LED driving power supply
By introducing PFC control circuit, dimming circuit and filtering circuit into the LED driving power supply, the problems of low power factor and poor dimming effect of the existing LED driving power supply are solved, and efficient and reliable LED lighting control and energy utilization are achieved.
Patent Information
- Application Number
- CN202421376311.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-17
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-06-17
AI Technical Summary
The existing LED driver power supply has problems such as low power factor and poor dimming effect, resulting in low energy utilization, uneven brightness of LED lamps and reduced reliability.
An LED driving power supply including a PFC control circuit, a dimming circuit and a filter circuit is designed. The PFC control circuit improves the power factor through NMOS tubes and drive controllers, the dimming circuit uses photosensitive transistors and dimmers to achieve dynamic isolation feedback and precise dimming, and the filtering circuit filters noise through inductors and capacitors.
It improves the energy utilization rate of LED driver power supply, achieves more accurate LED lighting control, enhances the reliability and safety of the system, reduces switching losses and heat losses, and extends the service life of LED driver power supply.
Smart Images
Figure CN222940938U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lamp power supplies, in particular to an LED driving power supply. Background Art
[0002] As the mainstream lighting method, LED lighting has become an indispensable part of people's life and work. In order to meet the lighting needs in different environments, LED driving power supplies have gradually become the mainstream choice in the market. However, there are some deficiencies in the existing LED driving power supplies, which limit their performance and reliability in practical applications.
[0003] Low power factor and poor dimming effect are also the main problems of the existing LED driving power supplies. Traditional LED driving power supplies usually adopt a rectifier circuit, but this may lead to a low power factor and affect the energy utilization rate. At the same time, the dimming effect is unstable, which may cause flickering and uneven brightness, affecting the user experience and the lifespan of LED lamps.
[0004] Traditional LED driving power supplies usually adopt a rectifier circuit to convert alternating current into direct current, but these circuits may cause the problem of low power factor. In practical applications, due to the large voltage ripple after rectification, it is usually necessary to add electrolytic capacitors for filtering. However, adding electrolytic capacitors improves the voltage ripple factor but leads to a reduction in power factor and insufficient power conversion efficiency. For example, the power factor of an LED driving power supply is 0.7, which means that its actual energy utilization rate is only 70%, and 30% of the electric energy is wasted. In this case, the light provided by the LED lamp does not fully utilize the electric energy effectively.
[0005] Regarding the poor dimming effect, the existing LED driving power supplies may have unstable dimming effects during actual use. For example, a certain LED lamp may have uneven bright and dark changes during the dimming process, or obvious flickering at low brightness. In this case, the user experience will be affected, and at the same time, it may also reduce the reliability and lifespan of the LED lamp. Summary of the Utility Model
[0006] The purpose of the utility model is to provide an LED driving power supply to solve the technical problem of insufficient power conversion efficiency.
[0007] To achieve the above purpose, the specific technical solution of an LED driving power supply of the utility model is as follows:
[0008] An LED driving power supply includes a rectification circuit that processes alternating current into a first direct current. A filtering circuit for filtering the first direct current is provided at the subsequent stage of the rectification circuit. A voltage regulation circuit is provided at the subsequent stage of the filtering circuit. The voltage regulation circuit includes a transformer, a PFC control circuit provided at the front stage of the transformer, and a dimming circuit provided at the rear stage of the transformer. The dimming circuit includes a dimmer and a light-emitting diode. The reference voltage output terminal of the dimmer U9 is sequentially connected to the output terminal of the error amplifier through a resistor R43 and a light-emitting diode. The PFC control circuit includes a drive controller and an NMOS transistor. A photosensitive triode for sensing the brightness of the light-emitting diode is provided. The emitter of the photosensitive triode is connected to the inverting input terminal of the error amplifier in the drive controller through a resistor R3. The collector of the photosensitive triode is connected to the positive terminal of the rectification circuit through a pull-up circuit. The drive terminal of the drive controller is connected to the gate of the NMOS transistor through a resistor R7. Diodes D4 and a resistor R8 are provided at both ends of the resistor R7. The cathode of the diode D4 is connected to the drive terminal. The anode of the diode D4 is connected to the gate of the NMOS transistor through a resistor R8. The source of the NMOS transistor is grounded through a current-sensing resistor. The current detection terminal of the drive controller is connected to the source of the NMOS transistor through a current-limiting resistor R15.
