A power supply and light source system

Abstract

The present application discloses a power supply and a light source system. The power supply includes a control circuit and at least one constant current circuit. The control circuit is configured to receive a current command and generate a control signal according to the current command. The constant current circuit is connected to the control circuit and includes a DC conversion circuit and an amplification circuit connected to each other. The DC conversion circuit is configured to receive a power supply signal and a control signal, and convert the power supply signal into a constant current signal according to the control signal. The amplification circuit is configured to convert the power supply signal into a voltage feedback signal and input the voltage feedback signal to the control circuit. The control circuit is further configured to control the DC conversion circuit after receiving the voltage feedback signal to dynamically adjust the magnitude of the current signal output by the DC conversion circuit. Wherein, the current value in the current command is the same as the current value of the constant current signal output by the DC conversion circuit. In the above manner, the present application can dynamically adjust the output current and simplify the control circuit.

Description

Technical Field

[0001] This application relates to the field of circuit technologies, and particularly to a power supply and a light source system. Background Art

[0002] With the rapid development of LED (Light Emitting Diode) and laser technologies, LEDs and lasers are widely used in many fields. There are many solutions for driving LEDs or lasers. For example, in the Local Dimming control of flat-panel TVs, since a large number of LEDs with very small currents are used, the current for driving the array is very small, which is not suitable for application scenarios with large currents. For the light source of a laser projector, the driving current is relatively large. In the existing driving method, the lasers are all connected in series and then driven, which is not convenient for individually adjusting each laser. If each laser is configured with a driver, the volume and cost of the driver will be relatively high, which is not suitable for product applications. There is also a solution that uses a multi-channel linear constant current method to solve the problem of inability to adjust individually, but the analog quantity of each current is adjusted uniformly, which is not convenient for separate adjustment and has low usability. Summary of the Invention

[0003] This application provides a power supply and a light source system that can dynamically adjust the output current and simplify the control circuit.

[0004] To solve the above technical problems, the technical solution adopted in this application is: providing a power supply, which includes a control circuit and at least one constant current circuit. The control circuit is used to receive a current instruction and generate a control signal according to the current instruction, where the current instruction includes at least one current value. The constant current circuit is connected to the control circuit and includes a DC conversion circuit and an amplification circuit connected to each other. The DC conversion circuit is used to receive a power supply signal and a control signal, and convert the power supply signal into a constant current signal according to the control signal. The amplification circuit is used to convert the power supply signal into a voltage feedback signal and input the voltage feedback signal to the control circuit. The control circuit is further used to control the DC conversion circuit after receiving the voltage feedback signal to dynamically adjust the magnitude of the current signal output by the DC conversion circuit. Wherein, the current value in the current instruction is the same as the current value of the constant current signal output by the DC conversion circuit.

[0005] To solve the above technical problems, another technical solution adopted in this application is: to provide a light source system, which includes: a processing circuit, a power supply, and a light source. The processing circuit is configured to receive an image signal, process the image signal to obtain a corresponding current value, and generate a current command according to the current value. The power supply is connected to the processing circuit and is configured to receive the current command and output a constant current value corresponding to the current command. The light source is connected to the power supply and is configured to receive the current value output by the power supply and emit light with a corresponding brightness. Among them, the power supply is the above-mentioned power supply.

[0006] Through the above solution, the beneficial effects of this application are as follows: The control circuit can judge whether the current value output by the constant current circuit is the same as the corresponding current value in the current command by receiving the voltage feedback signal. If they are not the same, the control of the DC conversion circuit is performed to dynamically adjust the current output by the constant current circuit. When the power supply is applied to the light source system, one constant current circuit can control multiple constant current circuits at the same time, realizing the driving of the light source by the constant current circuit, which can simplify the control circuit, improve the integration degree of the control circuit, help reduce the circuit volume, and save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. Among them:

[0008] Figure 1 is a schematic structural diagram of an embodiment of the power supply provided by this application;

