Driving circuit and projector circuit
By classifying the target devices, using an AC rectifier module and a DC/DC boost module to perform two DC/DC conversions on devices severely affected by harmonics, and a single voltage conversion on devices less affected by harmonics, the problem of balancing harmonic elimination with cost, power consumption and size in the drive circuit is solved, achieving efficient and low-cost harmonic suppression.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2026-03-20
AI Technical Summary
Existing drive circuits cannot simultaneously eliminate harmonics while meeting the requirements of cost, power consumption, and size, resulting in high device cost, significant power consumption, and large size.
After adopting the AC rectifier module, the target device that is severely affected by harmonics is subjected to two DC/DC conversions through the DC/DC boost module and the first DC/DC buck module. For the target device that is less affected by harmonics, the voltage is converted by the second DC/DC buck module, thereby reducing the conversion stage of the DC/DC buck module.
It effectively eliminates harmonic effects, reduces the cost, power consumption, and size of the drive circuit, and improves overall efficiency.
Smart Images
Figure CN224021628U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of drive technology, and in particular to a drive circuit and a projector circuit. Background Technology
[0002] In home appliances such as projectors and audio equipment, the alternating current and voltage are often distorted by power electronic devices such as rectifiers and frequency converters in the circuit, which in turn generate harmonics that affect the performance and lifespan of the home appliances. Specifically, this manifests as: projection distortion in projectors, sound quality distortion in audio equipment, increased current and voltage stress on internal electronic components leading to overheating, and excessive wear and tear on the light source of projectors.
[0003] Therefore, the current method for suppressing harmonics in the drive circuits of household appliances is to rectify the AC power from the mains, then perform DC / DC boost, and then DC / DC step down to the target voltage to power the target device. This eliminates harmonics by using two voltage transformations, thus protecting the target device from harmonic effects.
[0004] However, this results in a large power requirement in the DC / DC boost stage when there are multiple target devices, leading to high device costs and significant power consumption in the DC / DC boost circuit. Consequently, the overall cost, power consumption, and size of the drive circuit are greatly increased, making it a losing proposition. Utility Model Content
[0005] To address the aforementioned shortcomings, the purpose of this invention is to propose a driving circuit and a projector circuit that solves the problem of the driving circuit being unable to simultaneously meet the requirements of cost, power consumption, and size while eliminating harmonics.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] A driving circuit includes an AC rectifier module, a DC / DC boost module, a first DC / DC buck module, and a second DC / DC buck module; the AC rectifier module is electrically connected to the DC / DC boost module and the first DC / DC buck module in sequence, and then electrically connected to a first target device to drive the first target device.
[0008] The AC rectifier module is also electrically connected to the second DC / DC step-down module, and then electrically connected to the second target device to drive the second target device.
[0009] Furthermore, the DC / DC boost module is a PFC boost circuit, the first DC / DC buck module is a buck constant current source circuit, and the second DC / DC buck module is a buck constant voltage source circuit.
[0010] Furthermore, the first DC / DC step-down module includes a constant current source circuit, a step-down transformer T4, a constant current feedback circuit, and a constant current output processing circuit; the AC rectifier module is electrically connected to the constant current source circuit, the constant current source circuit is electrically connected to the primary side of the step-down transformer T4, the secondary side of the step-down transformer T4 is electrically connected to the constant current output processing circuit, and the constant current output processing circuit is electrically connected to the first target device;
[0011] The constant current feedback circuit is electrically connected between the constant current source circuit and the constant current output processing circuit; the constant current feedback circuit is connected to an external PWM signal and transmitted to the constant current source circuit to control the output signal of the constant current output processing circuit.
[0012] Furthermore, the second DC / DC step-down module includes a constant voltage source circuit, a step-down transformer T3, a constant voltage feedback circuit, and at least one constant voltage output processing circuit; the AC rectifier module is electrically connected to the constant voltage source circuit, the constant voltage source circuit is electrically connected to the primary side of the step-down transformer T3, the secondary side of the step-down transformer T3 is electrically connected to the constant voltage output processing circuit, and the constant voltage output processing circuit is electrically connected to the second target device;
[0013] The constant voltage feedback circuit is electrically connected to the constant voltage output processing circuit and then electrically connected to the constant voltage source circuit.