[0009] The PFC control circuit improves the power factor of the power supply, making it closer to 1. Through the PFC control circuit, the LED driving power supply can make more effective use of the input power supply, reduce the loss of reactive power, and thus improve the energy utilization rate.
[0010] The dimmer is connected to the light-emitting diode. A photosensitive triode is provided in the PFC control circuit to sense the brightness of the light-emitting diode and achieve dynamic isolation feedback according to the state of the rear stage of the transformer, so that the drive controller can be dynamically adjusted.
[0011] The drive controller detects the current of the NMOS transistor through the current detection terminal and is connected to the NMOS transistor through the current-limiting resistor R15 at the same time. This design can effectively monitor the working state of the LED driving power supply, provide an overload protection function, and protect the LED lamp and the drive circuit from damage. The resistor R7 limits the drive current to protect the driver and the NMOS transistor. The diode D4 provides a gate discharge path to accelerate the turn-off process of the NMOS transistor. The resistor R8 and the diode D4 together form an accelerating turn-off network to further increase the switching speed and reduce the gate charge storage time.
[0012] This drive network ensures the fast turn-on and turn-off of the NMOS transistor Q1, improves the conversion efficiency, and reduces the switching loss and heat loss.
[0013] The design of this LED driving power supply combines functions such as PFC, dimming, light induction control, and current detection, improving the efficiency, flexibility, and safety of the LED lighting system.
[0014] Further, the pull-up circuit includes a resistor R24 and a resistor R17 connected in sequence. The first end of the resistor R24 is connected to the positive terminal of the rectifier circuit. The first end of the resistor R24 and the first end of the resistor R17 are connected. The second end of the resistor R17 is connected to the collector of the photosensitive triode. The emitter of the photosensitive triode is connected to the first ground through a resistor R5. The output end of the error amplifier is connected to the inverting input end of the error amplifier of the drive controller through a resistor R4 and a capacitor C2 in sequence.
[0015] The pull-up circuit provides a stable level through the resistor R24 and the resistor R17 for connection to the collector of the photosensitive triode. Doing so can ensure that the photosensitive triode operates within the correct level range, which helps improve the stability and reliability of the system.
[0016] Further, the transformer T4 includes a first coil acting as the primary side, a second coil acting as the first secondary side, a third coil acting as the second secondary side, and a fourth coil acting as the third secondary side. The first end of the first coil is used to input the first direct current. The second end of the first coil is connected to the drain of the NMOS transistor. The first end of the second coil is connected to the first ground. The first end of the second coil is connected to the power input end of the drive controller through a diode D5 and a resistor R16 in sequence.
[0017] The transformer includes multiple coils, which are used to convert the input first direct current into the required higher or lower voltage and achieve electrical isolation. This voltage transformation function helps to match the voltage difference between the LED drive power supply and the LED load, ensures that the LED lamp can work properly, and provides electrical isolation protection, improving the safety of the system.
[0018] Connecting to the power input end of the drive controller through the resistor R16 and the diode D5 of the second coil can provide a stable power input. This helps to ensure that the drive controller can operate under a stable working voltage, guaranteeing the reliability and stability of the LED drive power supply.