[0009] Figure 2 is a schematic structural diagram of another embodiment of the power supply provided by this application;

[0010] Figure 3 is Figure 2 the schematic structural diagram of the driving circuit in the embodiment shown;

[0011] Figure 4 is a schematic structural diagram of an embodiment of the light source system provided by this application;

[0012] Figure 5 is a schematic structural diagram of another embodiment of the light source system provided by this application;

[0013] Figure 6 is Figure 5 the schematic structural diagram of the light-emitting component in the embodiment shown;

[0014] Figure 7 is Figure 5Another layout schematic diagram of the light source system in the illustrated embodiment. Detailed implementation manners

[0015] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0016] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of an embodiment of a power supply provided by the present application. The power supply 10 includes: a control circuit 11 and at least one constant current circuit 12.

[0017] The control circuit 11 is configured to receive a current command and generate a control signal according to the current command. Specifically, the control circuit 11 may be an MCU (Microcontroller Unit), and the current command includes at least one current value.

[0018] The constant current circuit 12 is connected to the control circuit 11. The constant current circuit 12 includes a DC conversion circuit 121 and an amplification circuit 122 connected to each other. The constant current circuit 12 can output multiple constant current values under the control of the control circuit 11. Each constant current corresponds to the current value in the current command. For example, the power supply 10 is connected to a light emitting component, and the light emitting component includes a red light source, a green light source, and a blue light source. The light sources (including the red light source, the green light source, and the blue light source) may be LED light sources or laser light sources. At least one current value in the current command includes three current values I1 - I3. After receiving the current command, the control circuit 11 can first output a constant current value I1 to the red light source, then output a constant current value I2 to the green light source, and finally output a constant current value I3 to the blue light source, so that the light emitting component emits light with corresponding brightness.

[0019] The DC conversion circuit 121 is configured to receive a power supply signal and a control signal, and convert the power supply signal into a constant current signal according to the control signal. Specifically, the current value in the current command is the same as the current value of the constant current signal output by the DC conversion circuit 121. The power supply signal is a DC signal, such as 12V. The DC conversion circuit 121 may be a BUCK circuit (step-down conversion circuit), which can process the input power supply signal and output a current signal.

[0020] The amplifying circuit 122 is used to convert the power supply signal into a voltage feedback signal and input the voltage feedback signal to the control circuit 11. After receiving the voltage feedback signal, the control circuit 11 controls the DC conversion circuit 121 to dynamically adjust the magnitude of the current signal output by the DC conversion circuit 121.

[0021] In this embodiment, the voltage feedback signal is obtained through the amplifying circuit 122. The control circuit 11 can judge whether the current value output by the constant current circuit 12 is the same as the corresponding current value in the current command according to the voltage feedback signal. If they are not the same, the control circuit 11 controls the DC conversion circuit 121 to dynamically adjust the current output by the constant current circuit 12, so that the constant current circuit 12 outputs a constant current value that is the same as the corresponding current value in the current command.

[0022] Please refer to Figure 2 , Figure 2 FIG. is a schematic structural diagram of another embodiment of the power supply provided by the present application. In this embodiment, the power supply 10 further includes a fuse 13 and a common mode coil 14. The constant current circuit 12 further includes: a current detection circuit 123 and a drive circuit 124.

[0023] To prevent the circuit from short - circuiting due to excessive current or voltage, a fuse 13 is provided. One end of the fuse 13 is used to receive the power supply signal, and the other end of the fuse 13 is connected to the current detection circuit 123. When the amplitude of the power supply signal is greater than the second preset voltage value, the fuse 13 can prevent the power supply signal from flowing into the DC conversion circuit 121; specifically, the second preset voltage value is the safety voltage of the DC conversion circuit 121. When the voltage of the power supply signal is greater than the second preset voltage value, the fuse 13 cuts off the path between it and the DC conversion circuit 121, so that the power supply signal cannot flow into the DC conversion circuit 121.

