WO2022002185A1 - 电流控制方法、开关电源电路以及投影设备 - Google Patents

电流控制方法、开关电源电路以及投影设备 Download PDF

Info

Publication number
WO2022002185A1
WO2022002185A1 PCT/CN2021/103942 CN2021103942W WO2022002185A1 WO 2022002185 A1 WO2022002185 A1 WO 2022002185A1 CN 2021103942 W CN2021103942 W CN 2021103942W WO 2022002185 A1 WO2022002185 A1 WO 2022002185A1
Authority
WO
WIPO (PCT)
Prior art keywords
light source
signal
switch tube
driving current
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2021/103942
Other languages
English (en)
French (fr)
Inventor
叶慈凯
黄国生
林逸铭
李屹
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Appotronics Corp Ltd
Original Assignee
Appotronics Corp Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Appotronics Corp Ltd filed Critical Appotronics Corp Ltd
Publication of WO2022002185A1 publication Critical patent/WO2022002185A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

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
    • G03B21/206—Control of light source other than position or intensity
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters

Definitions

  • the present application relates to the technical field of projection display, and in particular, to a current control method, a switching power supply circuit, and a projection device.
  • the color wheel is an important device in the existing projection system, which is mainly used to receive the light of the light source and emit sequential light in sequence. Due to the light emission requirements of different colors and the differences in the characteristics of phosphors in different segmented regions of the color wheel, the light source has different current requirements in different segmented regions of the color wheel.
  • the light source When the light source is switched in the adjacent segmented areas of the color wheel, it needs to pass through the spoke area between the adjacent segmented areas of the color wheel. In order to avoid the sequential light mixing emitted by the color wheel in the spoke area, it is usually necessary to turn off the spoke area. light source, and then turn on the light source again after the end of the spoke area. Therefore, when the light source switches the current in different segmented regions of the color wheel, the current first drops rapidly to zero, and then rises again to the desired current value.
  • embodiments of the present application provide a current control method, a switching power supply circuit, and a projection device, which can realize fast and stable switching of any current of a light source.
  • an embodiment of the present application provides a current control method, which is applied to a switching power supply circuit, where the switching power supply circuit at least includes a load capacitor for charging the light source and a first switch tube for controlling the on-off of the light source.
  • the current control method includes when the driving current of the light source needs to be switched, comparing the second driving current required after switching with the first driving current before switching; if the second driving current is greater than or equal to the first driving current, Then, the load capacitor is precharged during the spoke time of the color wheel; if the second driving current is less than the first driving current, the conduction signal of the first switch tube is delayed, and control is performed during the delay period.
  • the first switch tube works in the linear region.
  • an embodiment of the present application provides a switching power supply circuit, including a main power supply circuit and a control module, the main power supply circuit includes a load capacitor for charging the light source and a first switch tube for controlling the light source on and off; the control module
  • the main power supply circuit is connected, and is configured to compare the second driving current required after switching with the first driving current before switching when the driving current of the light source needs to be switched; if the second driving current is greater than or equal to the first driving current If the second driving current is smaller than the first driving current, the on-signal of the first switch tube is delayed, and when the second driving current is smaller than the first driving current, the load capacitor is precharged during the spoke time of the color wheel. During the delay period, the first switch tube is controlled to work in the linear region.
  • an embodiment of the present application provides a projection device, including the switching power supply circuit of any one of the above; the projection device further includes a light source and a color wheel; wherein the light source is electrically connected to the switching power supply circuit; the color wheel is located in the the light path of the light source.
  • the current control method, the switching power supply circuit and the projection device provided by the embodiments of the present application are applied to the switching power supply circuit.
  • the second driving current required after switching is compared with the first driving current before switching, if the second driving current is greater than or equal to the first driving current If the second drive current is smaller than the first drive current, the on-signal of the first switch tube is delayed, and after the delay During this period, the first switch tube is controlled to work in the linear region, so that when the second driving circuit is greater than or equal to the first driving current, the light source is turned on and skips the time from stop working to recovery, so that the current of the light source rises rapidly to the second driving current; and when the second driving current is smaller than the first driving current, the first switch tube is made to bear a part of the voltage drop of the output voltage, thereby suppressing the current overshoot at the moment when the light source is turned on.
  • FIG. 1 shows a projection system provided by an embodiment of the present application.
  • FIG. 2 shows a schematic structural diagram of the color wheel in FIG. 1 .
  • FIG. 3 shows a schematic flowchart of a current control method provided by an embodiment of the present application.
  • FIG. 4 shows a schematic flowchart of another current control method provided by an embodiment of the present application.
  • FIG. 5 shows a schematic structural diagram of a switching power supply circuit provided by an embodiment of the present application.
  • FIG. 6 shows a schematic diagram of a conventional control of a switching power supply circuit provided by an embodiment of the present application.
  • FIG. 7 shows a schematic control diagram of the current control method provided by the embodiment of the present application.
  • FIG. 8 shows another schematic control diagram of the current control method provided by the embodiment of the present application.
  • FIG. 9 shows a block diagram of a switching power supply circuit provided by an embodiment of the present application.
  • FIG. 10 shows a schematic structural diagram of a switching power supply circuit provided by an embodiment of the present application.
  • FIG. 11 shows a working principle diagram of the switching power supply circuit provided by the embodiment of the present application.
  • FIG. 12 shows another working principle diagram of the switching power supply circuit provided by the embodiment of the present application.
  • FIG. 13 shows a schematic diagram of signals in the switching power supply circuit provided by the embodiment of the present application.
  • FIG. 14 shows a schematic structural diagram of a projection system provided by an embodiment of the present application.
  • FIG. 1 schematically shows a projection system 10, which includes a light source control device 11, a light source 12, a color wheel driving device 13, a color wheel 14, a controller 15, and a spatial light modulator 16 and projection lens 17.
  • the light source control device 11 is used to drive the light source 12 to emit light
  • the color wheel drive device 13 is used to drive the color wheel 14 to move
  • the color wheel 14 is used to receive the light emitted by the light source 12 and emit at least two colors of light
  • the spatial light modulator 16 is used for Image modulation is performed on at least two color lights according to the image data DATA to generate image light
  • the projection lens 17 is used for projecting according to the image light to display a projected image.
  • the controller 15 is used for controlling the light source control device 11 to turn on and off the light source 12 , the driving speed of the color wheel driving device 13 and the modulation sequence of the spatial light modulator 16 to make the three compatible.
  • the light source control device 11 is used to control the opening and closing of the light source 12, and the light source 12 is used to receive the driving signal sent by the light source control device 11 and emit light source light, such as blue light source light, and the light source can be a blue light source.
  • the light source 12 can also be a light source of other colors, and is not limited to a blue light source.
  • the light source can be an ultraviolet light source, so as to emit ultraviolet light source light.
  • the light source 12 can be a semiconductor diode laser light source for providing high-brightness light source light.
  • the color wheel 14 is located on the optical path where the light source light emitted by the light source 12 is located. As shown in FIG. 2 , the color wheel 14 includes at least two segmented areas A, at least one of the at least two segmented areas A carries a wavelength conversion material, and at least two of the segmented areas A receive light from the light source and Correspondingly emit at least two colors of light, at least one of the at least two colors of light is the converted light generated by the wavelength conversion material excited by the light source, and each segment area A emits at least one of the two colors of light. Color light.
  • the color wheel driving device 13 is used for driving the color wheel 14 to move, so that the at least two segmented areas A are periodically located on the light path where the light source light is located and correspondingly periodically emit at least two colors of light.
  • at least two segmented areas A are arranged along the circumferential direction, and the color wheel driving device 13 drives the color wheel 14 to rotate along the center of the color wheel 14, so that the at least two segmented areas A are periodically located in the light where the light source light is located.
  • the at least two segmented areas A periodically emit light of at least two colors. Since the brightness and light output requirements of each color are different, the driving current corresponding to each segment area A of the light source 12 may be different.
  • the driving current corresponding to the light source 12 in the first segment region a1 is the first driving current
  • the driving current corresponding to the light source 12 in the second segment region a2 is the second driving current. Therefore, when the light source 12 experiences different segment regions A, the driving current may need to be adjusted, and the second driving current is the required driving current after adjustment.
  • the spoke area B Between two adjacent segmented areas A is the spoke area B.
  • the light source 12 passes through two adjacent segmented regions A, it is bound to pass through the spoke region B.
  • the color wheel 14 emits mixed light of colors corresponding to two adjacent segment areas A, that is, spoke light.
  • the light source 12 is turned off when the light source 12 passes through the spoke area B, so that the light source 12 does not emit light in the spoke area B. That is, the light source 12 is turned off when entering the spoke area B and turned on when leaving the spoke area B.
  • the light source 12 When the light source 12 experiences two adjacent segment areas A, the light source 12 is turned off when entering the spoke area A so that the driving current flowing through the light source 12 is zero, and since the driving current of the light source 12 in different segment areas A corresponds to zero It may be different. Therefore, after the light source 12 leaves the spoke area B, the driving current of the light source 12 may need to be readjusted to meet the light output requirement of the next segment area A.
  • the inventor found that when the light source is going through two adjacent segmented areas, if the driving current corresponding to the next segmented area is greater than the driving current corresponding to the previous segmented area, the light source will be turned on again when it leaves the spoke area.
  • the driving current of the light source rises too slowly; and if the driving current corresponding to the next segment area is smaller than the driving current corresponding to the previous segment area, when the light source is turned on again after leaving the spoke area, the voltage carried by both ends of the light source is too large. , resulting in a current overshoot.
  • the inventor has conducted a lot of research and testing, and proposed the current control method, switching power supply circuit and projection equipment in the present application.
  • the charged load capacitor and the first switch tube used to control the on-off of the light source.
  • the second driving current required after switching is compared with the first driving current before switching, and if the second driving current is greater than or equal to the first driving current , the load capacitor is precharged during the spoke time of the color wheel.
  • the on-signal of the first switch tube is delayed, and during the delay period