[0019] Further, the first end of the third coil is connected to the positive pole of the power supply for supplying power to the LED through a diode D8 and an inductor L5 in sequence. An inductor L6 is provided. The first end of the inductor L6 is connected to the second ground through a current detection resistor R38. The second end of the inductor L6 serves as the negative pole of the power supply for supplying power to the LED. The second end of the third coil is connected to the second ground. The constant current input control end of the dimmer is connected to the first end of the inductor L6 through a resistor R39. The first end of the fourth coil is connected to the second ground. The second end of the fourth coil is grounded through a diode D7, a resistor R26, and a capacitor C11 in sequence. The common node of the resistor R26 and the capacitor C11 is used to supply power to the dimmer.
[0020] The third coil connects the power supply to the positive electrode of the LED through the diode D8 and the inductor L5, and at the same time connects the negative electrode of the LED to the ground through the inductor L6. It can ensure the power supply stability of the LED, help avoid the influence of voltage fluctuations on the LED, and improve the lighting stability and reliability of the LED lamp.
[0021] Through the combination of the current detection resistor R38 and the inductor L6, the detection and control of the LED current can be achieved. The constant current input control terminal of the dimmer is connected to the inductor L6 through the resistor R39, and the brightness of the LED can be adjusted as needed, improving the flexibility and adaptability of the LED lighting system.
[0022] The design of the fourth coil provides a stable power supply to the dimmer through the diode D7, the resistor R26 and the capacitor C11. This helps to ensure the normal operation of the dimmer and provides a stable working environment, thus improving the performance and reliability of the dimmer.
[0023] Furthermore, the anode of the diode D8 is connected to the first ends of the resistor R30 and the resistor R31, and the second ends of the resistor R30 and the resistor R31 are connected to the cathode of the diode D8 through the capacitor C12.
[0024] The capacitor C12 is connected in series with the parallel resistors R30 and R31 to form an RC filter circuit. It mainly filters out high-frequency noise and spike signals and smooths voltage fluctuations. The capacitor C12 can temporarily store charges when the voltage changes, smooth the current changes, and reduce the interference to the LED power supply.
[0025] Furthermore, a voltage stabilizing circuit is also provided, a voltage stabilizing circuit for supplying power to the dimmer, including a three-terminal voltage regulator. The anode of the three-terminal voltage regulator is connected to the ground two, the cathode of the three-terminal voltage regulator is connected to the power input terminal through the resistor R48, and the reference pole of the three-terminal voltage regulator is connected to its anode through the resistor R46 and to its cathode through the resistor R45.
[0026] Furthermore, it also includes an EMC circuit for noise reduction processing of the commercial power, including a common mode inductor L2 and a common mode inductor L3. The front stage of the common mode inductor L2 inputs alternating current, an X capacitor C1 is arranged between the common mode inductor L2 and the common mode inductor L3, and a varistor is arranged at the rear stage of the common mode inductor L3.
[0027] The design of common-mode inductors L2 and L3 helps to reduce the noise of the mains power supply, filter out high-frequency noise and interference signals in the mains power, improve the resistance of the LED driver power supply system to electromagnetic interference, and ensure the stable operation of the LED lamp. The X-capacitor C1 set between the common-mode inductor L2 and the common-mode inductor L3 can provide filtering for alternating current, further stabilizing the voltage and current output of the LED driver power supply, helping to reduce the brightness flicker and instability of the LED lamp during power supply voltage fluctuations or mains interference, and improving the stability and reliability of the LED lighting system.
[0028] The LED driver power supply provided by the present utility model has the following advantages:
[0029] Power factor correction improves the power factor of the power supply, making it closer to 1, thereby improving energy utilization efficiency. Dynamic isolation feedback enables the drive controller to dynamically adjust according to the state of the light-emitting diodes, achieving more precise LED lighting control, and improving the performance and efficiency of the LED lighting system. The overload protection function effectively protects the LED lamp and the drive circuit from being damaged by overload, improving the reliability and safety of the system. The increase in switching speed reduces the losses during the switching process, reduces heat loss, improves the conversion efficiency, and extends the service life of the LED driver power supply.
