High-efficiency LED power supply

Abstract

The utility model discloses a high-efficiency LED power supply, which relates to the field of power supply circuits and comprises a filter circuit, a rectifying circuit and a constant-current control circuit. The rectifying circuit rectifies commercial power into direct current; the filter circuit is used for suppressing interference, and input and output are low in impedance; and the constant current control circuit is used for converting high-voltage direct current into constant current for output, compared with the prior art, through the constant current output of the constant current control circuit, the overall efficiency is 94%-97%, and compared with 88%-91% of the power supply efficiency of a conventional voltage reduction scheme, the power supply efficiency is greatly improved.

Description

Technical Field

[0001] This application relates to the field of power supply circuits, and more particularly to a high-efficiency LED power supply. Background Technology

[0002] In the LED field, the evolution of power supply solutions has always revolved around efficiency improvement, cost optimization, and regulatory compliance. Early mainstream isolated power supplies used transformers for electrical isolation, offering advantages such as high safety and strong anti-interference capabilities. However, these were limited by the large size and high cost of transformers, and their efficiency was generally below 85%, making it difficult to meet the requirements of compact lighting fixtures and high energy efficiency standards. With technological advancements, non-isolated power supply solutions have gradually become the market mainstream. By omitting the transformer and simplifying the structure, efficiency can be increased to 88-91%. However, existing non-isolated solutions still have many shortcomings: for example, efficiency drops significantly with input voltage fluctuations, and they generate significant heat, requiring additional heat dissipation designs, increasing cost and size. Furthermore, they may cause visible flicker in the LED light source, which can lead to visual fatigue with prolonged use. Summary of the Invention

[0003] I. Technical problems to be solved

[0004] In view of the aforementioned shortcomings of existing technologies, how can we further improve the efficiency of non-isolated power supplies?

[0005] II. Technical Solution

[0006] To solve the above problems, a high-efficiency LED power supply is provided, including a filter circuit, a rectifier circuit, and a constant current control circuit;

[0007] The rectifier circuit rectifies the mains power into direct current;

[0008] The filter circuit is used to suppress interference, and its input and output are low impedance.

[0009] The constant current control circuit is used to convert high-voltage DC into constant current output.

[0010] The filter circuit is a π-type filter, including a first input capacitor, a filter inductor, and a second filter electrolytic capacitor; the first input capacitor is connected in parallel to the output of the rectifier circuit, and the filter inductor is connected in series between the first input capacitor and the second filter electrolytic capacitor.

[0011] The rectifier circuit includes a rectifier bridge and a fuse resistor; the fuse resistor is connected in series between the mains power line and the AC input terminal of the rectifier bridge, and a CBB capacitor or a safety capacitor is connected in parallel to the AC input terminal of the rectifier bridge.

[0012] The constant current control circuit includes a constant current IC, an energy storage inductor, a diode, and a switching transistor. The power supply pin of the constant current IC is connected to the negative terminal of the LED load. The switching transistor operates in a current saturation state. The switching transistor is controlled to turn on and off by a PWM signal, driving the energy storage inductor to charge and discharge.

[0013] The constant current control circuit also includes a dummy load resistor, which is connected in parallel between the output terminal and ground.

[0014] The power supply also features a low-ESR electrolytic capacitor at its output.

[0015] The dummy load resistor is a megaohm-level resistor.

[0016] III. Beneficial Effects of this Application

[0017] Compared with existing technologies, this application achieves an overall efficiency of 94%-97% through constant current output via a constant current control circuit, which is a significant improvement over the conventional step-down power supply efficiency of 88-91%. Attached Figure Description

[0018] Figure 1 is a circuit schematic diagram of Embodiment 1 of this application;

[0019] Figure 2 is a circuit schematic diagram of Embodiment 2 of this application. Detailed Implementation

[0020] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of this application. Example 1

[0021] like Figure 1 As shown, the LED power supply of this application includes a π-type filter, a rectifier circuit, and a constant current control circuit;

[0022] The π-type filter includes a first input capacitor CE1, a filter inductor L1, and a second filter electrolytic capacitor CE2. The first input capacitor CE1 is connected in parallel to the output of the rectifier circuit, and the filter inductor L1 is connected in series between the first input capacitor CE1 and the second filter electrolytic capacitor CE2. The input impedance and output impedance of the π-type filter are both less than 1Ω.