  • the first switch tube is controlled to work in the linear region, and when the second drive circuit is greater than or equal to the first drive current, the light source is turned on and skips the time from stop working to recovery, so that the current of the light source rises rapidly to the second driving current; and when the second driving current is smaller than the first driving current, the first switch tube is made to bear a part of the voltage drop of the output voltage, thereby suppressing the current overshoot at the moment when the light source is turned on. Therefore, when the driving current of the light source is switched between any current size, the turn-on instant has reached a steady state, thereby realizing fast and stable switching of any current.
  • FIG. 3 shows a schematic flowchart 100 of a current control method provided by an embodiment of the present application.
  • the current control method 100 is applied to a switching power supply circuit, and the switching power supply circuit at least includes a load capacitor for charging the light source and a first switch tube for controlling the on-off of the light source.
  • the current control method 100 may include the following steps S110-S30.
  • Step S110 when the driving current of the light source needs to be switched, the second driving current required after the switching is compared with the first driving current before the switching.
  • the period during which the light source passes through the segmented region of the color wheel is called the segment time
  • the period during which the light source passes through the spoke region of the color segment is called the spoke time
  • the spoke time may also be called the spoke time of the color wheel.
  • the first driving current needs to be switched to the second driving current
  • the second driving current is the driving current required after switching.
  • the second driving current after switching may be greater than the first driving current before switching, or the second driving current after switching may be smaller than the first driving current before switching, or the second driving current after switching may be equal to The first drive current before switching.
  • the second drive current required by the second segment area is compared with the first drive current corresponding to the first segment area , to determine whether the driving current of the light source needs to be increased or the driving current of the light source needs to be decreased when the light source enters the second segment area.
  • the drive current corresponding to each segmented area can be set in advance, so the size of the drive current required by the light source to experience different segmented areas has been determined. At this time, the light source needs to be switched When driving the current, step S120 or step S130 can be directly executed to speed up the response speed.
  • Step S120 If the second driving current is greater than or equal to the first driving current, precharge the load capacitor during the spoke time of the color wheel.
  • the second driving current is greater than the first driving current
  • the light source when the light source switches from the first segment time to the second segment time, its driving current needs to be switched from a large current to a small current, which also means that the driving current needs to decline.
  • the load capacitor is precharged during the spoke time period when the light source is turned off, so that the voltage across the light source is preliminarily increased from the voltage value corresponding to the first driving current to the voltage value corresponding to the second driving current during the spoke time period. voltage value.
  • the voltage across the light source has reached the voltage value corresponding to the second driving current required for the second segment time in advance, and the system has entered a steady state in advance and is ready for the light source to be turned on. This makes it possible to skip the time when the system resumes work after the light source is turned on when the second segment time comes and the temporary light source is turned on, speed up the current rising speed of the light source, and make the current of the light source quickly reach the second driving current.
  • the second drive current is equal to the first drive current
  • the magnitude of the drive current remains unchanged. Since the light source needs to go through the spoke time during the switching process, and the light source is turned off during the spoke time, the driving current in the process of switching the light source from the first segment time to the second segment time remains unchanged, but the driving current A rising process is still required, that is, the first driving current drops to zero, and then rises from zero to the second driving current.
  • the load capacitor is pre-charged during the spoke time period when the light source is turned off, so that the voltage across the light source is pre-raised from the voltage value corresponding to the first driving current to the value corresponding to the first driving current during the spoke time period.
  • the voltage value corresponding to the second driving current Therefore, even if the magnitudes of the second driving current and the first driving current remain unchanged, the current rising speed of the light source can be accelerated, the current of the light source can quickly reach the second driving current, and the switching speed of the current can be improved.
  • Step S130 if the second driving current is smaller than the first driving current, delay the turn-on signal of the first switch tube, and control the first switch tube to operate in the linear region during the delay period.
  • the driving current of the light source needs to be switched from a large current to a small current, which also means that the driving current needs to decline.
  • the light source is turned off; after the spoke time is over, the light source is turned on again in the second segmented time.
  • the first switch tube needs to be turned on to turn on the light source.
  • the conduction signal of the first switch tube is delayed, and the first switch is controlled during the delay period. The tube works in the linear region, so that the first switch tube is slowly turned on.
  • the turn-on signal completely turns on the first switch tube and turns on the light source. Since the first switch tube works in the linear region before it is turned on, its two ends bear a part of the voltage drop, so that the light source has reached a steady state at the moment of turning on, and the two ends of the light source will not bear the high voltage corresponding to the first driving current. Thus, current overshoot is suppressed.
  • the second driving current required after switching is compared with the first driving current before the switching, if the second driving current is greater than or equal to the first driving current If the drive current is used, the load capacitor is precharged during the spoke time of the color wheel, so that the moment the light source is turned on, the time for the system to resume operation after the light source is turned on can be skipped, and the current rising speed of the light source can be accelerated, so that the current of the light source quickly reaches the first Two drive current.
  • the current control method enables the switching of the driving current of the light source between any current magnitudes, and the turn-on instant has reached a steady state, thereby realizing fast and stable switching of any current.
  • FIG. 5 shows a schematic diagram of the circuit structure of a switching power supply circuit 20 .
  • the switching power supply circuit 20 is a Boost (boost) circuit.
  • the switching power supply circuit 20 may also be a Buck ( buck) circuit.
  • the switching power supply circuit 20 includes a first switch transistor Q1, a second switch transistor Q2, a load capacitor C1, an inductor L1 and a diode D1, wherein the first switch transistor Q1 and the second switch transistor Q2 are NMOS transistors.
  • One end of the inductor L1 is connected to the power supply, and the other end is connected to the anode of the diode D1; the cathode of the diode D1 is connected to the first end of the load capacitor C1; the drain of the second switch tube Q2 is connected between the inductor L1 and the diode D1, the source
  • the first end of the load capacitor C1 is also used to connect one end of the light source, and the second end is connected to the source of the second switch tube Q2; the drain of the first switch tube Q1 is used to connect the other end of the light source, the source Connected to the second end of the load capacitor C1.
  • FIG. 6 shows a schematic diagram of conventional control based on the above-mentioned switching power supply circuit 20 .
  • the main board outputs the signal SPK to the constant current control chip, so that the constant current control chip outputs the signal Sq1 to the first switch transistor Q1 and the output signal Sq2 to the second switch transistor Q2.
  • the signal SPK When the light source is at the spoke time, the signal SPK is at a low level, at this time both the signal Sq1 and the signal Sq2 are at a low level, the first switch Q1 and the second switch Q2 are turned off, and the light source is turned off; During a period of time, the signal SPK is at a high level, so that the sq1 signal is at a high level, the first switch tube Q1 is turned on to turn on the light source, and the signal Sq2 works with high-frequency PWM (Pulse Width Modulation, pulse width modulation) to charge the load capacitor.
  • PWM Pulse Width Modulation, pulse width modulation
  • the main board outputs the current amplitude signal I2C to the MCU (Microcontroller Unit), and the MCU outputs the amplitude control signal V1 to the constant current control chip according to the current amplitude signal I2C, so that the constant current control chip controls according to the amplitude
  • the signal V1 controls the duty cycle of the signal Sq2, thereby increasing the voltage across the load capacitor C1 to a voltage value corresponding to the driving current of the power supply, thereby increasing the driving current of the light source to a corresponding current value.
  • the voltage at both ends of the load capacitor needs to rise from the voltage value corresponding to the first driving current to the voltage value corresponding to the second driving current, which in turn causes the driving current of the light source to rise too slowly;
  • the second current amplitude signal of the segmented time is smaller than the first current amplitude signal of the first segmented time, at the moment when the first switch tube is turned on in the second segmented time, since the voltage across the load capacitor cannot change abruptly , at this time, the voltage across the load capacitor needs to drop from the voltage value corresponding to the first driving current to the voltage value corresponding to the second driving current, so that the two ends of the light source are subjected to a large voltage corresponding to the first driving current at the moment when the light source is turned on, cause current overshoot.
  • the current control method 200 provided by this embodiment aims to solve the above problems.
  • the current control method provided by this embodiment may include the following steps S210 to S240 .
  • Step S210 when the driving current of the light source needs to be switched, the second driving current required after the switching is compared with the first driving current before the switching.
  • the current amplitude signal after switching is compared with the current amplitude signal before switching. It can be understood that the current amplitude signal can represent the segment time. The current value of the driving current required by the internal light source.
  • the driving current of the light source is changed to the first driving current according to the first current amplitude signal; during the second segment time, the driving current of the light source is changed according to the second current amplitude signal to the second drive current.
  • the light source ends the first segment time compare the second current amplitude signal corresponding to the next segment time with the first amplitude signal corresponding to the previous segment time to determine the upcoming second segment time The magnitude of the second drive current required within the first segment time and the magnitude of the first drive current.
  • steps S220 to S230 may be executed. If the second driving current is greater than or equal to the first driving current, step S240 can be executed.
  • Step S220 When the rising edge of the turn-on signal of the light source is triggered, keep outputting the first conduction signal to the first switch tube within the first preset time, and adjust the rising edge speed of the first conduction signal.
  • the second driving current is smaller than the first driving current
  • the turn-on signal of the first switch tube is delayed, and the first switch is controlled during the delay period.
  • the gate drive voltage of the tube makes the first switch tube work in the linear region.
  • FIG. 7 a schematic diagram of the control of the current control method provided in this embodiment when the second driving current is smaller than the first driving current is shown.
  • the control schematic diagram is a schematic diagram of the internal control principle of the main controller on the motherboard.
  • the main controller of the main board outputs a turn-on signal V2, which is the synchronization signal of the signal SPK.
  • V2 When the turn-on signal V2 is at a high level, it means that the light source is in the segmented time, the first switch tube Q1 is turned on, and the light source is turned on. It works normally; when the turn-on signal is at a low level, it means that the light source is in the spoke time, the first switch tube Q2 is turned off, and the light source is turned off.
