A PWM constant current control circuit

Abstract

The utility model relates to light control technical field, especially a kind of PWM constant current control circuit, including power supply circuit, main control unit, gear adjusting circuit, test working circuit, the power supply circuit is connected with Buck circuit;Between the main control unit and power supply circuit is equipped with voltage stabilizing circuit, main control unit is equipped with signal adjusting pin, and is equipped with button unit, main control unit is under the action of button unit and exports corresponding control signal at signal adjusting pin;Gear adjusting circuit and voltage stabilizing circuit are mutually parallel, and it is connected between power supply circuit and Buck circuit, gear adjusting circuit is equipped with control signal input end relative to signal adjusting pin;Test working circuit is connected in Buck circuit far away from the side of power supply circuit, and test working circuit is electrically connected to at least one test pin of main control unit.The utility model aims at reducing the complexity of circuit structure, and guaranteeing the control stability of circuit.

Description

Technical Field

[0001] This utility model relates to the field of lighting control technology, and in particular to a PWM constant current control circuit. Background Technology

[0002] As a new type of light source, LEDs have been widely used in various fields due to their advantages of low energy consumption, high brightness, and long lifespan. To ensure that LED lamps can provide stable, efficient, and long-term illumination, current technologies generally employ switching power supply circuits to achieve constant current drive control of the LEDs, thereby enabling the LED lamps to operate stably within a fixed operating current range.

[0003] Traditional constant current drive schemes utilize a constant output voltage connected to a boost, buck, or step-up topology circuit for DC-DC conversion. This traditional constant current dimming scheme requires a dedicated LED constant current dimming driver chip and energy storage inductor, resulting in complex circuitry, high cost, high failure rate, and low efficiency. This not only leads to waste but also increases maintenance costs. Utility Model Content

[0004] The main purpose of this invention is to provide a PWM constant current control circuit, which aims to reduce the complexity of the circuit structure and ensure the control stability of the circuit.

[0005] To achieve the above objectives, this utility model proposes a PWM constant current control circuit, characterized in that it includes a power supply circuit, a main control unit, a gear adjustment circuit, and a test working circuit, wherein the power supply circuit is connected in series with a Buck circuit.

[0006] A voltage regulator circuit is provided between the main control unit and the power supply circuit. The main control unit is provided with a signal adjustment pin and a button unit. Under the action of the button unit, the main control unit outputs the corresponding control signal at the signal adjustment pin.

[0007] The gear adjustment circuit and the voltage regulator circuit are connected in parallel and are connected between the power supply circuit and the Buck circuit. The gear adjustment circuit has a control signal input terminal relative to the signal adjustment pin.

[0008] The test circuit is connected to the side of the Buck circuit away from the power supply circuit, and the test circuit is electrically connected to at least one test pin of the main control unit.

[0009] In one embodiment of this application, the power supply circuit is connected to multiple filter units, one end of the voltage regulator circuit is connected in parallel to at least one filter unit, and the other end is connected to the main control unit;

[0010] The voltage regulator circuit is equipped with a voltage conversion resistor, one side of which is grounded, and a surface-mount Zener diode.

[0011] In one embodiment of this application, the gear adjustment circuit includes a first transistor disposed relative to the main control unit, and a second transistor and a third transistor connected to the first transistor. The base of the first transistor is provided with a control signal input terminal, and the emitter is grounded. The collector of the first transistor is connected in parallel to the base of the second transistor and the third transistor, and a second resistor for connecting to the power supply circuit is connected in parallel.

[0012] The second transistor is an NPN transistor, and the third transistor is a PNP transistor. The emitters of the second and third transistors are connected to the Buck circuit.

[0013] In one embodiment of this application, the Buck circuit is provided with a PMOS transistor relative to the power supply circuit. The source (S) terminal of the PMOS transistor is connected to the power supply circuit, and the gate (G) terminal of the PMOS transistor is connected to the emitter of the second transistor and the third transistor through a third resistor. The third resistor is connected in series with a first resistor for connection to the power supply circuit, and the first resistor is connected to the source (S) terminal of the PMOS transistor.

[0014] In one embodiment of this application, the power supply circuit is provided with a reverse connection protection unit.

[0015] In one embodiment of this application, the main control unit is provided with an input voltage detection pin and an output voltage detection pin. The input voltage detection pin is provided with a first detection circuit relative to the power supply circuit. The output voltage detection pin is connected to a second detection circuit, which is connected in parallel to the test working circuit.