[0023] The rectifier circuit rectifies the mains power into DC power, including the rectifier bridge DB1 and the fuse resistor FRS; the fuse resistor FRS is connected in series between the mains live wire L and the AC input terminal of the rectifier bridge DB1, and a CBB capacitor or a safety capacitor is connected in parallel to the AC input terminal of the rectifier bridge DB1.

[0024] The constant current control circuit is used to convert high voltage DC to constant current output. It includes constant current ICU1, energy storage inductor L2, fast recovery diode D1 and switching transistor D2. The power supply pin VIN of constant current ICU1 is connected to the negative terminal of the LED load. Switching transistor D2 is a MOSFET or BJT. Switching transistor D2 operates in current saturation state and controls the charging and discharging of energy storage inductor L2 through PWM signal to achieve constant current output and reduce LED flicker.

[0025] The constant current control circuit also includes a megohm-level dummy load resistor R5, which is connected in parallel between the output terminal and ground, so that the standby power consumption is reduced to below 0.5W.

[0026] The power supply output is also equipped with a low ESR electrolytic capacitor CE3, with a capacitance of 2.2μF-220μF and a withstand voltage of ≥250V, which is used to suppress the output current ripple to below 5%.

[0027] The power supply has an input voltage range of AC220-240V±20%, an output voltage of DC180-200V, and an output current accuracy of ±5%.

[0028] With constant current output through constant current control circuit, the overall efficiency is 94%-97%, a significant improvement compared to the 88-91% efficiency of conventional step-down power supplies, and it also meets EU electromagnetic compatibility directives.

[0029] Limits for radiated interference (RE) and conducted interference (CE) in 2014 / 30 / EU. Example 2

[0030] like Figure 2 As shown, the difference between this embodiment and embodiment 1 is that in this embodiment, the fast recovery diode, the switching transistor, and the rectifier bridge are all packaged in the constant current ICU1, and the working principle and working process are the same as in embodiment 1.

[0031] The above embodiments are only used to illustrate this application and are not intended to limit this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this application. Therefore, all equivalent technical solutions also fall within the scope of this application, and the patent protection scope of this application should be defined by the claims.

Claims

1. A high efficiency LED power supply characterized by, The power supply comprises a filter circuit, a rectifier circuit and a constant current control circuit; The rectifier circuit rectifies the mains into direct current; The filter circuit is used for suppressing interference, and the input and output are low impedance; The constant current control circuit is used for converting high voltage direct current into constant current output.

2. A high efficiency LED power supply as defined in claim 1, characterized in that The filter circuit is a π-type filter, comprising a first input capacitor (CE1), a filter inductor (L1) and a second filter electrolytic capacitor (CE2); the first input capacitor (CE1) is connected in parallel to the output end of the rectifier circuit, and the filter inductor (L1) is connected in series between the first input capacitor (CE1) and the second filter electrolytic capacitor (CE2).

3. A high efficiency LED power supply as defined in claim 1, characterized in that The rectifier circuit comprises a rectifier bridge (DB1) and a fuse resistor (FRS); the fuse resistor (FRS) is connected in series between the live wire (L) of the mains and the AC input end of the rectifier bridge (DB1), and the AC input end of the rectifier bridge (DB1) is connected in parallel with a CBB capacitor or a safety capacitor.

4. A high efficiency LED power supply as defined in claim 1, characterized in that, The constant current control circuit comprises a constant current IC (U1), an energy storage inductor (L2), a diode (D1) and a switch tube (D2); the supply pin (VIN) of the constant current IC (U1) is connected to the negative electrode of the LED load, the switch tube (D2) works in a current saturation state, the switch tube (D2) is controlled to be turned on and turned off through a PWM signal, and the energy storage inductor (L2) is driven to charge and discharge. The constant current control circuit further comprises a dummy load resistor (R5) connected in parallel between the output end and the ground.

5. A high efficiency LED power supply as claimed in claim 4, characterised in that, The output end of the power supply is further provided with a low ESR electrolytic capacitor (CE3).

6. A high efficiency LED power supply as defined in claim 1, characterized by The dummy load resistor (R5) is a mega-ohm resistor.

7. A high efficiency LED power supply as defined in claim 5, characterized by ​

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