LED lamp constant current control circuit

Abstract

The utility model discloses an LED lamp constant-current control circuit, and relates to the technical field of LED constant-current control, and the circuit comprises a reference voltage configuration module, an LED current sampling module, a constant-current control module, an LED lamp and a switching tube Q1. The input end of the LED lamp is connected with power supply voltage VIN, and the output end of the LED lamp is grounded through a switching tube Q1; the LED current sampling module is connected between the switching tube Q1 and the ground; the constant current control module is connected with the control end of the switch tube Q1; the reference voltage configuration module outputs a reference voltage value to the constant current control module; the LED current sampling module collects an actual current value of the LED lamp in real time, converts the actual current value into a corresponding actual voltage value and feeds back the actual voltage value to the constant current control module; and the constant current control module adjusts the on-off of the switching tube Q1 based on the reference voltage value and the actual voltage value, so that the LED lamp works in a constant current state. According to the invention, the stability of the working current of the LED lamp is improved.

Description

Technical Field

[0001] This application relates to the technical field of LED constant current control, and particularly to a constant current control circuit for an LED lamp. Background Art

[0002] With the popularization of LED lighting technology, LED lamps are widely used in various occasions such as homes, commercial, industrial, roads, electronic products, automotive lighting, architectural lighting, and plant growth due to their advantages of high efficiency, energy conservation, and environmental protection;

[0003] However, in actual use, due to the fluctuations of the power supply voltage and various interferences in the circuit, the current of the LED lamp will be affected, resulting in changes in the brightness of the LED lamp and inability to maintain stability. This not only affects its lifespan but also the usage effect. Therefore, how to improve the stability of the working current of the LED lamp and ensure that the LED lamp can work stably in a constant current state under different power supply voltages is an urgent problem to be solved at present. Utility Model Content

[0004] In order to improve the stability of the working current of the LED lamp, this application provides a constant current control circuit for an LED lamp.

[0005] This application provides a constant current control circuit for an LED lamp, adopting the following technical solution: The constant current control circuit for an LED lamp includes a reference voltage configuration module, an LED current sampling module, a constant current control module, an LED lamp, and a switching transistor Q1; the input end of the LED lamp is connected to the power supply voltage VIN, and the output end is grounded through the switching transistor Q1;

[0006] The LED current sampling module is connected between the switching transistor Q1 and the ground; the constant current control module is connected to the control end of the switching transistor Q1;

[0007] The reference voltage configuration module outputs a reference voltage value to the constant current control module; the LED current sampling module real-time samples the actual current value of the LED lamp, and converts the actual current value into a corresponding actual voltage value and then feeds it back to the constant current control module; the constant current control module adjusts the on / off of the switching transistor Q1 based on the reference voltage value and the actual voltage value, so that the LED lamp works in a constant current state.

[0008] By adopting the above technical solution, on the one hand, the reference voltage configuration module configures a stable reference voltage value for the constant current control module; on the other hand, through the LED current sampling module, the actual current value of the LED lamp is collected in real time and converted into a corresponding actual voltage value feedback to the constant current control module; finally, through the constant current control module, according to the stable reference voltage value and the actual current value of the LED lamp fed back in real time, when the actual current value of the LED lamp fluctuates due to the fluctuation of the power supply voltage VIN or other interferences, the constant current control module can sense and adjust in time. By adjusting the on-off of the switching transistor Q1, the current of the LED lamp is controlled, so that the LED lamp always works in a constant current state, realizing the constant current control of the LED lamp and improving the stability of the working current of the LED lamp.

[0009] In a specific implementable embodiment, the constant current control module includes a comparator U1, a resistor R1, and a capacitor C1;

[0010] Two input terminals of the comparator U1 are respectively connected to the reference voltage configuration module and the LED current sampling module; the output terminal of the comparator U1 is connected to the control terminal of the switching transistor Q1 through the resistor R1; one end of the capacitor C1 is connected to the output terminal of the comparator U1 and the other end is grounded.

[0011] By adopting the above technical solution, the comparator U1 is adopted in the constant current control module. When the actual current value of the LED lamp changes, the level state of the output terminal of the comparator U1 changes. By driving the on-off of the switching transistor Q1, the current of the LED lamp is stabilized to a constant current value. At the same time, the resistor R1 plays a current limiting role, and the capacitor C1 plays a filtering role.