[0016] In one embodiment of this application, the main control unit is provided with a programming unit, which is connected to a voltage regulator circuit and has a grounding pin.

[0017] By adopting the above technical solution, this utility model has the following advantages:

[0018] All electronic components in the PWM constant current control circuit of this application are basic electronic components. All functions of the PWM constant current control circuit are realized through circuit design. The circuit design is relatively simple and can ensure control efficiency. The above structure can effectively reduce the manufacturing cost of the circuit.

[0019] To ensure the stability of the control circuit in this application, the control circuit structure includes a power supply circuit, a main control unit, a gear adjustment circuit, and a test circuit. The power supply circuit has a Buck circuit connected in series. As a step-down DC-DC converter, the Buck circuit achieves voltage conversion through the periodic switching of switching devices including MOSFETs, diodes, and inductors. The Buck circuit utilizes the principle of inductor energy storage and release to achieve voltage reduction. The end of the Buck circuit furthest from the power supply circuit is connected in series to the test circuit. The main control unit and gear adjustment circuit can be considered as a single unit connected in series and in parallel between the power supply circuit and the Buck circuit. The entire circuit uses the main control unit and gear adjustment circuit to implement the PWM constant current control function, with other structures providing auxiliary control, thus forming a complete control circuit. This circuit structure is relatively simple and ensures the stability of the actual control function.

[0020] The main control unit (main control chip) is connected to the power supply circuit through a voltage regulator circuit, which can ensure the stability of the operating voltage of the main control chip. One end of the main control unit is connected in series with the control signal input terminal of the gear adjustment circuit, and the other end is connected in series with the voltage regulator circuit. Both the voltage regulator circuit and the gear adjustment circuit are connected in parallel to the power supply circuit, which can ensure the stability of the function.

[0021] The button unit itself is connected to the power supply terminal of the main control unit, and the button unit is also connected to a signal input pin of the main control unit. When the button unit is pressed, the main control unit can receive the corresponding signal and output the corresponding control signal from the signal adjustment pin relative to the control signal input terminal. Different control signals can work with the gear adjustment circuit to achieve constant current control.

[0022] The test circuit can be connected to either the working LED group or the test LED group. The test pin is connected to the main control unit, which can detect the current at the end of the control circuit. The test LED group can reflect the working status of the constant current control circuit. After the test is stable, the working LED group can be connected to ensure the stability of the entire circuit's working status. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the PWM constant current control circuit of this utility model;

[0025] Figure 2 This is a schematic diagram of the power supply circuit of the PWM constant current control circuit of this utility model;

[0026] Figure 3 This is a schematic diagram of the gear adjustment circuit of the PWM constant current control circuit of this utility model;

[0027] Figure 4 This is a schematic diagram of the Buck circuit in the PWM constant current control circuit of this utility model;

[0028] Figure 5 This is a schematic diagram of the test circuit of the PWM constant current control circuit of this utility model;

[0029] Figure 6 This is a schematic diagram of the main control unit of the PWM constant current control circuit of this utility model.

[0030] Explanation of icon numbers:

[0031] 1. Power supply circuit; 11. Buck circuit; 2. Main control unit; 21. Voltage regulator circuit; 22. Button unit; 23. First detection circuit; 24. Second detection circuit; 25. Programming unit; 3. Gear adjustment circuit; 31. First transistor; 32. Second transistor; 33. Third transistor; 34. Control signal input terminal; 4. Test circuit.

[0032] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] The following is in conjunction with the appendix Figures 1 to 6 The present invention will be further described below.

[0035] To achieve the above objectives, this utility model proposes a PWM constant current control circuit, characterized in that it includes a power supply circuit 1, a main control unit 2, a gear adjustment circuit 3, and a test working circuit 4, wherein the power supply circuit 1 is connected in series with a Buck circuit 11.

[0036] A voltage regulator circuit 21 is provided between the main control unit 2 and the power supply circuit 1. The main control unit 2 is provided with a signal adjustment pin and a button unit 22. Under the action of the button unit 22, the main control unit 2 outputs the corresponding control signal at the signal adjustment pin.

[0037] The gear adjustment circuit 3 and the voltage regulator circuit 21 are connected in parallel and are connected between the power supply circuit 1 and the Buck circuit 11. The gear adjustment circuit 3 has a control signal input terminal 34 relative to the signal adjustment pin.