  • the turn-on signal of the first switch transistor Q1 includes a first turn-on signal and a second turn-on signal, and the voltage of the second turn-on signal is greater than the voltage of the first turn-on signal.
  • the second turn-on signal is the Sq1 signal, which is a conventional driving signal for controlling the turn-on and turn-off of the first switch transistor Q1.
  • the rising edge of the turn-on signal V2 is detected, and the rising edge of the turn-on signal V2 indicates the time when the light source leaves the spoke time and enters the segmented time.
  • the rising edge of the turn-on signal V2 indicates The moment when the light source leaves the spoke time and enters the second segment time. Further, the rising edge of the open signal V2 triggers the generation of the signal Stq1. At this time, the signal Stq1 is at a high level and triggers the delay module to work.
  • the trigger signal SPK is delayed, that is, the low level of the extended signal SPK continues. time, so that the signal Sq1 delays turning on the first switch transistor Q1.
  • the signal Stq1 triggers the generation of the signal Saq1.
  • the signal Saq1 is also the above-mentioned first turn-on signal.
  • the signal Saq1 is kept input to the first switch transistor Q1 for the first preset time, and the signal Saq1 is the first switch transistor Q1 at this time. gate drive voltage.
  • the first switch transistor Q1 works in the linear region within the first preset time, and due to the characteristics of the MOS transistor, when the MOS transistor works in the linear region. , which is equivalent to a variable resistor. Therefore, at this time, the first switch tube Q1 is equivalent to a variable resistor connected in series with the light source, so that it can bear a part of the voltage drop when the subsequent light source is turned on.
  • Step S230 when the rising edge is triggered, delay the second preset time, and output the second conduction signal to the first switch tube when the second preset time arrives.
  • the signal Stq1 when the rising edge of the turn-on signal V2 triggers the generation of the signal Stq1, the signal Stq1 is at a high level and triggers the delay module to work, and the delay time of the delay module is the second preset time , when the second preset time arrives, the main controller delays the generation of the signal SPK through the delay module and outputs it to the constant current control chip.
  • the signal Sq1 is at a high level to make the first switch tube Q1 work in the conduction region, and then The first switch transistor Q1 is turned on. At the moment when the first switch transistor Q1 is turned on, the first switch transistor Q1 bears a part of the voltage drop, thereby suppressing current overshoot.
  • the first preset time and the second preset time are two different time periods.
  • the first preset time is greater than the second preset time, that is, the signal Saq1 is turned off after the delay time expires, so as to ensure that the signal Saq1 can be kept input to the entire delay period of the delay module.
  • the first switch tube is
  • Step S240 When the falling edge of the turn-on signal of the light source is triggered, keep outputting the PWM signal to the second switch tube within the third preset time.
  • the PWM signal is output to the second switch tube for the third preset time to control the charging of the load capacitor.
  • the third preset time is less than the spoke time of the color wheel.
  • Fig. 8 shows a schematic diagram of the control of the current control method provided in this embodiment when the second driving current is greater than or equal to the first driving current.
  • the control schematic diagram is a schematic diagram of the internal control principle of the main controller on the motherboard.
  • the PWM signal includes a first PWM signal and a second PWM signal.
  • the first PWM signal is input to the second switch tube when the turn-on signal of the light source is at a high level, and the second PWM signal is at a high level. Keep the input to the second switch tube for the third preset time.
  • the first PWM signal is the Sq2 signal, which is a traditional PWM signal for driving the second switch transistor Q2 to work with high-frequency PWM;
  • the second PWM signal is the Saq2 signal.
  • the falling edge of the turn-on signal V2 is detected.
  • the falling edge of the turn-on signal V2 indicates the moment when the light source leaves the segment time and enters the spoke time.
  • the falling edge of the turn-on signal V2 indicates that The moment when the light source leaves the first segment time and enters the spoke time. Further, the falling edge of the turn-on signal V2 triggers the generation of the signal Stq2.
  • Stq2 is at a high level and triggers the PWM working module to generate the signal Saq2.
  • the signal Saq2 is input to the second switch tube Q2 to drive the second switch tube Q2 to be high during the spoke time.
  • the frequency PWM works, and then the load capacitor C1 is precharged within the spoke time, so that the voltage across the light source reaches the voltage value corresponding to the second driving current in advance before turning on, the system enters the steady state in advance and is ready for the light source to turn on Preparation, so that when the second segment time comes and the temporary light source is turned on, the time for the system to resume operation after the light source is turned on can be skipped, and the current rising speed of the light source can be accelerated, so that the current of the light source can quickly reach the second driving current.
  • the timing of the signal SPK is synchronized with the timing of the turn-on signal.
  • the light source leaves the spoke time and enters the second segment time.
  • the signal Sq2 drives The second switch tube works with high frequency PWM, and the signal Sq1 turns on the first switch tube at a high level to turn on the light source.
  • the voltage across the light source has risen in advance to a level corresponding to the second driving current during the spoke time. Therefore, at this time, the driving current of the light source can quickly reach the second driving current.
  • the third preset time can be in any time period within the spoke time, that is, the second switch tube can be triggered to work by high frequency PWM in any time period within the spoke time to precharge the load capacitor.
  • the second driving current required after switching is compared with the first driving current before switching, and if the second driving current is greater than the first driving current, Then, the load capacitor is precharged during the spoke time of the color wheel, so that when the light source is turned on, the time for the system to resume operation after the light source is turned on can be skipped, and the current rising speed of the light source can be accelerated, so that the current of the light source can quickly reach the second driving current.
  • the current control method enables the switching of the driving current of the light source between any current magnitudes, and the turn-on instant has reached a steady state, thereby realizing fast and stable switching of any current.
  • an embodiment of the present application further provides a switching power supply circuit 300 .
  • the switching power supply circuit 300 includes a main power supply circuit 310 and a control module 320 connected to the main power supply circuit 310 .
  • the main power circuit 310 includes a load capacitor for charging the light source and a first switch tube for controlling the on-off of the light source; the control module 320 is configured to switch the required second driving current when the driving current of the light source needs to be switched.
  • the current is compared with the first drive current before switching; if the second drive current is greater than or equal to the first drive current, the load capacitor is precharged during the spoke time of the color wheel; if the second drive current is less than the first drive current, Then, the turn-on signal of the first switch tube is delayed, and the first switch tube is controlled to work in the linear region during the delay period.
  • the period during which the light source passes through the segmented regions of the color wheel is referred to as the segmentation time
  • the period during which the light source passes through the spoke regions of the color segment is referred to as the spoke time.
  • the light source experiences two adjacent first segment regions and second segment regions
  • the light source needs to sequentially experience the first segment time, the spoke time, and the second segment time.
  • the driving current required by the light source corresponding to the first segment time is the first driving current
  • the driving current required by the light source corresponding to the second segment time is the second driving current.
  • the first driving current needs to be switched to the second driving current
  • the second driving current is the driving current required after switching.
  • the control module 320 compares the second driving current required after switching with the first driving current before switching, and if the second driving current is greater than the first driving current, when the light source changes from the first segment time to the second segment time, The drive current needs to be switched from a large current to a small current, which also means that the drive current needs to drop.
  • the load capacitor is precharged during the spoke time period when the light source is turned off, so that the voltage across the light source is preliminarily increased from the voltage value corresponding to the first driving current to the voltage value corresponding to the second driving current during the spoke time period. voltage value.
  • the voltage across the light source has reached the voltage value corresponding to the second driving current required for the second segment time in advance, and the system has entered a steady state in advance and is ready for the light source to be turned on. This makes it possible to skip the time when the system resumes work after the light source is turned on when the second segment time comes and the temporary light source is turned on, speed up the current rising speed of the light source, and make the current of the light source quickly reach the second driving current.
  • the second drive current is equal to the first drive current
  • the magnitude of the drive current remains unchanged. Since the light source needs to go through the spoke time during the switching process, and the light source is turned off during the spoke time, the driving current in the process of switching the light source from the first segment time to the second segment time remains unchanged, but the driving current A rising process is still required, that is, the first driving current drops to zero, and then rises from zero to the second driving current.
  • the load capacitor is pre-charged during the spoke time period when the light source is turned off, so that the voltage across the light source is pre-raised from the voltage value corresponding to the first driving current to the value corresponding to the first driving current during the spoke time period.
  • the voltage value corresponding to the second driving current Therefore, even if the magnitudes of the second driving current and the first driving current remain unchanged, the current rising speed of the light source can be accelerated, the current of the light source can quickly reach the second driving current, and the switching speed of the current can be improved.
  • the driving current of the light source needs to be switched from a large current to a small current when the light source is from the first segment time to the second segment time, which also means that the driving current needs to be reduced.
  • the light source is turned off; after the spoke time is over, the light source is turned on again in the second segmented time.
  • the first switch tube needs to be turned on to turn on the light source.
  • the conduction signal of the first switch tube is delayed, and the first switch is controlled during the delay period. The tube works in the linear region, so that the first switch tube is slowly turned on.
  • the turn-on signal completely turns on the first switch tube and turns on the light source. Since the first switch tube works in the linear region before it is turned on, its two ends bear a part of the voltage drop, so that the light source has reached a steady state at the moment of turning on, and the two ends of the light source will not bear the high voltage corresponding to the first driving current. Thus, current overshoot is suppressed.
  • the switching power supply circuit 300 provided in this embodiment makes the driving current of the light source switch between any current magnitudes, and the turn-on instant has reached a steady state, thereby realizing fast and stable switching of any current.
  • the main power supply circuit 310 includes a first switch transistor Q1, a second switch transistor Q2, a load capacitor C1, an inductor L1 and a diode D1, wherein the first switch transistor Q1 and the second switch transistor Q2 are NMOS tube.
  • One end of the inductor L1 is connected to the power supply, and the other end is connected to the anode of the diode D1; the cathode of the diode D1 is connected to the first end of the load capacitor C1; the drain of the second switch tube Q2 is connected between the inductor L1 and the diode D1, the source The pole is grounded, and the gate is connected to the control module 320; the first end of the load capacitor C1 is also used to connect one end of the light source, and the second end is connected to the source of the second switch tube Q2; the drain of the first switch tube Q1 is used to connect The other end and the source of the light source are connected to the second end of the load capacitor C1 , and the gate is connected to the control module 320 .