[0012] In a specific implementable embodiment, the reference voltage configuration module includes a three-terminal voltage regulator Q2, a resistor R3, and a resistor R4;

[0013] The cathode of the three-terminal voltage regulator Q2 is connected to the power supply voltage VIN, the anode is grounded, and the reference terminal of the three-terminal voltage regulator Q2 is connected to the cathode of the three-terminal voltage regulator Q2; the reference terminal of the three-terminal voltage regulator Q2 is also connected in series with the resistor R3 and the resistor R4 and then grounded; the middle node of the resistor R3 and the resistor R4 is connected to the input terminal of the constant current control module.

[0014] By adopting the above technical solution, through the setting of the reference voltage configuration module, when the power supply voltage VIN fluctuates, the reference terminal of the three-terminal voltage regulator Q2 can output a fixed voltage value and will not be affected by the fluctuation of the power supply voltage. Through the voltage division setting of the resistor R3 and the resistor R4, a suitable reference voltage value is provided for the constant current control module; the reference voltage configuration module uses the power supply voltage VIN to output a fixed reference voltage value without using an additional power source.

[0015] In a specific feasible implementation, the LED current sampling module includes resistor R5, resistor R6, and resistor R7;

[0016] The first ends of resistor R5, resistor R6, and resistor R7 are all connected to switch Q1; the second ends of resistor R5 and resistor R6 are both grounded; the second end of resistor R7 is connected to the constant current control module.

[0017] By adopting the above technical solution, in the design of the LED current sampling module, a sampling structure is formed by resistor R5, resistor R6, and resistor R7. When the current of the LED lamp changes, the voltage value input to the constant current control module changes accordingly. The constant current control module can timely sense the current change of the LED lamp and make corresponding adjustments.

[0018] In a specific feasible implementation, the LED lamp constant current control circuit further includes a comparator working power supply configuration module; the comparator working power supply configuration module includes resistor R8 and voltage stabilizing diode D2; one end of resistor R8 and voltage stabilizing diode D2 in series is connected to power supply voltage VIN, and the other end is grounded; the middle node of resistor R8 and voltage stabilizing diode D2 is connected to the power supply terminal of comparator U1;

[0019] The comparator working power supply configuration module provides a working power supply for comparator U1 based on power supply voltage VIN.

[0020] By adopting the above technical solution, the comparator working power supply configuration module converts power supply voltage VIN into the power supply required for comparator U1 to work on the basis of power supply voltage VIN, without an additional power source.

[0021] In a specific feasible implementation, the LED lamp constant current control circuit further includes a high-frequency filtering module; the high-frequency filtering module includes capacitor C7, and capacitor C7 is connected in parallel across the two ends of the LED lamp.

[0022] By adopting the above technical solution, the high-frequency filtering module filters out high-frequency interference in the circuit and ensures the stable operation of the LED lamp.

[0023] In a specific feasible implementation, the LED lamp constant current control circuit further includes a protection module; the protection module is connected to the power supply output terminal for outputting power supply voltage VIN;

[0024] The protection module includes a diode D1, a TVS tube TVS1, a resistor R9, a capacitor C5, and a capacitor C6; the anode of the diode D1 is connected to the power output terminal, and the cathode is respectively connected to the first end of the TVS tube TVS1, the first end of the resistor R9, the first end of the capacitor C5, and the first end of the capacitor C6; the second ends of the TVS tube TVS1, the resistor R9, the capacitor C5, and the capacitor C6 are all grounded.

[0025] By adopting the above technical solution, by adding a protection module at the power output terminal, the diode D1 prevents reverse connection, the TVS tube TVS1 absorbs high-voltage spike pulses, and the resistor R9, the capacitor C5, and the capacitor C6 play a filtering role, making the voltage entering the subsequent stage more stable and clean, and improving the reliability of the circuit.

[0026] In a specific implementable embodiment, the reference voltage configuration module further includes a capacitor C2 and a capacitor C3; the capacitor C2 is connected in parallel across both ends of the three-terminal voltage regulator Q2, and the capacitor C3 is connected in parallel across both ends of the resistor R4.

[0027] By adopting the above technical solution, the capacitor C2 and the capacitor C3 play a filtering role and improve the reliability of the circuit.