[0014] Furthermore, the constant current feedback circuit includes an optocoupler U5 and a feedback chip U3; the VCC terminal of the feedback chip U3 is electrically connected to the secondary side of the step-down transformer T4 through a power supply circuit, the voltage detection terminal of the feedback chip U3 is electrically connected to the positive terminal of the constant current output processing circuit through an external circuit, the current detection terminal of the feedback chip U3 is electrically connected to the negative terminal of the constant current output processing circuit through an external circuit, and the output terminal of the feedback chip U3 is electrically connected to the constant current source circuit through the optocoupler U5.
[0015] The voltage detection terminal of the feedback chip U3 is also connected to an external PWM signal via a peripheral circuit.
[0016] Furthermore, the constant voltage feedback circuit includes an optocoupler U6, a capacitor C16, a controllable voltage regulator U8, resistors R50, R51, R49, R53, R59, and a capacitor C27; the collector of the photodetector of the optocoupler U6 is electrically connected to the constant voltage regulator circuit, the emitter of the photodetector of the optocoupler U6 is connected to the GND ground terminal, and the capacitor C16 is connected in parallel between the collector and emitter of the photodetector of the optocoupler U6;
[0017] The anode of the light source of the optocoupler U6, one end of the resistor R50, and one end of the resistor R51 are all electrically connected. The cathode of the light source of the optocoupler U6, the other end of the resistor R50, and one end of the capacitor C27 are all electrically connected to the cathode of the controllable voltage regulator U8. The other end of the capacitor C27 is electrically connected to one end of the resistor R49. The other end of the resistor R49, one end of the resistor R59, and one end of the resistor R53 are all electrically connected to the reference electrode of the controllable voltage regulator U8. The anode of the controllable voltage regulator U8 and the other end of the resistor R53 are both connected to the SGND ground terminal. The other end of the resistor R51 and the other end of the resistor R59 are electrically connected.
[0018] When there is only one constant voltage output processing circuit, the other end of the resistor R59 is electrically connected to the constant voltage output processing circuit.
[0019] When there is more than one constant voltage output processing circuit, a resistor R55 is added for each additional constant voltage feedback circuit; one end of the resistor R59 is electrically connected to the reference electrode of the controllable voltage regulator U8, and the other end of the resistor R59 is electrically connected to the corresponding constant voltage output processing circuit.
[0020] Furthermore, the positive terminal of the AC rectifier module, which is electrically connected to the second DC / DC buck module, is connected in series with a thermistor NTC2, and the positive terminal of the DC / DC boost module, which is electrically connected to the first DC / DC buck module, is connected in series with a thermistor NTC1.
[0021] A projector circuit includes the aforementioned driving circuit, and further includes a projection light source and at least one electrical component; the first DC / DC step-down module of the driving circuit is electrically connected to the projection light source, and the second DC / DC step-down module of the driving circuit is electrically connected to the electrical component.
[0022] The technical solution provided by this utility model can include the following beneficial effects: Considering the cost, power consumption, and size of the drive circuit, the target devices are classified. The first target device, which is affected by harmonics and may cause distortion or failure (such as the light source of a projector and the speaker of an audio device), is rectified by an AC rectifier module (HV1) for safety, and then converted twice by a DC / DC boost module (HV2) and a first DC / DC buck module before driving the first target device, thus achieving the purpose of harmonic elimination. The second target device, which is less affected by harmonics (such as the cooling fan and the notification speaker in the projector, whose functional characteristics are not the core functional characteristics of the projector), is rectified by an AC rectifier module (HV1) for safety, and then driven by a second DC / DC buck module to the voltage level required by the second target device. This reduces the impact of harmonics on the drive circuit, and the cost, power consumption, and size of the drive circuit are greatly reduced because the DC / DC conversion stage of the first DC / DC buck module in the drive circuit is reduced. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of a driving circuit according to one embodiment of the present invention.
[0024] Figure 2 Is it like this? Figure 1 The circuit diagrams for the AC rectifier module and the DC / DC boost module are shown below.
[0025] Figure 3 Is it like this? Figure 1 The circuit diagram of the first DC / DC step-down module is shown.
[0026] Figure 4 Is it like this? Figure 1 The circuit diagram of the second DC / DC step-down module is shown.
[0027] Figure 5 This is a schematic diagram of a projector circuit according to one embodiment of the present invention.
