.
  • a monochromatic laser or may include a multi-color laser, such as a two-color laser including a red laser and a blue laser, or as shown in FIG. 1 , a three-color laser including a red laser, a blue laser and a green laser.
  • the number of optical driving circuits 40 and the number of lasers 51 are the same and correspond one to one.
  • the laser light source 50 includes a three-color laser including a red laser, a blue laser, and a green laser.
  • the projection device includes a red light driving circuit 40_R, a green light driving circuit 40_G, and a blue light driving circuit 40_B.
  • Each laser 51 among the three lasers 51 is connected to its corresponding one optical driving circuit 40 .
  • the three color lasers 51 can emit red light, green light and blue light respectively under the driving of driving current. Based on the principle of color synthesis in optics, it can be known that white light can be obtained after combining and homogenizing the three colors of light.
  • the light beam emitted by the laser light source 50 is transmitted to the opto-mechanical component 60 .
  • the optical-mechanical component 60 integrates digital micromirror devices (DMD) and a DMD drive circuit.
  • DMD is the core light modulation device of the opto-mechanical component 60 .
  • the DMD drive circuit is used to drive the DMD to work based on the video signal. In this way, the DMD is used to modulate the light beam emitted by the laser light source 50 under the control of the DMD drive circuit to obtain an image to be projected and displayed.
  • DMD receives the drive control signal corresponding to the image signal, flips thousands of tiny mirrors on its surface to the positive or negative angle corresponding to the drive signal, and forms the image to be projected and displayed by the light beam that illuminates its surface. and reflected into the projection lens 70 .
  • the optical-mechanical component 60 transmits the image to be projected and displayed to the projection lens 70 .
  • the projection lens 70 can amplify the image to be projected and displayed, and use the light beam to project the image to be projected and displayed. projected onto the target object.
  • the target object may be a projection screen or a wall.
  • the projection lens 70 may be an ultra-short throw projection lens.
  • the ultra-short throw projection lens is used to project the image beam onto the projection screen to display the projected image.
  • the laser projection device exemplified in this embodiment may be an ultra-short throw laser projection device.
  • the power circuit 10 and the light driving circuit 40 may be integrated.
  • the power circuit 10 and the light driving circuit 40 are integrated on a single board.
  • the power supply circuit 10 and the light driving circuit 40 may also be arranged separately.
  • the power circuit 10 is arranged on one single board, which can be called a power board
  • the optical driving circuit 40 is arranged on another single board, which can be called an optical driving board.
  • the multimedia processing circuit 20, the display control circuit 30 and the optical-mechanical component 60 may be arranged on a single board.
  • the single board is referred to as a display board.
  • the multimedia processing circuit 20 may also include a system on chip (SoC).
  • SoC system on chip
  • the chip-level system may include a digital light processor (digital light processing, DLP) and may also include a driver.
  • DLP digital light processing
  • the laser light source 50 needs to cooperate with the working timing of the DLP and the DMD of the opto-mechanical component 60 .
  • the DLP outputs an image enable signal, which can also be called a primary color light enable signal, usually expressed as X_EN, where X is the abbreviation of different primary color lights, and also outputs a dimming signal at the same time.
  • the laser light source needs to synchronously output the primary color light beam of the corresponding color. That is, the DLP outputs a primary color light enable signal to notify the laser light source to light up the laser of a certain color, and outputs a dimming signal to notify the laser light source at what brightness to light up the laser of that color.
  • the operating frequency of the optical drive circuit 40 is relatively high, the operating current is relatively large, and the operating state of the optical drive circuit 40 is periodically switched between on and off at high frequency.
  • the changing electric field generated by the switching of this working state will generate a changing magnetic field, and the changing magnetic field will further generate a changing electric field.
  • the changing electric field and changing magnetic field will generate electromagnetic waves that can be radiated outward. This electromagnetic wave can also be called electromagnetic disturbance.
  • the electromagnetic waves radiated by the projection equipment should be lower than a certain limit, otherwise the electromagnetic waves will easily affect the working status of the internal components of the projection equipment and the working status of other electronic equipment around the projection equipment, thereby damaging its internal components. and other electronic equipment performance.
  • FIG. 2 is a schematic partial structural diagram of a projection device in the related art.
  • a power circuit and multiple light drive circuits can be integrated and provided on the power board of the projection device.
  • each optical drive circuit is also connected to the ground terminal.
  • the direction of the drive current flowing through the laser can be: the positive electrode of the power circuit - the laser - the optical drive circuit - the ground terminal.
  • the ground terminal may be a common ground terminal of the power board. Therefore, the transmission line of the driving current can form a loop (ie, the driving current loop.
  • the current loops mentioned in this article, unless otherwise specified, are all current loops of the driving current).
  • connection method in which the anodes of multiple lasers are directly connected to the power circuit, and the cathodes are respectively connected to an optical drive circuit is called common anode drive.
  • the common anode drive is generally related to the packaging method of the laser light source.
  • the packaging method of the common anode type laser light source is that multiple lasers are packaged together, and the positive and negative poles of each laser are independent of each other. Then, after packaging The laser light source includes multiple anode pins and multiple cathode pins. When the laser light source of this packaging method is connected to the optical drive circuit, multiple anode pins are generally connected together and then connected to the power circuit. This wiring method is called common anode drive.
  • This method of common anode driven laser emitting light often has strong electromagnetic disturbance for the following reasons.
  • the transistor switch in the optical drive circuit will cause high-frequency changes in the drive current during high-frequency on-off switching.
  • the drive current changes it is easy to cause changes in the magnetic field and electric field around the transmission line of the drive current. Changes in magnetic and electric fields produce electromagnetic waves.
  • This electromagnetic wave may also be called electromagnetic interference (or noise).
  • the change rate of the driving current is faster, the bandwidth of the noise is also wider.
  • the average change in the signal value of the driving current is larger, the amplitude of the noise is larger.
  • the electric field intensity E of the electromagnetic radiation disturbance electric field generated around the transmission line can satisfy:
  • f is the frequency of the driving current
  • A is the current loop area of the driving current, and is positively related to the length of the transmission line of the driving current.
  • the unit of the current loop area can be square centimeters (cm 2 )
  • I As the current value of the driving current (ie, the intensity of the driving current), the unit of the driving current may be milliamps (mA).
  • r is the distance between the test antenna used to test the electric field strength E and the transmission line of the driving current.
  • the value of r can be 3 meters.
  • the electric field intensity E is positively related to the current loop area A of the driving current, the current intensity I of the driving current, and the frequency f of the driving current.
  • the frequency f of the driving current and the current intensity I of the driving current are both fixed values.
  • the current loop area A of the driving current is the main factor affecting the current intensity E. Since the current loop area of the driving current is positively related to the length of the transmission line of the driving current, then the length of the transmission line of the driving current , is the main factor affecting the current intensity E.
  • the drive current flows from the power board to the laser, and then flows back to the power board to connect with the light drive circuit.
  • the dotted arrows in Figure 3 indicate the direction of the drive current.
  • the corresponding current loop area is recorded as S1.
  • the power board and the laser are located at different positions of the projection equipment, with a certain distance between them. Therefore, it can be seen that the driving current line includes the flow from the power board to the laser, and from the laser back to the power board, the transmission line of the driving current is relatively long. Then, the current loop area A of the driving current is also larger.
  • the electromagnetic wave will interfere with the working status and performance of the infrared sensor in the projection equipment, which is designed to protect human eyes from approaching the projection lens. It will also interfere with the far-field speech circuit in the projection equipment, which is used to recognize the user's voice. The working status and performance will also interfere with the working status and performance of the audio output current in the projection equipment. Moreover, the electromagnetic waves radiated by the projection device will also affect the working status of other electronic devices around the projection device, thereby damaging the performance of other electronic devices.
  • the projection equipment also has other problems. Please refer to the following.
  • the light driving circuit 40 is a DC-DC conversion circuit, and specifically it can be a boost circuit or a buck circuit.
  • FIG. 4 is a schematic diagram of the connection between the power circuit 10, the light drive circuit 40 and the laser light source 50 of the projection equipment. As shown in Figure 4, taking the projection equipment including a three-color laser as an example, each laser 51 corresponds to a light drive circuit. 40. Receive the power supply input voltage V in output by the power supply circuit 10 , convert the power supply input voltage V in into the corresponding power supply output voltage V out , and output it to the corresponding laser 51 through the output terminal.
  • the anode of the laser 51 is connected to the output end of the light driving circuit 40, and the cathode of the laser 51 is grounded. Then, the potential of the anode of the laser 51 is V out and the potential of the cathode is 0. Therefore, the power supply at both ends of the laser Voltage V d is the power supply output voltage V out .
  • the voltage V d at both ends of the laser can be adjusted by adjusting the power supply output voltage V out , thereby adjusting the brightness of the laser.
  • the voltage at both ends can be recorded as the rated driving voltage. , recorded as V′ d , then, when the voltage V d across the laser is V′ d , the laser can emit light.
  • the optical drive circuit 40 needs to increase the power supply input voltage V in to V′ d , and the amount of increase is V′ d -V in , so Negative values cannot be raised, so V in is less than or equal to V′ d .
  • the optical drive circuit 40 needs to reduce the power supply input voltage V in to V' d by a reduction amount of V in -V' d . Since it cannot reduce a negative value, V in is greater than or equal to V' d .
  • the size of the power supply input voltage V in output by the power supply circuit 10 is limited, and it needs to satisfy V in ⁇ V′ d in the boost circuit and V in ⁇ V′ d in the buck circuit.
  • the power supply input voltage V in needs to be set based on the rated drive voltage of the lowest brightness laser.
  • the optical drive circuit is a buck circuit, it needs to be based on the rated drive voltage of the lowest brightness laser.
  • the rated drive voltage of the highest brightness laser is the reference set supply input voltage V in .
  • the corresponding rated drive voltages of red lasers, blue lasers and green lasers are 8V, 15V and 18V respectively.
  • the red light drive circuit needs to increase the power supply input voltage V in As high as 8V
  • the blue light driving circuit needs to increase the electrical input voltage V in to 15V
  • the green light driving circuit needs to increase the power supply input voltage V in to 18V.
  • the power supply input voltage V in needs to be less than or equal to that of all lasers.
  • Rated driving voltage V′ d the voltage of 8V needs to be used as the benchmark.
  • the power supply input voltage V in can be set to be less than or equal to 8V. If the power supply input voltage V in is 6V, then the three optical drive circuits will convert 6V The power supply input voltage V in is converted into the power supply output voltage V out of 8V, 15V and 18V respectively.
  • the power supply circuit Since the selected power supply input voltage V in is relatively low and the output power of the power supply circuit is certain, the power supply circuit will input a relatively large current into the three optical drive circuits, so that the rated drive is significantly different from the selected V in For lasers with corresponding voltages, some components in the optical drive circuit connected to them will be damaged due to the large current they bear. For example, for a laser with a rated drive voltage of 18V, some components in the connected optical drive circuit will be damaged due to withstanding a large current.
  • the red light drive circuit needs to reduce the power supply input voltage V in to 8V
  • the blue light drive circuit needs to reduce the electrical input voltage V in to 15V
  • the green light drive circuit needs to reduce the electrical input voltage V in.
  • Voltage V in is reduced to 18V.
  • the optical drive circuit is a buck circuit type
  • the power supply input voltage V in needs to be greater than or equal to the rated drive voltage V′ d of all lasers. Therefore, when setting the power supply input voltage V in , the voltage of 18V needs to be used as the benchmark.
  • the power supply input voltage V in can be set to be greater than or equal to 18V. For example , the power supply input voltage V in is 21V. Then, the three optical drive circuits convert the power supply input voltage V in of 21V into the power supply output voltage V out of 8V, 15V and 18V respectively.
  • the optical drive circuit is a boost circuit or a buck circuit, in related technologies, the selected V in will have a large difference with the rated drive voltage at both ends of some lasers, resulting in the optical drive connected to these lasers. Some components in the circuit have higher current or voltage, which makes the service life of these light drive circuits shorter.
  • the power supply input voltage V in provided by the power circuit is loaded on the laser connected to the short-circuited optical drive circuit, causing the laser to withstand a larger voltage and be damaged.
  • this embodiment provides a projection device that can solve the above problems.
  • the technical features of the projection device will be introduced below.
  • the projection device may include a power supply circuit 10 , a display control circuit 30 , a laser light source 50 and at least one light driving circuit 40 .
  • the laser light source 50 includes at least one laser 51 , and the laser 51 and the light driving circuit 40 are one by one.
  • one laser 51 is driven by a light driving circuit 40 to emit light.
  • the number of lasers 51 may be one or multiple.
  • a three-color laser as shown in FIG. 1 may be included as an example.
  • the output terminal of the power supply circuit 10 is connected to the display control circuit 30 and the first terminal 1 (i.e., the input terminal) of at least one light driving circuit 40 respectively.
  • the power supply circuit 10 is used to provide power to the display control circuit 30 Power is provided to enable the display control circuit 30 to send and receive signals (such as video signals and dimming lights), and the power circuit 10 is used to supply power to at least one light driving circuit 40 to provide driving voltage to at least one light driving circuit 40 .
  • the driving voltage mentioned in this article is the driving voltage input to the optical driving circuit, that is, V in , and the voltage output by the optical driving circuit 40 , unless otherwise specified. , both are the power supply output voltage, that is, V out .
  • the display control circuit 30 is connected to the second terminal 2 of at least one light driving circuit 40 respectively, so that the display control circuit 30 provides a dimming signal to each light driving circuit 40 .
  • the dimming signal may include an Adim signal that controls the size of the driving current, and a Pwm signal that controls the presence or absence of the driving current.
  • each optical drive circuit 40 is connected to the first end 1 (ie, the anode end) of a corresponding laser 51.
  • Each optical drive circuit 40 is used to drive based on the drive voltage.
  • the dimming signal provides drive current to the laser to which it is connected.
  • the driving current described in this article is the current input to the laser 51 unless otherwise specified.
  • each laser 51 is used to It emits light when driven by a driving current.
  • each light driving circuit 40 in at least one light driving circuit 40 can adjust the current value of the driving current it outputs based on the Adim signal in the received dimming signal, and can adjust the current value of the driving current it outputs based on the Adim signal in the received dimming signal.
  • the Pwm signal in the dimming signal controls the presence or absence of the drive current output. For example, if the duty cycle of the Pwm signal is 50% in 1 second, the light driving circuit 40 outputs the driving current for 0.5 seconds in 1 second, and does not output the driving current in the remaining 0.5 seconds.
  • the current value of the driving current may be positively correlated with the signal value of the Adim signal. That is, when the signal value of the Adim signal is larger, the current value of the driving current is larger.
  • the display control circuit 30 can simultaneously output the dimming signal (including the Adim signal and the Pwm signal) to at least one light driving circuit 40 .
  • the display control circuit 30 may include at least one group of ports for outputting the dimming signal.
  • Each group of ports includes two ports for outputting the Adim signal and the Pwm signal respectively, and the two ports in each group of ports are related to An optical driver circuit 40 is connected.
  • the display control circuit 30 can output the Adim_R signal and the Pwm_R signal to the red light driving circuit 40_R, the Adim_G signal and the Pwm_G signal to the green light driving circuit 40_G, and the blue light driving circuit 40_B.
  • Adim_B signal and Pwm_B signal are examples of the display control circuit 30 .
  • the display control circuit 30 may not include a group of ports, but may include multiple ports, each port having a pin for transmitting the Adim signal and a pin for transmitting the Pwm signal. That is, the pins used to transmit Adim signals and the pins used to transmit Pwm signals are integrated into one port.
  • the cathodes of at least one laser 51 are interconnected, and the cathodes of at least one laser 51 are interconnected, which can reduce the length of the transmission line of the driving current, and also allows the selection of the power supply input voltage of the optical driving circuit 40 to be unrestricted. .
  • the anodes of such multiple lasers 51 are respectively connected to a light driving circuit 40 , and the cathode interconnection connection method can be called common cathode driving.
  • common cathode driving is generally related to the packaging method of the laser light source.
  • the packaging method of the common cathode type laser light source is that multiple lasers are packaged together, and the anodes of each laser are independent of each other, and the cathodes of each laser are connected. Together, sharing one pin, the packaged laser light source includes multiple anode pins and one cathode pin.
  • the laser light source of this packaging method is connected to the light driving circuit, multiple anode pins can be connected to one light driving circuit respectively, while the cathode pin can be grounded nearby or connected to the output end of the power circuit 10. This wiring method is called common cathode drive.
  • the power circuit 10 and the optical drive circuit 40 are integrated on a single board.
  • the single board is marked as a power board.
  • the flow direction of the driving current is: the power board where the power circuit 10 and the optical drive circuit 40 are located.
  • the dotted arrow in Figure 6 represents the transmission line of the driving current, and the corresponding current loop area is marked as S2.
  • FIG. 7 it is a schematic diagram of the power circuit 10 and the optical drive circuit 40 being separated.
  • the optical drive circuit 40 can be arranged close to the laser 51 .
  • the flow direction of the drive current is: optical drive circuit 40 - laser 51-Ground terminal GND.
  • the dotted arrow in Figure 6 represents the transmission line of the driving current, and the corresponding current loop area is marked as S3.
  • the driving current in this common cathode driving mode will directly flow into the ground terminal GND after flowing through the laser 51 instead of flowing into the optical driving circuit 40 .
  • the current loop area of the drive current can be effectively reduced.
  • the power circuit 10 and at least one light driving circuit 40 in the projection device can be integrated on a single board, for example, can be provided on a power board.