  • the control module 320 is connected to the first switch transistor Q1 and the second switch transistor Q2 to control the on-off of the first switch transistor Q1 and the second switch transistor Q2.
  • the control module 320 may include a main board, a constant current control chip, and an MCU (Microcontroller Unit, micro control unit), wherein a main controller is provided on the main board.
  • the control module 320 may only include a mainboard; the constant current control chip and the MCU may be external chips.
  • control module 320 is configured to delay the turn-on signal of the first switch tube Q1 when the rising edge of the turn-on signal of the light source is triggered if the second drive current is smaller than the first drive current, and then delay the turn-on signal of the first switch transistor Q1 when the rising edge of the turn-on signal of the light source is triggered.
  • the gate driving voltage of the first switch tube Q1 is controlled, so that the first switch tube Q1 works in the linear region; if the second driving current is greater than or equal to the first driving current, when the falling edge of the turn-on signal of the light source is triggered, the The third preset time keeps outputting a PWM (Pulse Width Modulation, pulse width modulation) signal to the second switch tube Q2 to control the charging of the load capacitor C1; wherein, the third preset time is less than the spoke time of the color wheel.
  • PWM Pulse Width Modulation, pulse width modulation
  • FIG. 11 and FIG. 12 are schematic diagrams showing the working principle of the switching power supply circuit 300 provided in this embodiment. It should be noted that, FIG. 11 and FIG. 12 are schematic diagrams of the principle of the control module.
  • the main controller on the main board outputs the SPK signal to the constant current control chip, so that the constant current control chip outputs the signal Sq1 to the first switch Q1 and the output signal Sq2 to the second switch Q2 according to the signal SPK.
  • FIG. 13 it is a schematic diagram showing the change of the control quantity and the state quantity of the system with time when the light source switches between different segmented regions in this embodiment.
  • the principles of the embodiments of the present application will be described below with reference to FIGS. 11 to 13 . It should be noted that the embodiments of the present application only take the time control manner of the control signal as an example for description, and in fact, the control manner of the control signal is not limited to this.
  • the synchronization signal is the turn-on signal V2 used to instruct the light source to turn on.
  • the synchronization signal is at a high level, it is used to indicate that the light source is turned on, and when the synchronization signal is at a low level, it is used to indicate that the light source is turned off;
  • the signal Sq1 and the signal Saq1 are the turn-on signals of the first switch transistor Q1;
  • the signal Sq2 and the signal Saq2 are the control signals of the second switch transistor Q2.
  • the light source sequentially goes through the first segmented area, the first spoke area, the second segmented area, the second spoke area, and the third segmented area of the color wheel.
  • T0-T1 are the first segment time
  • T1-T3 are the first spoke time
  • T3-T4 are the second segment time
  • T4-T5 are the second spoke time
  • T5-T8 are the third segment time. It is assumed that the second driving current corresponding to the second segment region is greater than the first driving current corresponding to the first segment region; the third driving current corresponding to the third segment region is smaller than the second driving current corresponding to the second segment region.
  • the driving current when the light source is switched from the first segmented area to the second segmented area, the driving current needs to increase; when the light source is switched from the second segmented area to the third segmented area, the driving current needs to be decreased.
  • the principle when the second driving current is equal to the first driving current is the same as the principle when the second driving current is greater than the first driving current, the following only uses the principle when the second driving current is greater than the first driving current. The case is described as an example.
  • the light source is in the first segment time, the main board outputs the signal SPK with a high level signal to the constant current control chip, at this time the signal Sq1 output by the constant current control chip to the first switch tube Q1 is high level, and then Turn on the light source; the signal Sq2 output by the constant current control chip to the second switch tube Q2 is a high-frequency PWM signal.
  • Time T1 As shown in Figure 12 and Figure 13, the light source leaves the first segment time and enters the first spoke time, and the synchronization signal is the falling edge. That is, the timing of the synchronization signal is synchronized with the timing of the signal SPK.
  • the main board triggers the generation of signal Stq2 when the synchronization signal is a falling edge, and at the same time the signal Stq2 triggers the PWM working module to generate a signal Saq2, the signal Saq2 is a high-frequency PWM signal, and the high-frequency PWM signal is output to the second switch transistor Q2 to control the high-frequency PWM operation of the second switch transistor Q2.
  • Stage T1 ⁇ T2 This stage is during the first spoke time, when the light source is turned off.
  • the signal Sq2 drives the second switch tube Q2 to perform high-frequency PWM operation, thereby charging the load capacitor C1.
  • the frequency, duty cycle and duration can further increase the voltage of the load capacitor C1 to a voltage value corresponding to the second driving current before the light source is turned on.
  • the signal Sq2 can be input to the second switch tube Q2 and drive the second switch tube Q2 to work at high frequency PWM at any time period within the first spoke time, and is not limited to being input to the second switch tube at the time T1. Q2.
  • Time T3 The light source leaves the first spoke time and enters the second segment time. At this time, the synchronization signal is a rising edge, and the signal SPK is also a rising edge.
  • the constant current control chip outputs a high-level signal Sq1 to the first switch tube Q1 to turn on the light source. , and output the Sq2 signal of the high frequency PWM to the second switch tube Q2.
  • the voltage across the load capacitor C1 has risen to the voltage value corresponding to the second driving current in advance
  • the voltage across the light source has also risen to the voltage value corresponding to the second driving current in advance, then at this moment when the light source is turned on In an instant, the driving current of the light source can rapidly rise to a current value corresponding to the second driving current, and the system quickly enters a constant-current closed-loop steady state.
  • Stages T3 to T4 The light source continues to emit light during the second segment time, and the system is in a constant current closed-loop steady state at this time.
  • Stages T4 to T5 the light source is at the second spoke time, the synchronization signal is at a low level, the signal SPK is also at a low level, and the constant current control chip outputs a low-level signal Sq1 to the first switch tube Q1 and outputs a low level
  • the flat signal Sq2 is sent to the second switch transistor Q2, and the light source is turned off.
  • Time T5 As shown in Figure 11 and Figure 13, the light source leaves the second spoke time and enters the third segment time, and the synchronization signal is a rising edge at this time. Since the third drive current required for the next segment time is smaller than the second drive current for the previous segment time, the generation of the signal Stq1 is triggered when the synchronization signal is a rising edge.
  • the signal Stq1 triggers the delay module to work, and further triggers the signal SPK to delay, that is, prolongs the low level duration of the signal SPK, so that the signal Sq1 delays the first switch transistor Q1.
  • the signal Stq1 triggers to generate a signal Saq1, and the signal Saq1 is input to the first switch transistor Q1.
  • Stages T5 to T7 In this stage, the hold signal Saq1 is input to the first switch tube Q1. By setting the rising edge speed of Saq2, the first switch tube Q1 is triggered to turn on slowly. At this time, the first switch tube Q1 works in the linear region. Due to the characteristics of the MOS tube, when the MOS tube operates in the linear region, it is equivalent to a variable resistor, so at this time the first switch is equivalent to a variable resistor connected in series with the light source, which can then bear a part of the voltage drop for the light source.
  • Stage T5 ⁇ T6 This stage is the delay time of the delay module.
  • the durations of the stages T5-T7 are longer than the durations of T5-T6, so that the signal Saq2 can be kept input to the first switch transistor Q1 during the entire delay period of the delay module.
  • the signal SPK is at a low level, so both the signal Sq1 and the signal Sq2 are at a low level.
  • Time T6 the delay is over, the main board outputs a high-level signal SPK to the constant current control chip.
  • the delay module keeps the signal SPK at a low level during the delay period, that is, it extends the low level time of the signal SPK, and then turns the signal SPK to a high level after the delay.
  • the timing of the SPK signal is the same as The sync signal is out of sync.
  • the constant current control chip outputs a high level Sq1 signal to the first switch tube Q1 so that the first switch tube Q1 is completely turned on. At the moment when the light source is turned on, the first switch tube Q1 assumes a portion of the voltage drop, thereby suppressing current overshoot.
  • Stages T6 to T8 the light source continues to emit light during the third segment time, and the system is in a constant-current closed-loop steady state at this time.
  • the load capacitor C1 is precharged during the spoke time of the color wheel, so that the current rises rapidly at the moment when the light source is turned on, and the system The steady state is quickly reached; if the driving current needs to decrease, the turn-on signal of the first switch tube Q1 is delayed, and the first switch tube Q1 is controlled to work in the linear region during the delay period, so as to suppress the current over-current when the light source is turned on. rush. Therefore, no matter how different the driving currents of the light source before and after switching the segmented area, the ideal control effect can be achieved, and the fast and stable control of any segmented current can be realized.
  • the difference between the segmented currents can be larger, thereby reducing the constraints on the ratio of the color angle of the color wheel, and the system deviation of the white balance can be corrected through the segmented current, which improves the yield of the product and achieves a better display effect.
  • the switching power supply circuit provided by the embodiment of the present application is provided with a main power supply circuit and a control module.
  • the control module compares the second driving current required after switching with the first driving current before switching. , if the second drive current is greater than or equal to the first drive current, the load capacitor is precharged during the spoke time of the color wheel, so that the moment the light source is turned on, the time for the system to resume work after the light source is turned on can be skipped, speeding up the light source The current rising speed makes the current of the light source quickly reach the second driving current.
  • the current control method enables the switching of the driving current of the light source between any current magnitudes, and the turn-on instant has reached a steady state, thereby realizing fast and stable switching of any current.
  • an embodiment of the present application further provides a projection device 400 .
  • the projection device 400 includes a light source 410 , a color wheel 420 , and the above-mentioned switching power supply circuit 300 .
  • the color wheel 410 is located on the optical path of the light source 420 , and the switching power supply circuit 300 is electrically connected to the light source to control the light source 410 to emit light.
  • the projection device provided by the embodiment of the present application is provided with a light source, a color wheel, and a switching power supply circuit.
  • the switching power supply circuit converts the second driving current required after switching with the first driving current before switching.
  • Current comparison if the second driving current is greater than or equal to the first driving current, the load capacitor will be pre-charged during the spoke time of the color wheel, so that the moment the light source is turned on, the time for the system to resume work after the light source is turned on can be skipped, speeding up
  • the current rising speed of the light source makes the current of the light source rapidly reach the second driving current.
  • the current control method enables the switching of the driving current of the light source between any current magnitudes, and the turn-on instant has reached a steady state, thereby realizing fast and stable switching of any current.
  • the difference between the segmented currents can be larger, thereby reducing the constraints on the ratio of the color angles of the color wheel, and the system deviation of the white balance can be corrected through the segmented currents, improving the yield of the product and achieving a better display effect.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