[0028] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0029] On the one hand, the reference voltage configuration module configures a stable reference voltage value for the constant current control module; on the other hand, through the LED current sampling module, the actual current value of the LED lamp is collected in real time and converted into a corresponding actual voltage value feedback to the constant current control module; finally, through the constant current control module, according to the stable reference voltage value and the real-time feedback actual current value of the LED lamp, when there are fluctuations in the power supply voltage VIN or other interferences that cause fluctuations in the actual current value of the LED lamp, the constant current control module can sense and adjust in a timely manner, and control the current of the LED lamp by adjusting the on-off of the switching transistor Q1, so that the LED lamp always operates in a constant current state, realizing the constant current control of the LED lamp and improving the stability of the working current of the LED lamp. Description of the Drawings

[0030] Figure 1 is a schematic structural diagram of the LED lamp constant current control circuit in the embodiment of the present application;

[0031] Description of the Reference Numerals:

[0032] 1. Reference voltage configuration module; 2. LED current sampling module; 3. Constant current control module; 4. Comparator working power supply configuration module; 5. High-frequency filtering module; 6. Protection module. Detailed implementation mode

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following will further elaborate on the implementation modes of this application in conjunction with the accompanying drawings.

[0034] The embodiment of this application provides a constant current control circuit for an LED lamp, as Figure 1 shown, which includes a reference voltage configuration module 1, an LED current sampling module 2, a constant current control module 3, an LED lamp, and a switching transistor Q1; the input end of the LED lamp is connected to the power supply voltage VIN, and the output end is grounded through the switching transistor Q1;

[0035] The LED current sampling module 2 is connected between the switching transistor Q1 and the ground; the constant current control module 3 is connected to the control end of the switching transistor Q1;

[0036] The reference voltage configuration module 1 outputs a reference voltage value to the constant current control module 3; the LED current sampling module 2 continuously samples the actual current value of the LED lamp, and after converting the actual current value into a corresponding actual voltage value, feeds it back to the constant current control module 3; the constant current control module 3 adjusts the on / off of the switching transistor Q1 based on the reference voltage value and the actual voltage value, so that the LED lamp operates in a constant current state.

[0037] It should be noted that the LED lamp may include one or more parallel-connected LED lamp strings, and each LED lamp string may also contain one or more series-connected LED lamp beads. Figure 1 The case where each LED lamp string contains 3 series-connected LED lamp beads is shown in. Those skilled in the art can determine the number of parallel-connected LED lamp strings according to actual needs, and can also adjust the number of series-connected LED lamp beads in each LED lamp string according to the magnitude of the power supply voltage VIN. This application does not make specific limitations on this.

[0038] The technical solution of this application, on the one hand, the reference voltage configuration module 1 configures a stable reference voltage value for the constant current control module 3; on the other hand, through the LED current sampling module 2, the actual current value of the LED lamp is continuously sampled, and it is converted into a corresponding actual voltage value and fed back to the constant current control module 3; finally, through the constant current control module 3, according to the stable reference voltage value and the actual current value of the LED lamp fed back in real time, when there is a fluctuation in the power supply voltage VIN or other interferences cause a fluctuation in the actual current value of the LED lamp, the constant current control module 3 can sense and adjust in a timely manner, and control the current of the LED lamp by adjusting the on / off of the switching transistor Q1, so that the LED lamp always operates in a constant current state, realizing the constant current control of the LED lamp and improving the stability of the working current of the LED lamp.

[0039] In a possible implementation mode, asFigure 1 As shown, the constant current control module 3 includes a comparator U1, a resistor R1, and a capacitor C1;

[0040] Two input terminals of the comparator U1 are respectively connected to the reference voltage configuration module 1 and the LED current sampling module 2; an output terminal of the comparator U1 is connected to a control terminal of the switching transistor Q1 through the resistor R1; one end of the capacitor C1 is connected to the output terminal of the comparator U1, and the other end is grounded.

[0041] Therefore, in the constant current control module 3, the comparator U1 is adopted. When the actual current value of the LED lamp changes, the level state of the output terminal of the comparator U1 changes. By driving the on / off of the switching transistor Q1, the current of the LED lamp is stabilized to a constant current value. At the same time, the resistor R1 plays a current limiting role, and the capacitor C1 plays a filtering role.

[0042] In a possible implementation manner, as Figure 1 shown, the reference voltage configuration module 1 includes a three-terminal voltage regulator Q2, a resistor R3, and a resistor R4;

[0043] The cathode of the three-terminal voltage regulator Q2 is connected to the power supply voltage VIN, the anode is grounded, and the reference terminal of the three-terminal voltage regulator Q2 is connected to the cathode of the three-terminal voltage regulator Q2; the reference terminal of the three-terminal voltage regulator Q2 is also connected in series with the resistor R3 and the resistor R4 and then grounded; a middle node of the resistor R3 and the resistor R4 is connected to an input terminal of the constant current control module 3.

