Stroboflash-free LED power supply

Abstract

The utility model relates to the technical field of LED power supplies, and discloses a stroboflash-free LED power supply in order to solve the technical problem that people feel uncomfortable due to stroboflash of an LED power supply, the stroboflash-free LED power supply comprises a voltage regulating circuit and a constant current control circuit, the voltage regulating circuit comprises a transformer T7 and a step-down driver U12, the transformer T7 comprises a primary side coil and a secondary side coil, and the step-down driver U12 is connected with the primary side coil. The first end of the secondary coil is used as a positive electrode for supplying power to the LED, and the second end of the secondary coil is grounded through a current detection resistor and a diode D14; the constant-current control circuit comprises a current stabilizer U13 and a voltage-regulator tube Z5. The feedback compensation end of the current stabilizer U13 is grounded through a capacitor C38 and a resistor R53. The drain electrode of the current stabilizer U13 is used as a negative electrode for supplying power to the LED; the ground end of the current stabilizer U13 is grounded; and the power supply end of the current stabilizer U13 is connected with the first end of the secondary coil through a voltage-regulator tube Z5. By arranging the constant current control circuit, ripple waves are restrained, it is ensured that the current for supplying power to the LED is stable, LED brightness changes caused by current fluctuation are avoided, and fatigue and discomfort caused by stroboscopic light to human eyes are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of LED power supplies, in particular to a flicker-free LED power supply. Background Art

[0002] In recent years, LED light sources have been widely used due to their long life, energy saving and high efficiency. However, the power supply of LED light sources usually adopts switching power supply, and the low-frequency ripple generated may cause fluctuations in light output, which in turn causes LED flicker. In addition, when there are inductive or capacitive devices in the power grid, the power grid may be distorted, and flickering may occur in low-brightness dimming state, affecting user experience.

[0003] The flicker of LED light sources may cause visual fatigue and vision damage. Even though the human eye cannot subjectively perceive flicker of certain frequencies, the retina can still detect it, which may cause discomfort, difficulty in reading, impaired vision, and even headaches. Utility Model Content

[0004] The utility model aims to provide a flicker-free LED power supply to solve the technical problem that the flicker of the LED power supply causes discomfort to people.

[0005] To achieve the above purpose, the specific technical solution of the flicker-free LED power supply of the present invention is as follows:

[0006] A flicker-free LED power supply comprises an AC input circuit, a rectifier filter circuit arranged at the rear stage of the AC input circuit, and a voltage regulator circuit arranged at the rear stage of the rectifier filter circuit, and a constant current control circuit arranged at the rear stage of the voltage regulator circuit, wherein the voltage regulator circuit comprises a transformer T7 and a buck driver U12 for adjusting the power factor, the transformer T7 comprises a primary coil and a secondary coil, the first end of the secondary coil is used as a positive electrode for supplying power to an LED, and the second end of the secondary coil is grounded through a current detection resistor and a diode D14; the constant current control circuit comprises a current stabilizer U13 and a voltage regulator tube Z5, the feedback compensation end of the current stabilizer U13 is grounded through a capacitor C38 and a resistor R53 respectively; the drain of the current stabilizer U13 is used as a negative electrode for supplying power to the LED; the ground end of the current stabilizer U13 is grounded; the power supply end of the current stabilizer U13 is connected to the first end of the secondary coil through the voltage regulator tube Z5.

[0007] The combination of transformer T7 and buck driver U12 in the voltage regulation circuit effectively improves the energy conversion efficiency, reduces power loss, improves the overall efficiency of the power supply, and saves energy. The buck driver U12 adjusts the power factor, reduces the consumption of reactive power, improves the power factor, reduces the load on the power grid, and improves the efficiency and stability of the power supply system.

[0008] The current stabilizer U13 and the voltage regulator Z5 in the constant current control circuit ensure the stability of the current supplied to the LED, avoid the change of LED brightness due to current fluctuation, extend the service life of the LED, and improve the reliability of the lamp.

[0009] The current-sensing resistor and diode D14 in the circuit monitor and protect the circuit in real time. When the current is too large, the circuit can be cut off in time to avoid damage to circuit components and improve the safety of the circuit.

[0010] The feedback compensation terminal of the current stabilizer U13 is grounded through the capacitor C38 and the resistor R53, realizing real-time feedback and compensation of the current, further stabilizing the output current and reducing the impact of current fluctuations on the LED.

[0011] By integrating multiple functions into the current stabilizer U13 and the buck driver U12, the circuit design is simplified, the use of external components is reduced, the circuit complexity is reduced, and the circuit stability and reliability are improved.

[0012] The flicker-free LED driver provides high-quality lighting effects through efficient energy conversion, stable constant current output and multiple protection measures.