[0030] By setting a power factor correction circuit, a stable dimming control circuit, and an efficient power conversion circuit, the present utility model provides an LED driver power supply that is efficient, stable, and can effectively reduce electromagnetic interference, improving the performance and reliability of the LED driver power supply. Brief Description of the Drawings
[0031] Figure 1 It is the EMC circuit and the schematic diagram provided by the present utility model;
[0032] Figure 2 It is the schematic diagram of the PFC control circuit provided by the present utility model;
[0033] Figure 3 It is the schematic diagram of the dimming circuit provided by the utility model.
[0034] In the figure: D11, light-emitting diode; D12, three-terminal voltage regulator; Q1, NMOS transistor; Q2, photosensitive transistor; C1, X-capacitor; CVX, varistor; T4, transformer; T4-1, first coil; T4-2, second coil; T4-3, third coil; T4-4, fourth coil; U6, drive controller; U9, dimmer. Detailed Description of the Embodiment
[0035] In order to make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.
[0036] Referring to Figures 1 to 3 , an LED driving power supply provided by the present utility model includes an EMC circuit for processing and reducing noise of the mains power. A rectifying circuit for processing alternating current into a first direct current is provided at the subsequent stage of the EMC circuit. A filtering circuit for filtering the first direct current is provided at the subsequent stage of the rectifying circuit. A voltage regulating circuit is provided at the subsequent stage of the filtering circuit. The voltage regulating circuit includes a PFC control circuit, a transformer T4 and a dimming circuit.
[0037] The filtering circuit includes an inductor L1. A resistor R23 is connected in parallel at both ends of the inductor L1. Both ends of the inductor L1 are respectively grounded through a capacitor C8 and a capacitor C9. The first end of the inductor L1 is connected to the positive terminal V+ of the rectifying circuit. The second end of the inductor L1 is connected to the first end of the primary side.
[0038] The direct current voltage output by the rectifying circuit is filtered through the inductor L1. When the input voltage changes, the inductor L1 will generate a current change to reduce the voltage ripple. The capacitors C8 and C9 are respectively grounded to further filter out high-frequency noise. The resistor R23 serves as a damping resistor of the inductor L1 to prevent high-frequency self-excitation oscillation of the inductor.
[0039] The transformer T4 includes a first coil T4-1 acting as the primary side, a second coil T4-2 acting as the first secondary side, a third coil T4-3 acting as the second secondary side, and a fourth coil T4-4 acting as the third secondary side. The positive pole of the output of the filtering circuit is connected to the first end of the primary side. The second end of the primary side is connected to the drain of the NMOS transistor Q1. The source of the NMOS transistor Q1 is grounded through a current detection resistor (due to the isolation effect of the transformer T4, it is divided into two different ground planes, Figure 2 and Figure 3 the ground on the left side in
[0040] is defined as ground one, and the ground on the right side is defined as ground two). The gate of the NMOS transistor Q1 is connected to the driving end of the driving controller U6.
[0041] The alternating current generated by the second secondary side of transformer T4 is rectified by diode D8, and then filtered by filter inductors L5 and L6 to obtain a stable DC voltage to provide driving current for the LED. A resistive-capacitive filter network including resistor R30, resistor R31, and capacitor C12 is provided at both ends of diode D8. Resistors R30 and R31 are in parallel and then in series with capacitor C12 for filtering and stabilizing the output voltage.
[0042] A dimmer U9 and a light-emitting diode D11 are provided to detect the load current and feedback to the PFC controller. The light-emitting diode D11 feeds back an optical signal to the photosensitive triode Q2. The photosensitive triode Q2 is connected to the ground through resistors R5, R6, etc. to adjust the error signal. The error signal is transmitted to the second terminal of U6, processed by the internal amplifier, and a control signal is output to the gate of Q1.