[0044] In a possible implementation manner, as Figure 1 shown, the reference voltage configuration module 1 further includes a capacitor C2 and a capacitor C3; the capacitor C2 is connected in parallel across the two ends of the three-terminal voltage regulator Q2, the capacitor C3 is connected in parallel across the two ends of the resistor R4, and the capacitor C2 and the capacitor C3 play a filtering role.

[0045] Further, the reference voltage configuration module 1 further includes a resistor R2. The resistor R2 is connected between the three-terminal voltage regulator Q2 and the power supply voltage VIN. The resistor R2 plays a current limiting role. By configuring the voltage input to the cathode of the three-terminal voltage regulator Q2 through the resistor R2, the three-terminal voltage regulator Q2 can be reversely broken down.

[0046] Through the setting of the reference voltage configuration module 1, when the power supply voltage VIN fluctuates, the reference terminal of the three-terminal voltage regulator Q2 can output a fixed voltage value and will not be affected by the power supply voltage fluctuation. Then, through the voltage division setting of the resistor R3 and the resistor R4, a suitable reference voltage value is provided for the constant current control module 3; the reference voltage configuration module 1 uses the power supply voltage VIN to output a fixed reference voltage value without the need to adopt an additional power source.

[0047] In a possible implementation, as Figure 1 shown, the LED current sampling module 2 includes a resistor R5, a resistor R6, and a resistor R7;

[0048] The first ends of the resistor R5, the resistor R6, and the resistor R7 are all connected to the switching transistor Q1; the second ends of the resistor R5 and the resistor R6 are both grounded; the second end of the resistor R7 is connected to the constant current control module 3.

[0049] Furthermore, the LED current sampling module 2 further includes a capacitor C4. One end of the capacitor C4 is connected to the second end of the resistor R7 and the other end is grounded. The capacitor C4 functions as a filter.

[0050] Through the design of the LED current sampling module 2, a sampling structure is formed by the resistor R5, the resistor R6, and the resistor R7. When the current of the LED lamp changes, the voltage value input to the constant current control module 3 changes accordingly. The constant current control module 3 can timely sense the current change of the LED lamp and make corresponding adjustments.

[0051] In a possible implementation, as Figure 1 shown, the LED lamp constant current control circuit further includes a comparator operating power supply configuration module 4; the comparator operating power supply configuration module 4 includes a resistor R8 and a voltage stabilizing diode D2; the resistor R8 and the voltage stabilizing diode D2 are connected in series, one end is connected to the power supply voltage VIN, and the other end is grounded; the middle node of the resistor R8 and the voltage stabilizing diode D2 is connected to the power supply terminal of the comparator U1;

[0052] The comparator operating power supply configuration module 4 provides the operating power supply for the comparator U1 based on the power supply voltage VIN. The ground terminal of the comparator U1 is grounded.

[0053] The comparator operating power supply configuration module 4 converts the power supply voltage VIN into the power supply required for the comparator U1 to operate on the basis of the power supply voltage VIN, without an additional power source.

[0054] In a possible implementation, as Figure 1 shown, the LED lamp constant current control circuit further includes a high-frequency filtering module 5; the high-frequency filtering module 5 includes a capacitor C7, and the capacitor C7 is connected in parallel across the two ends of the LED lamp.

[0055] Through the high-frequency filtering module 5, high-frequency interference in the circuit is filtered out to ensure the stable operation of the LED lamp.

[0056] In a possible implementation, as Figure 1As shown, the LED constant current control circuit further includes a protection module 6; the protection module 6 is connected to the power output terminal for outputting the power supply voltage VIN;

[0057] The protection module 6 includes a diode D1, a TVS tube TVS1, a resistor R9, a capacitor C5 and a capacitor C6; the anode of the diode D1 is connected to the power output terminal, and the cathode is respectively connected to the first end of the TVS tube TVS1, the first end of the resistor R9, the first end of the capacitor C5 and the first end of the capacitor C6; the second ends of the TVS tube TVS1, the resistor R9, the capacitor C5 and the capacitor C6 are all grounded.