  • the power circuit 10 and the plurality of light driving circuits 40 can be provided separately.
  • the power circuit 10 is disposed on a single board, which can be recorded as a power board.
  • the at least one optical driving circuit 40 is not disposed on the power board, but is disposed on another single board.
  • the single board can be Marked as optical driver board.
  • the transmission line where the drive current is located includes the transmission line between the power board where the drive circuit 40 is located and the laser 51 transmission line, and the transmission line between laser 51 and ground.
  • the transmission line where the drive current is located includes the transmission line between the optical drive board where the drive circuit 40 is located and the laser 51, as well as the laser 51 and the ground. transmission line between terminals.
  • the optical drive board on which the optical drive circuit 40 is located is located between the power board and the laser 51. Therefore, compared with Figure 6, the transmission line of the drive current is further shortened.
  • the electromagnetic disturbance generated by the driving current is smaller than the electromagnetic disturbance generated by the driving current when the power circuit 10 and at least one optical driving circuit 40 are integrated.
  • the power board where the power circuit 10 is located and the laser light source 50 can be fixed on the internal metal bracket of the projection equipment through screws and studs.
  • the internal metal bracket can be connected to the ground terminal. Connection, where the ground terminal can be the common ground terminal of the power strip.
  • common cathode driving can realize the power supply input voltage provided by the power supply circuit 10 to the light driving circuit 40 and is not limited for the following reasons.
  • the cathode of the laser 51 may not be grounded, but may be connected to the line between the power circuit 10 and the light driving circuit.
  • the potential of the cathode of the laser 51 is the power supply input voltage V in provided by the power supply circuit 10 .
  • V d is 0, and when the optical drive circuit 40 outputs the drive current to the laser, V d is V′ d , so V out ⁇ V in .
  • V out is a boost circuit or a buck circuit
  • the light driving circuit 40 increases the power supply input voltage V in by V′ d instead of raising it to V′ d . Therefore, no matter what value the power supply input voltage V in is selected, the light driving circuit can raise the output voltage by V′ d , so when selecting the power supply input voltage V in , there is no need to select it based on the minimum rated driving voltage.
  • the negative electrode of the laser 51 is connected to the connection line between the power supply circuit 10 and the optical drive circuit 40, so that the rated drive voltage (normal light emission) of each laser can be adjusted regardless of the selection of the power supply input voltage of the power supply circuit 10. required voltage).
  • the selection of the power supply input voltage of the power supply circuit 10 is not limited by the rated drive voltage of each laser, then, When selecting V in , you can select neither the minimum rated drive voltage nor the maximum rated drive voltage. Then, there is no problem that the selected V in is significantly different from the maximum rated driving voltage, or is significantly different from the minimum rated driving voltage.
  • the power supply input voltage V in of the power supply circuit 10 can be set to 12V. Therefore, compared with the cathode grounding of the laser 51, the connection method as shown in Figure 8 can reduce the difference between the power supply input voltage V in and the rated drive voltage of each laser 51, and further can reduce the input voltage to each optical driver. Current or voltage of some components in the circuit to avoid component damage due to large current or voltage input into the optical drive circuit.
  • the optical drive circuit 40 when the optical drive circuit 40 is short-circuited, the voltages at both ends of the laser 51 are equal and the voltage difference is zero. Then, the laser 51 will not withstand a large power supply input voltage and can operate in the optical drive circuit 40 In the event of a short circuit, damage to the laser 51 is avoided.
  • optical driving circuit 40 introduced below is any one of at least one optical driving circuit 40. Since the optical driving circuit 40 is introduced, the related drawings all illustrate one optical driving circuit 40, and The laser 51 is connected to the optical drive circuit 40 .
  • the cathode of the laser 51 in the drawing can be grounded to achieve the effect of reducing electromagnetic interference, or it can be connected to the line between the power supply circuit 10 and the optical drive circuit 40 to achieve the power supply input voltage provided by the power supply circuit 10.
  • the effect is not limited by the rated drive voltage of the laser 51.
  • FIG. 9 is a schematic diagram of an optical drive circuit provided by an embodiment of the present disclosure.
  • the optical drive circuit 40 may include a control circuit 410, a switch circuit 420, and a charge and discharge circuit 430.
  • the switch circuit 420 has a control end, a first end and a second end. As shown in FIG. 9 , the control circuit 410 is connected to the output end of the power circuit 10 and the control end of the switch circuit 420 respectively. In this way, the control circuit 410 can generate a switch driving signal (recorded as a Drv signal) based on the received dimming signal, and input the Drv signal to the control end of the switch circuit 420 to control the first end and the second end of the switch circuit 420. On time and off time.
  • a switch driving signal recorded as a Drv signal
  • the Drv signal may also be called the switch signal SW, and the Drv signal may be a level signal, including a first level and a second level, where the first level is a high level and the second level is a low level.
  • the Drv signal when the Drv signal is at the first level, the first terminal and the second terminal of the switch circuit 420 are connected, and when the Drv signal is at the second level, the first terminal and the second terminal of the switch circuit 420 are disconnected. . It can be seen that the turning on and off of the switch circuit 420 is controlled by the Drv signal.
  • the switching circuit 420 is turned on and off in order to realize the charging and discharging of the charge and discharge circuit 430 , that is, the charging and discharging of the charging and discharging circuit 430 is controlled by the turning on of the switch circuit 420 and disconnect.
  • the switch circuit 420 when the switch circuit 420 is turned on, the charge and discharge circuit 430 is in the charging state or in the discharging state; and when the switch circuit 420 is turned off, when the switch circuit 420 is turned on, the charge and discharge circuit 430 is in the charging state. Whether it is still in the discharge state depends on the specific circuit of the light driving circuit 40 .
  • the charging and discharging circuit 430 is connected to the corresponding laser 51 for providing a driving current to the laser 51 so that the laser 51 emits light under the action of the driving current.
  • the charge and discharge circuit 430 is specifically used to continuously charge and discharge under the continuous on and off switching of the switch circuit 420 when the Pwm signal in the dimming signal is high level, so as to provide the connected laser 51 with The driving current, and when the Pwm signal in the dimming signal is low level, stops providing the driving current to the light source.
  • the on time and off time of the switch circuit 420 are related to the duty cycle of the Drv signal.
  • the ratio is the ratio of the energization time to the total time within a pulse cycle.
  • the duty cycle of the Drv signal is proportional to the Adim signal in the dimming signal.
  • the greater the Adim signal the greater the duty cycle of the Drv signal (refer to Figure 15).
  • the greater the duty cycle of the Drv signal the greater the power supply output voltage V out of the charge and discharge circuit 430, and the greater the driving current provided by the charge and discharge circuit 430 to the laser 51.
  • the Drv signal output by the control circuit 410 is the first level
  • the first terminal and the second terminal of the switch circuit 420 are turned on.
  • the power supply input voltage provided by the power supply circuit 10 can charge the charge and discharge circuit 430, and the charge and discharge circuit 430 can also output a driving current to the laser 51.
  • the Drv signal output by the control circuit 410 is at the second level, the first terminal 1 and the second terminal 2 of the switch circuit 420 are turned off. At this time, if the Pwm signal in the dimming signal is still at a high level, the charge and discharge circuit 430 is in the discharge state. Therefore, the charge and discharge circuit 430 can still output the driving current and can still drive the laser 51 to emit light.
  • the control circuit 410 may input the Drv signal to the switch circuit 420, or may not input the Drv signal to the switch circuit 420.
  • the control circuit 410 inputs the Drv signal to the switch circuit 420, no matter whether the Drv signal is the first level (high level) or the second level (low level), the charge and discharge circuit 430 will not supply the signal to the laser 51
  • the laser 51 stops emitting light at this time. That is to say, when the Pwm signal in the dimming signal is low level, no matter whether the first end and the second end of the switch circuit 420 are in a conductive state or in a disconnected state, the charge and discharge circuit 430 will not supply power to the laser. 51 provides driving current, then at this time, the laser 51 stops emitting light.
  • the rise time and fall time of the driving current can be made smaller, for example, the rise time and fall time of the driving current can be both less than 20 microseconds (us).
  • the ripple current flowing into the laser can also be made smaller, thereby making the driving current flowing through the laser more precise.
  • the ripple current is the high-order harmonic component in the driving current waveform.
  • the electromagnetic disturbance generated during the transmission of the driving current is also positively related to the size of the ripple current. Therefore, reducing the size of the ripple current through the charge and discharge circuit 430 can further reduce the electromagnetic disturbance generated during the transmission of the driving current.
  • the first end of the switch circuit 420 is connected to the power circuit 10
  • the second end of the switch circuit 420 is connected to the charge and discharge circuit 430 .
  • the first terminal 1 of the control circuit 410 and the first terminal 1 of the switch circuit 420 are both connected to the output terminal of the power circuit 10 .
  • the first terminal 1 of the control circuit 410 and the first terminal 1 of the switch circuit 420 are both connected to the power supply interface of the optical drive circuit 40 (that is, the first terminal 1 of the optical drive circuit 40 is also the first terminal 1 of the optical drive circuit 40
  • the power supply input terminal is connected, and the power interface of the optical drive circuit 40 is connected to the power connector of the power circuit 10 (ie, the output terminal of the power circuit 10).
  • the second terminal of the control circuit 410 serves as the second terminal of the light driving circuit 40 and is connected to the display control circuit 30 .
  • the second end of the control circuit 410 and the second end of the optical drive circuit 40 are independent of each other, and are connected through a transmission line.
  • the second end of the control circuit 410 is connected to the second end of the optical drive circuit 40, and the optical drive circuit 410 is connected to the second end of the optical drive circuit 40.
  • the second terminal of the circuit 40 is connected to the display control circuit 30 .
  • the third terminal 3 of the control circuit 410 is connected to the control terminal C of the switch circuit 420 to transmit the Drv signal to the switch circuit 420 .
  • the first end of the switch circuit 420 is connected to the charge and discharge circuit 430
  • the second end of the switch circuit 420 is connected to the ground
  • the charge and discharge circuit 430 is connected to the power circuit 10 .
  • the switching circuit 420 may include a switching transistor Q1.
  • the gate (Gate, G) of the switching transistor Q1 can be used as the control terminal C of the switching circuit 420 and is connected to the third terminal 3 of the control circuit 410.
  • the first pole of the switching transistor Q1 can be used as the first terminal of the switching circuit 420.
  • the second pole of the switching transistor Q1 can be used as the second terminal of the switching circuit 420 and connected to the first terminal of the charging and discharging circuit 430 .
  • the gate G of the switching transistor Q1 is connected to the control terminal C of the switching circuit 420, the first pole of the switching transistor Q1 is connected to the first terminal of the switching circuit 420, and the second pole of the switching transistor Q1 is connected to the second terminal of the switching circuit 420. end connection.
  • the Drv signal transmitted from the control circuit 410 to the switching circuit 420 can also be input into the switching transistor Q1, thereby causing the first and second poles of the switching transistor Q1 to be turned on or off.
  • the switching transistor Q1 may be a P-type metal oxide semiconductor (metal oxide semiconductor, MOS) transistor.
  • the first electrode of the switching transistor Q1 may be a source electrode (Source, S), and the second electrode of the switching transistor Q1 may be a drain electrode (Drain, D).
  • the power supply circuit 10 loads the voltage at the source S of the switching transistor Q1, is lower than the voltage at gate G.
  • the absolute value of the voltage between the gate G and the source S of the switching transistor Q1 is less than the threshold voltage of the switching transistor Q1.
  • the switch circuit 420 may further include: a first diode D1 , a first resistor R1 and a second resistor R2 .
  • the first resistor R1 and the second resistor R2 are connected in parallel between the control circuit 410 and the control terminal of the switch circuit 420. Specifically, they can be connected in parallel between the control circuit 410 and the gate G of the transistor switch Q1.
  • the first diode D1 is connected in series with the first resistor R1 or the second resistor R2, and the cathode of the first diode D1 is connected to the control circuit 410 .
  • an example can be given where the first diode D1 and the first resistor R1 are connected in series.
  • the cathode terminal of the first diode D1 serves as the control terminal C of the switch circuit 420 and is connected to the third terminal 3 of the control circuit 410 and one end of the second resistor R2 respectively.
  • the anode of the tube D1 is connected to one end of the first resistor R1.
  • the other end of the first resistor R1 and the other end of the second resistor R2 are both connected to the gate G of the switching transistor Q1.
  • the cathode of the first diode D1 is connected to the control terminal C of the switching circuit 420, the anode is connected in series to one end of the first resistor R1, the other end of the first resistor R1 is connected to the gate G of the switching transistor Q1, and the second One end of the resistor R2 is connected to the control terminal C of the switching circuit 420, and the other end is connected to the gate G of the switching transistor Q1.
  • This also enables the first resistor R1 and the second resistor R2 to be connected in parallel between the control circuit 410 and the gate of the switching transistor Q1. Between poles G, the first diode D1 and the first resistor R1 are connected in series.
  • the circuit composed of the first resistor R1, the second resistor R2 and the first diode D1 is connected between the control circuit 410 and the gate G of the switching transistor Q1, so that the third gate of the switching transistor Q1 can be The first pole and the second pole are turned on slowly and turned off quickly.
  • the first pole and the second pole of the switching transistor Q1 are slowly turned on, reducing the change rate of the driving current, thereby reducing the intensity of the generated electromagnetic field, while the first pole and the second pole of the switching transistor Q1 are quickly disconnected, which can Reduce circuit loss. This is because when the switching transistor Q1 is turned off, the voltage drops and the power remains unchanged, the current rises. The loss caused by large current is large. Quick disconnection can quickly cut off the current, thereby reducing circuit loss.
  • the impact on the driving current can be seen as shown in (d1) in Figure 15.
  • the rising slope of the driving current is smaller than the falling slope, where each falling start time point corresponds to the conduction start time point of the switching transistor Q1.
  • the switching circuit 420 may further include a second capacitor C2 , and the second capacitor C2 is connected in parallel between the first pole and the second pole of the switching transistor Q1 , for example, in parallel between the S pole and the D pole.
  • the second capacitor C2 is connected in parallel between the first pole and the second pole of the switching transistor Q1 , for example, in parallel between the S pole and the D pole.
  • one capacitive plate of the second capacitor C2 is connected to the first pole (such as the S pole) of the switching transistor Q1
  • the other capacitive plate of the first capacitor C1 is connected to the second pole (such as the D pole) of the switching transistor Q1.
  • the first capacitor C1 is used to stabilize the voltage between the first pole and the second pole of the switching transistor Q1.
  • the charge and discharge circuit 430 may include an inductor L and a second diode D2.
  • One end of the inductor L and the cathode of the second diode D2 are both connected to the second end 2 of the switch circuit 420.
  • the other end of the inductor L is connected to the first end 1 (ie, the anode) of the laser 51, and the anode of the second diode D2 is connected to the ground terminal GND.
  • the inductor L and the cathode of the second diode D2 are both connected to the second pole of the switching transistor Q1.
  • the light driving circuit 40 may further include a current detection circuit 440 .
  • the current detection circuit 440 is connected in series with the laser 51 and connected with the control current 410 to monitor the driving current of the laser 51 .
  • the current detection circuit 440 is used to enable the control circuit 410 to determine the driving current flowing through the laser 51 . Therefore, the control circuit 410 generates the switch drive signal Drv according to the dimming signal and the drive current determined by the current detection circuit 440 to control the on-time and off-time of the first terminal 1 and the second terminal 2 of the switch circuit 420 .
  • the current detection circuit 440 is connected between the power supply circuit 10 and the switch circuit 420 , and the current detection circuit 440 is connected to the control circuit 410 .
  • control circuit 410 can obtain the potential at both ends of the current detection circuit 440, thereby determining the voltage at both ends of the current detection circuit 440.
  • the first terminal 1 of the current detection circuit 440 is connected to the output terminal of the power circuit 10, the power terminal Vin of the control circuit 410, and the first detection terminal Isen+ of the control circuit 410 respectively.
  • the second terminal 2 of the circuit 440 is connected to the first terminal 1 of the switch circuit 420 and the second detection terminal Isen- of the control circuit 410 respectively.
  • the current detection circuit 440 and the laser 51 can be connected in series, and both ends of the current detection circuit 440 and the laser 51 can be connected to the control circuit 410 respectively.
  • the power terminal V in of the control circuit 410 is the first terminal 1 of the control circuit 410 and is used to be connected to the output terminal of the power circuit 10 .
  • the control circuit 410 can sample the driving current flowing through the laser 51 through the current detection circuit 440 to obtain the current detection signal Isen.
  • the control circuit 410 can collect the potential of the first terminal and the second terminal of the current detection circuit 440, and then obtain the voltage loaded on both ends of the current detection circuit 440.
  • the voltage can be The current is obtained, which is the driving current.
  • control circuit 410 can control the on-time and off-time of the first terminal 1 and the second terminal 2 of the switch circuit 420 based on the relationship between the detected driving current and the rated driving current.
  • the rated driving current is the current that drives the laser 51 to emit light normally.
  • the current detection signal Isen is a current value
  • the control circuit 410 can compare the determined current detection signal Isen with the rated driving current.
  • the rated driving current is the current required by the laser to emit light.
  • the control circuit 410 if it is determined that the current detection signal Isen is lower than the rated driving current, the duty cycle of the Drv signal output to the switching circuit 420 can be increased, that is, the conduction time of the first terminal 1 and the second terminal 2 of the switching circuit 420 can be increased until This current detection signal Isen is equal to the rated drive current.