[0013] Furthermore, the first end of the primary coil is connected to the positive electrode of the output end of the rectifier and filter circuit through diode D15, resistor R52, resistor R48, and resistor R46 in sequence, the second end of the primary coil is connected to the cathode of diode D14, the anode of diode D14 is grounded, and diode D14 is connected in parallel with capacitor C36; the source of the buck driver U12 is connected to the second end of the primary coil, the drain of the buck driver U12 is connected to the positive electrode of the output end of the rectifier and filter circuit, the feedback compensation end of the buck driver U12 is connected to the second end of the primary coil through capacitor C35, and the current detection end of the buck driver U12 is connected to the second end of the secondary coil.

[0014] The first end of the primary coil is connected to the positive electrode of the output end of the rectifier filter circuit through the diode D15 and the resistors R52, R48 and R46, effectively controlling the current and voltage. The anode of the diode D14 is grounded and connected in parallel with the capacitor C36, which can effectively suppress voltage spikes and surges, protect key components in the circuit, and improve the stability and reliability of the circuit.

[0015] The source of the buck driver U12 is connected to the second end of the primary coil, which ensures stability during the buck process. At the same time, the drain is connected to the positive output terminal of the rectifier and filter circuit, which helps to provide a stable buck output voltage.

[0016] The feedback compensation terminal of the buck driver U12 is connected to the second end of the primary coil through the capacitor C35, which can provide real-time voltage feedback, ensure the stability of the output voltage, reduce the impact of voltage fluctuations on the LED, and further improve the accuracy and stability of the output voltage.

[0017] The current detection end of the buck driver U12 is connected to the second end of the secondary coil, which can monitor the current change in real time and adjust the current in time to avoid overcurrent damage to the circuit and LED, thereby improving the safety and reliability of the power supply.

[0018] The parallel design of capacitor C36 can effectively filter out high-frequency noise and interference, provide purer power output, reduce the impact of electromagnetic interference on circuits and LEDs, and improve lighting quality.

[0019] Based on the original design, the flicker-free LED power supply circuit further optimizes the circuit structure and component configuration, improves the conversion efficiency and stability of the power supply, and enhances the protection function and anti-interference ability of the circuit.

[0020] Furthermore, the AC input circuit includes a fuse F2 and an inductor L2 connected in series in the live line L, and an inductor L3 connected in series in the neutral line N, an X capacitor C41 connected in parallel between the live line L and the neutral line N is provided in the front stage of the inductor L2 and the inductor L3, and a varistor RV connected in parallel between the live line L and the neutral line N is provided in the rear stage of the inductor L2 and the inductor L3. This circuit constitutes an electromagnetic compatibility circuit, which can effectively reduce the low-frequency jitter caused by the distortion of the mains, and improve the smoothness and stability of the dimming effect.

[0021] Inductor L2 and inductor L3 can effectively suppress electromagnetic interference in the AC input circuit, ensure the stability and purity of the AC input voltage, and reduce the impact on subsequent circuits.

[0022] The X capacitor C41 is connected in parallel between the live wire L and the neutral wire N, and can play the role of filtering and voltage reduction, thereby improving the adaptability of the AC input circuit to voltage fluctuations and ensuring the stable operation of subsequent circuits.

[0023] The varistor RV is connected in parallel between the live wire L and the neutral wire N, which can effectively protect the circuit from overvoltage. When the input voltage exceeds a certain threshold, the varistor will change resistance, consume the overvoltage, and protect the subsequent circuit from the impact of overvoltage.

[0024] Furthermore, a resistor R55 and a resistor R56 are respectively connected in parallel to both ends of the inductor L2 and the inductor L3.

[0025] The role of inductance in the circuit is to store energy and suppress current changes, but the inductance itself may cause loop resonance or resonance problems. The parallel connection of resistors R55 and R56 can stabilize the characteristics of the inductance, reduce the occurrence of resonance and resonance, and maintain the stability of the circuit.

[0026] Resistors R55 and R56 can limit the current across the inductor to prevent excessive current from damaging the inductor or affecting the normal operation of the circuit, thus playing a role in overcurrent protection.

[0027] The functions of resistors R55 and R56 also include damping high-frequency oscillations in the circuit, reducing electromagnetic interference of the circuit, improving the anti-interference ability of the circuit, and ensuring the stable output of the LED power supply.