[0043] Figure 2 Specifically, in it, the second terminal of the drive controller U6 is the inverting input terminal of the internal error amplifier, and the fifth terminal of the drive controller U6 is the output terminal of the internal error amplifier. A pull-up circuit is provided, including resistors R24 and R17 connected in sequence. The first terminal of resistor R24 is connected to the positive terminal V+ of the rectifier circuit. The first terminal of resistor R24 and the first terminal of resistor R17 are connected. The second terminal of resistor R17 is connected to the collector of the photosensitive triode Q2. The emitter of the photosensitive triode Q2 is grounded through resistor R5. Resistor R5 is in parallel with resistor R6. The emitter of the photosensitive triode Q2 is connected to the second terminal of the drive controller U6 through resistor R3. The fifth terminal of the drive controller U6 is connected to the second terminal of the drive controller U7 through resistor R4 and capacitor C2 in sequence. The fifth terminal of the drive controller U6 is also connected to the second terminal of the drive controller U7 through capacitor C3.
[0044] The pull-up resistor is used to provide voltage for the collector of the photosensitive triode Q2. Resistors R5 and R6 in parallel are used to set the current passing through the photosensitive triode Q2 to ensure the stability and accuracy of the feedback signal.
[0045] The light-receiving end (equivalent to the base) of the photosensitive triode Q2 receives the control from the light-emitting diode D11 in the peripheral circuit of the dimmer U9.
[0046] Resistor R3 connects the emitter of the photosensitive triode Q2 to the second terminal of the drive controller U6 to transmit the feedback signal to the inverting input terminal of the error amplifier.
[0047] Resistor R4 and capacitor C2 are connected in series between the fifth terminal of the drive controller U6 and the second terminal of the drive controller U7 to form a compensation network for stabilizing the feedback control loop, preventing oscillation and improving the system response speed.
[0048] The capacitor C3 is connected between the fifth terminal of the drive controller U6 and the second terminal of the drive controller U7, providing additional compensation and filtering functions to further stabilize the control signal.
[0049] The sixth terminal of the drive controller U6 is the input terminal of the internal multiplier stage. It is connected to the terminal through the first series voltage dividing circuit to receive the rectified first DC power. A voltage signal proportional to the voltage of the rectified first DC power will be output in the first series voltage dividing circuit.
[0050] The positive terminal V+ of the rectifier circuit is grounded through the first series voltage dividing circuit. The first series voltage dividing circuit includes the resistor R25, the resistor R36, and the resistor 27 connected in series in sequence. A capacitor C10 is also connected in parallel with the resistor R27. The first end of the resistor R27 is connected to the input terminal of the internal multiplier stage, and the second end of the resistor R27 is grounded.
[0051] The input terminal of the multiplier stage receives the rectified DC voltage through the first series voltage dividing circuit (R25, R26, R27). This voltage dividing circuit outputs a voltage signal proportional to the voltage of the rectified first DC power. This signal is input to the sixth terminal for internal calculation in the multiplier, thereby adjusting the duty cycle of the PWM signal, controlling the conduction time of the NMOS transistor Q1, and finally achieving PFC control.
[0052] The resistors R25, R26, and R27 form a voltage dividing circuit to divide the high-voltage DC voltage into a low-voltage signal suitable for the input of U6. The capacitor C10 is connected in parallel with the resistor R27 for filtering to remove high-frequency noise and ensure the stability of the input signal.
[0053] The first terminal of the drive controller U6 is the zero-current detection input terminal. The second secondary side is connected to the zero-current detection input terminal of the drive controller U6 through the resistor R28.
[0054] The zero-current detection input terminal is used to detect the zero-crossing point of the inductor current to achieve quasi-resonant control. This control method can reduce switching losses and improve conversion efficiency. By detecting the zero-crossing point of the current, the drive controller can turn on the NMOS transistor when the current is zero, reducing electromagnetic interference and switching losses, and improving the power efficiency and reliability of the power supply.
[0055] The fourth terminal of the drive controller U6 is the grounding terminal, which is connected to ground.