一种电流控制方法（100、 200）、开关电源电路（20、 300）以及投影设备（400），电流控制方法（100、 200）应用于开关电源电路（20、 300），开关电源电路（20、 300）至少包括用于对光源（12、 410）充电的负载电容（C1）以及用于控制光源（12、 410）通断的第一开关管（Q1），电流控制方法（100、 200）包括当光源（12、 410）的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较（S110、 S210）；若第二驱动电流大于或等于第一驱动电流，则在色轮（14、 420）的轮辐时间期间对负载电容（C1）进行预充电（S120）；若第二驱动电流小于第一驱动电流，则对第一开关管（Q1）的导通信号进行延时，并在延时期间控制第一开关管（Q1）工作在线性区（S130）。电流控制方法（100、 200）能够实现光源（12、 410）任意电流快速、稳定地切换。

Description

电流控制方法、开关电源电路以及投影设备 技术领域
本申请涉及投影显示技术领域，具体涉及一种电流控制方法、开关电源电路以及投影设备。
背景技术
色轮是现有投影系统中的重要设备，其主要用于接收光源的光线并按顺序射出时序光。由于不同颜色的出光需求和色轮不同分段区域荧光粉特性的差异，使得光源在色轮的不同分段区域有不同的电流需求。当光源在色轮的相邻分段区域切换时，需要经过色轮相邻分段区域之间的轮辐区，而为了避免色轮在轮辐区射出的时序光混合，通常需要在轮辐区关断光源，并在轮辐区结束后再重新开通光源。因此，光源在色轮的不同分段区域切换电流时，电流首先快速地下降为零，然后再重新上升到需要的电流值。
现有技术中，当光源从大电流向小电流切换时，在光源开通的瞬间，往往会产生电流过冲；而当光源从小电流向大电流切换时，在光源开通后，电流上升速度又过慢。因此，现有技术实有改善的必要。
发明内容
鉴于以上问题，本申请实施方式提供一种电流控制方法、开关电源电路以及投影设备，能够实现光源任意电流快速、稳定地切换。
第一方面，本申请实施例提供一种电流控制方法，应用于开关电源电路，所述开关电源电路至少包括用于对光源充电的负载电容以及用于控制光源通断的 第一开关管，该电流控制方法包括当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较；若所述第二驱动电流大于或等于所述第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电；若所述第二驱动电流小于所述第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管工作在线性区。
第二方面，本申请实施例提供一种开关电源电路，包括主电源电路以及控制模块，主电源电路包括用于对光源充电的负载电容以及用于控制光源通断的第一开关管；控制模块连接主电源电路，被配置为当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较；若所述第二驱动电流大于或等于所述第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电；若所述第二驱动电流小于所述第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管工作在线性区。
第三方面，本申请实施例提供一种投影设备，包括上述任一项的开关电源电路；所述投影设备还包括光源和色轮；其中，光源电连接于所述开关电源电路；色轮位于所述光源的光路。
相对于现有技术，本申请实施例提供的电流控制方法、开关电源电路以及投影设备，电流控制方法应用于开关电源电路，开关电源电路至少包括用于对光源充电的负载电容以及用于控制光源通断的第一开关管。该电流控制方法同通过当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较，若所述第二驱动电流大于或等于所述第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电，若所述第二驱动电流小于所述第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管工作在线性区，进而在第二驱动电路大于或等于第一驱动电流时，使得光源开通瞬间跳过从停止工作到恢复的时间，从而使光源的电流快速地上升至第二驱动 电流；并且在第二驱动电流小于第一驱动电流时，使得第一开关管承受输出电压的一部分压降，从而在光源开通瞬间抑制电流过冲。因此，光源的驱动电流在任意电流大小之间切换时，开通瞬间均已达到稳态，从而实现任意电流快速、稳定的切换。
本申请的这些方面或其他方面在以下实施例的描述中会更加简明易懂。
附图说明
为了更清楚地说明本申请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申请的一些实施例，对于本领域技术人员来讲，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示出了本申请实施例提供的一种投影系统。
图2示出了图1中色轮的结构示意图。
图3示出了本申请实施例提供的一种电流控制方法的流程示意图。
图4示出了本申请实施例提供的另一种电流控制方法的流程示意图。
图5示出了本申请实施例提供的一种开关电源电路的结构示意图。
图6示出了本申请实施例提供的开关电源电路的传统控制示意图。
图7示出了本申请实施例提供的电流控制方法的一种控制示意图。
图8示出了本申请实施例提供的电流控制方法的另一种控制示意图。
图9示出了本申请实施例提供的开关电源电路的模块框图。
图10示出了本申请实施例提供的开关电源电路的结构示意图。
图11示出了本申请实施例提供的开关电源电路的一种工作原理图。
图12示出了本申请实施例提供的开关电源电路的另一种工作原理图。
图13示出了本申请实施例提供的开关电源电路中的信号示意图。
图14示出了本申请实施例提供的投影系统的结构示意图。
具体实施方式
下面详细描述本申请的实施方式，所述实施方式的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施方式是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。
为了使本技术领域的人员更好地理解本申请方案，下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整的描述。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
如图1所示，图1示意性地示出了一种投影系统10，该投影系统包括光源控制装置11、光源12、色轮驱动装置13、色轮14、控制器15、空间光调制器16以及投影镜头17。光源控制装置11用于驱动光源12发光，色轮驱动装置13用于驱动色轮14运动，色轮14用于接收光源12发出的光并射出至少两种颜色光，空间光调制器16用于依据图像数据DATA对至少两种颜色光进行图像调制以产生图像光，投影镜头17用于依据图像光进行投影以显示投影图像。控制器15用于控制光源控制装置11对光源12开启及关闭时序、色轮驱动装置13的驱动速度及空间光调制器16的调制时序以使得三者相适应。
具体地，光源控制装置11用于控制光源12的开启与关闭，光源12用于接收光源控制装置11发出的驱动信号并发出光源光，如蓝色光源光，光源可以为蓝色光源。在一些实施方式中，光源12也可以是其他颜色的光源，并不以蓝色光源为限，如光源可以是紫外光源，从而发出紫外光源光。进一步地，光源12可以为半导体二极管激光光源，用以提供高亮度的光源光。
色轮14位于光源12发出的光源光所在的光路上。如图2所示，色轮14包括至少两个分段区域A，至少两个分段区域A中至少一个分段区域A上承载有波长转换材料，至少两个分段区域A接收光源光并对应射出至少两种颜色光，至少两种颜色光中的至少一种颜色光为波长转换材料受光源光激发而产生的转换光，每个分段区域A射出至少两种颜色光中的一种颜色光。色轮驱动装置13用于驱动色轮14运动，以使至少两个分段区域A周期性的位于光源光所在的光路上并对应周期性的射出至少两种颜色光。本实施方式中，至少两个分段区域A沿圆周方向设置，色轮驱动装置13驱动色轮14沿色轮14中心旋转，使得至少两个分段区域A周期性的位于光源光所在的光路上，从而至少两个分段区域A周期性的射出至少两种颜色光。由于每种颜色的亮度、出光需求不同，光源12在每个分段区域A对应的驱动电流可能不同。例如，光源12在第一分段区域a1对应的驱动电流是第一驱动电流，光源12在第二分段区域a2对应的驱动电流是第二驱动电流。因此，当光源12在经历不同的分段区域A时，驱动电流可能要被调整，并且第二驱动电流即为调整后所需的驱动电流。
相邻两个分段区域A之间为轮辐区B。光源12在经历两个相邻的分段区域A时，势必要经过轮辐区B。当光源12经过轮辐区B时，色轮14射出的是相邻两个分段区域A对应的颜色的混合光，也即轮辐光。通常来说，为了避免轮辐光的产生，在光源12经过轮辐区B时使光源12关闭，使得光源12在轮辐区B不出光。也就是说，光源12在进入轮辐区B时关闭，在离开轮辐区B时开启。
在光源12在经历两个相邻的分段区域A，光源12在进入轮辐区A时被关闭使得流经光源12的驱动电流为零，而由于光源12在不同分段区域A对应的驱动电流可能不同，因此，在光源12离开轮辐区B后光源12的驱动电流可能要被重新调整以适应下个分段区域A的出光需求。
发明人经过严格的测试发现，当光源在经历两个相邻的分段区域时，如果下个分段区域对应的驱动电流大于上个分段区域对应的驱动电流，在离开轮辐区 重新开启光源时，光源的驱动电流上升过于缓慢；而如果下个分段区域对应的驱动电流小于上个分段区域对应的驱动电流，在离开轮辐区重新开启光源的瞬间，光源两端承载的电压过大，导致发生电流过冲。
针对这一问题，发明人进行了大量的研究与测试，提出了本申请中的电流控制方法、开关电源电路以及投影设备，电流控制方法应用于开关电源电路，开关电源电路至少包括用于对光源充电的负载电容以及用于控制光源通断的第一开关管。该电流控制方法通过当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较，若所述第二驱动电流大于或等于所述第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电，若所述第二驱动电流小于所述第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管工作在线性区，进而在第二驱动电路大于或等于第一驱动电流时，使得光源开通瞬间跳过从停止工作到恢复的时间，从而使光源的电流快速地上升至第二驱动电流；并且在第二驱动电流小于第一驱动电流时，使得第一开关管承受输出电压的一部分压降，从而在光源开通瞬间抑制电流过冲。因此，光源的驱动电流在任意电流大小之间切换时，开通瞬间均已达到稳态，从而实现任意电流快速、稳定的切换。
如图3所示，图3示出了本申请实施例提供的一种电流控制方法的流程示意图100。该电流控制方法100应用于开关电源电路，该开关电源电路至少包括用于对光源充电的负载电容以及用于控制光源通断的第一开关管。该电流控制方法100可以包括以下步骤S110～S30。
步骤S110：当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较。
本申请实施例中，将光源经历色轮分段区域期间称之为分段时间，将光源经历色段轮辐区期间称之为轮辐时间，该轮辐时间也可叫作色轮的轮辐时间。当光源经历两个相邻的第一分段区域和第二分段区域时，光源需要依次经历第一分段时间、轮辐时间以及第二分段时间。光源在第一分段时间对应所需的驱动电流 为第一驱动电流，光源在第二分段时间对应所需的驱动电流为第二驱动电流。当光源经历两个相邻的第一分段区域和第二分段区域时，需要将第一驱动电流切换到第二驱动电流，第二驱动电流即为切换后所需的驱动电流。本实施例中，切换后的第二驱动电流可以大于切换前的第一驱动电流，或者切换后的第二驱动电流可以小于切换前的第一驱动电流，或者切换后的第二驱动电流可以等于切换前的第一驱动电流。
本实施例中，当光源离开第一分段区域的瞬间，在进入轮辐区之前，将第二分段区域所需的第二驱动电流与第一分段区域所对应的第一驱动电流进行比较，以判断光源进入第二分段区域时需要将光源的驱动电流上升还是需要将光源的驱动电流下降。
在一些实施方式中，每个分段区域所对应的驱动电流可以被提前设置好，因此在光源在经历不同的分段区域所需的驱动电流的大小已经已经被确定，此时在光源需要切换驱动电流时，可以直接执行步骤S120或步骤S130，以加快响应速度。
步骤S120：若第二驱动电流大于或等于第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电。
本实施例中，若第二驱动电流大于第一驱动电流，光源从第一分段时间切换至第二分段时间时，其驱动电流要从大电流切换到小电流，也意味着驱动电流需要下降。在进入轮辐时间期间时，光源被关闭；轮辐时间结束后进入第二分段时间光源重新开启。本实施例中，在光源关闭时进入轮辐时间期间对负载电容进行预充电，使得在轮辐时间期间即预先将光源两端的电压从与第一驱动电流对应的电压值上升至与第二驱动电流对应的电压值。也就是说，在光源开通前，光源两端的电压已经预先达到了与第二分段时间所需的第二驱动电流对应的电压值，系统提前进入稳态并为光源的开启做好了准备，使得在第二分段时间来临时光源开启的瞬间，可以跳过光源开启后系统恢复工作的时间，加快光源的电流上升速度，使光源的电流迅速达到第二驱动电流。