[0024] The DC conversion circuit 121 includes: a storage capacitor C1, an inductor L, a diode D, and a first switching transistor T1. One end of the storage capacitor C1 is used to receive the power supply signal transmitted through the fuse 13, and the other end of the storage capacitor C1 is connected to one end of the inductor L. The storage capacitor C1 may include multiple capacitors connected in parallel. The other end of the inductor L is connected to the first end of the first switching transistor T1; one end of the diode D is connected to one end of the storage capacitor C1, and the other end of the diode D is connected to the other end of the inductor L; the second end of the first switching transistor T1 is connected to the drive circuit 124, and the third end of the first switching transistor T1 is grounded; specifically, the first switching transistor T1 is an N - type MOS transistor (Negative channel Metal Oxide Semiconductor), and the first end, the second end, and the third end are the drain, the gate, and the source respectively.

[0025] The common-mode coil 14 is used to filter out interference signals. The first end of the common-mode coil 14 is connected to the current detection circuit 123, and the second end of the common-mode coil 14 is connected to the DC conversion circuit 121. Specifically, it is connected to the other end of the storage capacitor C1. The third end of the common-mode coil 14 serves as the positive electrode LD+ of the power supply 10, outputting a constant current signal, and the fourth end of the common-mode coil 14 serves as the negative electrode LD- of the power supply 10.

[0026] The current detection circuit 123 is connected to the amplification circuit 122 and the DC conversion circuit 121. It is used to detect the average current of the signal input to the constant current circuit 12 and the peak current of the signal output by the constant current circuit 12, and can accurately detect the peak current week by week to avoid misdetection or malfunction. Moreover, a grounding resistor is used to detect the peak current, with good anti-interference performance, and there is no need for operational amplifier conversion, improving the response speed. Specifically, as Figure 2 shown, the current detection circuit 123 includes a first resistor R1 and a second resistor R2. One end of the first resistor R1 receives a power supply signal, which is connected to the other end of the fuse 13. The other end of the first resistor R1 is connected to the amplification circuit 122. Specifically, it is connected to the first end of the common-mode coil 14. The first resistor R1 can be connected to the control circuit 11. By detecting the current flowing into the first resistor R1, the average current detection can be achieved. The second resistor R2 is the grounding resistor. One end of the second resistor R2 is connected to the DC conversion circuit 121. Specifically, it is connected to the third end of the first switching tube T1. The other end of the second resistor R2 is grounded. The second resistor R2 can be connected to the control circuit 11. By detecting the current flowing through the second resistor R2, the peak current detection can be achieved.

[0027] The drive circuit 124 is connected to the control circuit 11 and the DC conversion circuit 121. It is used to provide a drive signal to the DC conversion circuit 121 to enable the DC conversion circuit 121 to operate. Specifically, in combination with Figure 3 and Figure 4, the driving circuit 124 includes a driving chip 1241 and a peripheral circuit. The peripheral circuit is used to supply power to the driving chip 1241, limit the magnitude of the signal input to the driving chip 1241, or limit the magnitude of the signal input to the first switching transistor T1. It includes a third resistor R3 to a seventh resistor R7 and a capacitor C2. One end of the third resistor R3 receives a power supply signal, the other end of the third resistor R3 is connected to one end of the capacitor C2 and the power supply terminal VDD of the driving chip 1241, and the other end of the capacitor C2 is grounded; one end of the fourth resistor R4 is connected to the control circuit 11, the other end of the fourth resistor R4 is connected to one end of the fifth resistor R5 and the signal input terminal Vin of the driving chip 1241, the other end of the fifth resistor R5 is connected to the ground terminal GND of the driving chip 1241 and is grounded, one end of the sixth resistor R6 is connected to the signal output terminal Vout of the driving chip 1241, the other end of the sixth resistor R6 is connected to one end of the seventh resistor R7 and the second end of the first switching transistor T1, and the other end of the seventh resistor R7 is grounded.