[0056] The eighth terminal of the drive controller U6 is the driving terminal. The driving terminal of the drive controller U6 is connected to the gate of the NMOS transistor Q1 through the resistor R7. Diodes D4 and resistor R8 are provided at both ends of the resistor R7. The cathode of the diode D4 is connected to the driving terminal of the drive controller U6, and the anode of the diode D4 is connected to the gate of the NMOS transistor Q1 through the resistor R8.
[0057] The resistor R7 limits the drive current to protect the driver and the NMOS transistor. The diode D4 provides a gate discharge path to accelerate the turn-off process of the NMOS transistor. The resistor R8 and the diode D4 together form an acceleration turn-off network to further increase the switching speed and reduce the gate charge storage time.
[0058] This drive network ensures the fast turn-on and turn-off of the NMOS transistor Q1, improves the conversion efficiency, and reduces the switching loss and thermal loss.
[0059] The third terminal of the drive controller U6 is the current detection terminal, which is grounded through the capacitor C4. The source electrode of the NMOS transistor Q1 is connected to the current detection terminal of the NMOS transistor Q1 through the resistor R15, and the source electrode of the NMOS transistor Q1 is connected to the current detection terminal through the resistor R15.
[0060] The resistor R15 is used to detect the current passing through Q1 and convert the current signal into a voltage signal to be provided to the current detection terminal. The capacitor C4 is used to filter out the high-frequency noise in the detection signal to ensure the stability of the current detection signal. Through the current detection terminal, the drive controller can monitor the current of the NMOS transistor Q1 and make real-time adjustments according to the feedback signal to ensure the stability and safety of the LED drive current and prevent overcurrent and overload situations.
[0061] The current detection resistor includes three parallel resistors R12, R13, and R14 to disperse the current and avoid overheating of a single resistor.
[0062] The seventh terminal of the drive controller U6 is the power input terminal. The first end of the first secondary side is connected to ground one, and the second end of the first secondary side is used to supply power to the power input terminal of the drive controller U6 after being rectified by the diode D5 and limited by the resistor R16 in sequence.
[0063] Figure 3 In, the first end of the second secondary side is output through the diode D8 and the inductor L5 in sequence and is used as the second direct current for supplying power to the LED, that is, the positive power supply LED+ for supplying power to the LED. An inductor L6 is provided. The first end of the inductor L6 is connected to ground two through the current detection resistor R38, and the second end of the inductor L6 is used as the negative power supply LED- for supplying power to the LED. The anode of the diode D8 is connected to the first ends of the resistors R30 and R31, and the second ends of the resistors R30 and R31 are connected to the cathode of the diode D8 through the capacitor C12.
[0064] The second end of the second secondary side is grounded to two, and parallel capacitors C13, C14, and a resistor R32 are provided between the first end and the second end of the second secondary side.
[0065] Diode D8 rectifies the alternating current of the third secondary side (T4-3) of transformer T4 into direct current, and at the same time prevents current reflux to protect the circuit. Inductor L5 is used to filter the rectified direct current, smooth the current, reduce current ripple, and thus provide stable direct current to the LED. Capacitors C13 and C14 are connected in parallel to form a filtering network for eliminating high-frequency noise and providing a smoother DC voltage. Resistor R32 acts as a damping resistor to suppress high-frequency oscillations and prevent the capacitor and inductor from forming an oscillating circuit. Capacitor C12 is connected in series with parallel resistors R30 and R31 to form an RC filtering circuit. It mainly filters out high-frequency noise and spike signals and smooths voltage fluctuations. Capacitor C12 can temporarily store charges when the voltage changes, smooth the change of current, and reduce the interference to the LED power supply.
[0066] The first end of the third secondary side is grounded at GND2, and the second end of the third secondary side is connected to GND2 through diode D7, resistor R29, and capacitor C11 in sequence. The anode of diode D7 is connected to the second end of the third secondary side, and the cathode of diode D7 is connected to resistor R29.