[0028] The circuit includes: AC rectifier module 1, DC / DC boost module 2, first DC / DC buck module 3, second DC / DC buck module 4, constant current source circuit 31, buck transformer T4, constant current feedback circuit 32, constant current output processing circuit 33, constant voltage source circuit 41, buck transformer T3, constant voltage feedback circuit 42, constant voltage output processing circuit 43, optocoupler U5, feedback chip U3, optocoupler U6, capacitor C16, controllable voltage regulator U8, resistor R50, resistor R51, resistor R49, resistor R53, resistor R59, capacitor C27, thermistor NTC1, and thermistor NTC2.
[0029] Drive circuit 10, projection light source 20, electrical components 30. Detailed Implementation
[0030] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0031] In the description of embodiments of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0032] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model according to the specific circumstances.
[0033] The following is combined Figures 1 to 5 This describes a driving circuit and a projector circuit according to an embodiment of the present invention.
[0034] Example 1
[0035] A driving circuit includes an AC rectifier module 1, a DC / DC boost module 2, a first DC / DC buck module 3, and a second DC / DC buck module 4. The AC rectifier module 1 is electrically connected to the DC / DC boost module 2 and the first DC / DC buck module 3 in sequence, and then electrically connected to a first target device to drive the first target device.
[0036] After the AC rectifier module 1 is electrically connected to the second DC / DC step-down module 4, it is also electrically connected to the second target device to drive the second target device.
[0037] This utility model proposes a preferred embodiment of a driving circuit, such as... Figure 1As shown, considering the cost, power consumption, and size of the drive circuit, the target devices are classified. The first target device, which is susceptible to distortion or failure due to harmonics (such as the light source of a projector and the speaker of an audio device), is rectified by the AC rectifier module 1 (HV1) for safety purposes, and then converted twice by the DC / DC boost module 2 (HV2) and the first DC / DC buck module 3 before driving the first target device, thus achieving harmonic elimination. The second target device, which is less affected by harmonics (such as the cooling fan and the notification speaker in the projector, whose functional characteristics are not core functional characteristics of the projector), is rectified by the AC rectifier module 1 (HV1) for safety purposes, and then driven by the second DC / DC buck module 4 after voltage conversion to the voltage level required by the second target device. This reduces the impact of harmonics on the drive circuit, and the cost, power consumption, and size of the drive circuit are greatly reduced because the DC / DC conversion stage of the first DC / DC buck module 3 in the drive circuit is reduced.
[0038] Furthermore, the DC / DC boost module 2 is a PFC boost circuit, the first DC / DC buck module 3 is a buck constant current source circuit, and the second DC / DC buck module 4 is a buck constant voltage source circuit.
[0039] In this embodiment, to further reduce power consumption, the DC / DC boost module 2 preferably adopts a PFC boost circuit, which improves the output voltage while correcting its power factor to achieve DC / DC boost conversion; specifically as follows: Figure 2 As shown, the PFC chip U4 can be a BP2628 chip. The Boost PFC application circuit structure composed of this chip and its peripheral circuits can perform DC / DC boost conversion on the output voltage of the rectifier bridge DB1 of the AC rectifier module 1. Then, the common cathode and common anode diode D7 is turned on to one or more capacitors (such as capacitor C3, capacitor C5, and capacitor EC2) for filtering output (HV2).
[0040] Since the first target device is usually distorted or fails due to the influence of harmonic current, the first DC / DC step-down module 3 is preferably a step-down constant current source circuit to realize DC / DC step-down conversion and constant current output. As the functional characteristics of the second target device are not core functional characteristics of the installation equipment of the drive circuit, it is sufficient to keep the power supply of the second target device stable and maintain normal operation. Therefore, the second DC / DC step-down module 4 is preferably a step-down constant voltage source circuit to provide a stable voltage for the second target device.
[0041] Furthermore, the first DC / DC step-down module 3 includes a constant current source circuit 31, a step-down transformer T4, a constant current feedback circuit 32, and a constant current output processing circuit 33; the AC rectifier module 1 is electrically connected to the constant current source circuit 31, the constant current source circuit 31 is electrically connected to the primary side of the step-down transformer T4, the secondary side of the step-down transformer T4 is electrically connected to the constant current output processing circuit 33, and the constant current output processing circuit 33 is electrically connected to the first target device;
[0042] The constant current feedback circuit 32 is electrically connected between the constant current source circuit 31 and the constant current output processing circuit 33; the constant current feedback circuit 32 is connected to an external PWM signal and transmitted to the constant current source circuit 31 to control the output signal of the constant current output processing circuit 33.