[0028] The amplifying circuit 122 includes a differential operational amplifying circuit 1221 and an operational amplifying circuit 1222 connected to each other. The differential operational amplifying circuit 1221 is connected to the current detection circuit 123. It is used to receive a first differential signal and a second differential signal output by the current detection circuit 123, and output a differential amplified signal to the operational amplifying circuit 1222; the operational amplifying circuit 1222 is used to amplify the differential operational amplified signal and output a voltage feedback signal to the control circuit 11.

[0029] The control circuit 11 is further configured to compare the voltage feedback signal with a first preset voltage value after receiving the voltage feedback signal output by the operational amplifying circuit 1222, and output a control signal to the driving circuit 124 according to the comparison result to adjust the duty cycle of the first switching transistor T1.

[0030] The power supply 10 can be connected to a load to drive the load to work. The load can be an LED or a laser. Specifically, when the power supply 10 is connected to the load, when the driving circuit 124 drives the first switching transistor T1 to conduct, the power supply signal sequentially passes through the first resistor R1 and the common mode coil 14, and is input to the load from the third terminal of the common mode coil 14, flows through the load into the inductor L, and then flows through the first switching transistor T1 and the second resistor R2 into the ground to complete energy storage, and the load enters the working state; when the first switching transistor T1 is turned off, the inductor L charges the storage capacitor C1 through the diode D, and the load does not work.

[0031] Please refer to Figure 4 , Figure 4 is a schematic structural diagram of an embodiment of a light source system provided by the present application. The light source system includes: a power supply 10, a processing circuit 20, and a light source 30.

[0032] The processing circuit 20 is configured to receive an image signal, process the image signal to obtain a corresponding current value, and generate a current command according to the current value. Specifically, the image signal may be a digital image signal, and the processing circuit 20 may be an FPGA (Field Programmable Gate Array).

[0033] Further, the processing circuit 20 is configured to analyze the image signal to obtain the brightness value corresponding to each pixel in the image, convert the brightness value into a current value, and issue the current command through a Serial Peripheral Interface (SPI). Specifically, for a color image, the brightness value corresponding to each pixel includes a red brightness value, a green brightness value, and a blue brightness value.

[0034] The power supply 10 is connected to the processing circuit 20. It is configured to receive the current command issued by the processing circuit 20 and output a corresponding constant current value. The power supply 10 is the power supply 10 in the above embodiment. Specifically, the power supply 10 includes at least one control circuit 11 and at least one constant current circuit 12. The control circuit 11 is configured to adjust the output signal after receiving the current command and the frame synchronization signal, so that the current value received by the light source 30 matches the brightness value of the image. The control circuit 11 may be a digital control chip, and the frame synchronization signal may be a signal output by a DLP (Digital Light Processing) chip or a video signal chip. After receiving the current command, the digital control chip quickly changes the output current value when the frame synchronization signal appears, realizing the rapid change of the currents of the three colors of red, green, and blue. The amplitude of the current output by each constant current circuit 12 can be dynamically adjusted between 0.5 A and 5 A. When quickly refreshing the current values of each constant current circuit 12, the refresh rate can reach 120 Hz.

[0035] The light source 30 is connected to the power supply 10. It is configured to receive the current value output by the power supply 10 and emit light with a corresponding brightness.

[0036] In a specific embodiment, in combination with Figure 4 and Figure 5 , the light source 30 includes a plurality of light-emitting components 31 arranged in an array. The light-emitting component 31 includes a red light-emitting element 311, a green light-emitting element 312, and a blue light-emitting element 313. The light-emitting elements (including the red light-emitting element 311, the green light-emitting element 312, or the blue light-emitting element 313) may be LEDs or lasers. For example, each power supply 10 includes two control circuits 11, and each control circuit 11 can control 4 constant current circuits 12. Since each light-emitting component 31 includes 3 light-emitting elements, each constant current circuit 12 can alternately drive 3 light-emitting elements, so 24 light-emitting elements can be driven to work.