[0038] The test circuit 4 is connected to the side of the Buck circuit 11 away from the power supply circuit 1, and the test circuit 4 is electrically connected to at least one test pin of the main control unit 2.

[0039] All electronic components in the PWM constant current control circuit of this application are basic electronic components. All functions of the PWM constant current control circuit are realized through circuit design. The circuit design is relatively simple and can ensure control efficiency. The above structure can effectively reduce the manufacturing cost of the circuit.

[0040] To ensure the stability of the control circuit in this application, the control circuit structurally includes a power supply circuit 1, a main control unit 2, a gear adjustment circuit 3, and a test circuit 4. The power supply circuit 1 is connected in series with a Buck circuit 11, which, as a step-down DC-DC converter, achieves voltage conversion through the periodic switching of switching devices including MOSFETs, diodes, and inductors. The Buck circuit 11 utilizes the principle of inductor energy storage and release to achieve the step-down function. The end of the Buck circuit 11 furthest from the power supply circuit 1 is connected in series with the test circuit 4. The main control unit 2 and the gear adjustment circuit 3 can be considered as a single unit connected in series and in parallel between the power supply circuit 1 and the Buck circuit 11. The main control unit 2 and the gear adjustment circuit 3 implement the PWM constant current control function, with other structures providing auxiliary control, forming a complete control circuit. This circuit structure is relatively simple and ensures the stability of the actual control function.

[0041] The main control unit 2 (main control chip) is connected to the power supply circuit 1 through the voltage regulator circuit 21, which can ensure the stability of the operating voltage of the main control chip. One end of the main control unit 2 is connected in series with the control signal input terminal 34 of the gear adjustment circuit 3, and the other end is connected in series with the voltage regulator circuit 21. The voltage regulator circuit 21 and the gear adjustment circuit 3 are both connected in parallel to the power supply circuit 1, which can ensure the stability of the function.

[0042] The button unit 22 is connected to the power supply terminal of the main control unit 2, and the button unit 22 is connected to a signal input pin of the main control unit 2. When the button unit 22 is pressed, the main control unit 2 can receive the corresponding signal and output the corresponding control signal from the signal adjustment pin relative to the control signal input terminal 34. Different control signals can work with the gear adjustment circuit 3 to achieve constant current control.

[0043] The test circuit 4 can be connected to either the working LED group or the test LED group. The test pin is connected to the main control unit 2, which can detect the current at the end of the control circuit. The test LED group can reflect the working status of the constant current control circuit. After the test is stable, the working LED group can be connected to ensure the stability of the entire circuit's working status.

[0044] In one embodiment of this application, the power supply circuit 1 is connected to multiple filter units, one end of the voltage regulator circuit 21 is connected in parallel to at least one filter unit, and the other end is connected to the main control unit 2;

[0045] The voltage regulator circuit 21 is equipped with a voltage conversion resistor, one side of which is grounded, and a surface-mount Zener diode is also provided. Through the cooperation of the voltage conversion resistor and the surface-mount Zener diode, the main control unit 2 can have a stable working environment.

[0046] The power supply circuit 1 is connected to multiple filter units, which can ensure the temperature of the output power of the power supply circuit 1. In particular, one end of the voltage regulator circuit 21 is connected in parallel with a filter unit, which can further ensure the stable operation of the main control unit 2.

[0047] In one embodiment of this application, the gear adjustment circuit 3 includes a first transistor 31 disposed relative to the main control unit 2, and a second transistor 32 and a third transistor 33 connected to the first transistor 31. The base of the first transistor 31 is provided with a control signal input terminal 34, and the emitter is grounded. The collector of the first transistor 31 is connected in parallel to the base of the second transistor 32 and the third transistor 33, and a second resistor for connecting to the power supply circuit 1 is connected in parallel.

[0048] The second transistor 32 is an NPN transistor, and the third transistor 33 is a PNP transistor. The emitters of the second transistor 32 and the third transistor 33 are connected to the Buck circuit 11.

[0049] The base of the first transistor 31 in the gear adjustment circuit 3 can receive control signals of different signal strengths from the main control unit 2, and the emitters of the second transistor 32 and the third transistor 33 are connected to the Buck circuit 11 to achieve a stable constant current control effect.

[0050] In one embodiment of this application, the Buck circuit 11 is provided with a PMOS transistor relative to the power supply circuit 1. The source (S) terminal of the PMOS transistor is connected to the power supply circuit 1, and the gate (G) terminal of the PMOS transistor is connected to the emitter of the second transistor 32 and the third transistor 33 through a third resistor. The third resistor is connected in series with a first resistor for connection to the power supply circuit 1. The first resistor is connected to the source (S) terminal of the PMOS transistor.