进一步地，若第二驱动电流等于第一驱动电流，光源从第一分段时间切换至第二分段时间时，其驱动电流的大小不变。由于在切换的过程中光源需要经过轮辐时间，而在轮辐时间内光源被关闭，因此光源从第一分段时间切换至第二分段时间的过程，驱动电流的大小虽然不变，但是驱动电流仍然需要一个上升的过程，也即从第一驱动电流下降到零，再从零上升到第二驱动电流。本实施例中，在该过程中，在光源关闭时进入轮辐时间期间对负载电容进行预充电，使得在轮辐时间期间即预先将光源两端的电压从与第一驱动电流对应的电压值上升至与第二驱动电流对应的电压值。因此，即使第二驱动电流与第一驱动电流的大小不变，也能够加快光源的电流上升速度，使光源的电流迅速达到第二驱动电流，提高电流的切换速度。
步骤S130：若第二驱动电流小于第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制第一开关管工作在线性区。
本实施例中，若第二驱动电流小于第一驱动电流，光源从第一分段时间切换至第二分段时间时，其驱动电流要从大电流切换到小电流，也意味着驱动电流需要下降。在进入轮辐时间期间时，光源被关闭；轮辐时间结束后进入第二分段时间光源重新开启。光源进入轮辐时间时需要导通第一开关管以开启光源，本实施例中，在光源进入轮辐时间时，对第一开关管的导通信号进行延时，并在延时期间控制第一开关管工作在线性区，使第一开关管缓慢导通，在延时时间结束时，导通信号完全导通第一开关管进而开启光源。由于第一开关管在导通之前工作在线性区，其两端承受了一部分压降，使得光源在开通的瞬间已达到稳态，光源两端不会承受与第一驱动电流对应的高电压，从而抑制电流过冲。
本申请实施例提供的电流控制方法，在当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较，若第二驱动电流大于或等于第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电，使得光源开启的瞬间，可以跳过光源开启后系统恢复工作的时间，加快光源的电流上升速度，使光源的电流迅速达到第二驱动电流。同时，若第二驱动电流小于第一驱 动电流，则对第一开关管的导通信号进行延时，并在延时期间控制第一开关管工作在线性区，使第一开关管两端承受一部分压降，进而使得光源在开通的瞬间，光源两端不会承受与第一驱动电流对应的高电压，从而抑制电流过冲。因此，本申请实施例提供的电流控制方法使得光源的驱动电流在任意电流大小之间切换时，开通瞬间均已达到稳态，从而实现任意电流快速、稳定的切换。
如图4所示，本申请实施例还提供另一种电流控制方法200，该电流控制方法应用于开关电源电路20，以对光源的驱动电流进行切换。如图5所示，图5示出了一种开关电源电路20的电路结构示意图，该开关电源电路20为Boost(升压)电路，在一些实施方式中，开关电源电路20也可以为Buck(降压)电路。该开关电源电路20包括第一开关管Q1、第二开关管Q2、负载电容C1、电感L1以及二极管D1，其中第一开关管Q1和第二开关管Q2为NMOS管。电感L1的一端连接于电源、另一端连接于二极管D1的正极；二极管D1的负极连接于负载电容C1的第一端；第二开关管Q2的漏极连接在电感L1与二极管D1之间、源极接地；负载电容C1的第一端还用于连接光源的一端、第二端连接于第二开关管Q2的源极；第一开关管Q1的漏极用于连接光源的另一端、源极连接于负载电容C1的第二端。
如图6所示，图6示出了基于上述开关电源电路20的传统控制示意图。主板输出信号SPK至恒流控制芯片，以使恒流控制芯片输出信号Sq1至第一开关管Q1、输出信号Sq2至第二开关管Q2。当光源处于轮辐时间时，信号SPK为低电平，此时信号Sq1和信号Sq2均为低电平，第一开关管Q1和第二开关管Q2关断，光源被关断；当光源进入分段时间时，信号SPK为高电平，使得sq1信号为高电平，第一开关管Q1导通开启光源，同时信号Sq2以高频PWM(Pulse Width Modulation，脉冲宽度调制)工作以为负载电容充电；同时主板输出电流幅值信号I2C至MCU(Microcontroller Unit，微控制单元)，MCU根据该电流幅值信号I2C输出幅值控制信号V1至恒流控制芯片，使得恒流控制芯片根据该幅值控制信号V1控制信号Sq2的占空比，进而将负载电容C1两端的电压上升至与 电源驱动电流对应的电压值，从而使得光源的驱动电流上升至对应的电流值。
当光源经过两个相邻的分段时间时，如果相邻两个分段时间的电流幅值信号不一致，由于负载电容两端的电压不能突变，会导致无法实现电流的快速上升和下降。例如进入第二分段时间的第二电流幅值信号大于进入第一分段时间的第一电流幅值信号时，在进入第二分段时间第一开关管导通的瞬间，由于负载电容两端的电压不能突变，此时负载电容两端的电压需要从与第一驱动电流对应的电压值上升至与第二驱动电流对应的电压值，进而导致光源的驱动电流上升过慢；再例如进入第二分段时间的第二电流幅值信号小于进入第一分段时间的第一电流幅值信号时，在进入第二分段时间第一开关管导通的瞬间，由于负载电容两端的电压不能突变，此时负载电容两端的电压需要从与第一驱动电流对应的电压值下降至与第二驱动电流对应的电压值，进而使得光源开通的瞬间两端承受与第一驱动电流对应的大电压，导致电流过冲。
本实施提供的电流控制方法200致力于解决上述问题，以上述开关电源电路20为例，如图4所示，本实施例他提供的电流控制方法可以包括以下步骤S210～步骤S240。
步骤S210：当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较。
本实施例中，当光源经历相邻两个分段时间时，将切换后的电流幅值信号与切换前的电流幅值信号比较，可以理解的是，电流幅值信号可以表征该分段时间内光源所需驱动电流的电流值。
例如，当光源经历相邻第一分段时间以及第二分段时间。其中在第一分段时间内，根据第一电流幅值信号将光源的驱动电流改变为第一驱动电流；在第二分段时间内，根据第二电流幅值信号将光源的驱动电流改变为第二驱动电流。当光源结束第一分段时间时，将下一分段时间对应的第二电流幅值信号与上一分段时间对应的第一幅值信号进行比较，以判断即将进入的第二分段时间内所需要 的第二驱动电流与第一分段时间内第一驱动电流的大小。
进一步地，若第二驱动电流小于第一驱动电流，则可执行步骤S220～步骤S230。若第二驱动电流大于或等于第一驱动电流，则可执行步骤S240。
步骤S220：在光源的开启信号上升沿触发时，在第一预设时间内保持输出第一导通信号至第一开关管，并调整第一导通信号的上升沿速度。
在本实施例中，若第二驱动电流小于第一驱动电流，则在光源的开启信号上升沿触发时，对第一开关管的导通信号进行延时，并在延时期间控制第一开关管的门极驱动电压，使第一开关管工作在线性区。
如图7所示，图示出了本实施例提供的电流控制方法在第二驱动电流小于第一驱动电流时的控制示意图。需要说明的是，该控制示意图为主板上的主控器的内部控制原理示意图。主板的主控制器输出一个开启信号V2，该开启信号V2为信号SPK的同步信号，当该开启信号V2为高电平时，即说明光源处于分段时间，第一开关管Q1导通，光源开通正常工作；当开启信号为低电平时，即说明光源处于轮辐时间，第一开关管Q2关断，光源关闭。
进一步地，第一开关管Q1的导通信号包括第一导通信号和第二导通信号，且第二导通信号的电压大于第一导通信号的电压。在光源的开启信号V2上升沿触发时，在第一预设时间内保持输出第一导通信号至第一开关管，并调整第一导通信号的上升沿速度。
本实施例中，第二导通信号为Sq1信号，其为传统的控制第一开关管Q1通断的驱动信号。当第二驱动电流小于第一驱动电流时，检测开启信号V2的上升沿，开启信号V2的上升沿表示光源离开轮辐时间进入分段时间的时刻，本实施例中，开启信号V2的上升沿表示光源离开轮辐时间进入第二分段时间的时刻。进一步地，开启信号V2的上升沿触发产生信号Stq1，此时信号Stq1为高电平并触发延时模块工作，延时模块工作时触发信号SPK进行延时，也即延长信号SPK低电平持续时间，进而使得信号Sq1延时导通第一开关管Q1。同时，信号 Stq1触发产生信号Saq1，该信号Saq1也即上述的第一导通信号，在第一预设时间内保持信号Saq1输入至第一开关管Q1，此时信号Saq1为第一开关管Q1的门极驱动电压。进一步地，通过调整信号Saq1的上升沿速度和信号Saq1的电压，使得在第一预设时间内第一开关管Q1工作在线性区，而由于MOS管的特性，当MOS管工作在线性区时，其相当于可变电阻，因此此时第一开关管Q1相当于与光源串联的可变电阻，从而能够在后续光源开通的瞬间承担一部分的压降。
步骤S230：在上升沿触发时，延时第二预设时间，并在第二预设时间到达时输出第二导通信号至第一开关管。
如图7所示，本实施例中，开启信号V2的上升沿触发产生信号Stq1时，信号Stq1为高电平并触发延时模块工作，延时模块的延时时间为该第二预设时间，在第二预设时间到达时，主控制器通过延时模块延时产生信号SPK输出至恒流控制芯片，此时信号Sq1为高电平使第一开关管Q1工作在导通区，进而导通第一开关管Q1。在第一开关管导通Q1的瞬间，第一开关管Q1承担一部分压降，从而抑制电流过冲。
需要说明的是，第一预设时间和第二预设时间为两个不同的时间段。在本实施例中，第一预设时间大于第二预设时间，也即在延时时间结束后才关闭信号Saq1，以保证在延时模块的整个延时期间都能使信号Saq1保持输入至第一开关管。
步骤S240：在光源的开启信号下降沿触发时，在第三预设时间内保持输出PWM信号至第二开关管。
本实施例中，若第二驱动电流大于或等于第一驱动电流，则在光源的下降沿触发时，在第三预设时间内保持输出PWM信号至第二开关管，以控制负载电容充电。其中，第三预设时间小于色轮的轮辐时间。
如图8所示，图8示出了本实施例提供的电流控制方法在第二驱动电流大 于或等于第一驱动电流时的控制示意图。需要说明的是，该控制示意图为主板上的主控器的内部控制原理示意图。PWM信号包括第一PWM信号以及第二PWM信号，第一PWM信号在光源的开启信号高电平时，第一PWM信号在光源的开启信号高电平时输入至第二开关管，第二PWM信号在第三预设时间内保持输入至第二开关管。本实施例中，第一PWM信号为Sq2信号，其为传统的驱动第二开关管Q2高频PWM工作的PWM信号；第二PWM信号为Saq2信号。当第二驱动电流大于第一驱动电流时，检测开启信号V2的下降沿，开启信号V2的下降沿表示光源离开分段时间进入轮辐时间的时刻，本实施例中，开启信号V2的下降沿表示光源离开第一分段时间进入轮辐时间的时刻。进一步地，开启信号V2的下降沿触发产生信号Stq2，此时Stq2为高电平并触发PWM工作模块产生信号Saq2，信号Saq2输入至第二开关管Q2驱动第二开关管Q2在轮辐时间内高频PWM工作，进而在轮辐时间内对负载电容C1预充电，使光源两端的电压在开通之前便预先达到与第二驱动电流对应的电压值，系统提前进入稳态并为光源的开启做好了准备，使得在第二分段时间来临时光源开启的瞬间，可以跳过光源开启后系统恢复工作的时间，加快光源的电流上升速度，使光源的电流迅速达到第二驱动电流。
值得指出的是，由于信号Stq2不触发延时模块工作，因此信号SPK的时序与开启信号的时序同步，在开启信号上升沿时，光源离开轮辐时间进入第二分段时间，此时信号Sq2驱动第二开关管高频PWM工作，信号Sq1高电平导通第一开关管进而开通光源，在光源开通的瞬间，由于在轮辐时间期间光源两端的电压已经预先上升至了与第二驱动电流对应的电压值，因此此时光源的驱动电流能够快速地达到第二驱动电流。
本实施例中，第三预设时间可以处于轮辐时间内的任意时间段，也即在轮辐时间内的任意时间段内可以触发第二开关管高频PWM工作，以对负载电容预充电。
本实施例提供的电流控制方法，在当光源的驱动电流需要切换时，将切换后 所需的第二驱动电流与切换前的第一驱动电流比较，若第二驱动电流大于第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电，使得光源开启的瞬间，可以跳过光源开启后系统恢复工作的时间，加快光源的电流上升速度，使光源的电流迅速达到第二驱动电流。同时，若第二驱动电流小于第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制第一开关管工作在线性区，使第一开关管两端承受一部分压降，进而使得光源在开通的瞬间，光源两端不会承受与第一驱动电流对应的高电压，从而抑制电流过冲。因此，本申请实施例提供的电流控制方法使得光源的驱动电流在任意电流大小之间切换时，开通瞬间均已达到稳态，从而实现任意电流快速、稳定的切换。
如图9所示，本申请实施例还提供一种开关电源电路300，该开关电源电路300包括主电源电路310以及连接于主电源电路310的控制模块320。主电源电路310包括用于对光源充电的负载电容以及用于控制光源通断的第一开关管；控制模块320被配置为当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较；若第二驱动电流大于或等于第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电；若第二驱动电流小于第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制第一开关管工作在线性区。