[0037] As Figure 6 shown, the negative electrodes LD of the red light emitting element 311, the green light emitting element 312, and the blue light emitting element 313 are all connected to the negative electrode LD- of the power supply 10. The positive electrodes of the red light emitting element 311, the green light emitting element 312, and the blue light emitting element 313 are respectively connected to the positive electrode LD+ of the power supply 10 through the second switching tubes T21 - T23. The control terminals of the second switching tubes are connected to the control circuit 11. The control circuit 11 is used to output an enabling signal to the control terminals of the second switching tubes, so that the second switching tubes T21 - T23 corresponding to the red light emitting element 311, the green light emitting element 312, and the blue light emitting element 313 are turned on in turn, thereby realizing sequential light emission.

[0038] Furthermore, the control circuit 11 respectively generates a red light enabling signal RED_EN, a green light enabling signal GRE_EN, and a blue light enabling signal BLU_EN. When the red light enabling signal RED_EN is at a high level, and both the green light enabling signal GRE_EN and the blue light enabling signal BLU_EN are at a low level, the second switching tube T21 corresponding to the red light emitting element 311 is turned on, and the constant current circuit 12 outputs a signal to the red light emitting element 311 through the second switching tube T21, so that the red light emitting element 311 emits red light; when the green light enabling signal GRE_EN is at a high level, and both the red light enabling signal RED_EN and the blue light enabling signal BLU_EN are at a low level, the second switching tube T22 corresponding to the green light emitting element 312 is turned on, and the constant current circuit 12 sends a signal to the green light emitting element 312 through the second switching tube T22, so that the green light emitting element 312 emits green light; when the blue light enabling signal BLU_EN is at a high level, and both the red light enabling signal RED_EN and the green light enabling signal GRE_EN are at a low level, the second switching tube T23 corresponding to the blue light emitting element 313 is turned on, and the constant current circuit 12 sends a signal to the blue light emitting element 313 through the second switching tube T23, so that the blue light emitting element 313 emits blue light.

[0039] To avoid interference between the power supply line (i.e., the power channel) and the output line of the constant current circuit 12 (i.e., the control channel), the control channel and the power channel are staggered, as Figure 7 shown, the processing circuit 20 can be set at the upper middle position of the circuit board. The processing circuit 20 communicates with the two control circuits 11 respectively. The power supply interface 40 is set at the lower middle position of the circuit board. The power supply interface 40 is used to access the power supply signal.

[0040] This embodiment provides a solution suitable for local dimming of a projector. A digital control chip is used to control four constant current circuits 12. Each constant current circuit 12 can drive the red light-emitting element 311, the green light-emitting element 312, and the blue light-emitting element 313 in a time-sharing manner in combination with a frame synchronization signal. The control is precise, and local dimming of the projector can be achieved by cascading multiple circuits. Since multiple constant current circuits 12 can share a digital control chip, the number of digital control chips can be effectively reduced, which helps to simplify the control circuit, reduce the circuit volume, and save costs.

[0041] The above are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A power supply, characterized in that, Including: A control circuit, configured to receive a current command and a frame synchronization signal, and generate a control signal according to the current command and the frame synchronization signal, wherein the current command includes at least one current value; At least one constant current circuit, connected to the control circuit, configured to output a plurality of constant current values under the control of the control circuit, including a DC conversion circuit and an amplification circuit connected to each other, the DC conversion circuit is configured to receive a power supply signal and the control signal, and convert the power supply signal into a constant current signal according to the control signal; the amplification circuit is configured to convert the power supply signal into a voltage feedback signal, and input the voltage feedback signal to the control circuit; The control circuit is further configured to, after receiving the voltage feedback signal, control the DC conversion circuit, and dynamically adjust the magnitude of the current signal output by the DC conversion circuit, so as to dynamically adjust the output current of the at least one constant current circuit; Wherein, the current value in the current command is the same as the current value of the constant current signal output by the DC conversion circuit; The constant current circuit further includes a current detection circuit, connected to the amplification circuit and the DC conversion circuit, configured to detect the average current of the signal input to the constant current circuit and the peak current of the signal output by the constant current circuit; The amplification circuit includes an operational amplifier circuit and a differential operational amplifier circuit connected to each other, the differential operational amplifier circuit is connected to the current detection circuit, configured to receive a first differential signal and a second differential signal output by the current detection circuit, and output a differential amplified signal to the operational amplifier circuit; the operational amplifier circuit is configured to amplify the differential amplified signal, and output the voltage feedback signal to the control circuit.