  • the current value of the driving current flowing through the laser can be gradually increased, thereby enabling the light source to emit light normally.
  • control circuit 410 determines that the current detection signal Isen is higher than the rated driving current, it can reduce the duty cycle of the Drv signal output to the switching circuit 420, that is, reduce the conduction of the first terminal 1 and the second terminal 2 of the switching circuit 420.
  • the current detection signal Isen is equal to the rated driving current.
  • control circuit 410 can also control the on and off of the first terminal 1 and the second terminal 2 of the switch circuit 420 based on the relationship between the voltage at both ends of the current detection circuit 440 and the preset threshold voltage of the current detection circuit 440. open.
  • the current detection signal Isen is a voltage value
  • the control circuit 410 can compare the determined current detection signal Isen with a pre-stored voltage threshold.
  • the voltage threshold may be the voltage value across the first terminal 1 and the second terminal 2 of the current detection circuit 440 when the current flowing through the current detection circuit 440 is the rated driving current of the laser. If the control circuit 410 determines that the current detection signal Isen is lower than the voltage threshold, it can increase the duty cycle of the Drv signal output to the switch circuit 420, that is, increase the conduction of the first terminal 1 and the second terminal 2 of the switch circuit 420. until the current detection signal Isen is equal to the voltage threshold. As a result, the current value of the driving current flowing through the laser can be gradually increased, thereby enabling the light source to emit light normally.
  • control circuit 410 determines that the voltage value corresponding to the current detection signal Isen is higher than the voltage threshold, it can reduce the duty cycle of the Drv signal output to the switch circuit 420, that is, reduce the first terminal 1 and the second terminal of the switch circuit 420.
  • the conduction time of the two terminals 2 is until the voltage value corresponding to the current detection signal Isen is equal to the voltage threshold.
  • the current detection circuit 440 includes a detection resistor Rsns, where the detection resistor Rsns is a sensitive resistor with a small resistance value.
  • One end of the detection resistor Rsns serves as the first end 1 of the current detection circuit 440 and is connected to the output end of the power circuit 10, the power end V in of the control circuit 410, and the first detection end Isen+ of the control circuit 410 respectively.
  • the other end of the detection resistor Rsns serves as the second terminal 2 of the current detection circuit 440 and is connected to the first terminal 1 of the switch circuit 420 and the second detection terminal Isen- of the control circuit 410 respectively.
  • one end of the detection resistor Rsns is connected to the first end of the current detection circuit 440 , and the other end of the detection resistor Rsns is connected to the second end of the current detection circuit 440 .
  • the detection resistor Rsns and the laser 51 can also be connected in series, and both ends of the detection resistor Rsns can be connected to the control circuit 410 .
  • the voltage of the detection resistor Rsns can be obtained, and then the relationship between the voltage value of the detection resistor Rsns and the voltage threshold can be determined.
  • the current of the line where the detection resistor Rsns is located can be obtained, and the detection resistor Rsns and The lasers 51 are connected in series, and the relationship between the driving current of the laser 51 and its rated driving current can be determined.
  • the control circuit 410 if the control circuit 410 generates a Drv signal according to the relationship between the collected driving current and the rated driving current of the laser to control the on-off state of the switching circuit 420, then the above-mentioned current detection signal Isen is the collected driving current. And if the control circuit 410 generates a Drv signal based on the relationship between the collected voltage across the detection resistor Rsns and the preset voltage threshold to control the on-off state of the switch circuit 420, then the above-mentioned current detection Signal Isen may be a voltage threshold.
  • each light driving circuit 40 may further include a voltage stabilizing circuit 450 , wherein the first terminal of the voltage stabilizing circuit 450 is connected to the line of the power circuit 10 and the light driving circuit 40 , and the second terminal is connected to ground.
  • the voltage stabilizing circuit 450 may include at least one capacitor.
  • the voltage stabilizing circuit 450 is used to stabilize the driving voltage output by the power circuit 10 to the light driving circuit 40 . Therefore, the positive plate of the at least one capacitor is connected to the line between the output end of the power circuit 10 and the input end of the light driving circuit, and the negative plate of the at least one capacitor is grounded.
  • an example includes two capacitors, namely the third capacitor C3 and the fourth capacitor C4.
  • the positive plates of the third capacitor C3 and the fourth capacitor C4 are both connected to the line between the output end of the power circuit 10 and the input end of the light driving circuit 40, and the cathode plates of the third capacitor C3 and the fourth capacitor C4 are both grounded.
  • one end of the fourth capacitor C4 and one end of the third capacitor C3 serve as the first end 1 of the voltage stabilizing circuit 450 and are connected to the output end of the power circuit 10 and the control circuit 410 respectively.
  • the power terminal is connected to the first terminal 1 of the switching circuit 420.
  • the other end of the fourth capacitor C4 and the other end of the third capacitor C3 serve as the second end 2 of the voltage stabilizing circuit 450 and are connected to the ground terminal GND.
  • one end of the fourth capacitor C1 and one end of the third capacitor C3 are both connected to the first end of the voltage stabilizing circuit 450 , and the other end of the fourth capacitor C1 and the other end of the third capacitor C3 are both connected to the voltage stabilizing circuit 450 The second end of the connection.
  • one end of the third capacitor C3 and the fourth capacitor C4 can be connected to the line of the power circuit 10 and the light driving circuit 40, and the other end can be connected to the ground.
  • the fourth capacitor C4 and the third capacitor C3 can filter the driving voltage output by the power supply circuit 10 to the light driving circuit 40, so that the driving voltage output by the power supply circuit 10 is relatively stable. This ensures that the light driving circuit 40 can drive the light source to emit light within a certain driving voltage range.
  • the enable signal of the optical driving circuit 40 is Fault.
  • the control circuit 410 in the light driving circuit 40 can also transmit the enable signal Fault to the power circuit 10 .
  • the power circuit 10 can output a driving voltage based on the enable signal Fault. When the enable signal Fault is at a high level, the power circuit 10 outputs a driving voltage to the light driving circuit 40 . When the enable signal Fault is low level, the power circuit 10 stops outputting the driving voltage to the light driving circuit 40 .
  • control circuit 410 can determine that the light source has an open circuit or short circuit fault based on the current detection signal Isen, and then can control the level of the enable signal Fault to be low level. As a result, the power circuit 10 stops outputting the driving voltage, thereby protecting the light source.
  • the control circuit 410 detects that the value of the current detection signal Isen is normal and can determine that there is no abnormality in the light driving circuit. Then, the level of the enable signal Fault can be controlled to be high level.
  • the control circuit 410 detects that the value of the current detection signal Isen is abnormal. For example, if it is much larger than the rated driving current of the laser, it can be judged that there may be a short circuit in the optical drive circuit. For example, if the Pwm signal is high level, but the current detection signal Isen is 0, It can be determined that there may be an open circuit in the optical driving circuit, and then the level of the enable signal Fault can be controlled to be low level.
  • the current loop of the driving current is as follows.
  • the inductor L is in the charging state and slowly transmits the driving current transmitted by the switching transistor Q1 to the laser 51 to drive the laser 51 to emit light.
  • the current loop of the driving current is: power circuit 10 - source S of switching transistor Q1 - drain D of switching transistor Q1 - inductor L - laser - ground terminal GND.
  • the inductor L When the switching transistor Q1 is in the off state, the inductor L is in the discharge state.
  • the inductor L, the laser 51 and the second diode D2 can form a discharge circuit to continue to provide driving current to the laser 51 so that the laser 51 continues to emit light.
  • the current loop of the driving current is: ground terminal GND - second diode D2 - inductor L - light source - ground terminal GND.
  • the following describes the relationship between the driving current and the dimming signal (including Adim and Pwm) and the Drv signal respectively.
  • FIG. 15 are schematic diagrams showing how the signal value (ie, voltage value, unit: V) of the Adim signal in the dimming signal provided by the display control circuit 30 changes over time.
  • (b1) and (b2) in FIG. 15 are schematic diagrams showing how the duty cycle (unit: %) of the Pwm signal in the dimming signal provided by the control circuit 30 changes with time.
  • (c1) and (c2) in FIG. 15 are schematic diagrams of the duty cycle of the Drv signal output by the control circuit 410 changing with time.
  • (d1) and (d2) in Figure 15 are schematic diagrams showing how the current value of the driving current I flowing through the laser changes over time, where the unit of the current is ampere (A).
  • the current value of the driving current in a certain period of time is positively related to the signal value of the Adim signal in that period. Therefore, as mentioned above, the Adim signal is used to control the driving The magnitude of the current value.
  • the control circuit 410 still provides the switch driving signal Drv to the switch circuit 420.
  • the duty cycle of the Pwm signal is 0 during the period from t0′ to t3′, the light driving circuit 40 stops providing driving current to the light source, and the driving current value flowing through the light source is 0. Therefore, as mentioned above, The Pwm signal is used to control the presence or absence of the drive current.
  • the changing frequency of the driving current corresponds to the signal frequency of the switch driving signal Drv.
  • a change period of the Drv signal includes high level and low level, and a change period of the drive current includes a rise and a fall.
  • the drive current also completes a change cycle, so,
  • the changing frequency of the driving current is consistent with the changing frequency of the Drv signal, and the Drv signal is used to control the on and off of the switching transistor Q1. Therefore, as mentioned above, high-frequency switching of the switch circuit 420 results in high-frequency changes in the driving current.
  • the current value of the driving current flowing through the laser fluctuates in a zigzag shape within a certain period of time.
  • the average value of the current value in a certain period of time can be used to determine the driving current in the period of time.
  • the average value may be the average value of the maximum current value and the minimum current value within the period.
  • the driving current in the period from t0 to t1 is I0
  • the driving current in the period from t1 to t2 is I1
  • the driving current in the period from t2 to t3 is I2.
  • the waveform of the drive current shown in (d1) in FIG. 15 can also be called a drive current ripple.
  • the switching circuit 420 includes a switching transistor Q1.
  • the control terminal of the switching transistor Q1 is connected to the control circuit 410.
  • the first pole of the switching transistor Q1 is connected to the charge and discharge circuit 430, and the second pole of the switching transistor Q1 is connected to ground.
  • the switch circuit 420 may also include the above-mentioned first diode D1, first resistor R1, and second resistor R2.
  • first diode D1 first diode
  • resistor R1 first resistor
  • second resistor R2 second resistor
  • the switch circuit 420 may also include the above-mentioned second capacitor C2.
  • the second capacitor C is connected in parallel between the first end and the second end of the switch circuit 420. Specifically, it may be connected in parallel between the first end of the switch transistor Q1 and the second end of the second capacitor C2 of the switch transistor Q1. between the first pole and the second pole.
  • the switch circuit 420 may also include the above-mentioned second capacitor C2.
  • the second capacitor C is connected in parallel between the first end and the second end of the switch circuit 420. Specifically, it may be connected in parallel between the first end of the switch transistor Q1 and the second end of the second capacitor C2 of the switch transistor Q1. between the first pole and the second pole.
  • the charging and discharging circuit 430 includes an inductor L, a second diode D2 and a first capacitor C1.
  • One end of the inductor L is connected to the power circuit 10, and the other end is connected to the anode of the second diode D2.
  • the cathode of the diode D2 is connected to the cathode of the laser 51 corresponding to the light driving circuit 40 in which it is located.
  • the positive plate of the first capacitor C1 is connected to the cathode of the laser 51 corresponding to the light driving circuit 40, and the negative plate of the first capacitor C1 is connected to the ground.
  • the inductor L and the first capacitor C1 are both energy storage components.
  • the first terminal of the switch circuit 420 is connected to the charge and discharge circuit 430.
  • the first terminal of the switch circuit 420 is connected between the inductor L and the second diode D2. on the line.
  • the first end of the switch circuit 420 can also be connected to the line between the cathode of the second diode D2 and the detection resistor Rsns.
  • the power supply circuit 10 charges the inductor L.
  • the switching transistor Q1 is turned off, the inductor L is discharged and provides a driving current to the laser 51 .
  • the power circuit 10 charges the inductor L again.
  • the first capacitor C1 is discharged, and the discharge circuit is the circuit of the driving current, that is, the first capacitor C1 - laser 51 - inductor L - switch Transistor Q1 - ground terminal, first capacitor C1 provides driving current to laser 51 .
  • the inductor L is discharged again, providing a driving current for the laser 51 . It can be seen that the charge and discharge circuit 430 Through the continuous charging and discharging of the inductor L and the first capacitor C1, a driving current is provided for the laser 51.
  • the on-off state of the switching transistor Q1 is determined by the duty cycle (denoted as D) of the Drv signal, and the greater the duty cycle D of the Drv signal according to the following formula, the greater the drive current.
  • the power supply input voltage V in and the power supply output voltage V out of the light driving circuit 40 satisfy the following relationship:
  • the optical drive circuit 40 is equivalent to a boost circuit (note that the judgment standard here is V d > V in ).
  • V d is not greater than V in .
  • the optical drive circuit 40 is equivalent to a buck circuit (note that the judgment standard here is V d ⁇ V in ).
  • the light driving circuit 40 itself is still a boost circuit with V out ⁇ V in .
  • the rated drive current of the blue laser is 3A, and the corresponding rated drive voltage is 18V.
  • the rated drive current of the red laser is 1.5A, and the corresponding rated drive voltage is 9V.
  • the power supply input voltage V in is selected to be 12V.
  • the corresponding control circuit 410 of the blue laser outputs a Drv signal with a duty cycle of 0.8, and the corresponding charge and discharge circuit 430 outputs a power supply output voltage V out of 30V to realize the voltage increase at both ends of the laser.
  • the control circuit 410 corresponding to the red laser outputs a Drv signal with a duty cycle of 0.3, and the corresponding charge and discharge circuit 430 outputs a power supply output voltage V out of 21V to achieve a voltage drop at both ends of the laser.
  • the light driving circuit 40 itself is still a boost circuit with V out ⁇ V in .
  • this embodiment can control the voltage output by the optical drive circuit by controlling the duty cycle of the Drv signal, and thereby control the voltage V d across the laser. Moreover, when the duty cycle is greater than 0.5, the voltage V d at both ends of the laser is realized to be boosted relative to the power supply input voltage V in , and when the duty cycle of the Drv signal is not greater than 0.5, the voltage V d at both ends of the laser is realized to be boosted relative to The power supply input voltage V in is stepped down. Therefore, this embodiment can use the same type of optical drive circuit to realize voltage boosting and voltage reduction at both ends of the laser based on different scenarios.
  • the light driving circuit 40 may also include a current detection circuit 440 , wherein the current detection circuit 440 may also include a detection resistor Rsns as described above.
  • the current detection circuit 440 may also include a detection resistor Rsns as described above.
  • the light driving circuit 40 may also include a voltage stabilizing circuit 450.
  • the voltage stabilizing circuit 450 may include at least one capacitor, and the positive plates of these capacitors are connected between the power circuit 10 and the light driving circuit 40. On the line, the negative plate of these capacitors is connected to ground. For specific details, please refer to the above description and will not be repeated here.
  • the cathode of the laser 51 in Figure 16 can also be grounded to shorten the transmission line of the driving current and reduce electromagnetic interference.
  • the enable signal of the light driving circuit 40 is Fault.
  • control circuit 410 can also send an enable signal to the power circuit 10 .
  • an enable signal please refer to the above description, which will not be described again here.
  • the frequency of the driving current and the electromagnetic radiation generated during the transmission process are Schematic diagram of the relationship between the electric field intensity of the disturbance electric field.
  • the frequency of the driving current of the projection equipment is in the range of 30 megahertz (MHz) to 200MHz, the driving current of the projection equipment is generated during the transmission process.
  • the electric field intensity of the electromagnetic radiation disturbance electric field should not be greater than 40 millivolts (uV).
  • the electromagnetic radiation generated during the transmission process of the driving current of the projection device should not be greater than 47 millivolts (uV).
  • the projection device provided by the embodiment of the present disclosure uses a common cathode drive, and the cathode of the laser is grounded, the transmission line of the drive current can be effectively reduced, thereby reducing the current loop area of the drive circuit during the transmission process. This ensures that the electromagnetic interference generated during the transmission process of the driving current meets the GB/T 9254 standard.
  • the cathode of the laser can be grounded.
  • the transmission line through which the driving current flows can be effectively shortened, thereby reducing the current loop area of the driving current.
  • the electromagnetic waves radiated by the projection equipment affect the components inside the projection equipment and the The impact on the performance and working status of other electronic equipment around the projection equipment is also reduced.
  • the cathode of the laser can be connected to the line between the power supply circuit and the optical drive circuit, so that the voltage V d across the laser is the difference between the power supply output voltage V out output by the optical drive circuit and the power supply input voltage Vin input by the optical drive circuit. Then, in order to make the voltage V d across the laser equal to its rated drive voltage V′ d , it is only necessary to control the optical drive circuit to increase the output V out by V′ d relative to the input Vin.
  • the voltage raised by the optical drive circuit is not affected by the input Vin , so the power supply input voltage Vin output by the power supply circuit is not limited by the rated drive voltage of the laser.
  • the Vin selected by the power supply circuit is not prone to burn out components due to excessive input current, nor is it prone to damage components due to excessive input voltage.
  • Embodiments of the present disclosure also provide a projection device.
  • the projection device also includes a power supply circuit 10, a display control circuit 30, a laser light source 50 and at least one light driving circuit 40.
  • the laser light source 50 includes at least one laser 51 .
  • the power circuit 10 and at least one optical driving circuit 40 are arranged on different boards, and the optical driving board on which the at least one optical driving circuit 40 is located is close to the laser light source 50 .