[0028] The flicker-free LED power supply provided by the utility model has the following advantages:

[0029] By setting up a constant current control circuit, the ripple is suppressed, the current supplied to the LED is ensured to be stable, the LED brightness changes caused by current fluctuations are avoided, and the fatigue and discomfort caused by strobe lights to the human eye are reduced; the power factor can be adjusted through the voltage regulation circuit to improve the power efficiency. In addition, the electromagnetic compatibility characteristics of the AC input circuit can effectively reduce the low-frequency jitter caused by the distortion of the mains power, and improve the smoothness and stability of the dimming effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The AC input circuit and rectification and filtering circuit diagram provided by the utility model;

[0031] Figure 2 The voltage regulating circuit diagram provided by the utility model;

[0032] Figure 3 This is a constant current control circuit diagram provided by the utility model. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0034] See also Figures 1 to 3 The utility model provides a flicker-free LED power supply, including an AC input circuit, a rectifier and filter circuit arranged at the rear stage of the AC input circuit, a voltage regulating circuit arranged at the rear stage of the rectifier and filter circuit, and a constant current control circuit arranged at the rear stage of the voltage regulating circuit. The AC input circuit is used to suppress external power grid interference, the rectifier and filter circuit converts AC power into DC power and filters it, the voltage regulating circuit is used to control the output current and voltage range, and the constant current circuit is used to eliminate ripples to generate smooth DC output.

[0035] See also Figure 1 The AC input circuit includes a fuse F2 and an inductor L2 connected in series in the live line L, and an inductor L3 connected in series in the neutral line N. The two ends of the inductor L2 and the inductor L3 are respectively connected in parallel with a resistor R55 and a resistor R56. An X capacitor C41 connected in parallel between the live line L and the neutral line N is arranged at the front stage of the inductor L2 and the inductor L3. A varistor RV connected in parallel between the live line L and the neutral line N is arranged at the rear stage of the inductor L2 and the inductor L3.

[0036] By connecting the fuse F2, inductor L2 and inductor L3 in series in the AC input circuit, and connecting the X capacitor C41 and the varistor RV in parallel between the live wire L and the neutral wire N, the electromagnetic interference and voltage surge of the external power grid can be effectively suppressed. This design can not only improve the anti-interference ability of the power module, but also protect the circuit when overcurrent or overvoltage occurs, ensuring the safe and stable operation of the equipment. At the same time, connecting resistors R55 and R56 in parallel at both ends of the inductors L2 and L3 can further suppress high-frequency interference and improve the overall performance of the circuit.

[0037] The rectifier and filter circuit includes a rectifier bridge U2. The rectifier bridge U2 is composed of four diodes to form a full-bridge rectifier circuit. A filter capacitor C30 is provided at the rear stage of the rectifier bridge U2. The output end of the rectifier bridge U2 outputs a first DC power supply DC1.

[0038] By using the rectifier bridge U2 in the rectifier filter circuit, AC power can be converted into pulsating DC power. The filter capacitor C30 is set at the rear stage of the rectifier bridge U2, which can effectively smooth the pulsating DC power after rectification, reduce voltage ripple, and provide a stable DC power supply DC1. This design not only improves the conversion efficiency of the power supply, but also provides a more stable voltage output, ensuring the normal operation of the subsequent circuit and the reliability of the equipment.

[0039] See also Figure 2 and Figure 3 The voltage regulating circuit includes a transformer T7 and a step-down driver U12. The transformer T7 includes a primary coil and a secondary coil. The first end of the primary coil is connected to the first DC power supply DC1 through a diode D15, a resistor R52, a resistor R48, and a resistor R46 in sequence. The second end of the primary coil is connected to the cathode of a diode D14. The anode of the diode D14 is grounded. The diode D14 is connected in parallel with a capacitor C36.

[0040] The first end of the buck driver U12 is the source of the built-in MOS tube, which is connected to the second end of the primary coil; the second end of the buck driver U12 is the power supply end, which is connected to the first DC power supply DC1 through resistors R48 and R46 in sequence, and is connected to the first end through capacitors C33 and C34 respectively; the third end of the buck driver U12 is the feedback compensation end, which is connected to the second end of the primary coil through capacitor C35; the fourth end of the buck driver U12 is the current detection end, which is connected to the cathode of the diode D14 through a current sensing resistor.

[0041] The 5th to 8th terminals of the buck driver U12 are the drain of the built-in MOS tube, and the drain is connected to the first end of the secondary coil through the capacitor C7. The first end of the secondary coil is grounded through the capacitor C38 and the resistor R53 respectively; the second end of the secondary coil is connected to the cathode of the diode D14.

[0042] The buck driver U12 controls the primary coil of the transformer T7 through its internal MOS tube to perform a step-down operation. The transformer T7 realizes voltage conversion and steps down the high voltage DC to a suitable voltage range. In the feedback compensation circuit, the capacitor C35 stabilizes the output voltage.

[0043] The constant current control circuit includes a current stabilizer U13 and a voltage regulator Z5. The first and fifth terminals of the current stabilizer U13 are vacant, and the second terminal of the current stabilizer U13 is a feedback compensation terminal, which is grounded through a capacitor C38 and a resistor R53 respectively; the third and fourth terminals of the current stabilizer U13 are drains of a built-in MOS tube, which are used as the negative electrode of the output power supply; the seventh and eighth terminals of the current stabilizer U13 are ground terminals, which are directly grounded; the sixth terminal of the current stabilizer U13 is a power supply terminal, which is connected to the anode of the voltage regulator Z5, and the cathode of the voltage regulator Z5 is connected to the first end of the secondary coil.