[0051] The BUCK circuit is a step-down DC-DC converter circuit. It connects to power supply circuit 1 via a PMOS transistor and achieves voltage conversion through the periodic switching of inductors and diodes. The core structure of this circuit consists of a switching transistor, an inductor, and a freewheeling diode, utilizing the energy storage and release principle of the inductor to achieve the voltage reduction function. This ensures the stability of the circuit structure.

[0052] In one embodiment of this application, the power supply circuit 1 is provided with a reverse connection protection unit.

[0053] The reverse connection protection unit can effectively prevent circuit components from burning out due to reverse connection, thus protecting the entire control circuit.

[0054] In one embodiment of this application, the main control unit 2 is provided with an input voltage detection pin and an output voltage detection pin. The input voltage detection pin is provided with a first detection circuit 23 relative to the power supply circuit 1. The output voltage detection pin is connected to a second detection circuit 24, which is connected in parallel to the test working circuit 4.

[0055] By utilizing the input voltage detection pin and the output voltage detection pin, in conjunction with the first detection circuit 23 and the second detection circuit 24, the voltage at the current input terminal and the voltage at the current output terminal of the circuit of this application can be detected, thereby improving the control over the entire circuit.

[0056] In one embodiment of this application, the main control unit 2 is provided with a programming unit 25, which is connected to the voltage regulator circuit 21 and has a grounding pin.

[0057] The programming unit 25 can be used to update and upgrade the main control unit 2 system. The programming unit 25 is powered by the power output terminal of the voltage regulator circuit 21, which can ensure that the entire control circuit has a stable control effect and effectively improve the user experience.

[0058] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0059] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A PWM constant current control circuit, characterized in that, include: A power supply circuit, wherein a Buck circuit is connected in series; The main control unit is provided with a voltage regulator circuit between itself and the power supply circuit. The main control unit is provided with a signal adjustment pin and a button unit. Under the action of the button unit, the main control unit outputs a corresponding control signal at the signal adjustment pin. The gear adjustment circuit and the voltage regulator circuit are connected in parallel and are connected between the power supply circuit and the Buck circuit. The gear adjustment circuit has a control signal input terminal relative to the signal adjustment pin. The test circuit is connected to the side of the Buck circuit away from the power supply circuit and is electrically connected to at least one test pin of the main control unit.

2. The PWM constant current control circuit according to claim 1, characterized in that, The power supply circuit is connected to multiple filter units, and one end of the voltage regulator circuit is connected in parallel to at least one filter unit, while the other end is connected to the main control unit. The voltage regulator circuit is equipped with a voltage conversion resistor, one side of which is grounded, and a surface-mount Zener diode.

3. The PWM constant current control circuit according to claim 1, characterized in that, The gear adjustment circuit includes a first transistor positioned relative to the main control unit, and a second transistor and a third transistor connected to the first transistor. The base of the first transistor is provided with a control signal input terminal, and the emitter is grounded. The collector of the first transistor is connected in parallel to the base of the second transistor and the third transistor, and a second resistor for connecting to the power supply circuit is connected in parallel. The second transistor is an NPN transistor, and the third transistor is a PNP transistor. The emitters of the second and third transistors are connected to the Buck circuit.

4. The PWM constant current control circuit according to claim 1, characterized in that, The Buck circuit has a PMOS transistor relative to the power supply circuit. The source (S) terminal of the PMOS transistor is connected to the power supply circuit, and the gate (G) terminal of the PMOS transistor is connected to the emitter of the second and third transistors through a third resistor. The third resistor is connected in series with a first resistor for connection to the power supply circuit, and the first resistor is connected to the source (S) terminal of the PMOS transistor.

5. The PWM constant current control circuit according to claim 1, characterized in that, The power supply circuit is equipped with a reverse connection protection unit.

6. The PWM constant current control circuit according to claim 1, characterized in that, The main control unit is provided with an input voltage detection pin and an output voltage detection pin. The input voltage detection pin is provided with a first detection circuit relative to the power supply circuit. The output voltage detection pin is connected to a second detection circuit, which is connected in parallel to the test working circuit.

7. The PWM constant current control circuit according to claim 1, characterized in that, The main control unit is equipped with a programming unit, which is connected to the voltage regulator circuit and has a grounding pin.

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