[0067] A dimmer U9 is provided. The first terminal of dimmer U9 is the power input terminal and is connected to the middle node of capacitor C11 and resistor R29. A voltage stabilizing circuit is also provided, including a three-terminal voltage regulator D12. The anode of the three-terminal voltage regulator D12 is connected to GND2, the cathode of the three-terminal voltage regulator D12 is connected to the power input terminal through resistor R48, and the reference pole of the three-terminal voltage regulator D12 is connected to its anode through resistor R46 and to its cathode through resistor R45.
[0068] The fourth terminal of dimmer U9 is the error amplifier output terminal; the second terminal of dimmer U9 is the constant voltage input control terminal, which is connected to the cathode of diode D8 through resistor R44 and resistor R47 in sequence to obtain the output voltage of the second secondary side for detection. The constant voltage input control terminal is also grounded through resistor R40 and is connected to the fourth terminal through capacitor C20 and resistor R41 in sequence;
[0069] The third terminal of dimmer U9 is the reference voltage output terminal, which is connected to the fourth terminal through resistor R43 and light-emitting diode D11 in sequence. Resistor R42 is connected in parallel across both ends of the light-emitting diode D11;
[0070] The fifth terminal of the dimmer U9 is the constant current input control terminal, which is used for LED load current detection. It is connected to the first terminal of the inductor L6 through the resistor R39, and is sequentially connected to the fourth terminal through the resistor R33 and the capacitor C16. The capacitor C15 is connected in parallel across both ends of the resistor R33 and the capacitor C16; the resistor R33 and the capacitor C16 are connected in series to form an RC time constant circuit, which is used to filter out high-frequency noise and stabilize the control signal, can smooth the control signal, and reduce the influence of interference on current control. The capacitor C16 is connected in series with the resistor R33 to smooth the current control signal. The capacitor C16 temporarily stores charges when the current changes, reduces the fluctuation of the current change, and ensures the stability of the LED drive current. The capacitor C15 is connected in parallel across both ends of the resistor R33 and the capacitor C16 to further filter and smooth the voltage.
[0071] The sixth terminal of the dimmer U9 is the dimming capacitor access terminal, which is connected to ground two through the capacitor C17; the seventh terminal of the dimmer U9 is the PWM signal input terminal, which is connected to ground two through the resistor R34, and the PWM signal is input through the resistor R35; the eighth terminal of the dimmer U9 is the ground terminal, which is connected to ground two.
[0072] This circuit provides a stable LED drive power supply through rectification, filtering, voltage regulation and dimming control, ensuring the high efficiency and reliability of the power supply, and provides a good LED brightness adjustment effect through fine dimming control.
[0073] In summary, for the LED drive power supply provided by the present utility model, the power factor correction improves the power factor of the power supply, making it closer to 1, thereby improving the energy utilization rate. The dynamic isolation feedback enables the drive controller to dynamically adjust according to the state of the light-emitting diode, realizing more accurate LED lighting control, and improving the performance and efficiency of the LED lighting system. The overload protection function effectively protects the LED lamp and the drive circuit from being damaged by overload, improving the reliability and safety of the system. The increase in the switching speed reduces the loss during the switching process, reduces the heat loss, improves the conversion efficiency, and prolongs the service life of the LED drive power supply.
[0074] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.
Claims
1. An LED driving power supply, comprising a rectifier circuit for processing alternating current into a first direct current, a filter circuit for filtering the first direct current is arranged at a rear stage of the rectifier circuit, and a voltage regulating circuit is arranged at a rear stage of the filter circuit, characterized in that: The voltage regulation circuit includes a transformer T4, a PFC control circuit arranged at the front stage of the transformer T4, and a dimming circuit arranged at the rear stage of the transformer T4; The dimming circuit includes a dimmer U9 and a light emitting diode D11, and the reference voltage output end of the dimmer U9 is connected to the output end of the error amplifier through a resistor R43 and a light emitting diode D11 in sequence; The PFC control circuit includes a drive controller U6 and a NOMS tube Q1, and is provided with a phototransistor Q2 for sensing the brightness of a light-emitting diode D11. The emitter of the phototransistor Q2 is connected to the inverting input terminal of the error amplifier in the drive controller U6 through a resistor R3, and the collector of the phototransistor Q2 is connected to the positive terminal V+ of the rectifier circuit through a pull-up circuit. The driving end of the driving controller U6 is connected to the gate of the NMOS tube Q1 through the resistor R7, and the two ends of the resistor R7 are provided with a diode D4 and a resistor R8 connected in series, the cathode of the diode D4 is connected to the driving end, and the anode of the diode D4 is connected to the gate of the NMOS tube Q1 through the resistor R8; the source of the NMOS tube Q1 is grounded through the current detection resistor, and the current detection end of the driving controller U6 is connected to the source of the NMOS tube Q1 through the current limiting resistor R15.