[0043] In this embodiment, as Figure 3 As shown, the first DC / DC step-down module 3 needs to achieve DC / DC step-down conversion and constant current output, which requires a constant current source circuit 31, a step-down transformer T4, a constant current feedback circuit 32, and a constant current output processing circuit 33. The constant current source circuit 31 and the constant current feedback circuit 32 implement the constant current function. The constant current source circuit 31 mainly consists of a constant current chip U2 and its peripheral circuits (e.g., the constant current chip U2 is an LP8778 chip, and its peripheral circuits are as follows). Figure 3 The circuit within the dashed box (reference number 31) enables constant current operation; the step-down transformer T4 enables voltage reduction; and the final stable drive signal output is achieved by the constant current output processing circuit 33, as shown below. Figure 3 The circuit within the dashed box labeled 33 consists of an RCD circuit, a common-mode inductor LF12, and multiple capacitors, which achieves shaping and filtering of the output signal.
[0044] More importantly, since the first target device can usually achieve different effects by current regulation (for example, if the first target device is an LED lamp, color adjustment or brightness adjustment can be achieved by dimming current), the constant current feedback circuit 32 also needs to be able to receive an external PWM signal (which can come from the MCU) and adjust the constant current output by feeding it back to the constant current source circuit 31, so as to achieve the purpose of controlling the output of the constant current output processing circuit 33.
[0045] Furthermore, the second DC / DC step-down module 4 includes a constant voltage source circuit 41, a step-down transformer T3, a constant voltage feedback circuit 42, and at least one constant voltage output processing circuit 43; the AC rectifier module 1 is electrically connected to the constant voltage source circuit 41, the constant voltage source circuit 41 is electrically connected to the primary side of the step-down transformer T3, the secondary side of the step-down transformer T3 is electrically connected to the constant voltage output processing circuit 43, and the constant voltage output processing circuit 43 is electrically connected to the second target device;
[0046] After being electrically connected to the constant voltage output processing circuit 43, the constant voltage feedback circuit 42 is electrically connected to the constant voltage source circuit 41.
[0047] In this embodiment, as Figure 4 As shown, the principle of the second DC / DC step-down module 4 in realizing DC / DC step-down conversion and constant voltage output is similar to that of the first DC / DC step-down module 3, the difference being:
[0048] (1) The constant voltage source circuit 41 is composed of a constant voltage chip U1 and its peripheral circuit (the constant voltage chip U1 can also be an LP8778 chip, which also has a constant voltage mode).
[0049] (2) There may be multiple second target devices, so multiple constant voltage output processing circuits 43 may be required to receive voltages of different or the same voltage level from the step-down transformer T3 and perform output shaping and filtering (compared with the constant current output processing circuit 33, there is less common mode inductor to filter out common mode interference).
[0050] (3) The constant voltage feedback circuit 42 does not need an external PWM signal. It can be fed back to the constant voltage source circuit 41 by the output voltage signal of the constant voltage output processing circuit 43 for constant voltage.
[0051] Furthermore, the constant current feedback circuit 32 includes an optocoupler U5 and a feedback chip U3; the VCC terminal of the feedback chip U3 is electrically connected to the secondary side of the step-down transformer T4 through a power supply circuit, the voltage detection terminal of the feedback chip U3 is electrically connected to the positive terminal of the constant current output processing circuit 33 through an external circuit, the current detection terminal of the feedback chip U3 is electrically connected to the negative terminal of the constant current output processing circuit 33 through an external circuit, and the output terminal of the feedback chip U3 is electrically connected to the constant current source circuit 31 through the optocoupler U5;
[0052] The voltage detection terminal of the feedback chip U3 is also connected to an external PWM signal via an external circuit.
[0053] In this embodiment, the constant current feedback circuit 32 needs to connect the primary and secondary sides of the step-down transformer T4, so an optocoupler U5 is provided; the constant current feedback circuit 32 also needs to have the ability to receive external PWM signals, so a feedback chip U3 and its peripheral circuits are also provided, and connected to a power supply circuit (such as by...). Figure 3 The circuit consisting of diode D14, capacitor EC5 and capacitor C24 draws power from the secondary side of step-down transformer T4.
[0054] It should be noted that the feedback chip U3 can be an AP4313 chip. The VCTRL, ICTRL, and VOUT terminals of the AP4313 chip are used as the voltage detection terminal, current detection terminal, and output terminal of the feedback chip U3, respectively.