  • the power circuit 10 is connected to the display control circuit 30 and is used to supply power to the display control circuit 30 .
  • the display control circuit 30 is connected to at least one light driving circuit 40 and is used to provide a dimming signal to the at least one light driving circuit 40 .
  • the display control circuit 30 is connected to at least one light driving circuit 40 and is used to provide a dimming signal to the at least one light driving circuit 40 .
  • the light driving circuit 40 and the laser 51 are connected one by one and are used to provide driving current to the connected laser 51 based on the dimming signal, and the laser 51 is used to emit light driven by the driving current.
  • the projection device can be driven by a common anode or a common cathode. Therefore, if it is driven by a common anode, the anode of the laser 51 is connected to the power circuit 10 and the cathode of the laser 51 is connected to the light driver. Circuit 40 is connected. If common cathode driving is used, the anode of the laser 51 is connected to the light driving circuit 40, and the cathode of the laser 51 can be grounded nearby. For details, please refer to the above.
  • the transmission line of the driving current can be shortened, thereby reducing the current loop area of the driving current, thereby reducing the driving current.
  • the current loop area is reduced, and thus the impact of the electromagnetic waves radiated by the projection device on the performance and working status of the devices inside the projection device and other electronic devices around the projection device is also reduced.
  • the optical drive board where the optical drive circuit 40 is located is close to the laser light source. Then, the drive current flowing from the cathode of the laser 51 flows to the optical drive board and flows to the power board. In comparison, the transmission line is obviously shortened. Therefore, in the common anode drive scheme, the power circuit and the optical drive circuit are arranged separately, which can also shorten the transmission line of the drive current, thereby reducing the current loop area of the drive current, thereby reducing the current loop area of the drive current, and further, The impact of the electromagnetic waves radiated by the projection device on the performance and working status of components inside the projection device and other electronic devices around the projection device is also reduced.
  • FIG. 19 is a schematic flowchart of a method for driving a laser of a projection device provided by an embodiment of the present disclosure. This method can be applied to the above-mentioned projection device. Referring to Figure 19, the method includes:
  • step 101 the power supply circuit 10 supplies power to the display control circuit 30 and at least one light driving circuit 40 .
  • the driving voltage provided by the power circuit to the optical driving circuit may be 24V DC.
  • step 102 the display control circuit 30 provides a dimming signal to at least one light driving circuit 40 .
  • the dimming signal includes Pwm signal and Adim signal.
  • the Pwm signal is used to control whether the optical driving circuit transmits the driving current to the laser
  • the Adim signal is used to control the current value of the driving current.
  • step 103 the light driving circuit 40 provides a driving current to the connected laser 51 based on the dimming signal.
  • each light driving circuit is capable of providing driving current to the light source connected to it based on the received dimming signal, driven by the driving voltage.
  • the current value of the driving current may be positively correlated with the signal value of the Adim signal in the dimming signal. That is, when the signal value of the Adim signal is larger, the current value of the driving current is larger.
  • the frequency of the driving current output by the light driving circuit may be related to the duty cycle of the Pwm signal in the dimming signal.
  • step 104 the laser 51 emits light when driven by the driving current.
  • the first end of the plurality of lasers may be an anode (ie, positive electrode) end, and the second end may be a cathode (ie, negative electrode) end. Since the cathodes of the laser are interconnected and the anode is connected to the light driving circuit, this driving method can also be called common cathode driving.
  • the cathode of the laser In the common cathode driving mode, if the cathode of the laser is grounded, the driving current flowing from the laser can flow to the nearby reference ground without returning to the power circuit or the optical driving circuit. Compared with common anode driving, the transmission line of the driving current can be shortened, thereby effectively reducing the current loop area of the driving current. Based on the above formula (1), it can be seen that when the current loop area of the driving current decreases, the electric field intensity of the electromagnetic radiation disturbance electric field generated around the transmission line of the driving current will also decrease. Correspondingly, the impact of the electromagnetic waves radiated by the projection device on the performance and working status of other electronic devices around the projection device is also reduced.
  • the cathode of the laser can be connected to the line between the power circuit and the optical drive circuit, so that the voltage V d at both ends of the laser is the power supply output voltage V out output by the optical drive circuit and the power supply input by the optical drive circuit.
  • the difference between the input voltage V in in order to promote the voltage V d across the laser to its rated driving voltage V′ d , it is only necessary to control the optical drive circuit to increase the output V out relative to the input V in by V′ d .
  • the amount of voltage raised by the optical drive circuit is not affected by the input V in . Therefore, the power supply input voltage V in output by the power circuit is not limited by the rated drive voltage of the laser.
  • the selected V in of the power supply circuit is neither likely to cause the components to burn out due to excessive input current nor to damage the components due to excessive input voltage.
  • Figure 20 is a schematic flowchart of another driving method provided by an embodiment of the present disclosure, which method can be applied to a projection device. Referring to Figure 20, the method includes:
  • step 201 the power circuit provides a driving voltage to at least one optical driving circuit.
  • step 202 the voltage stabilizing circuit stabilizes the driving voltage output by the power circuit.
  • step 203 the display control circuit provides a dimming signal to each light driving circuit.
  • step 204 the control circuit is driven by the driving voltage and controls the on-off state of the first end and the second end of the switch circuit according to the dimming signal transmitted by the display control circuit.
  • step 205 the charging and discharging circuit provides driving current to the laser when the Pwm signal of the dimming signal is high level, and stops providing driving current to the laser when the Pwm signal is low level.
  • step 206 the laser emits light driven by the driving current.
  • step 207 the current detection circuit detects the driving current flowing through the laser.
  • step 208 the control circuit controls the conduction duration of the first terminal and the second terminal of the switch circuit according to the driving current.
  • step 202 can be deleted according to the situation.
  • step 207 and step 208 can be deleted according to the situation.
  • step 201 and step 203 can be executed simultaneously. Any person familiar with the technical field can easily think of changing methods within the technical scope disclosed in the present disclosure, which should be covered by the protection scope of the present disclosure, and therefore will not be described again.
  • Figure 21 is a schematic diagram of the hardware structure of the electronic device provided by the present disclosure. As shown in Figure 21, the electronic device 100 is used to implement any of the above method embodiments and correspond to the operation of the light driving circuit.
  • the electronic device 100 may include a memory 1001 and a processor 1002;
  • Memory 1001 is used to store computer programs.
  • the processor 1002 is used to execute the computer program stored in the memory to implement the driving method in the above embodiment. For details, please refer to the relevant descriptions in the foregoing method embodiments.