本申请实施例中，将光源经历色轮分段区域期间称之为分段时间，将光源经历色段轮辐区期间称之为轮辐时间。当光源经历两个相邻的第一分段区域和第二分段区域时，光源需要依次经历第一分段时间、轮辐时间以及第二分段时间。光源在第一分段时间对应所需的驱动电流为第一驱动电流，光源在第二分段时间对应所需的驱动电流为第二驱动电流。当光源经历两个相邻的第一分段区域和第二分段区域时，需要将第一驱动电流切换到第二驱动电流，第二驱动电流即为切换后所需的驱动电流。
控制模块320通过将切换后所需的第二驱动电流与切换前的第一驱动电流比较，若第二驱动电流大于第一驱动电流，光源从第一分段时间至第二分段时间 时，其驱动电流要从大电流切换到小电流，也意味着驱动电流需要下降。在进入轮辐时间期间时，光源被关闭；轮辐时间结束后进入第二分段时间光源重新开启。本实施例中，在光源关闭时进入轮辐时间期间对负载电容进行预充电，使得在轮辐时间期间即预先将光源两端的电压从与第一驱动电流对应的电压值上升至与第二驱动电流对应的电压值。也就是说，在光源开通前，光源两端的电压已经预先达到了与第二分段时间所需的第二驱动电流对应的电压值，系统提前进入稳态并为光源的开启做好了准备，使得在第二分段时间来临时光源开启的瞬间，可以跳过光源开启后系统恢复工作的时间，加快光源的电流上升速度，使光源的电流迅速达到第二驱动电流。
若第二驱动电流等于第一驱动电流，光源从第一分段时间切换至第二分段时间时，其驱动电流的大小不变。由于在切换的过程中光源需要经过轮辐时间，而在轮辐时间内光源被关闭，因此光源从第一分段时间切换至第二分段时间的过程，驱动电流的大小虽然不变，但是驱动电流仍然需要一个上升的过程，也即从第一驱动电流下降到零，再从零上升到第二驱动电流。本实施例中，在该过程中，在光源关闭时进入轮辐时间期间对负载电容进行预充电，使得在轮辐时间期间即预先将光源两端的电压从与第一驱动电流对应的电压值上升至与第二驱动电流对应的电压值。因此，即使第二驱动电流与第一驱动电流的大小不变，也能够加快光源的电流上升速度，使光源的电流迅速达到第二驱动电流，提高电流的切换速度。
若第二驱动电流小于第一驱动电流，光源从第一分段时间至第二分段时间时，其驱动电流要从大电流切换到小电流，也意味着驱动电流需要下降。在进入轮辐时间期间时，光源被关闭；轮辐时间结束后进入第二分段时间光源重新开启。光源进入轮辐时间时需要导通第一开关管以开启光源，本实施例中，在光源进入轮辐时间时，对第一开关管的导通信号进行延时，并在延时期间控制第一开关管工作在线性区，使第一开关管缓慢导通，在延时时间结束时，导通信号完全导通第一开关管进而开启光源。由于第一开关管在导通之前工作在线性区，其两端承 受了一部分压降，使得光源在开通的瞬间已达到稳态，光源两端不会承受与第一驱动电流对应的高电压，从而抑制电流过冲。
因此，本实施例提供的开关电源电路300使得光源的驱动电流在任意电流大小之间切换时，开通瞬间均已达到稳态，从而实现任意电流快速、稳定的切换。
具体而言，如图10所示，主电源电路310包括第一开关管Q1、第二开关管Q2、负载电容C1、电感L1以及二极管D1，其中第一开关管Q1和第二开关管Q2为NMOS管。电感L1的一端连接于电源、另一端连接于二极管D1的正极；二极管D1的负极连接于负载电容C1的第一端；第二开关管Q2的漏极连接在电感L1与二极管D1之间、源极接地、栅极连接控制模块320；负载电容C1的第一端还用于连接光源的一端、第二端连接于第二开关管Q2的源极；第一开关管Q1的漏极用于连接光源的另一端、源极连接于负载电容C1的第二端、栅极连接于控制模块320。
控制模块320连接于第一开关管Q1与第二开关管Q2以控制第一开关管Q1和第二开关管Q2的通断。本实施例中，控制模块320可以包括主板、恒流控制芯片以及MCU(Microcontroller Unit，微控制单元)，其中主板上设置有主控器。在一些实施方式中，控制模块320可以仅包括主板；恒流控制芯片和MCU可以为外置芯片。
本实施例中，控制模块320被配置为若第二驱动电流小于第一驱动电流，则在光源的开启信号上升沿触发时，对第一开关管Q1的导通信号进行延时，并在延时期间控制第一开关管Q1的门极驱动电压，使第一开关管Q1工作在线性区；若第二驱动电流大于或等于第一驱动电流，则在光源的开启信号下降沿触发时，在第三预设时间内保持输出PWM(Pulse Width Modulation，脉冲宽度调制)信号至第二开关管Q2，以控制负载电容C1充电；其中，第三预设时间小于色轮的轮辐时间。
如图11与图12所示，图11与图12示出了本实施例提供的开关电源电路 300的工作原理示意图。需要说明的是，图11与图12为控制模块的原理示意图。主板上的主控制器输出SPK信号至恒流控制芯片，使得恒流控制芯片根据该信号SPK输出信号Sq1至第一开关管Q1以及输出信号Sq2至第二开关管Q2。其中，当信号SPK为高电平时，信号Sq1为高电平、信号Sq2为高频PWM信号；当信号SPK为低电平时，信号Sq1和信号Sq2均为低电平。如图13所示，图示出了本实施例中，光源在且切换不同的分段区域时，系统的控制量与状态量随时间变化的示意图。以下将结合图11～13对本申请实施例的原理进行说明。需要说明的是，本申请实施例仅以控制信号的时间控制方式为例进行说明，实际上控制信号的控制方式不仅限于此。
首先对图13所示的各个信号进行说明，同步信号为用于指示光源开通的开启信号V2，同步信号为高电平时用于指示光源开通，同步信号为低电平时用于指示光源关闭；信号Sq1和信号Saq1为第一开关管Q1的导通信号；信号Sq2和信号Saq2为第二开关管Q2的控制信号。
在图13中，光源依次经历色轮的第一分段区域、第一轮辐区、第二分段区域、第二轮辐区以及第三分段区域。其中，T0～T1为第一分段时间、T1～T3为第一轮辐时间、T3～T4为第二分段时间、T4～T5为第二轮辐时间、T5～T8为第三分段时间。假设第二分段区域对应的第二驱动电流大于第一分段区域对应的第一驱动电流；第三分段区域对应的第三驱动电流小于第二分段区域对应的第二驱动电流。也就是说，光源从第一分段区域切换到第二分段区域时，驱动电流需要上升；光源从第二分段区域切换到第三分段区域时，驱动电流需要下降。需要说明的是，由于当第二驱动电流等于第一驱动电流时的原理与当第二驱动电流大于第一驱动电流时的原理一致，因此以下仅以第二驱动电流大于第一驱动电流时的情况为例进行说明。
T0～T1阶段：光源处于第一分段时间，主板输出信号高电平的信号SPK至恒流控制芯片，此时恒流控制芯片输出至第一开关管Q1的信号Sq1为高电平，进而开通光源；恒流控制芯片输出至第二开关管Q2的信号Sq2为高频PWM信 号。
T1时刻：如图12与图13所示，光源离开第一分段时间进入第一轮辐时间，同步信号为下降沿，该同步信号为与信号SPK同步且用于指示光源开通的开启信号V2，也即同步信号的时序与信号SPK的时序同步。此时由于下一分段时间所需的第二驱动电流大于上一分段时间的第一驱动电流，在同步信号为下降沿时主板触发产生信号Stq2，同时该信号Stq2触发PWM工作模块产生信号Saq2，信号Saq2为高频PWM信号，该高频PWM信号被输出入至第二开关管Q2以控制第二开关管Q2高频PWM工作。
T1～T2阶段：该阶段处于第一轮辐时间期间，此时光源被关闭，在光源关闭期间，信号Sq2驱动第二开关管Q2高频PWM工作，进而为负载电容C1充电，通过设置信号Sq2的频率、占空比以及持续时间，进而可以将负载电容C1的电压在光源开通前就预先上升至与第二驱动电流对应的电压值。值得说明的是，信号Sq2可以在第一轮辐时间内的任意时间段输入至第二开关管Q2并驱动第二开关管Q2高频PWM工作，而并不仅限于在T1时刻输入至第二开关管Q2。
T3时刻：光源离开第一轮辐时间进入第二分段时间，此时同步信号为上升沿，信号SPK也为上升沿，恒流控制芯片输出高电平的信号Sq1至第一开关管Q1开通光源，并输出高频PWM的Sq2信号至第二开关管Q2。此时，由于负载电容C1两端的电压已经预先上升到了与第二驱动电流对应的电压值，使得光源两端的电压也已经预先上升到了与第二驱动电流对应的电压值，那么此刻在光源开通的瞬间，光源的驱动电流能够迅速上升至与第二驱动电流对应的电流值，系统迅速进入恒流闭环稳态。
T3～T4阶段：光源处于第二分段时间持续发光，此时系统处于恒流闭环稳态。
T4～T5阶段：光源处于第二轮辐时间，此时同步信号为低电平，信号SPK也为低电平，恒流控制芯片输出低电平的信号Sq1至第一开关管Q1并输出低电 平的信号Sq2至第二开关管Q2，光源被关闭。
T5时刻：如图11与图13所示，光源离开第二轮辐时间进入第三分段时间，此时同步信号为上升沿。由于下一分段时间所需的第三驱动电流小于上一分段时间的第二驱动电流，此时在同步信号为上升沿时触发产生信号Stq1。该信号Stq1触发延时模块工作，进而触发信号SPK进行延时，也即延长信号SPK低电平持续时间，使得信号Sq1延时导通第一开关管Q1。同时信号Stq1触发产生信号Saq1，该信号Saq1被输入至第一开关管Q1。
T5～T7阶段：该阶段保持信号Saq1输入至第一开关管Q1，通过设置Saq2的上升沿速度，触发第一开关管Q1缓慢开通，此时第一开关管Q1工作在线性区。由于MOS管的特性，当MOS管工作在线性区时，其相当于可变电阻，因此此时第一开关相当于与光源串联的可变电阻，进而能够为光源承担一部分压降。
T5～T6阶段：该阶段为延时模块的延时时间。本实施例中，T5～T7阶段的持续时间大于T5～T6的持续时间，使得在延时模块的整个延时期间，都能够保持信号Saq2输入至第一开关管Q1。在此阶段，信号SPK为低电平，因此信号Sq1和信号Sq2均为低电平。
T6时刻：延时结束，主板输出高电平的信号SPK至恒流控制芯片。需要说明的是，延时模块在延时期间保持信号SPK为低电平，也即将信号SPK低电平时间延长，延时结束再将信号SPK转为高电平，此时SPK信号的时序与同步信号不同步。进一步地，当信号SPK转变为高电平时，恒流控制芯片即输出高电平的Sq1信号至第一开关管Q1使第一开关管Q1完全导通，在光源开通的瞬间，第一开关管Q1承担一部分压降，从而抑制电流过冲。
T6～T8阶段：光源处于第三分段时间持续发光，此时系统处于恒流闭环稳态。
综上所述，当光源经历色轮相邻的分段区域时，如果驱动电流需要上升，则 在色轮的轮辐时间期间对负载电容C1进行预充电，从而在光源开通瞬间电流快速上升，系统迅速达到稳态；如果驱动电流需要下降，则对第一开关管Q1的导通信号进行延时，并在延时期间控制第一开关管Q1工作在线性区，从而在光源开通瞬间抑制电流过冲。由此，不管光源在切换分段区域时前后的驱动电流相差多大，都能达到理想的控制效果，实现任意分段电流的快速、稳定控制。基于此，分段电流之间可以相差更大，从而减少对色轮各色角度比例的束缚，并且能够通过分段电流纠正白平衡的系统偏差，提升产品的良率，实现更好的显示效果。
本申请实施例提供的开关电源电路，设置有主电源电路以及控制模块，通过控制模块在光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较，若第二驱动电流大于或等于第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电，使得光源开启的瞬间，可以跳过光源开启后系统恢复工作的时间，加快光源的电流上升速度，使光源的电流迅速达到第二驱动电流。同时，若第二驱动电流小于第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制第一开关管工作在线性区，使第一开关管两端承受一部分压降，进而使得光源在开通的瞬间，光源两端不会承受与第一驱动电流对应的高电压，从而抑制电流过冲。因此，本申请实施例提供的电流控制方法使得光源的驱动电流在任意电流大小之间切换时，开通瞬间均已达到稳态，从而实现任意电流快速、稳定的切换。
如图14所示，本申请实施例还提供一种投影设备400，该投影设备400包括光源410、色轮420以及上述的开关电源电路300。其中，色轮410位于光源420的光路上，开关电源电路300电连接于光源，以控制光源410出光。
本申请实施例提供的投影设备，设置有光源、色轮以及开关电源电路，通过开关电源电路在光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较，若第二驱动电流大于或等于第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电，使得光源开启的瞬间，可以跳过光源开启后系统恢复工作的时间，加快光源的电流上升速度，使光源的电流迅速达到 第二驱动电流。同时，若第二驱动电流小于第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制第一开关管工作在线性区，使第一开关管两端承受一部分压降，进而使得光源在开通的瞬间，光源两端不会承受与第一驱动电流对应的高电压，从而抑制电流过冲。因此，本申请实施例提供的电流控制方法使得光源的驱动电流在任意电流大小之间切换时，开通瞬间均已达到稳态，从而实现任意电流快速、稳定的切换。由此，分段电流之间可以相差更大，从而减少对色轮各色角度比例的束缚，并且能够通过分段电流纠正白平衡的系统偏差，提升产品的良率，实现更好的显示效果。
以上所述，仅是本申请的较佳实施例而已，并非对本申请作任何形式上的限制，虽然本申请已以较佳实施例揭示如上，然而并非用以限定本申请，任何本领域技术人员，在不脱离本申请技术方案范围内，当可利用上述揭示的技术内容做出些许更动或修饰为等同变化的等效实施例，但凡是未脱离本申请技术方案内容，依据本申请的技术实质对以上实施例所作的任何简介修改、等同变化与修饰，均仍属于本申请技术方案的范围内。