[0055] Furthermore, the constant voltage feedback circuit 42 includes an optocoupler U6, a capacitor C16, a controllable voltage regulator U8, resistors R50, R51, R49, R53, R59, and a capacitor C27; the collector of the photodetector of the optocoupler U6 is electrically connected to the constant voltage source circuit 41, the emitter of the photodetector of the optocoupler U6 is connected to the GND ground terminal, and a capacitor C16 is connected in parallel between the collector and emitter of the photodetector of the optocoupler U6;
[0056] The anode of the light source of optocoupler U6 and one end of resistor R50 are electrically connected to one end of resistor R51. The cathode of the light source of optocoupler U6, the other end of resistor R50, and one end of capacitor C27 are electrically connected to the cathode of controllable voltage regulator U8. The other end of capacitor C27 is electrically connected to one end of resistor R49. The other end of resistor R49, one end of resistor R59, and one end of resistor R53 are all electrically connected to the reference electrode of controllable voltage regulator U8. The anode of controllable voltage regulator U8 and the other end of resistor R53 are both connected to the SGND ground terminal. The other end of resistor R51 and the other end of resistor R59 are electrically connected.
[0057] When there is only one constant voltage output processing circuit 43, the other end of resistor R59 is electrically connected to constant voltage output processing circuit 43.
[0058] When there is more than one constant voltage output processing circuit 43, a resistor R55 is added for each additional constant voltage feedback circuit 42; one end of the resistor R59 is electrically connected to the reference electrode of the controllable voltage regulator U8, and the other end of the resistor R59 is electrically connected to the corresponding constant voltage output processing circuit 43.
[0059] In this embodiment, the constant voltage feedback circuit 42 mainly uses the optocoupler U6 to bridge the primary and secondary sides of the step-down transformer T3 to feed back the output signal of the constant voltage output processing circuit 43 to the constant voltage source circuit 41. In order to be compatible with the feedback of multiple constant voltage output processing circuits 43, the constant voltage feedback circuit 42 is provided with a controllable voltage regulator U8 and its peripheral circuit on the light source side of the optocoupler U6, and uses the conduction range of the controllable voltage regulator U8 to receive feedback of the same or different voltage levels.
[0060] Furthermore, the positive terminal of the AC rectifier module 1, which is electrically connected to the second DC / DC buck module 4, is connected in series with a thermistor NTC2, and the positive terminal of the DC / DC boost module 2, which is electrically connected to the first DC / DC buck module 3, is connected in series with a thermistor NTC1.
[0061] In this embodiment, to ensure the stability of driving the first and second target devices, overheat protection is provided at the input terminals of the DC / DC converters on the front sides of the first and second target devices. Thermistors NTC1 and NTC2 are used to monitor the overall temperature of the driving circuit. When the temperature is too high, the resistance of the thermistors increases, preventing overheating. Figure 2 Normal output of HV1 and HV2.
[0062] Example 2
[0063] A projector circuit includes the aforementioned driving circuit 10, and further includes a projection light source 20 and at least one power supply device 30; the first DC / DC step-down module 3 of the driving circuit 10 is electrically connected to the projection light source 20, and the second DC / DC step-down module 4 of the driving circuit 10 is electrically connected to the power supply device 30.
[0064] In this embodiment, a preferred embodiment of the projector circuit is also proposed, such as... Figure 5 As shown, the aforementioned driving circuit 10 is used to distinguish between driving the projection light source 20 and other electrical components 30 (such as the cooling fan and notification speaker in the projector, whose functional characteristics are not the core functional characteristics of the projector), thereby reducing the cost, power consumption and size of the projector.
[0065] It should be noted that when there are multiple projection light sources 20, DC / DC boost module 2 and first DC / DC buck module 3 can be added to expand the range; and when the constant voltage output processing circuit 43 of the second DC / DC buck module 4 cannot meet the power demand of multiple electrical devices 30, the range can be expanded by adding the second DC / DC buck module 4.
[0066] Other configurations and operations of the driving circuit and projector circuit according to the embodiments of this utility model are known to those skilled in the art and will not be described in detail here.
[0067] In this specification, the terms "embodiment," "example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0068] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.
Claims
1. A driving circuit, characterized in that: It includes an AC rectifier module, a DC / DC boost module, a first DC / DC buck module, and a second DC / DC buck module; the AC rectifier module is electrically connected to the DC / DC boost module and the first DC / DC buck module in sequence, and then electrically connected to a first target device to drive the first target device; The AC rectifier module is also electrically connected to the second DC / DC step-down module, and then electrically connected to the second target device to drive the second target device.