  • the memory 1001 can be independent or integrated with the processor 1002.
  • the electronic device 100 may also include a bus 1003 for connecting the memory 1001 and the processor 1002.
  • this embodiment may also include a communication interface 1004, which may be connected to the processor 1002 through a bus 1003.
  • the processor 1002 can control the communication interface 1003 to implement the above-mentioned receiving and sending functions of the electronic device 100 .
  • Embodiments of the present disclosure provide a projection device.
  • the projection device includes: a memory, a processor, and a computer program stored on the memory.
  • the processor executes the computer program, it implements the driving method (for example, as provided in the above method embodiment). The method shown in Figure 19 or Figure 20).
  • Embodiments of the present disclosure provide a computer-readable storage medium. Instructions are stored in the computer-readable storage medium. The instructions are loaded and executed by a processor to implement the driving method provided by the above method embodiments (for example, FIG. 19 or FIG. The method shown in 20).
  • Embodiments of the present disclosure provide a computer program product containing instructions.
  • the computer program product When the computer program product is run on a computer, it causes the computer to execute the driving method provided by the above method embodiment (for example, the method shown in Figure 19 or Figure 20) .
  • the program can be stored in a computer-readable storage medium.
  • the storage medium can be read-only memory, magnetic disk or optical disk, etc.
  • first”, second and other words are used to distinguish the same or similar items with substantially the same functions and functions. It should be understood that the terms “first”, “second” and “nth” There is no logical or sequential dependency, and there is no limit on the number or execution order.

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Abstract

本公开提供了一种投影设备及其激光光源的驱动方法，涉及投影显示技术领域，该投影设备包括电源电路、显示控制电路、激光光源和至少一个光驱动电路，激光光源包括至少一个激光器；电源电路分别与显示控制电路和至少一个光驱动电路连接，用于向显示控制电路和至少一个光驱动电路供电；显示控制电路与至少一个光驱动电路连接，用于向至少一个光驱动电路提供调光信号；光驱动电路和激光器一一连接，且光驱动电路和激光器的阳极连接，至少一个激光器的阴极互连；光驱动电路用于基于调光信号，向所连的激光器提供驱动电流，激光器用于在驱动电流的驱动下发光。本公开，能降低投影设备辐射的电磁波，对元件的影响。

Description

投影设备及其激光光源的驱动方法
本公开要求于2022年09月16日提交的申请号为202211128274.X、发明名称为“投影设备及其光源的驱动方法”的中国专利申请的优先权，以及于2023年08月04日提交的申请号为202310978399.X、发明名称为“激光投影设备、控制方法及激光器驱动模块”的中国专利申请的优先权，其全部内容通过引用结合在本公开中。
技术领域
本公开涉及投影显示技术领域，特别涉及一种投影设备及其激光光源的驱动方法。
背景技术
投影设备，如激光投影设备，利用数字光处理技术(Digital Light Processing，DLP)，将影像信号经过数字处理，然后通过激光器发出光束投影出来的，激光投影设备具体色彩鲜明、亮度高、屏幕尺寸灵活的特点，得到了广泛的应用。
发明内容
本公开提供了一种投影设备及其光源的驱动方法，可以解决相关技术中投影设备辐射出的电磁波对其内部器件和其它电子设备的工作状态和性能产生影响的问题。所述技术方案如下：
第一方面，提供了一种投影设备包括电源电路、显示控制电路、激光光源和至少一个光驱动电路，所述激光光源包括至少一个激光器；
所述电源电路分别与所述显示控制电路和所述至少一个光驱动电路连接，用于向所述显示控制电路和所述至少一个光驱动电路供电；
所述显示控制电路与所述至少一个光驱动电路连接，用于向所述至少一个光驱动电路提供调光信号；
所述光驱动电路和所述激光器一一连接，且所述光驱动电路和所述激光器的阳极连接，所述至少一个激光器的阴极互连；
所述光驱动电路用于基于所述调光信号，向所连的激光器提供驱动电流，所述激光器用于在所述驱动电流的驱动下发光。
第二方面，提供了一种投影设备，其特征在于，电源电路、显示控制电路、激光光源和至少一个光驱动电路，所述激光光源包括至少一个激光器；
所述电源电路和所述至少一个光驱动电路布置在不同的板上，且所述至少一个光驱动电路所在光驱动板，与所述激光光源位置靠近；
所述电源电路与所述显示控制电路连接，用于向所述显示控制电路供电；
所述显示控制电路与所述至少一个光驱动电路连接，用于向所述至少一个光驱动电路提供调光信号；
所述光驱动电路和所述激光器一一连接，用于基于所述调光信号，向所连的激光器提供驱动电流，所述激光器用于在所述驱动电流的驱动下发光。
第三方面，提供了一种激光光源的驱动方法，应用于第一方面和第二方面所述的投影设备，所述方法包括：
所述电源电路向所述显示控制电路和所述至少一个光驱动电路供电；
所述显示控制电路向所述至少一个光驱动电路提供调光信号；
所述光驱动电路基于所述调光信号，向所连的激光器提供驱动电流；
所述激光器在所述驱动电流的驱动下发光。
在本实施例中，因激光器的阳极与光驱动电路连接，阴极连接在一起，例如，激光器的 阴极可以接地。激光器的阴极接地的方案中，能够有效缩短驱动电流流经的传输线路，从而减少驱动电流的电流环路面积，进而，该投影设备辐射出的电磁波，对该投影设备内部的器件，以及对该投影设备周围的其它电子设备的性能以及工作状态的影响也降低。
又例如，激光器的阴极可以接在电源电路和光驱动电路之间的线路上，从而使激光器两端的电压Vd，为光驱动电路向外输出的供电输出电压Vout，与光驱动电路输入的供电输入电压Vin之差。那么，为了促使激光器两端的电压Vd为其额定驱动电压V′d，则只需要控制光驱动电路将输出的Vout，相对于输入的Vin，升高V′d即可。而光驱动电路抬升的电压量，不受输入的Vin影响，那么，电源电路向外输出的供电输入电压Vin，便不受激光器的额定驱动电压所限制。进而，电源电路所选的Vin，既不容易出现因输入电流过大，而烧坏元件的情况，也不容易出现因输入电压过大，而损坏元件的情况。
附图说明
为了更清楚地说明本公开实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本公开的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本公开实施例提供的一种投影设备的电路示意图；
图2是相关技术中投影设备的电路示意图；
图3是本公开实施例提供的一种驱动激光器发光的驱动电流的传输线路示意图；
图4是本公开实施例提供的一种投影设备的电路示意图；
图5是本公开实施例提供的一种投影设备的电路示意图；
图6是本公开实施例提供的一种驱动激光器发光的驱动电流的传输线路示意图；
图7是本公开实施例提供的一种驱动激光器发光的驱动电流的传输线路示意图；
图8是本公开实施例提供的一种投影设备的电路示意图；
图9是本公开实施例提供的一种投影设备的电路示意图；
图10是本公开实施例提供的一种投影设备的电路示意图；
图11是本公开实施例提供的一种投影设备的电路示意图；
图12是本公开实施例提供的一种投影设备的电路示意图；
图13是本公开实施例提供的一种投影设备的电路示意图；
图14是本公开实施例提供的一种投影设备的电路示意图；
图15是本公开实施例提供的一种Adim信号、Pwm信号、Drv信号和驱动电流，分别随时间的变化示意图；
图16是本公开实施例提供的一种投影设备的电路示意图；
图17是本申请实施例提供的一种驱动电流的频率，所对应的无线电骚扰限值的示意图；
图18是本公开实施例提供的一种驱动激光器发光的驱动电流的传输线路示意图；
图19是本申请实施例提供的一种驱动方法的流程示意图；
图20是本申请实施例提供的一种驱动方法的流程示意图；
图21为本申请提供的电子设备的硬件结构示意图。
具体实施方式
为使本公开的目的、技术方案和优点更加清楚，下面将结合附图对本公开实施方式作进一步地详细描述。
图1是本公开实施例提供的一种投影设备的电路关系示意图。参考图1所示，该投影设备包括电源电路10、多媒体处理电路20、显示控制电路30、光驱动电路40、激光光源50、光机组件60以及投影镜头70。
其中，该电源电路10可以输出直流电压，例如，该电源电路10可以向光驱动电路40输出12伏(V)或24V的直流电压。
例如，电源电路10可以接收市电，并将市电进行滤波变压等处理后，向光驱动电路40 提供直流的供电输入电压Vin。
继续参考图1所示，电源电路10可以包括桥式整流电路11及功率转换电路12，其中，功率转换电路12可以包括功率因数校正(power factor correction，PFC)电路121，及LLC电路122。整流桥电路11接收市电，并对市电进行整流滤波后，输出至PFC电路121及LLC电路122，通过PFC电路121及LLC电路122进行功率转换，以向负载供电，如向光驱动电路40输出直流的供电输入电压Vin。
其中，整流桥电路，是电源电路中应用最广的一种整流电路，它由四个同方向的二极管和变压器组成。整流，即是把交流电变为直流电的过程，利用具有单向导电特性的器件，可以把方向和大小改变的交流电，转换为直流电。
其中，PFC电路，是采用电感补偿方法，调整输入电流波型，使其与输入电压波型尽可能相似，以使功率因数校正值趋近100％。其中，功率因数，是指有效功率与总耗电量(视在功率)之间的关系，也即是，有效功率除以总耗电量(视在功率)的比值。
其中，LLC电路，是一种通过控制开关频率(频率调节)，来实现输出电压恒定的谐振电路。该电路中含有电感、电容和电阻元件的单口网络，在某些工作频率上，出现端口电压和电流波型相位相同的情况时，称电路发生谐振，而能发生谐振的电路，称为谐振电路。
继续参考图1所示，电源电路10与多媒体处理电路20、显示控制电路30、光驱动电路40、激光光源50、光机组件60以及投影镜头70电连接，以向这些负载供电。
需要指出的是，电源电路10还能同时为投影设备中的其他功能模块和电路，例如，人眼保护模块、风扇和WIFI模块等供电，保障投影设备的各个部分正常工作。
其中，多媒体处理电路20也可以称为现场可编程逻辑门阵列(field programmable gate array，FPGA)电路。
继续参考图1所示，多媒体处理电路20用于接收TV板发送的视频信号，例如，多媒体处理电路20能够通过各类通信接口，例如，通用串行总线(universal serial bus，USB)接口，接收TV板传输的视频信号。
其中，TV板上可以设置有系统级芯片(system on chip，SoC)，能够将不同数据格式的数据，解码为归一化格式，并通过连接器(connector)，将归一化格式的数据(称为视频信号)，传输至多媒体处理电路20。
多媒体处理电路20接收到视频信号以后，可以对该视频信号进行一些处理，例如，运动估计和运动补偿(motion estimate and motion compensation，MEMC)倍频处理、图像的校正处理、图像的亮度处理、图像的清晰度处理，以及图像的颜色处理等。
继续参考图1所示，该多媒体处理电路20与显示控制电路30连接，以将处理后的视频信号，传输至显示控制电路30。
需要指出的是，多媒体处理电路20通常作为增强功能电路而存在，在一些低成本方案中，也可以不设置该电路部分，而是由显示控制电路30来接收TV板输出的视频信号。
其中，显示控制电路30接收到视频信号以后，能够对视频信号进行解码和格式转换处理，并对该视频信号进行进一步处理(例如几何校正处理)，并且还能基于处理后的视频信号，生成调光信号。
继续参考图1所示，显示控制电路30与光驱动电路40连接，那么，显示控制电路30能够向光驱动电路40，传输调光信号。
其中，该调光信号可以包括模拟调光(analog dimming，Adim)信号和脉冲宽度调制(pulse width modulation，Pwm)信号。
其中，Pwm信号用于，控制传输至激光光源50的驱动电流的有和无，该调光信号中的Adim信号用于控制该驱动电流的电流值的大小。
其中，光驱动电路40也可以称为激光驱动电路，具体为DC-DC转换电路，具体可以升压电路，也可以为降压电路。
光驱动电路40用于接收调光信号，以及接收电源电路10的供电输入电压，并基于调光信号，将输入的供电输入电压，转换为供电输出电压，而向激光光源50输出驱动电流。
其中，激光光源50在驱动电流的驱动下发光，并将光传输至光机组件60中。
该激光光源50可以包括至少一个激光器51，该至少一个激光器51发出的光束的颜色可以相同，也可以不同。
继续参考图1所示，每个激光器51均可以包括多个串联的发光二极管(light-emitting diode，LED)511。
激光光源50可以包括单色激光器，也可以包括多色激光器，如包括红光激光器和蓝光激光器的双色激光器，或者如图1所示，包括红光激光器、蓝光激光器和绿光激光器三色激光器。
其中，光驱动电路40的数量和激光器51的数量相同，且一一对应。
继续参考图1，激光光源50包括红光激光器、蓝光激光器和绿光激光器三色激光器。那么，该投影设备包括红光驱动电路40_R、绿光驱动电路40_G以及蓝光驱动电路40_B。三个激光器51中的每个激光器51与其对应的一个光驱动电路40连接。
其中，该三个颜色的激光器51在驱动电流的驱动下，能够分别发出红光、绿光和蓝光。基于光学中颜色的合成原理可知，该三个颜色的光进行合光和匀光处理后，能够得到白色光。
继续参考图1所示，激光光源50发出的光束，传输至光机组件60中。
其中，光机组件60中集成有数字微镜器件(digital micromirror devices，DMD)以及DMD驱动电路。其中，DMD是光机组件60的核心光调制器件。而DMD驱动电路用于基于视频信号，驱动DMD工作。这样，该DMD用于在DMD驱动电路的控制下，对激光光源50发射出的光束进行调制，以得到待投影显示的图像。
例如，DMD接收图像信号对应的驱动控制信号，将其表面成千上万个微小反射镜，进行对应驱动信号的正角度或者负角度的翻转，将照射其表面的光束形成待投影显示的图像，并反射进入投影镜头70中。
继续参考图1所示，光机组件60将待投影显示的图像，传输至投影镜头70，该投影镜头70能够对该待投影显示的图像进行放大处理，并将该待投影显示的图像以光束的方式投影至目标物。其中，该目标物可以是投影屏幕或者墙面等。
其中，投影镜头70可以为超短焦投影镜头，超短焦投影镜头用于将影像光束，投射至投影屏幕上，从而实现投影图像显示。本实施例示例的激光投影设备可以为超短焦激光投影设备。
需要指出的是，电源电路10和光驱动电路40可以集成布置。例如，电源电路10和光驱动电路40集成在一个单板上。
或者，电源电路10和光驱动电路40也可以分立布置。例如，电源电路10布置在一个单板上，可以记为电源板，光驱动电路40布置在另一个单板上，可以记为光驱动板。
需要指出的是，多媒体处理电路20、显示控制电路30和光机组件60可以布置在一个单板上，例如，该单板记为显示板。
需要指出的是，该多媒体处理电路20也可以包括芯片级系统(system on chip，SoC)，该芯片级系统可以包括数字光处理器(digital light processing，DLP)，还可以包括驱动器。
在DLP控制架构中，激光光源50需要配合DLP及光机组件60的DMD的工作时序。具体地，DLP输出图像使能信号，也可称为基色光使能信号，通常表示为X_EN，X为不同的基色光的缩写，以及同时还输出调光信号。伴随着DMD时序性，对不同基色图像分量进行的调制的过程，激光光源需要同步的输出对应颜色的基色光光束。也就是，DLP输出基色光使能信号，以通知激光光源使某种颜色的激光器点亮，以及，输出调光信号以通知激光光源中的该颜色的激光器以什么样的亮度进行点亮。
以上是为便于更好理解投影设备，而关于投影设备的简要介绍，下面将介绍目前的投影 设备存在的一些问题。
因光驱动电路40的工作频率较高，工作电流较大，且该光驱动电路的工作状态会在打开与关闭之间进行高频周期性切换。该种工作状态的切换所产生的变化电场会产生变化磁场，该变化磁场也会进一步产生变化电场。该变化电场和变化磁场会产生能够向外辐射的电磁波，该电磁波也可以称为电磁骚扰。
其中，投影设备辐射出的电磁波应低于一定的限值，否则该电磁波易对该投影设备内部器件的工作状态，以及该投影设备周围的其它电子设备的工作状态造成影响，进而损害其内部器件和其它电子设备的性能。
目前的投影设备，存在较强的电磁骚扰，理由如下。
图2是相关技术中投影设备的局部结构示意图，参考图2，电源电路和多个光驱动电路可以集成设置在投影设备的电源板上。
如图2所示，该多个激光器51的阳极(即正极)，以及该多个光驱动电路均与电源电路连接，每个激光器的阴极(即负极端)，与其对应的一个光驱动电路连接，每个光驱动电路还与接地端连接。
那么，每个光驱动电路在驱动激光器发光的过程中，流经激光器的驱动电流的流向可以为：电源电路的正极-激光器-光驱动电路-接地端。其中，该接地端可以为电源板的公共接地端。由此，该驱动电流的传输线路可以构成一个回路(即驱动电流环路，本文中所提及的电流环路，在无特殊说明的情况下，均为驱动电流的电流环路)。