[0044] Working principle:

[0045] The current stabilizer U13 achieves constant current output through the internal circuit to ensure the output current is stable. The voltage regulator diode Z5 is used to provide a stable voltage. In the feedback network, the resistor R12 and the capacitors C37 and C38 ensure the smoothness and stability of the output current.

[0046] The combination of transformer T7 and buck driver U12 can effectively realize voltage reduction and regulation, reduce power loss and improve power conversion efficiency. Buck driver U12 uses a built-in MOS tube with low conduction loss.

[0047] The feedback compensation terminal of the buck driver U12 is connected to the second terminal of the primary coil. Through precise feedback control, stable regulation of the output voltage is achieved, ensuring the stability and accuracy of the output voltage.

[0048] The current detection terminal of the buck driver U12 is connected to the cathode of the diode D14 through a current sensing resistor, so as to monitor the current in real time and provide an overcurrent protection function to avoid the circuit being damaged due to overcurrent.

[0049] The buck driver U12 and the current stabilizer U13 adopt a highly efficient internal MOS tube design, which reduces internal losses, reduces heat generation, improves the heat dissipation performance of the power module, and extends the service life of the power module.

[0050] In summary, the flicker-free LED power supply provided by the utility model has the following advantages:

[0051] The power factor-adjusting buck driver U12 reduces reactive power consumption, improves power factor, and enhances the efficiency and stability of the power supply system. The current stabilizer U13 and the voltage regulator Z5 ensure the current stability of the LED power supply, extend the LED life, and improve the reliability of the lamp. The current sensing resistor and the diode D14 monitor and protect the circuit in real time, improving the safety of the circuit. The feedback compensation of the current stabilizer U13 further stabilizes the output current and reduces the impact of current fluctuations on the LED. The integrated multifunctional current stabilizer U13 and buck driver U12 simplify the circuit design and improve stability and reliability. This flicker-free LED power supply provides high-quality lighting effects and reduces the adverse effects of flicker on the human eye through efficient energy conversion, stable constant current output, and multiple protection measures.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A flicker-free LED power supply, comprising an AC input circuit, a rectifier filter circuit disposed at the rear stage of the AC input circuit, and a voltage regulator circuit disposed at the rear stage of the rectifier filter circuit, characterized in that: A constant current control circuit is also arranged at the rear stage of the voltage regulating circuit, the voltage regulating circuit includes a transformer T7 and a buck driver U12 for adjusting the power factor, the transformer T7 includes a primary coil and a secondary coil, the first end of the secondary coil is used as the positive electrode for powering the LED, and the second end of the secondary coil is grounded through a current sensing resistor and a diode D14; the constant current control circuit includes a current stabilizer U13 and a voltage regulator tube Z5, the feedback compensation end of the current stabilizer U13 is grounded through a capacitor C38 and a resistor R53 respectively; the drain of the current stabilizer U13 is used as the negative electrode for powering the LED; the ground end of the current stabilizer U13 is grounded; the power supply end of the current stabilizer U13 is connected to the first end of the secondary coil through the voltage regulator tube Z5.

2. The flicker-free LED power supply according to claim 1, characterized in that: The first end of the primary coil is connected to the positive electrode of the output end of the rectifier and filter circuit through diode D15, resistor R52, resistor R48, and resistor R46 in sequence, the second end of the primary coil is connected to the cathode of diode D14, the anode of diode D14 is grounded, and diode D14 is connected in parallel with capacitor C36; the source of the buck driver U12 is connected to the second end of the primary coil, the drain of the buck driver U12 is connected to the positive electrode of the output end of the rectifier and filter circuit, the feedback compensation end of the buck driver U12 is connected to the second end of the primary coil through capacitor C35, and the current detection end of the buck driver U12 is connected to the second end of the secondary coil.

3. The flicker-free LED power supply according to claim 1 or 2, characterized in that: The AC input circuit includes a fuse F2 and an inductor L2 connected in series in the live line L, and an inductor L3 connected in series in the neutral line N. An X capacitor C41 connected in parallel between the live line L and the neutral line N is arranged at the front stage of the inductor L2 and the inductor L3, and a varistor RV connected in parallel between the live line L and the neutral line N is arranged at the rear stage of the inductor L2 and the inductor L3.

4. The flicker-free LED power supply according to claim 3, characterized in that: The two ends of the inductor L2 and the inductor L3 are respectively connected in parallel with a resistor R55 and a resistor R56.

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