2. The power supply according to claim 1, wherein The constant current circuit further includes a drive circuit, the drive circuit is connected to the control circuit and the DC conversion circuit, configured to provide a drive signal to the DC conversion circuit, so that the DC conversion circuit operates.

3. The power supply according to claim 2, wherein The DC conversion circuit includes: a storage capacitor, an inductor, a diode, and a first switching tube, one end of the storage capacitor is configured to receive the power supply signal, the other end of the storage capacitor is connected to one end of the inductor, the other end of the inductor is connected to the first end of the first switching tube; one end of the diode is connected to one end of the storage capacitor, the other end of the diode is connected to the other end of the inductor; the second end of the first switching tube is connected to the drive circuit, and the third end of the first switching tube is grounded.

4. The power supply according to claim 3, wherein The control circuit is further configured to, after receiving the voltage feedback signal, compare the voltage feedback signal with a first preset voltage value, and output a control signal to the drive circuit according to the comparison result, so as to adjust the duty cycle of the first switching tube.

5. The power supply according to claim 2, wherein The power supply also includes a fuse and a common-mode coil. The fuse is used to prevent the power supply signal from flowing into the DC conversion circuit when the amplitude of the power supply signal is greater than a second preset voltage value. One end of the fuse is used to receive the power supply signal, and the other end of the fuse is connected to the current detection circuit. The common-mode coil is used to filter out interference signals. The first end of the common-mode coil is connected to the current detection circuit, and the second end of the common-mode coil is connected to the DC conversion circuit. The third end of the common-mode coil serves as the positive pole of the power supply, and the fourth end of the common-mode coil serves as the negative pole of the power supply.

6. The power supply according to claim 2, wherein: The current detection circuit includes a first resistor and a second resistor, one end of the first resistor receives the power supply signal, and the other end of the first resistor is connected to the amplifier circuit; one end of the second resistor is connected to the DC conversion circuit, and the other end of the second resistor is grounded.

7. A light source system, characterized in that, include: a processing circuit, configured to receive an image signal, process the image signal to obtain a corresponding current value, and generate a current instruction according to the current value; a power supply connected to the processing circuit, configured to receive the current instruction and output a constant current value corresponding to the current instruction; a light source connected to the power supply, configured to receive the current value output by the power supply and emit light of corresponding brightness; Wherein, the power supply is the power supply according to any one of claims 1-6.

8. The light source system according to claim 7, wherein: The processing circuit is used to analyze the image signal to obtain the brightness value corresponding to each pixel in the image, convert the brightness value into a current value, and issue the current instruction through the serial peripheral interface; The power supply includes at least one control circuit, and the control circuit is used to adjust the output signal after receiving the current instruction and the frame synchronization signal so that the current value received by the light source matches the brightness value of the image.

9. The light source system according to claim 7, wherein: The light source includes a plurality of light-emitting components arranged in an array, the light-emitting components including a red light-emitting element, a green light-emitting element, and a blue light-emitting element. The cathodes of the red light-emitting element, the green light-emitting element, and the blue light-emitting element are all connected to the negative electrode of the power supply, and the anodes of the red light-emitting element, the green light-emitting element, and the blue light-emitting element are respectively connected to the positive electrode of the power supply through a second switching tube. The control end of the second switching tube is connected to the control circuit, and the control circuit is used to output an enable signal to the control end of the second switching tube so that the red light-emitting element, the green light-emitting element, and the blue light-emitting element emit light in turn.

Images