其中，这种多个激光器的阳极，均直接与电源电路连接，阴极分别与一个光驱动电路连接的连接方式，称为共阳极驱动。
需要指出的是，共阳极驱动一般与激光光源的封装方式相关，例如，共阳极类型的激光光源封装方式为，多个激光器封装在一起，且各个激光器的正负极相互独立，那么，封装后的激光光源包括多个阳极管脚和多个阴极管脚。这种封装方式的激光光源，在与光驱动电路连接时，一般将多个阳极管脚接在一起，再连接到电源电路，这种接线方式称为共阳极驱动。
这种共阳极驱动激光器发光的方式，往往存在较强的电磁骚扰，原因如下。
光驱动电路中的晶体管开关，在高频通断切换中，会引起驱动电流的高频变化，而当驱动电流发生变化时，易引起该驱动电流的传输线路周围的磁场和电场发生变化，该磁场和电场的变化会产生电磁波。该电磁波也可以称为电磁干扰(或噪声)。当该驱动电流的变化速率越快时，该噪声的带宽也越宽。当该驱动电流的信号值的变化平均值越大时，该噪声的幅度越大。
其中，驱动电流在传输过程中，其传输线路周围产生的电磁辐射骚扰电场的电场强度E可以满足：
其中，f为该驱动电流的频率，A为该驱动电流的电流环路面积，与驱动电流的传输线路的长度呈正相关，该电流环路面积，其单位可以为平方厘米(cm2)，I为该驱动电流的电流值(即驱动电流的强度)，该驱动电流的单位可以为毫安(mA)。r为用于测试该电场强度E的测试天线，与该驱动电流的传输线路的距离。可选地，r的取值可以为3米。
参考上述公式(1)可知，该电场强度E与该驱动电流的电流环路面积A，驱动电流的电流强度I以及驱动电流的频率f均正相关。
而为确保该投影设备的投影功能，该驱动电流的频率f和驱动电流的电流强度I均为固定值。
因此，驱动电流的电流环路面积A，为影响该电流强度E的主要因素，因驱动电流的电流环路面积，与驱动电流的传输线路的长度呈正相关，那么，驱动电流的传输线路的长度，为影响该电流强度E的主要因素。
因而，参考图3可知，在采用共阳极驱动的投影设备中，驱动电流由电源板，流向激光器后，还需流回电源板，以与光驱动电路连接，图3中虚线箭头表示驱动电流的传输方向，对应的电流环路面积记为S1。其中，电源板和激光器位于投影设备的不同位置，两者之间具有一定的距离。所以可见，驱动电流所在线路包括从电源板流向激光器，以及，从激光器回至电源板，驱动电流的传输线路比较长。那么，该驱动电流的电流环路面积A也较大。
那么，当该投影设备产生的电磁波超过一定的限值时，会对该投影设备内部的器件的工作状态和性能造成影响。
例如，该电磁波会干扰该投影设备中，用于防护人眼接近投影镜头而设计的，红外传感器的工作状态和性能，还会干扰该投影设备中，用于识别用户语音的远场语音电路的工作状态和性能，以及也会干扰该投影设备中，音频输出电流的工作状态和性能。并且，该投影设备辐射出的电磁波，还会对该投影设备周围的其它电子设备的工作状态造成影响，进而损害其它电子设备的性能。
上述是目前的投影设备存在的一个问题，除此之外，投影设备还存在其他问题，参考如下所述。
如上述所述，光驱动电路40为DC-DC转换电路，具体可以升压电路，也可以为降压电路。
相关技术中，为提高电路的统一性，通常设置不同激光器51对应的光驱动电路40的电路类型相同，例如，都为升压电路，或都为降压电路。图4为投影设备的电源电路10、光驱动电路40和激光光源50之间的连接示意图，如图4所示，还是以投影设备包括三色激光器为例，每个激光器51对应的光驱动电路40，接收电源电路10输出的供电输入电压Vin，并将供电输入电压Vin，转换为对应的供电输出电压Vout，通过输出端向对应的激光器51输出。
继续参考图4所示，激光器51的阳极与光驱动电路40的输出端连接，激光器51的阴极接地，那么，激光器51阳极的电位为Vout，阴极的电位为0，所以，激光器两端的供电电压Vd为供电输出电压Vout。
那么，投影设备工作时，便可以通过调节供电输出电压Vout的大小，来调节激光器两端的电压Vd，进而调节激光器的亮度，其中，激光器发光时，其两端的电压可以记为额定驱动电压，记为V′d，那么，当激光器两端的电压Vd为V′d时，激光器便能够发光。
因激光器两端的供电电压Vd等于Vout，所以，在升压电路中，光驱动电路40需要将供电输入电压Vin升高至V′d，升高量为V′d-Vin，因不能升高负值，所以，Vin小于等于V′d。
在降压电路中，光驱动电路40需要将供电输入电压Vin降低至V′d，降低量为Vin-V′d，因不能降低负值，所以，Vin大于等于V′d。
可见，电源电路10输出的供电输入电压Vin的大小是有限制的，需要满足在升压电路中，Vin≤V′d，在降压电路中，Vin≥V′d。
例如，实际应用中不同激光器的亮度不同，且会相差较大，这样不同激光器的额定驱动电压V′d也会相差较大。那么，在光驱动电路为升压电路的应用中，需要以最低亮度的激光器额定驱动电压为基准，来设定供电输入电压Vin，而在光驱动电路为降压电路的应用中，需要以最高亮度的激光器的额定驱动电压为基准设定供电输入电压Vin。
例如，红光激光器、蓝光激光器和绿光激光器对应的额定驱动电压，分别为8V、15V和18V，在光驱动电路为升压电路的应用中，红光驱动电路需要将供电输入电压Vin升高至8V，蓝光驱动电路需要将电输入电压Vin升高至15V，绿光驱动路需要将供电输入电压Vin升高至18V。
因在光驱动电路为升压电路类型中，供电输入电压Vin，需要小于或等于所有的激光器的 额定驱动电压V′d。所以，在设定供电输入电压Vin时，需要以8V的电压为基准，可以设定供电输入电压Vin小于等于8V，如供电输入电压Vin为6V，那么，三个光驱动电路将6V的供电输入电压Vin，分别转换为8V、15V和18V的供电输出电压Vout。
因所选供电输入电压Vin比较低，电源电路的输出功率一定，那么，电源电路将会向三个光驱动电路中，输入比较大的电流，这样与所选Vin相差较大的额定驱动电压对应的激光器，所连的光驱动电路中的部分元件，则会因为承受较大的电流而损坏。例如，额定驱动电压为18V激光器，所连的光驱动电路中的一些元件，会因为承受较大的电流而损坏。
而在光驱动电路为降压电路的应用中，红光驱动电路需要将供电输入电压Vin降低至8V，蓝光驱动电路需要将电输入电压Vin降低至15V，绿光驱动路需要将电输入电压Vin降低至18V。
因光驱动电路为降压电路类型中，供电输入电压Vin，需要大于或等于所有的激光器的额定驱动电压V′d。所以，在设定供电输入电压Vin时，设定供电输入电压Vin时，需要以18V的电压为基准，可以设定供电输入电压Vin大于等于18V，如供电输入电压Vin为21V，那么，三个光驱动电路将21V的供电输入电压Vin，分别转换为8V、15V和18V的供电输出电压Vout。
这样与所选Vin相差较大的额定驱动电压对应的激光器，所连的光驱动电路中的部分元件，则会因为承受较大的电压而损坏。例如，额定驱动电压为8V的激光器，所连的光驱动电路中的部分元件，则会因为承受较大的电压而损坏。
可见，光驱动电路无论是升压电路，还是降压电路，相关技术中都会因为所选的Vin，与其中一些激光器两端的额定驱动电压差值较大，而导致这些激光器所连的光驱动电路中的部分元件的电流或电压较高，使得这些光驱动电路的使用寿命较低。
此外，相关技术中，一旦光驱动电路发生短路等故障，则电源电路提供的供电输入电压Vin加载在短路光驱动电路所连的激光器上，使得该激光器承受较大的电压，而发生损坏。
基于上述问题，本实施例提供了一种投影设备，该投影设备能够解决上述问题，下面将介绍该投影设备的技术特征。
参考图4所示，该投影设备可以包括电源电路10、显示控制电路30、激光光源50和至少一个光驱动电路40，其中，激光光源50包括至少一个激光器51，激光器51和光驱动电路40一一对应，一个激光器51由一个光驱动电路40来驱动发光。
其中，关于电源电路10和显示控制电路30的有关介绍，参考上述所述，此处不再赘述。
其中，激光器51的数量可以是一个，也可以是多个，多个激光器的方案中，可以以包括如图1所示的三色激光器进行示例说明。
如图4所示，该电源电路10的输出端，分别与显示控制电路30和至少一个光驱动电路40的第一端1(即输入端)连接，该电源电路10用于向显示控制电路30供电，以使显示控制电路30收发信号(如视频信号和调光信号灯)，以及电源电路10用于向至少一个光驱动电路40供电，以向至少一个光驱动电路40提供驱动电压。
其中，本文中所提及的驱动电压，在无特殊说明的情况下，均为输入光驱动电路的驱动电压，即Vin，光驱动电路40向外输出的电压，在无特殊说明的情况下，均为供电输出电压，即Vout。
继续参考图4所示，显示控制电路30分别与至少一个光驱动电路40的第二端2连接，以使显示控制电路30向每个光驱动电路40提供调光信号。
如上述所述，该调光信号可以包括控制驱动电流大小的Adim信号，以及控制驱动电流有无的Pwm信号。
每个光驱动电路40的第三端3(即输出端)与其对应的一个激光器51的第一端1(即阳极端)连接，每个光驱动电路40用于在驱动电压的驱动下，基于调光信号，向其所连接的激光器提供驱动电流。
其中，本文所述的驱动电流，在无特殊说明的情况下，均为输入激光器51的电流。
如图5所示，至少一个激光器51的第二端2(即阴极端)互连，每个激光器51用于在 驱动电流的驱动下发光。
在本公开实施例中，至少一个光驱动电路40中的每个光驱动电路40，能够基于接收到的调光信号中的Adim信号，调节其输出的驱动电流的电流值的大小，并能够基于该调光信号中的Pwm信号，控制其输出的驱动电流的有无。例如，在1秒内，该Pwm信号的占空比是50％，则该光驱动电路40在1秒内输出驱动电流的时长为0.5秒，剩余的0.5秒内未输出驱动电流。
其中，该驱动电流的电流值可以与Adim信号的信号值正相关。也即是，当该Adim信号的信号值越大时，该驱动电流的电流值越大。
在一种示例中，显示控制电路30能够向至少一个光驱动电路40同时输出调光信号(包括Adim信号和Pwm信号)。那么，显示控制电路30可以包括至少一组组用于输出调光信号的端口，每组端口包括两个端口，分别用来输出Adim信号和Pwm信号，且每组端口中的两个端口均与一个光驱动电路40连接。
例如，参考图5所示，该显示控制电路30能够向红光驱动电路40_R，输出Adim_R信号和Pwm_R信号，向绿光驱动电路40_G，输出Adim_G信号和Pwm_G信号，以及向蓝光驱动电路40_B，输出Adim_B信号和Pwm_B信号。
需要指出的是，显示控制电路30也可以不包括成组的端口，而是包括多个端口，每个端口中具有用于传输Adim信号的管脚，以及用于传输Pwm信号的管脚，也即是，将用于传输Adim信号的管脚和用于传输Pwm信号的管脚，集成在一个端口中。
如上述所述，至少一个激光器51的阴极互连，至少一个激光器51的阴极均互连，能够减少驱动电流的传输线路的长度，也能实现光驱动电路40的供电输入电压的选择不受限制。
其中，关于如何减少驱动电流的传输线路的长度，以及如何实现光驱动电路40的供电输入电压的选择不受限制，下文将会详细介绍。
如图5所示，这种多个激光器51的阳极分别与一个光驱动电路40连接，而阴极互连的连接方式，可以称为共阴极驱动。
需要指出的是，共阴极驱动一般与激光光源的封装方式相关，例如，共阴极类型的激光光源封装方式为，多个激光器封装在一起，且各个激光器的阳极相互独立，而各个激光器的阴极连接在一起，共用一个管脚，那么，封装后的激光光源包括多个阳极管脚和一个阴极管脚。这种封装方式的激光光源，在与光驱动电路连接时，可以将多个阳极管脚分别与一个光驱动电路连接，而阴极管脚可以就近接地，也可以接在电源电路10的输出端，这种接线方式称为共阴极驱动。
其中，共阴极驱动能够缩短驱动电流的传输线路的原因如下。
共阴极驱动之所以能够缩短驱动电流的传输线路，是因为，激光器51的阳极已经与光驱动电路40连接，那么，激光器51的阴极可以就近接地而形成驱动电流所在的闭合回路，进而，能够缩短驱动电流的传输线路。
例如，如图6所示，为电源电路10和光驱动电路40集成在一个单板上，该单板记为电源板的示意图，驱动电流的流向为：电源电路10和光驱动电路40所在的电源板-激光器51-接地端GND。图6中虚线箭头表示驱动电流的传输线路，对应的电流环路面积记为S2。
又例如，如图7所示，为电源电路10和光驱动电路40分离设置的示意图，光驱动电路40可以布置在靠近激光器51的位置处，那么，驱动电流的流向为：光驱动电路40-激光器51-接地端GND。图6中虚线箭头表示驱动电流的传输线路，对应的电流环路面积记为S3。
根据图3、图6和图7可知，电流环路面积S1大于电流环路面积S2电流环路面积S3。
因此，相比于如图3所示的共阳极驱动方式，该共阴极驱动方式中的驱动电流在流经激光器51后，会直接流入接地端GND，而不会流入光驱动电路40。由此，能够有效降低该驱动电流的电流环路面积。
基于上述公式(1)可知，当驱动电流的电流环路面积减小时，该驱动电流的传输线路周 围，产生的电磁辐射骚扰电场的电场强度也会降低。相应的，该投影设备辐射出的电磁波，对该投影设备内部的器件，以及对该投影设备周围的其它电子设备的性能以及工作状态的影响也降低。
如上述所述，该投影设备中的电源电路10和至少一个光驱动电路40可以集成在一个单板上，例如，可以设置在电源板上。
或者，该电源电路10与多个光驱动电路40可以分立设置。例如，该电源电路10设置在一个单板上，该单板可以记为电源板，该至少一个光驱动电路40未设置在电源板上，而是设置在另一个单板上，该单板可以记为光驱动板。
如图6和图7所示，如果电源电路10和至少一个光驱动电路40集成设置，则如图6所示，驱动电流所在的传输线路，包括驱动电路40所在电源板与激光器51之间的传输线，以及激光器51与接地端之间的传输线。
而如果电源电路10与至少一个光驱动电路40分立设置，则如图7所示，驱动电流所在的传输线路，包括驱动电路40所在光驱动板与激光器51之间的传输线，以及激光器51与接地端之间的传输线。而如图7所示，光驱动电路40所在光驱动板，在位置上，是位于电源板与激光器51之间的，所以，与图6相比，进一步缩短了驱动电流的传输线路。
需要指出的是，只有高频变化的驱动电流(向激光器51输入的电流)，才能产生较强的电磁波，所以，如图7所示，电源板与光驱动电路40之间的传输线，用于向光驱动电路40提供供电电压，传输的电流较为稳定，产生的电磁波很微弱，不会对器件造成影响。
因此，电源电路10和至少一个光驱动电路40分立设置时，驱动电流产生的电磁骚扰，小于电源电路10和至少一个光驱动电路40集成设置时，驱动电流产生的电磁骚扰。
可见，在共阴极驱动方式中，由于驱动电流流经激光器后，可以直接流入接地端，无需回流至光驱动电路，因此无论电源电路10和至少一个光驱动电路是集成设置，还是分立设置，驱动电流在传输过程中所产生电磁骚扰也往往较小。
继续参考图6和图7所示，电源电路10所在的电源板，与激光光源50均可以通过螺钉和螺柱，固定在投影设备的机内金属支架上，该机内金属支架可以与接地端连接，其中，该接地端可以为电源板的公共接地端。
其中，共阴极驱动能实现电源电路10向光驱动电路40提供的供电输入电压，不受限制的原因如下。
如图8所示，激光器51的阴极可以不接地，而是接在电源电路10和光驱动电路之间的线路上。
这样，激光器51阴极的电位，即为电源电路10提供的供电输入电压Vin。那么，加载在激光器51阳极和阴极两端的电压Vd为Vout和Vin之差，即Vd＝Vout-Vin，进而，Vout＝Vd+Vin。
因当光驱动电路40停止向激光器输出驱动电流时，Vd为0，当光驱动电路40向激光器输出驱动电流时，Vd为V′d，所以，Vout≥Vin。
需要指出的是，如果以Vout和Vin之间的关系，判定光驱动电路为升压电路，还是降压电路，则因Vout恒大于等于Vin，那么，光驱动电路为升压电路。
由此可见，为了使激光器51两端的电压Vd，为促使其正常发光的额定驱动电压V′d，则光驱动电路只需要将供电输入电压Vin，升高V′d即可。所以，光驱动电路40将供电输入电压Vin升高V′d，而不是升高至V′d，因此，无论供电输入电压Vin选取何值，光驱动电路都可以将输出电压抬升V′d，所以，在选取供电输入电压Vin时，无需以最小的额定驱动电压为基准来选取。
因此，共阴极驱动方式中，激光器51的负极接在电源电路10和光驱动电路40的连接线路上，便能实现电源电路10的供电输入电压的选择不受，各个激光器的额定驱动电压(正常发光需要的电压)所限制。
既然电源电路10的供电输入电压的选择，不受各个激光器的额定驱动电压所限制，那么， 在选择Vin时，可以既不以最小额定驱动电压为基准选择，也不以最大的额定驱动电压为基准进行选择。那么，就不存在所选的Vin与最大的额定驱动电压相差较大，或者，与最小的额定驱动电压相差较大的问题。
例如，可以在各个光驱动电路中的元器件所能承受的电压范围内，尽可能选择大电压，这是因为，电压越大，功率一定的情况下，那么输入电流越小，输入电流越小，则传输中产生的线路损耗越小。
例如，还是以上述所述的红光激光器、蓝光激光器和绿光激光器对应的额定驱动电压分别为8V、15V和18V为例，那么，可以设定电源电路10的供电输入电压Vin为12V，因而与激光器51的阴极接地相比，如图8所示的连接方式，能够降低供电输入电压Vin，与各个激光器51的额定驱动电压之间的差值，进而能够降低，输入至各个光驱动电路中的部分元件的电流或电压，以避免因输入光驱动电路中的电流或电压较大，而出现元件损坏的情况。
而且，如图8所示，当光驱动电路40发生短路时，则激光器51两端的电压相等，压差为零，那么，激光器51不会承受较大的供电输入电压，能够在光驱动电路40发生短路时，避免激光器51损坏。
以上是关于电源电路10、显示控制电路30、光驱动电路40和激光光源50之间的连接关系介绍，以及关于该投影设备所具备的效果介绍，下面将介绍光驱动电路40所包括的具体电路。
需要指出的是，下面所介绍的光驱动电路40是至少一个光驱动电路40中的任意一个，因为是介绍光驱动电路40，所以，涉及到的附图均示意了一个光驱动电路40，以及与该光驱动电路40连接的激光器51。
需要指出的是，附图中激光器51的阴极可以接地，以实现降低电磁干扰的效果，也可以接在电源电路10与光驱动电路40的线路上，以实现电源电路10提供的供电输入电压，不受激光器51的额定驱动电压限制的效果。
图9是本公开实施例提供的一种光驱动电路示意图，参考图9所示，该光驱动电路40可以包括控制电路410、开关电路420和充放电电路430。
其中，开关电路420具有控制端、第一端和第二端，如图9所示，控制电路410分别与电源电路10的输出端，以及开关电路420的控制端连接。这样，控制电路410能够基于接收到的调光信号，生成开关驱动信号(记为Drv信号)，并向开关电路420的控制端输入Drv信号，以控制开关电路420的第一端和第二端的接通时长和断开时长。
其中，Drv信号也可以称为开关信号SW，Drv信号可以为电平信号，包括第一电平和第二电平，第一电平为高电平，第二电平为低电平。
作为一种示例，当Drv信号为第一电平时，开关电路420的第一端和第二端接通，当Drv信号为第二电平时，开关电路420的第一端和第二端断开。可见，开关电路420的接通和断开，受控于Drv信号。
在一种示例中，开关电路420的接通和断开，是为了实现充放电电路430的充电和放电，也即是，充放电电路430的充电和放电，受控于开关电路420的接通和断开。
需要指出的是，开关电路420导通时，充放电电路430是处于充电状态，还是处于放电状态，以及开关电路420断开时，开关电路420导通时，充放电电路430是处于充电状态，还是处于放电状态，与光驱动电路40的具体电路相关。
继续参考图9所示，充放电电路430与对应的激光器51连接，用于向激光器51提供驱动电流，而使激光器51在驱动电流作用下发光。
例如，该充放电电路430具体用于在调光信号中的Pwm信号为高电平时，在开关电路420的不断接通和断开切换下，不断进行充电和放电，以向所连激光器51提供驱动电流，以及在调光信号中的Pwm信号为低电平时，停止向光源提供驱动电流。
需要指出的是，开关电路420的接通时长和断开时长，和Drv信号的占空比相关，占空 比也即是在一个脉冲循环内，通电时间相对于总时间所占的比例。而Drv信号的占空比，与调光信号中的Adim信号呈正比，例如，Adim信号越大，则Drv信号的占空比越大(可以参考图15所示)。而参考如下公式，Drv信号的占空比越大，则充放电电路430的供电输出电压Vout越大，那么，充放电电路430向激光器51提供的驱动电流也越大。