2. The driving circuit according to claim 1, characterized in that: The DC / DC boost module is a PFC boost circuit, the first DC / DC buck module is a buck constant current source circuit, and the second DC / DC buck module is a buck constant voltage source circuit.
3. The driving circuit according to claim 2, characterized in that: The first DC / DC step-down module includes a constant current source circuit, a step-down transformer T4, a constant current feedback circuit, and a constant current output processing circuit; the AC rectifier module is electrically connected to the constant current source circuit, the constant current source circuit is electrically connected to the primary side of the step-down transformer T4, the secondary side of the step-down transformer T4 is electrically connected to the constant current output processing circuit, and the constant current output processing circuit is electrically connected to the first target device; The constant current feedback circuit is electrically connected between the constant current source circuit and the constant current output processing circuit; the constant current feedback circuit is connected to an external PWM signal and transmitted to the constant current source circuit to control the output signal of the constant current output processing circuit.
4. A driving circuit according to claim 2, characterized in that: The second DC / DC step-down module includes a constant voltage source circuit, a step-down transformer T3, a constant voltage feedback circuit, and at least one constant voltage output processing circuit; the AC rectifier module is electrically connected to the constant voltage source circuit, the constant voltage source circuit is electrically connected to the primary side of the step-down transformer T3, the secondary side of the step-down transformer T3 is electrically connected to the constant voltage output processing circuit, and the constant voltage output processing circuit is electrically connected to the second target device; The constant voltage feedback circuit is electrically connected to the constant voltage output processing circuit and then electrically connected to the constant voltage source circuit.
5. A driving circuit according to claim 3, characterized in that: The constant current feedback circuit includes an optocoupler U5 and a feedback chip U3; the VCC terminal of the feedback chip U3 is electrically connected to the secondary side of the step-down transformer T4 through a power supply circuit; the voltage detection terminal of the feedback chip U3 is electrically connected to the positive terminal of the constant current output processing circuit through an external circuit; the current detection terminal of the feedback chip U3 is electrically connected to the negative terminal of the constant current output processing circuit through an external circuit; and the output terminal of the feedback chip U3 is electrically connected to the constant current source circuit through the optocoupler U5. The voltage detection terminal of the feedback chip U3 is also connected to an external PWM signal via a peripheral circuit.
6. A driving circuit according to claim 4, characterized in that: The constant voltage feedback circuit includes an optocoupler U6, a capacitor C16, a controllable voltage regulator U8, resistors R50, R51, R49, R53, R59, and a capacitor C27; the collector of the photodetector of the optocoupler U6 is electrically connected to the constant voltage regulator circuit, the emitter of the photodetector of the optocoupler U6 is connected to the GND ground terminal, and the capacitor C16 is connected in parallel between the collector and emitter of the photodetector of the optocoupler U6; The anode of the light source of the optocoupler U6, one end of the resistor R50, and one end of the resistor R51 are all electrically connected. The cathode of the light source of the optocoupler U6, the other end of the resistor R50, and one end of the capacitor C27 are all electrically connected to the cathode of the controllable voltage regulator U8. The other end of the capacitor C27 is electrically connected to one end of the resistor R49. The other end of the resistor R49, one end of the resistor R59, and one end of the resistor R53 are all electrically connected to the reference electrode of the controllable voltage regulator U8. The anode of the controllable voltage regulator U8 and the other end of the resistor R53 are both connected to the SGND ground terminal. The other end of the resistor R51 and the other end of the resistor R59 are electrically connected. When there is only one constant voltage output processing circuit, the other end of the resistor R59 is electrically connected to the constant voltage output processing circuit. When there is more than one constant voltage output processing circuit, a resistor R55 is added for each additional constant voltage feedback circuit. One end of the resistor R59 is electrically connected to the reference electrode of the controllable voltage regulator U8, and the other end of the resistor R59 is electrically connected to the corresponding constant voltage output processing circuit.
7. A driving circuit according to claim 1, characterized in that: The AC rectifier module is connected in series with a thermistor NTC2 at its positive terminal, which is electrically connected to the second DC / DC buck module. The DC / DC boost module is connected in series with a thermistor NTC1 at its positive terminal, which is electrically connected to the first DC / DC buck module.
8. A projector circuit, characterized in that: The driving circuit includes any one of claims 1 to 7, and further includes a projection light source and at least one electrical device; the first DC / DC step-down module of the driving circuit is electrically connected to the projection light source, and the second DC / DC step-down module of the driving circuit is electrically connected to the electrical device.