2. The LED driving power supply according to claim 1, characterized in that: The pull-up circuit includes a resistor R24 and a resistor R17 connected in sequence, the first end of the resistor R24 is connected to the positive terminal V+ of the rectifier circuit, the first end of the resistor R24 is connected to the first end of the resistor R17, the second end of the resistor R17 is connected to the collector of the phototransistor Q2, the emitter of the phototransistor Q2 is connected to the ground through the resistor R5, and the output end of the error amplifier is connected to the inverting input end of the error amplifier of the drive controller U6 through the resistor R4 and the capacitor C2 in sequence.
3. The LED driving power supply according to claim 2, characterized in that: The transformer T4 includes a first coil T4-1 serving as a primary side, a second coil T4-2 serving as a first secondary side, a third coil T4-3 serving as a second secondary side, and a fourth coil T4-4 serving as a third secondary side. The first end of the first coil T4-1 is used to input a first direct current, the second end of the first coil T4-1 is connected to the drain of the NMOS tube Q1, the first end of the second coil T4-2 is connected to the ground, and the first end of the second coil T4-2 is connected to the power input end of the driving controller U6 via a diode D5 and a resistor R16 in sequence.
4. The LED driving power supply according to claim 3, characterized in that: The first end of the third coil T4-3 is connected to the positive power supply LED+ for supplying power to the LED through the diode D8 and the inductor L5 in sequence. An inductor L6 is provided. The first end of the inductor L6 is connected to the ground two through the current detection resistor R38. The second end of the inductor L6 is used as the negative power supply LED- for supplying power to the LED. The second end of the third coil T4-3 is connected to the ground two. The constant current input control end of the dimmer U9 is connected to the first end of the inductor L6 through the resistor R39; the first end of the fourth coil T4-4 is connected to the ground two, and the second end of the fourth coil T4-4 is connected to the ground through the diode D7, the resistor R26 and the capacitor C11 in sequence. The common node of the resistor R26 and the capacitor C11 is used to supply power to the dimmer U9.
5. The LED driving power supply according to claim 4, characterized in that: The anode of the diode D8 is connected to the first ends of the resistors R30 and R31 , and the second ends of the resistors R30 and R31 are connected to the cathode of the diode D8 via the capacitor C12 .
6. The LED driving power supply according to claim 4, characterized in that: A voltage stabilizing circuit is also provided, and a voltage stabilizing circuit is also provided for supplying power to the dimmer U9, including a three-terminal voltage stabilizer D12, the anode of the three-terminal voltage stabilizer D12 is connected to ground two, the cathode of the three-terminal voltage stabilizer D12 is connected to the power input terminal through a resistor R48, and the reference electrode of the three-terminal voltage stabilizer D12 is connected to its anode through a resistor R46 and to its cathode through a resistor R45.
7. The LED driving power supply according to any one of claims 1 to 6, characterized in that: It also includes an EMC circuit for reducing the noise of the mains power, including common-mode inductors L2 and L3. The front-stage input of the common-mode inductor L2 has alternating current, an X capacitor C1 is arranged between the common-mode inductor L2 and the common-mode inductor L3, and a varistor CVR is arranged at the rear stage of the common-mode inductor L3.