作为一种示例，当该控制电路410输出的Drv信号为第一电平时，开关电路420的第一端和第二端导通。而此时，如果调光信号中的Pwm信号为高电平，则该电源电路10提供的供电输入电压，能够为充放电电路430充电，充放电电路430也能向激光器51输出驱动电流。
当控制电路410输出的Drv信号为第二电平时，该开关电路420的第一端1和第二端2关断。而此时，如果调光信号中的Pwm信号依然为高电平，则充放电电路430处于放电状态，所以，充放电电路430依然能够输出驱动电流，依然能够驱动激光器51发光。
而当调光信号中的Pwm信号为低电平时，控制电路410可以向开关电路420输入Drv信号，也可以不向开关电路420输入Drv信号。在控制电路410向开关电路420输入Drv信号的情况下，无论Drv信号是第一电平(高电平)，还是第二电平(低电平)，充放电电路430均不会向激光器51提供驱动电流，那么此时，激光器51停止发光。也即是，当调光信号中的Pwm信号为低电平时，无论开关电路420的第一端和第二端是处于导通状态，还是处于断开状态，充放电电路430均不会向激光器51提供驱动电流，那么此时，激光器51停止发光。
在一种示例中，通过在光源驱动电路40的充放电电路430，能够实现向激光器51提供稳定的驱动电流。由此，可以使得驱动电流的上升时间和下降时间较小，例如使得驱动电流的上升时间和下降时间均小于20微秒(us)。
并且，通过设置该充放电电路430，还可以使得流入至激光器的纹波电流较小，进而使得流经激光器的驱动电流的精度较高。其中，该纹波电流即为驱动电流波形中的高次谐波成分。
其中，该驱动电流传输过程中产生的电磁骚扰还与该纹波电流大小正相关。因此，通过该充放电电路430来降低纹波电流的大小，能够进一步降低该驱动电流传输过程中产生的电磁骚扰。
关于电源电路10、开关电路420和充放电电路430之间的连接关系，可以具有多种布局方式，下面将介绍其中的两种。
(1)一种电源电路10、开关电路420和充放电电路430之间的连接关系。
如图10所示，开关电路420的第一端与电源电路10连接，开关电路420的第二端与充放电电路430连接。
例如，如图10所示，该控制电路410的第一端1和开关电路420的第一端1，均与电源电路10的输出端连接。
作为一种示例，控制电路410的第一端1和开关电路420的第一端1，均与光驱动电路40的电源接口(即光驱动电路40的第一端1，也是光驱动电路40的供电输入端)连接，而光驱动电路40的电源接口与电源电路10的电源接头(即电源电路10的输出端)连接。
继续参考图10所示，控制电路410的第二端，作为光驱动电路40的第二端，与显示控制电路30连接。或者，控制电路410的第二端和光驱动电路40的第二端相互独立，两者之间通过传输线连接，进而，控制电路410的第二端与光驱动电路40的第二端连接，光驱动电路40的第二端与显示控制电路30连接。
继续参考图10所示，控制电路410的第三端3与开关电路420的控制端C连接，以向开关电路420传输Drv信号。
(2)另一种电源电路10、开关电路420和充放电电路430之间的连接关系。
如图11所示，开关电路420的第一端与充放电电路430连接，开关电路420的第二端接地，充放电电路430与电源电路10连接。
下面将分别介绍图10所示的光驱动电路40的具体电路，以及图11所示的光驱动电路40的具体电路。
(一)图10所示的光驱动电路40的具体电路如下。
(1)光驱动电路40的开关电路420的特征。
如图12所示，该开关电路420可以包括开关晶体管Q1。
该开关晶体管Q1的栅极(Gate，G)可以作为开关电路420的控制端C，与控制电路410的第三端3连接，开关晶体管Q1的第一极可以作为开关电路420的第一端，与电源电路10连接，开关晶体管Q1的第二极可以作为开关电路420的第二端，与充放电电路430的第一端连接。
或者，开关晶体管Q1的栅极G与开关电路420的控制端C连接，开关晶体管Q1的第一极与开关电路420的第一端连接，开关晶体管Q1的第二极与开关电路420的第二端连接。这样，控制电路410向开关电路420传输的Drv信号，也能够输入至开关晶体管Q1中，而促使开关晶体管Q1的第一极和第二极接通或断开。
在一种示例中，该开关晶体管Q1可以为P型金属氧化物半导体(metal oxide semiconductor，MOS)管。该开关晶体管Q1的第一极可以为源极(Source，S)，该开关晶体管Q1的第二极可以为漏极(Drain，D)。
可以理解的是，参考图15(c1)和(d1)，当开关晶体管Q1的栅极G的电平为第一电平(高电平)时，电源电路10加载至开关晶体管Q1的源极S处的电压，高于栅极G处的电压。由此，该开关晶体管Q1的栅极G和源极S之间能形成负向电压，且该负向电压的绝对值大于该开关晶体管Q1的阈值电压，从而使得该开关晶体管Q1的源极S和漏极D导通。
参考图15(c1)和(d1)，当开关晶体管Q1的栅极G的电平为第二电平(低电平)时，电源电路10加载至开关晶体管Q1的源极S处的电压，低于该栅极G处电压。该开关晶体管Q1的栅极G和源极S之间的电压的绝对值小于该开关晶体管Q1的阈值电压。由此，使得该开关晶体管Q1的源极S和漏极D断开，该开关晶体管Q1处于截止状态。
继续参考图12，该开关电路420还可以包括：第一二极管D1、第一电阻R1和第二电阻R2。
如图12所示，第一电阻R1和第二电阻R2并联在控制电路410和开关电路420的控制端之间，具体的，可以并联在控制电路410和晶体管开关Q1的栅极G之间。而第一二极管D1与第一电阻R1或者第二电阻R2串联，且第一二极管D1的阴极与控制电路410连接。为便于介绍，如图12所示，可以以第一二极管D1与第一电阻R1串联进行示例说明。
例如，如图12所示，第一二极管D1的阴极端，作为开关电路420的控制端C，分别与控制电路410的第三端3和第二电阻R2的一端连接，第一二极管D1的阳极与第一电阻R1的一端连接。该第一电阻R1的另一端和第二电阻R2的另一端均与开关晶体管Q1的栅极G连接。
或者，第一二极管D1的阴极与开关电路420的控制端C连接，阳极与第一电阻R1的一端串联，第一电阻R1的另一端与开关晶体管Q1的栅极G连接，而第二电阻R2的一端与开关电路420的控制端C连接，另一端与开关晶体管Q1的栅极G连接，这样也能实现第一电阻R1和第二电阻R2并联在控制电路410和开关晶体管Q1的栅极G之间，第一二极管D1与第一电阻R1串联。
关于第一电阻R1、第二电阻R2和第一二极管D1接在控制电路410和开关晶体管Q1的栅极G之间，所实现的效果如下。
如图12所示，第一电阻R1、第二电阻R2和第一二极管D1所构成的电路，连接在控制电路410和开关晶体管Q1的栅极G之间，能够使开关晶体管Q1的第一极和第二极缓慢导通，而快速断开。
这是因为，电流由控制电路410向开关晶体管Q1传输中，线路电阻比较大，对线路的限 流作用明显，使得开关晶体管Q1缓慢接通。而电流由开关晶体管Q1向控制电路410传输中，线路电阻比较小，对线路的限流作用减弱，使得开关晶体管Q1快速断开。
其中，开关晶体管Q1的第一极和第二极缓慢导通，降低驱动电流的变化速率，从而降低所产生的电磁场的强度，而开关晶体管Q1的第一极和第二极快速断开，能够减少电路损耗，这是因为，开关晶体管Q1断开中，电压下降，功率不变，则电流上升，大电流产生的损耗大，快速断开，能够将电流快速切断，从而减少电路损耗。
对驱动电流的影响可以参考图15中的(d1)所示，驱动电流的上升斜率，小于下降斜率，其中，每个下降开始时间点，对应开关晶体管Q1的导通开始时间点。
继续参考图12所示，开关电路420还可以包括第二电容C2，第二电容C2并联在开关晶体管Q1的第一极和第二极之间，例如，并联在S极和D极之间。例如，第二电容C2的一个电容板与开关晶体管Q1的第一极(如S极)连接，第一电容C1的另一个电容板与开关晶体管Q1的第二极(如D极)连接。
该第一电容C1用于稳定开关晶体管Q1的第一极和第二极之间的电压。
上述是关于开关电路420的特征，下面将介绍充放电电路430的特征。
(2)光驱动电路40的充放电电路430的特征。
参考图12所示，该充放电电路430可以包括电感L和第二二极管D2，电感L的一端和第二二极管D2的阴极，均与开关电路420的第二端2连接，该电感L的另一端与激光器51的第一端1(即阳极)连接，第二二极管D2的阳极与接地端GND连接。
因开关晶体管Q1的第二极与开关电路420的第二端连接，那么，电感L和第二二极管D2的阴极，均与开关晶体管Q1的第二极连接。
(3)光驱动电路40的电流检测电路440的特征。
参考图13所示，光驱动电路40还可以包括：电流检测电路440。其中，电流检测电路440与激光器51串联，且与控制电流410连接，以监测激光器51的驱动电流。
该电流检测电路440用于使控制电路410确定流经激光器51的驱动电流。以使控制电路410根据调光信号，以及电流检测电路440确定的驱动电流，生成开关驱动信号Drv，以控制开关电路420的第一端1与第二端2的导通时长和断开时长。
例如，如图13所示，电流检测电路440连接在电源电路10和开关电路420之间，且电流检测电路440与控制电路410连接。
其中，控制电路410可以获取到电流检测电路440两端的电位，从而确定电流检测电路440两端的电压。
例如，如图13所示，电流检测电路440的第一端1，分别与电源电路10的输出端、控制电路410的电源端Vin，以及控制电路410的第一检测端Isen+连接，该电流检测电路440的第二端2，分别与开关电路420的第一端1和控制电路410的第二检测端Isen-连接。这样，即可实现电流检测电路440与激光器51串联，也能实现其两端分别接在控制电路410上。
其中，该控制电路410的电源端Vin即为该控制电路410的第一端1，用于和电源电路10的输出端连接。
在本公开实施例中，控制电路410能够通过电流检测电路440，对流经激光器51的驱动电流进行采样，得到电流检测信号Isen。例如，控制电路410可以采集到电流检测电路440的第一端和第二端的电位，进而得到加载在电流检测电路440两端的电压，电流检测电路440中的电阻一定的情况下，由电压便可以得到电流，该电流即为驱动电流。
那么，控制电路410可以通过检测到的驱动电流，与额定驱动电流之间的关系，来控制开关电路420第一端1和第二端2的导通时长和断开时长。其中，额定驱动电流，为驱动激光器51正常发光的电流。
例如，电流检测信号Isen为电流值，控制电路410能够将确定的电流检测信号Isen，与额定驱动电流进行比较。其中，该额定驱动电流为激光器发光所需的电流。控制电路410若 确定该电流检测信号Isen低于额定驱动电流，则可以增加其输出至开关电路420的Drv信号的占空比，即增大开关电路420第一端1和第二端2的导通时长，直至该电流检测信号Isen与额定驱动电流相等。由此，能够逐渐增大流经激光器的驱动电流的电流值，进而使得光源能够正常发光。
而控制电路410若确定该电流检测信号Isen高于额定驱动电流，则可以减少其输出至开关电路420的Drv信号的占空比，即降低开关电路420第一端1和第二端2的导通时长，直至该电流检测信号Isen与额定驱动电流相等。
当然，控制电路410也可以通过电流检测电路440两端的电压，与预先设定的电流检测电路440的阈值电压的关系，来控制开关电路420第一端1和第二端2的导通和断开。
例如，电流检测信号Isen为电压值，控制电路410能够将确定的电流检测信号Isen，与预先存储的电压阈值进行比较。其中，该电压阈值可以为流经该电流检测电路440的电流为激光器的额定驱动电流时，该电流检测电路440的第一端1和第二端2两端的电压值。控制电路410若确定该电流检测信号Isen低于电压阈值，则可以增加其输出至开关电路420的Drv信号的占空比，即增大开关电路420第一端1和第二端2的导通时长，直至该电流检测信号Isen与电压阈值相等。由此，能够逐渐增大流经激光器的驱动电流的电流值，进而使得光源能够正常发光。
而控制电路410若确定电流检测信号Isen所对应的电压值高于电压阈值，则可以减小其输出至开关电路420的Drv信号的占空比，即减小开关电路420第一端1和第二端2的导通时长，直至该电流检测信号Isen所对应的电压值与电压阈值相等。
作为一种示例，如图14所示，该电流检测电路440包括检测电阻Rsns，其中，检测电阻Rsns为电阻值较小的灵敏电阻。
其中，该检测电阻Rsns的一端，作为电流检测电路440的第一端1，分别与电源电路10的输出端，控制电路410的电源端Vin，以及控制电路410的第一检测端Isen+连接。该检测电阻Rsns的另一端，作为电流检测电路440的第二端2分别与开关电路420的第一端1和控制电路410的第二检测端Isen-连接。
或者，检测电阻Rsns的一端与电流检测电路440的第一端连接，检测电阻Rsns的另一端与电流检测电路440的第二端连接。这样，也能实现检测电阻Rsns和激光器51串联，以及检测电阻Rsns的两端均与控制电路410连接。
可以理解的是，通过检测检测电阻Rsns的第一端和第二端的电位，并可以得到检测电阻Rsns的电压，进而可以判断该检测电阻Rsns的电压值与电压阈值的大小关系。
也可以理解的是，通过检测检测电阻Rsns的第一端和第二端的电位，再基于检测电阻Rsns的电阻值，通过欧姆定律，便可以得到检测电阻Rsns所在线路的电流，而检测电阻Rsns与激光器51串联，进而可以判断激光器51的驱动电流，与其额定驱动电流之间的大小关系。
需要指出的是，如果控制电路410，根据采集到的驱动电流，与激光器的额定驱动电流之间的关系，生成Drv信号，以控制开关电路420的通断状态，则上述所述的电流检测信号Isen为采集到的驱动电流。而如果控制电路410，根据采集到的检测电阻Rsns两端的电压，与预先设定的电压阈值之间的关系，生成Drv信号，以控制开关电路420的通断状态，则上述所述的电流检测信号Isen可以为电压阈值。
(4)光驱动电路40的稳压电路450的特征。
继续参考图14，每个光驱动电路40还可以包括稳压电路450，其中，稳压电路450的第一端接在电源电路10和光驱动电路40的线路上，第二端接地。
如图14所示，稳压电路450可以包括至少一个电容。该稳压电路450用于稳定电源电路10向光驱动电路40输出的驱动电压。所以，这至少一个电容的正极板，均连接在电源电路10的输出端和光驱动电路的输入端之间的线路上，至少一个电容的负极板均接地。
例如，如图14所示，以包括两个电容进行示例，分别即为第三电容C3和第四电容C4， 第三电容C3和第四电容C4的正极板，均连接在电源电路10的输出端和光驱动电路40的输入端之间的线路上，第三电容C3和第四电容C4的阴极板均接地。
例如，如图14并参考图13所示，第四电容的C4一端和第三电容C3的一端，均作为稳压电路450的第一端1，分别与电源电路10的输出端、控制电路410的电源端，以及开关电路420的第一端1连接。第四电容C4的另一端和第三电容C3的另一端，均作为稳压电路450的第二端2，与接地端GND连接。
或者，第四电容C1的一端和第三电容C3的一端，均与稳压电路450的第一端连接，第四电容C1的另一端和第三电容C3的另一端，均与稳压电路450的第二端连接。这样也能实现第三电容C3和第四电容C4的一端，接在电源电路10和光驱动电路40的线路上，另一端接地。
在本公开实施例中，第四电容的C4和第三电容C3，能够对电源电路10向光驱动电路40，输出的驱动电压进行滤波处理，从而使得该电源电路10输出的驱动电压较为稳定，以确保光驱动电路40能够在一定的驱动电压范围内驱动光源发光。
(5)光驱动电路40的使能信号Fault。
该光驱动电路40中的控制电路410，还可以向电源电路10传输使能信号Fault。该电源电路10可以基于该使能信号Fault，输出驱动电压。其中，当该使能信号Fault为高电平时，该电源电路10向光驱动电路40，输出驱动电压。当该使能信号Fault为低电平时，该电源电路10停止向光驱动电路40，输出驱动电压。
在本公开实施例中，控制电路410可以基于该电流检测信号Isen，确定该光源存在开路或短路故障时，那么，可以控制该使能信号Fault的电平为低电平。由此，电源电路10停止输出驱动电压，从而起到保护光源的作用。
例如，在正常情况下，控制电路410检测到电流检测信号Isen的数值正常，可以判断出光驱动电路无异常，那么，可以控制使能信号Fault的电平为高电平。而控制电路410检测到电流检测信号Isen的数值异常，如比激光器的额定驱动电流大很多，可以判断出光驱动电路可能存在短路，又如Pwm信号为高电平，但是电流检测信号Isen为0，可以判断出光驱动电路可能存在开路，那么，可以控制该使能信号Fault的电平为低电平。
基于上述所述，如图14所示，开关电路420的开关晶体管Q1导通和断开时，驱动电流的电流环路分别如下所述。
参考图14所示，当开关晶体管Q1处于导通状态时，该电感L处于充电状态，并将开关晶体管Q1传输的驱动电流，缓慢传输至激光器51，以驱动激光器51发光。此时，该驱动电流的电流环路为：电源电路10-开关晶体管Q1的源极S-开关晶体管Q1的漏极D-电感L-激光器-接地端GND。
当开关晶体管Q1处于截止状态时，该电感L处于放电状态，电感L、激光器51，以及第二二极管D2能够组成放电回路，继续为激光器51提供驱动电流，以使激光器51继续发光。此时，该驱动电流的电流环路为：接地端GND-第二二极管D2-电感L-光源-接地端GND。
下面基于图14所示的光驱动电路420，阐述驱动电流分别与调光信号(包括Adim和Pwm)和Drv信号之间的关系。
示例的，参见图15，图15中的(a1)和(a2)为显示控制电路30提供的调光信号中Adim信号的信号值(即电压值，单位为V)，随时间变化的示意图。图15中的(b1)和(b2)为显示控制电路30提供的调光信号中Pwm信号的占空比(单位为％)，随时间变化的示意图。图15中的(c1)和(c2)为控制电路410输出的Drv信号的占空比，随时间变化的示意图。图15中的(d1)和(d2)为流经激光器的驱动电流I的电流值，随时间变化的示意图，其中，电流的单位为安培(A)。
参考图15中的(a1)和(d1)可知，某一时段内驱动电流的电流值，与该时段内Adim信号的信号值正相关，所以，如上述所述，Adim信号用于控制该驱动电流的电流值的大小。
参考图15中(b1)和(d1)可知，在t0至t3时段内，Pwm信号的占空比为100％，光驱动电路40会持续向激光器51提供驱动电流，无论开关电路420是处于导通状态，还是处于断开状态。
参考图15中的(b2)和(d2)可知，在t0′至t3′时段内，控制电路410仍会向开关电路420提供开关驱动信号Drv。但由于在t0′至t3′时段内，Pwm信号的占空比为0，因此光驱动电路40停止向光源提供驱动电流，流经光源的驱动的电流值为0，所以，如上述所述，Pwm信号用于控制该驱动电流的有无。
参考图15中的(c1)和(d1)可知，在t0′至t3′时段内，Drv的占空比越大，也即是，开关电路420的导通时长越长，驱动电流越大。
参考图15中的(c1)和(d1)可知，驱动电流的变化频率与开关驱动信号Drv的信号频率相对应。例如，Drv信号的一个变化周期包括高电平和低电平，驱动电流的一个变化周期包括一个上升和一个下降，那么，当Drv信号完成一个变化周期时，驱动电流也完成一个变化周期，所以，驱动电流的变化频率与Drv信号的变化频率一致，而Drv信号用于控制开关晶体管Q1的导通断开。因此，如上述所述，由于开关电路420的高频通断，导致了驱动电流的高频变化。
参考图15中的(d1)可以看出，流经激光器的驱动电流的电流值，在某一时段内呈锯齿形波动。在本公开实施例中，可以将某一时段内的电流值的均值，确定该时段内的驱动电流。其中，该均值可以是该时段内的电流最大值和电流最小值的平均值。例如，如图15中的(d1)所示，t0至t1时段内的驱动电流为I0，t1至t2时段内的驱动电流为I1，t2至t3时段内的驱动电流为I2。
其中，图15中的(d1)所示的驱动电流的波形也可以称为驱动电流纹波。
(二)图11所示的光驱动电路40的具体电路如下。
(1)光驱动电路40的开关电路420的特征。
如图16所示，开关电路420包括开关晶体管Q1，开关晶体管Q1的控制端与控制电路410连接，开关晶体管Q1的第一极接在充放电电路430上，开关晶体管Q1的第二极接地。