Claims (10)

  1. 一种电流控制方法，应用于开关电源电路，所述开关电源电路至少包括用于对光源充电的负载电容以及用于控制光源通断的第一开关管，其特征在于，包括：
    当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较；
    若所述第二驱动电流大于或等于所述第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电；
    若所述第二驱动电流小于所述第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管工作在线性区。
  2. 如权利要求1所述的电流控制方法，其特征在于，所述对第一开关管的导通信号进行延时，并在延时期间将所述第一开关管工作在线性区，包括：
    在光源的开启信号上升沿触发时，对所述第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管的门极驱动电压，使所述第一开关管工作在线性区。
  3. 如权利要求2所述的电流控制方法，其特征在于，所述导通信号包括第一导通信号以及第二导通信号，所述第二导通信号的电压大于所述第一导通信号的电压；所述在光源的开启信号上升沿触发时，对所述第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管的门极驱动电压，使所述第一开关管工作在线性区，包括：
    在光源的开启信号上升沿触发时，在第一预设时间内保持输出所述第一导通信号至所述第一开关管，并调整所述第一导通信号的上升沿速度；以及
    在光源的开启信号上升沿触发时，延时第二预设时间，并在所述第二预设时 间到达时输出所述第二导通信号至所述第一开关管；其中，所述第一预设时间大于所述第二预设时间。
  4. 如权利要求1所述的电流控制方法，其特征在于，所述开关电源电路还包括用于控制所述负载电容充电的第二开关管；所述在色轮的轮辐时间期间对负载电容进行预充电，包括：
    在光源的开启信号下降沿触发时，在第三预设时间内保持输出PWM信号至所述第二开关管，以控制负载电容充电；所述第三预设时间小于色轮的轮辐时间。
  5. 如权利要求4所述的电流控制方法，其特征在于，所述PWM信号包括第一PWM信号以及第二PWM信号；所述第一PWM信号在光源的开启信号高电平时输入至所述第二开关管，所述第二PWM信号在所述第三预设时间内保持输入至所述第二开关管。
  6. 一种开关电源电路，其特征在于，包括：
    主电源电路，包括用于对光源充电的负载电容以及用于控制光源通断的第一开关管；
    控制模块，连接所述主电源电路，被配置为：
    当光源的驱动电流需要切换时，将切换后所需的第二驱动电流与切换前的第一驱动电流比较；
    若所述第二驱动电流大于或等于所述第一驱动电流，则在色轮的轮辐时间期间对负载电容进行预充电；
    若所述第二驱动电流小于所述第一驱动电流，则对第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管工作在线性区。
  7. 如权利要求6所述的开关电源电路，其特征在于，所述控制模块还被配 置为：若所述第二驱动电流小于所述第一驱动电流，则在光源的开启信号上升沿触发时，对所述第一开关管的导通信号进行延时，并在延时期间控制所述第一开关管的门极驱动电压，使所述第一开关管工作在线性区。
  8. 如权利要求6所述的开关电源电路，其特征在于，所述主电源电路还包括用于控制负载电容充电的第二开关管；所述控制模块还被配置为：
    若所述第二驱动电流大于或等于所述第一驱动电流，则在光源的开启信号下降沿触发时，在第三预设时间内保持输出PWM信号至所述第二开关管，以控制负载电容充电；所述第三预设时间小于色轮的轮辐时间。
  9. 如权利要求6～8任一项所述的开关电源电路，其特征在于，所述主电源电路包括第一开关管、第二开关管、负载电容、电感以及二极管；所述电感的一端连接于电源、另一端连接于所述二极管的正极；所述二极管的负极连接于所述负载电容的第一端；所述第二开关管的漏极连接在所述电感与所述二极管之间、源极接地、栅极连接所述控制模块；所述负载电容的第一端还用于连接光源的一端、第二端连接于所述第二开关管的源极；所述第一开关管的漏极用于连接光源的另一端、源极连接于所述负载电容的第二端、栅极连接于所述控制模块。
  10. 一种投影设备，其特征在于，包括上述权利要求6～9任一项所述开关电源电路；所述投影设备还包括：
    光源，电连接于所述开关电源电路；以及
    色轮，位于所述光源的光路。
PCT/CN2021/103942 2020-07-02 2021-07-01 电流控制方法、开关电源电路以及投影设备 Ceased WO2022002185A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010633849.8A CN113885279B (zh) 2020-07-02 2020-07-02 电流控制方法、开关电源电路以及投影设备
CN202010633849.8 2020-07-02

Publications (1)

Publication Number Publication Date
WO2022002185A1 true WO2022002185A1 (zh) 2022-01-06

Family

ID=79012665

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/103942 Ceased WO2022002185A1 (zh) 2020-07-02 2021-07-01 电流控制方法、开关电源电路以及投影设备

Country Status (2)

Country Link
CN (1) CN113885279B (zh)
WO (1) WO2022002185A1 (zh)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN120454687B (zh) * 2025-04-21 2026-04-14 中国舰船研究设计中心 一种时序调制高压脉冲功率发生器及其时序调制方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101065974A (zh) * 2004-11-24 2007-10-31 皇家飞利浦电子股份有限公司 投影系统及操作放电灯的方法
JP2007292882A (ja) * 2006-04-21 2007-11-08 Sharp Corp プロジェクタ
US20130169184A1 (en) * 2011-12-28 2013-07-04 Minebea Co., Ltd. Light source control device and light source control method
CN103728824A (zh) * 2013-12-30 2014-04-16 苏州佳世达光电有限公司 光源系统
CN106154711A (zh) * 2015-04-09 2016-11-23 深圳市光峰光电技术有限公司 一种投影系统及其色域控制方法
CN108255001A (zh) * 2016-12-28 2018-07-06 深圳市光峰光电技术有限公司 投影系统

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7327128B2 (en) * 2004-12-29 2008-02-05 Intel Corporation Switching power supply transient suppression
JP2006259654A (ja) * 2005-03-19 2006-09-28 Zero Rabo Kk プロジェクタ
JP5151565B2 (ja) * 2008-03-06 2013-02-27 ウシオ電機株式会社 プロジェクタ用の光源装置の駆動方法
CN103676427B (zh) * 2012-08-31 2016-01-06 卡西欧计算机株式会社 有效利用轮辐期间提供高画质图像的投影装置、投影方法
CA2935772C (en) * 2014-02-04 2021-08-03 Canrig Drilling Technology Ltd. Generator load control
CN106371275B (zh) * 2015-07-22 2018-07-24 浙江欣邦科技信息有限公司 一种对光源进行时序脉冲补偿的激光投影机
DE102016203355A1 (de) * 2016-03-01 2017-09-07 Kuka Roboter Gmbh Elektrische Vorrichtung mit einem getakteten Netzteil und Verfahren zum Überprüfen des Netzteils der elektrischen Vorrichtung
US10013032B1 (en) * 2017-10-03 2018-07-03 Western Digital Technologies, Inc. Current balancing circuit for multiple supply voltage systems

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101065974A (zh) * 2004-11-24 2007-10-31 皇家飞利浦电子股份有限公司 投影系统及操作放电灯的方法
JP2007292882A (ja) * 2006-04-21 2007-11-08 Sharp Corp プロジェクタ
US20130169184A1 (en) * 2011-12-28 2013-07-04 Minebea Co., Ltd. Light source control device and light source control method
CN103728824A (zh) * 2013-12-30 2014-04-16 苏州佳世达光电有限公司 光源系统
CN106154711A (zh) * 2015-04-09 2016-11-23 深圳市光峰光电技术有限公司 一种投影系统及其色域控制方法
CN108255001A (zh) * 2016-12-28 2018-07-06 深圳市光峰光电技术有限公司 投影系统

Also Published As

Publication number Publication date
CN113885279B (zh) 2025-09-30
CN113885279A (zh) 2022-01-04

Similar Documents

Publication Publication Date Title
CN100452934C (zh) 发光二极管驱动器
CN100481164C (zh) 发光二极管驱动器
EP3005837B1 (en) Slew rate controlled driver circuits
US20110109537A1 (en) Backlight control for display devices
JP2010124676A (ja) 電源装置
TWI423727B (zh) 發光二極體的驅動電路
JP2019129109A (ja) 光源装置、投写型表示装置、及び、半導体装置
US20230299766A1 (en) Darlington transistor drive circuit, method and switching power supply management chip
US11172556B2 (en) Light emitting element drive device
CN114552991B (zh) 可实现输出功率快速切换的dc-dc电源架构及其控制方法
WO2022002185A1 (zh) 电流控制方法、开关电源电路以及投影设备
TWI815768B (zh) 顯示裝置及其驅動器
WO2021121300A1 (zh) 电流控制电路、方法以及投影设备
WO2021179769A1 (zh) 驱动电路、功率电路以及投影设备
CN112822818B (zh) 实现无极调光功能的电路结构
CN105120561B (zh) 一种调光控制电路及其方法
KR20130015720A (ko) 백라이트 유닛, 제어 장치 및 그 제어 방법
CN118885044A (zh) 闭环电流驱动电路及功率管输出电压摆率控制电路、方法
TWI449469B (zh) 光源之作動方法及電路裝置
CN114499179B (zh) 一种可变输出功率dc-dc电源架构及其控制方法
CN112996184B (zh) 固态光源调光控制电路及应用其的投影机
CN100574079C (zh) 逆变器及其驱动方法、以及使用了它的发光装置和液晶电视
US20190288675A1 (en) Pulse-width modulation controller and tri-state voltage generation method
CN222786094U (zh) 驱动电路及投影设备
CN223942863U (zh) 一种数字式调光调色电路

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21832899

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21832899

Country of ref document: EP

Kind code of ref document: A1