[0058] By adding the protection module 6 at the power output terminal, the diode D1 prevents reverse connection, the TVS tube TVS1 absorbs high-voltage spike pulses, and the resistor R9, the capacitor C5 and the capacitor C6 play a filtering role, making the voltage entering the subsequent stage more stable and clean, and improving the reliability of the circuit.

[0059] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape and principle of this application should be covered within the protection scope of this application.

Claims

1. A constant current control circuit for an LED lamp, characterized in that: It comprises a reference voltage configuration module (1), an LED current sampling module (2), a constant current control module (3), an LED lamp and a switch tube Q1; the input end of the LED lamp is connected to a power supply voltage VIN, and the output end is grounded through the switch tube Q1; The LED current sampling module (2) is connected between the switch tube Q1 and the ground; the constant current control module (3) is connected to the control end of the switch tube Q1; The reference voltage configuration module (1) outputs a reference voltage value to the constant current control module (3); the LED current sampling module (2) collects the actual current value of the LED lamp in real time, converts the actual current value into a corresponding actual voltage value, and then feeds it back to the constant current control module (3); the constant current control module (3) adjusts the on and off of the switch tube Q1 based on the reference voltage value and the actual voltage value, so that the LED lamp works in a constant current state.

2. The LED lamp constant current control circuit according to claim 1, characterized in that: The constant current control module (3) comprises a comparator U1, a resistor R1 and a capacitor C1; The two input ends of the comparator U1 are respectively connected to the reference voltage configuration module (1) and the LED current sampling module (2); the output end of the comparator U1 is connected to the control end of the switch tube Q1 through the resistor R1; one end of the capacitor C1 is connected to the output end of the comparator U1 and the other end is grounded.

3. The LED lamp constant current control circuit according to claim 1, characterized in that: The reference voltage configuration module (1) comprises a three-terminal voltage regulator Q2, a resistor R3 and a resistor R4; The cathode of the three-terminal voltage regulator Q2 is connected to the power supply voltage VIN, and the anode is grounded; the reference end of the three-terminal voltage regulator Q2 is connected to the cathode of the three-terminal voltage regulator Q2; the reference end of the three-terminal voltage regulator Q2 is also connected in series with the resistor R3 and the resistor R4 and then grounded; the middle node of the resistor R3 and the resistor R4 is connected to the input end of the constant current control module (3).

4. The LED lamp constant current control circuit according to claim 1, characterized in that: The LED current sampling module (2) comprises a resistor R5, a resistor R6 and a resistor R7; The first end of the resistor R5, the first end of the resistor R6 and the first end of the resistor R7 are all connected to the switch tube Q1; the second end of the resistor R5 and the second end of the resistor R6 are both grounded; and the second end of the resistor R7 is connected to the constant current control module (3).

5. The LED lamp constant current control circuit according to claim 2, characterized in that: It also includes a comparator working power supply configuration module (4); the comparator working power supply configuration module (4) includes a resistor R8 and a voltage regulator tube D2; the resistor R8 and the voltage regulator tube D2 are connected in series, one end of which is connected to a power supply voltage VIN and the other end is grounded; the middle node between the resistor R8 and the voltage regulator tube D2 is connected to the power supply end of the comparator U1; The comparator working power configuration module (4) provides working power for the comparator U1 based on the power supply voltage VIN.

6. The LED lamp constant current control circuit according to claim 1, characterized in that: It also includes a high-frequency filtering module (5); the high-frequency filtering module (5) includes a capacitor C7, and the capacitor C7 is connected in parallel at both ends of the LED lamp.

7. The LED lamp constant current control circuit according to claim 1, characterized in that: It also includes a protection module (6); the protection module (6) is connected to a power supply output terminal for outputting a power supply voltage VIN; The protection module (6) comprises a diode D1, a TVS tube TVS1, a resistor R9, a capacitor C5 and a capacitor C6; the anode of the diode D1 is connected to the power supply output end, and the cathode is respectively connected to the first end of the TVS tube TVS1, the first end of the resistor R9, the first end of the capacitor C5 and the first end of the capacitor C6; the second end of the TVS tube TVS1, the second end of the resistor R9, the second end of the capacitor C5 and the second end of the capacitor C6 are all grounded.

8. The LED lamp constant current control circuit according to claim 3, characterized in that: The reference voltage configuration module (1) further includes a capacitor C2 and a capacitor C3; The capacitor C2 is connected in parallel to both ends of the three-terminal voltage regulator Q2, and the capacitor C3 is connected in parallel to both ends of the resistor R4.

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