关于开关晶体管Q1的特征，可以参考上述所述，此处不再赘述。
在一种示例中，开关电路420也可以包括上述所述的第一二极管D1、第一电阻R1和第二电阻R2。具体可以参见上述所述，此处不再赘述。
在一种示例中，开关电路420也可以包括上述所述的第二电容C2，第二电容C并联在开关电路420的第一端和第二端之间，具体可以并联在开关晶体管Q1的第一极和第二极之间。具体可以参见上述所述，此处不再赘述。
(2)光驱动电路40的充放电电路430的特征。
如图16所示，充放电电路430包括电感L、第二二极管D2和第一电容C1，电感L的一端与电源电路10连接，另一端与第二二极管D2的阳极连接，第二二极管D2的阴极与所在光驱动电路40对应的激光器51的阴极连接。第一电容C1的正极板与光驱动电路40对应的激光器51的阴极连接，第一电容C1的负极板接地。
其中，电感L和第一电容C1均为储能元件。
如上述所述，开关电路420的第一端接在充放电电路430上，例如，如图16所示，开关电路420的第一端，连接在电感L和第二二极管D2之间的线路上。当然，开关电路420的第一端，也可以连接在第二二极管D2的阴极和检测电阻Rsns之间的线路上。
这样，开关晶体管Q1导通时，电源电路10为电感L充电，开关晶体管Q1断开时，电感L放电，向激光器51提供驱动电流。当开关晶体管Q1再次导通时，电源电路10再次为电感L充电，此时，第一电容C1放电，放电回路为即为驱动电流的回路，即第一电容C1-激光器51-电感L-开关晶体管Q1-接地端，第一电容C1向激光器51提供驱动电流。当开关晶体管Q1再次断开时，电感L再次放电，为激光器51提供驱动电流。可见，充放电电路430 通过电感L和第一电容C1的不断充电和放电，为激光器51提供驱动电流。
如上述所述，开关晶体管Q1的通断状态，由Drv信号的占空比(记为D)决定，而如下公式Drv信号的占空比D越大，则驱动电流越大。其中，光驱动电路40的供电输入电压Vin和供电输出电压Vout满足如下关系：
那么，如果激光器51的阴极接在电源电路10和光驱动电路40的连接线路上，则如上述所述，加载在激光器51两端的电压Vd满足关系：Vd＝Vout-Vin，那么，可以得到如下公式。
可见，当Drv信号的占空比大于0.5时，Vd大于Vin，从光驱动电路40的整体效果上看，光驱动电路40相当于升压电路(注意该处的判断标准为Vd＞Vin)。
而当占空比不大于0.5时，Vd不大于Vin，从光驱动电路40的整体效果上看，光驱动电路40相当于降压电路(注意该处的判断标准为Vd≤Vin)。
但光驱动电路40本身仍为Vout≥Vin的升压电路。
例如，以激光投影设备包括双色激光器为例，蓝光激光器的额定驱动电流为3A，对应的额定驱动电压为18V。红光激光器的额定驱动电流为1.5A，对应的额定驱动电压为9V。其中，供电输入电压Vin选择12V。那么，蓝光激光器对应的控制电路410输出，占空比为0.8的Drv信号，对应的充放电电路430，输出30V的供电输出电压Vout，来实现激光器两端的电压上升。红光激光器对应的控制电路410输出，占空比为0.3的Drv信号，对应的充放电电路430，输出21V的供电输出电压Vout，来实现激光器两端的电压下降。而光驱动电路40本身仍为Vout≥Vin的升压电路。
由上述可知，本实施例可以通过控制Drv信号的占空比，来控制光驱动电路输出的电压，进而控制激光器两端的电压Vd。而且，并在占空比大于0.5时，实现激光器两端的电压Vd，相对供电输入电压Vin升压，以及在Drv信号的占空比不大于0.5时，实现激光器两端的电压Vd，相对供电输入电压Vin降压。因而本实施例能够通过同一类型的光驱动电路，基于不同的场景，实现激光器两端电压的升压及降压。
(3)光驱动电路40的电流检测电路440的特征。
如图16所示，光驱动电路40也可以包括电流检测电路440，其中，电流检测电路440如上述所述，也可以包括检测电阻Rsns。具体的，可以参考上述所述，此处不再一一赘述。
(4)光驱动电路40的稳压电路450的特征。
在一种示例中，光驱动电路40也可以包括稳压电路450，如上述所述，稳压电路450可以包括至少一个电容，这些电容的正极板接在电源电路10和光驱动电路40之间的线路上，这些电容的负极板接地。具体的，可以参考上述所述，此处不再一一赘述。
需要指出的是，图16中的激光器51的阴极也可以接地，以缩短驱动电流的传输线路，降低电磁干扰。
(5)光驱动电路40的使能信号Fault。
如图16所示的光驱动电路40中，控制电路410也可以向电源电路10发送使能信号，具体可以参考上述所述，此处不再赘述。
如图17所示，是本公开实施例提供的一种国家标准GB/T 9254(信息技术设备的无线电骚扰限值和测量方法)中，驱动电流的频率与其在传输过程中，产生的电磁辐射骚扰电场的电场强度的关系示意图。如图17可知，在GB/T 9254所规定的标准中，当投影设备的驱动电流的频率位于30兆赫兹(MHz)至200MHz范围内时，该投影设备的驱动电流，在传输过程中产生的电磁辐射骚扰电场的电场强度应不大于40毫伏(uV)。当投影设备的驱动电流的频率位于200MHz至1000MHz范围内时，该投影设备的驱动电流，在传输过程中产生的电磁辐 射骚扰电场的电场强度(即无线电骚扰)应不大于47毫伏(uV)。
可以理解的是，由于本公开实施例提供的投影设备采用共阴极驱动，而且，激光器的阴极接地，因此能够有效降低驱动电流的传输线路，从而降低驱动电路在传输过程中的电流环路面积，从而确保该驱动电流在传输过程中产生的电磁干扰满足GB/T 9254标准。
在本实施例中，因激光器的阳极与光驱动电路连接，阴极连接在一起，例如，激光器的阴极可以接地。激光器的阴极接地的方案中，能够有效缩短驱动电流流经的传输线路，从而减少驱动电流的电流环路面积，进而，该投影设备辐射出的电磁波，对该投影设备内部的器件，以及对该投影设备周围的其它电子设备的性能以及工作状态的影响也降低。
又例如，激光器的阴极可以接在电源电路和光驱动电路之间的线路上，从而使激光器两端的电压Vd，为光驱动电路向外输出的供电输出电压Vout，与光驱动电路输入的供电输入电压Vin之差。那么，为了促使激光器两端的电压Vd为其额定驱动电压V′d，则只需要控制光驱动电路将输出的Vout，相对于输入的Vin，升高V′d即可。而光驱动电路抬升的电压量，不受输入的Vin影响，那么，电源电路向外输出的供电输入电压Vin，便不受激光器的额定驱动电压所限制。进而，电源电路所选的Vin，既不容易出现因输入电流过大，而烧坏元件的情况，也不容易出现因输入电压过大，而损坏元件的情况。
本公开实施例还提供一种投影设备，该投影设备，如上述所述，也是包括电源电路10、显示控制电路30、激光光源50和至少一个光驱动电路40，激光光源50包括至少一个激光器51。
其中，电源电路10和至少一个光驱动电路40布置在不同的板上，且至少一个光驱动电路40所在光驱动板，与激光光源50位置靠近。
其中，电源电路10与显示控制电路30连接，用于向显示控制电路30供电。
关于电源电路10和显示控制电路30的特征，可以参见上述所述，此处不再赘述。
其中，显示控制电路30与至少一个光驱动电路40连接，用于向至少一个光驱动电路40提供调光信号。具体可以参考上述所述，此处不再赘述。
其中，光驱动电路40和激光器51一一连接，用于基于调光信号，向所连的激光器51提供驱动电流，激光器51用于在驱动电流的驱动下发光。
在一种示例中，该投影设备可以是共阳极驱动，也可以是共阴极驱动，所以相应的，如果是共阳极驱动，则激光器51的阳极与电源电路10连接，激光器51的阴极与光驱动电路40连接。如果是共阴极驱动，则激光器51的阳极与光驱动电路40连接，激光器51的阴极可以就近接地。具体的可以参考上述所述。
如上述所述，共阴极驱动，且电源电路10和光驱动电路40分离设置，参考图7所示，可以缩短驱动电流的传输线路，进而，减少驱动电流的电流环路面积，从而，减少驱动电流的电流环路面积，进而，该投影设备辐射出的电磁波，对该投影设备内部的器件，以及对该投影设备周围的其它电子设备的性能以及工作状态的影响也降低。
而在共阳极驱动中，如图18所示，光驱动电路40所在的光驱动板，与激光光源位置接近，那么，从激光器51的阴极流出的驱动电流，流向光驱动板，与流向电源板相比，显然传输线路缩短了。所以，共阳极驱动的方案中，电源电路和光驱动电路分离布置，也能缩短驱动电流的传输线路，进而，减少驱动电流的电流环路面积，从而，减少驱动电流的电流环路面积，进而，该投影设备辐射出的电磁波，对该投影设备内部的器件，以及对该投影设备周围的其它电子设备的性能以及工作状态的影响也降低。
关于投影设备的特征，可以参考上述所述，便不再一一赘述。
图19是本公开实施例提供的一种投影设备的激光器的驱动方法的流程示意图，该方法可应用于上述所述的投影设备。参考图19，该方法包括：
在步骤101中，电源电路10向显示控制电路30和至少一个光驱动电路40供电。
其中，电源电路向光驱动电路提供的驱动电压可以为直流的24V。
在步骤102中，显示控制电路30向至少一个光驱动电路40提供调光信号。
其中，该调光信号包括Pwm信号和Adim信号。该Pwm信号用于控制光驱动电路传输至激光器的驱动电流的有无，该Adim信号用于控制该驱动电流的电流值的大小。
在步骤103中，光驱动电路40基于调光信号，向所连的激光器51提供驱动电流。
在本公开实施例中，每个光驱动电路能够在驱动电压的驱动下，基于接收到的调光信号，向其所连接的光源提供驱动电流。其中，该驱动电流的电流值可以与调光信号中的Adim信号的信号值正相关。也即是，当该Adim信号的信号值越大时，该驱动电流的电流值越大。该光驱动电路输出的驱动电流有或无的频率可以与该调光信号中的Pwm信号的占空比相关。
在步骤104中，激光器51在驱动电流的驱动下发光。
在本公开实施例中，该多个激光器的第一端可以为阳极(即正极)端，第二端可以为阴极(即负极)端。由于激光器的阴极互连，阳极与光驱动电路连接，因此该种驱动方式也可以称为共阴极驱动。
在共阴极驱动方式中，如果激光器的阴极接地，则自激光器流出的驱动电流，可以就近流向参考地，无需回到电源电路，也无需回到光驱动电路。相比于共阳极驱动，能够缩短驱动电流的传输线路，进而能够有效降低该驱动电流的电流环路面积。基于上述公式(1)可知，当驱动电流的电流环路面积减小时，该驱动电流的传输线路周围，产生的电磁辐射骚扰电场的电场强度也会降低。相应的，该投影设备辐射出的电磁波，对该投影设备周围的其它电子设备的性能以及工作状态的影响也降低。
又例如，激光器的阴极可以接在电源电路和光驱动电路之间的线路上，从而使激光器两端的电压Vd，为光驱动电路向外输出的供电输出电压Vout，与光驱动电路输入的供电输入电压Vin之差。那么，为了促使激光器两端的电压Vd为其额定驱动电压V′d，则只需要控制光驱动电路将输出的Vout，相对于输入的Vin，升高V′d即可。而光驱动电路抬升的电压量，不受输入的Vin影响，那么，电源电路向外输出的供电输入电压Vin，便不受激光器的额定驱动电压所限制。进而，电源电路所选的Vin，既不容易出现因输入电流过大，而烧坏元件的情况，也不容易出现因输入电压过大，而损坏元件的情况。
图20是本公开实施例提供的另一种驱动方法的流程示意图，该方法可应用于投影设备。参考图20，该方法包括：
在步骤201中，电源电路向至少一个光驱动电路提供驱动电压。
在步骤202中稳压电路稳定电源电路输出的驱动电压。
在步骤203中，显示控制电路向每个光驱动电路提供调光信号。
在步骤204中，控制电路在驱动电压的驱动下，根据显示控制电路传输的调光信号，控制开关电路的第一端与第二端的通断状态。
在步骤205中，充放电电路在调光信号的Pwm信号为高电平时，向激光器提供驱动电流，在Pwm信号为低电平时，停止向激光器提供驱动电流。
在步骤206中，激光器在驱动电流的驱动下发光。
在步骤207中，电流检测电路检测流经激光器的驱动电流。
在步骤208中，控制电路根据驱动电流，控制开关电路的第一端与第二端的导通时长。
可以理解的是，上述方法实施例中各步骤的实现过程可以参考前述的相关描述，此处不再赘述。
还可以理解的是，本公开实施例提供的光源的驱动方法的步骤的先后顺序可以进行适当调整，步骤也可以根据情况进行相应增减。例如，步骤202可以根据情况删除。或者，步骤207和步骤208可以根据情况删除。又或者，步骤201和步骤203可以同步执行。任何熟悉本技术域的技术人员在本公开揭露的技术范围内，可轻易想到变化的方法，都应涵盖在本公开的保护范围之内，因此不再赘述。
图21为本公开提供的电子设备的硬件结构示意图。如图21所示，该电子设备100，用于实现上述任一方法实施例中，对应于光驱动电路的操作，电子设备100可以包括存储器1001和处理器1002；
存储器1001，用于存储计算机程序。
处理器1002，用于执行存储器存储的计算机程序，以实现上述实施例中的驱动方法。具体可以参见前述方法实施例中的相关描述。
可选地，存储器1001既可以是独立的，也可以跟处理器1002集成在一起。
当存储器1001是独立于处理器1002之外的器件时，电子设备100还可以包括总线1003，用于连接存储器1001和处理器1002。
可选地，本实施例还可以包括通信接口1004，该通信接口1004可以通过总线1003与处理器1002连接。处理器1002可以控制通信接口1003来实现电子设备100的上述的接收和发送的功能。
本公开实施例提供了一种投影设备，该投影设备包括：存储器，处理器及存储在该存储器上的计算机程序，该处理器执行该计算机程序时实现如上述方法实施例提供的驱动方法(例如图19或图20所示的方法)。
本公开实施例提供了一种计算机可读存储介质，该计算机可读存储介质中存储有指令，该指令由处理器加载并执行以实现如上述方法实施例提供的驱动方法(例如图19或图20所示的方法)。
本公开实施例提供了一种包含指令的计算机程序产品，当计算机程序产品在计算机上运行时，使得该计算机执行如上述方法实施例提供的驱动方法(例如图19或图20所示的方法)。
本领域普通技术人员可以理解实现上述实施例的全部或部分步骤可以通过硬件来完成，也可以通过程序来指令相关的硬件完成，该程序可以存储于一种计算机可读存储介质中，上述提到的存储介质可以是只读存储器，磁盘或光盘等。
可以理解的是，本公开中术语“多个”的含义是指两个或两个以上。
本公开中术语“第一”“第二”等字样用于对作用和功能基本相同的相同项或相似项进行区分，应理解，“第一”、“第二”、“第n”之间不具有逻辑或时序上的依赖关系，也不对数量和执行顺序进行限定。
以上所述仅为本公开的示例性实施例，并不用以限制本公开，凡在本公开的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本公开的保护范围之内。

Claims (18)

  1. 一种投影设备，其特征在于，包括电源电路、显示控制电路、激光光源和至少一个光驱动电路，所述激光光源包括至少一个激光器；
    所述电源电路分别与所述显示控制电路和所述至少一个光驱动电路连接，用于向所述显示控制电路和所述至少一个光驱动电路供电；
    所述显示控制电路与所述至少一个光驱动电路连接，用于向所述至少一个光驱动电路提供调光信号；
    所述光驱动电路和所述激光器一一连接，且所述光驱动电路和所述激光器的阳极连接，所述至少一个激光器的阴极互连；
    所述光驱动电路用于基于所述调光信号，向所连的激光器提供驱动电流，所述激光器用于在所述驱动电流的驱动下发光。
  2. 根据权利要求1所述的投影设备，其特征在于，所述至少一个激光器的阴极均接地。
  3. 根据权利要求1所述的投影设备，其特征在于，所述至少一个激光器的阴极均连接在所述电源电路和所述光驱动电路之间的线路上。
  4. 根据权利要求1至3任一所述的投影设备，其特征在于，所述光驱动电路包括控制电路、开关电路和充放电电路；
    所述开关电路具有控制端、第一端和第二端，所述控制电路分别与所述电源电路和所述开关电路的控制端连接，用于基于所述调光信号，生成开关驱动信号，并通过所述开关驱动信号，控制所述开关电路的第一端和第二端的接通时长和断开时长；
    所述充放电路与所在光驱动电路对应的激光器连接，用于向所在光驱动电路对应的激光器提供驱动电流。
  5. 根据权利要求4所述的投影设备，其特征在于，所述开关电路的第一端与所述电源电路连接，第二端与所述充放电电路连接。
  6. 根据权利要求5所述的投影设备，其特征在于，所述充放电电路包括电感和第二二极管；
    所述电感的一端和所述第二二极管的阴极，均与所述开关电路的第二端连接，所述电感的另一端和所在光驱动电路对应的激光器连接，所述第二二极管的阳极接地。
  7. 根据权利要求4所述的投影设备，其特征在于，所述开关电路的第一端与所述充放电电路连接，第二端接地，所述充放电电路与所述电源电路连接。
  8. 根据权利要求7所述的投影设备，其特征在于，所述充放电电路包括电感、第二二极管和第一电容；
    所述电感的一端与所述电源电路连接，另一端与所述第二二极管的阳极连接，所述第二二极管的阴极与所在光驱动电路对应的激光器连接；
    所述第一电容的正极板与所在光驱动电路对应的激光器连接，负极板接地；
    所述开关电路的第一端，连接在所述电感和所述第二二极管之间的线路上。
  9. 根据权利要求4所述的投影设备，其特征在于，所述光驱动电路还包括电流检测电路，所述电流检测电路和所在光驱动电路对应的激光器连接；
    所述控制电路与所述电流检测电路连接，用于通过所述电流检测电路，获取对应的激光器的驱动电流，并基于所述调光信号和所述驱动电流，生成开关驱动信号。
  10. 根据权利要求9所述的投影设备，其特征在于，所述电流检测电路包括检测电阻，所述检测电阻和所在光驱动电路对应的激光器串联，且所述检测电阻的两端均与所述控制电路连接。
  11. 根据权利要求4所述的投影设备，其特征在于，所述开关电路还包括第一电阻、第二电阻和第一二极管；
    所述第一电阻和所述第二电阻，并联在所述控制电路和所述开关电路(420)的控制端之间；
    所述第一二极管的阴极与所述控制电路连接，阳极与所述第一电阻或者第二电阻连接；
    所述第一电阻、所述第二电阻和所述第一二极管所在电路。
  12. 根据权利要求4所述的投影设备，其特征在于，所述光驱动电路还包括稳压电路，所述稳压电路包括至少一个电容；
    所述至少一个电容的正极板，均连接在所述电源电路和所述光驱动电路之间的线路上，负极板均接地。
  13. 根据权利要求4所述的投影设备，其特征在于，所述光驱动电路还包括第二电容，所述第二电容并联在所述开关电路的第一端和第二端之间。
  14. 根据权利要求1所述的投影设备，其特征在于，所述电源电路和所述至少一个光驱动电路集成在一起。
  15. 根据权利要求1所述的投影设备，其特征在于，所述电源电路和所述至少一个光驱动电路布置在不同的板上，且所述至少一个光驱动电路所在光驱动板，与所述激光光源位置靠近。
  16. 一种投影设备，其特征在于，电源电路、显示控制电路、激光光源和至少一个光驱动电路，所述激光光源包括至少一个激光器；
    所述电源电路和所述至少一个光驱动电路布置在不同的板上，且所述至少一个光驱动电路所在光驱动板，与所述激光光源位置靠近；
    所述电源电路与所述显示控制电路连接，用于向所述显示控制电路供电；
    所述显示控制电路与所述至少一个光驱动电路连接，用于向所述至少一个光驱动电路提供调光信号；
    所述光驱动电路和所述激光器一一连接，用于基于所述调光信号，向所连的激光器提供驱动电流，所述激光器用于在所述驱动电流的驱动下发光。
  17. 根据权利要求16所述的投影设备，其特征在于，所述至少一个激光器(51)的阳极均与所述电源电路连接，阴极与对应的光驱动电路连接。
  18. 一种激光光源的驱动方法，其特征在于，应用于权利要求1至17任一所述的投影设备，所述方法包括：
    所述电源电路向所述显示控制电路和所述至少一个光驱动电路供电；
    所述显示控制电路向所述至少一个光驱动电路提供调光信号；
    所述光驱动电路基于所述调光信号，向所连的激光器提供驱动电流；
    所述激光器在所述驱动电流的驱动下发光。
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