LED drive circuit and LED lamp

Abstract

The utility model relates to an LED driving circuit and an LED lamp, and the LED driving circuit comprises an AC input end which comprises a first AC input end and a second AC input end; the first voltage reduction unit is coupled between the first alternating current input end and the second alternating current input end; the rectifying and filtering unit is simultaneously coupled to the first alternating current input end and the second alternating current input end and is used for converting alternating current into direct current; the constant current unit is coupled to the rectifying and filtering unit, is used for supplying power to an LED load and is provided with a signal input end; and the adjusting unit is provided with a signal output end coupled to the signal input end, and the signal input end receives an adjusting signal of the signal output end, so that the constant current unit correspondingly changes the output power. On the basis that two working modes of the mains supply and the ballast are compatible, the output power of the LED driving circuit can be adjusted in the two working modes.

Description

Technical Field

[0001] This application relates to the field of lighting technology, and in particular to an LED driver circuit and an LED luminaire. Background Technology

[0002] Traditional fluorescent lamps have been widely replaced by LED lighting fixtures. The original installation location of fluorescent lamps still retains the old ballast, which provides AC power at a higher voltage than the mains voltage. Consequently, two types of LED lighting fixtures are available on the market, referred to as Type A and Type B. Type A refers to LED fixtures connected directly after the ballast, while Type B refers to LED fixtures connected after the mains power (with the ballast wires cut and bypassed), and the luminous power can be adjusted using a driver power supply.

[0003] Distinguishing between Type A and Type B installations can be technically challenging for non-professionals. Therefore, Chinese patent CN109526093A, concerning a lamp driver circuit and LED lighting equipment, offers a compatible solution. This lamp driver circuit is compatible with both Type A and Type B. When operating at mains frequency, the second power supply module functions normally, while the first power supply module is shut off by the isolation module. When operating on high-frequency, high-voltage AC power after the ballast, the isolation module conducts, the first power supply module functions normally, and simultaneously triggers the signal sampling module, which disconnects the second power supply module, thus achieving overall compatibility with both Type A and Type B lamps.

[0004] Although the above-mentioned technology achieves compatibility with both Type A and Type B, it can only adjust the luminous power in Type B mode and cannot adjust the luminous power in Type A mode. Utility Model Content

[0005] Therefore, it is necessary to provide an LED driver circuit to address the aforementioned technical problems.

[0006] The LED driver circuit of this application includes:

[0007] The AC input terminals include a first AC input terminal and a second AC input terminal;

[0008] The first step-down unit is coupled between the first AC input terminal and the second AC input terminal;

[0009] The rectifier and filter unit is simultaneously coupled to the first AC input terminal and the second AC input terminal, and is used to convert AC power into DC power.

[0010] A constant current unit, coupled to the rectifier and filter unit, is used to supply power to the LED load and has a signal input terminal;

[0011] The adjustment unit has a signal output terminal coupled to the signal input terminal, wherein the signal input terminal receives the adjustment signal from the signal output terminal, causing the constant current unit to change its output power accordingly.

[0012] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0013] Optionally, the step-down unit includes a capacitor.

[0014] Optionally, the AC input terminal includes a third AC input terminal;

[0015] The second step-down unit of the LED driving circuit is coupled between the first AC input terminal and the third AC input terminal.

[0016] Optionally, the capacitive reactance of the first step-down unit is 1 to 2 nF, and the capacitive reactance of the second step-down unit is 10 to 20 nF.

[0017] Optionally, the capacitive reactance of the first step-down unit is 1.5 to 1.8 nF, and the capacitive reactance of the second step-down unit is 15 to 18 nF.

[0018] Optionally, the constant current unit includes a switching transistor having a first terminal, a second terminal, and a control terminal for controlling the conduction of the first and second terminals. The control terminal is used to receive a PWM signal, the second terminal is used to supply power to the LED load, and the first terminal is coupled to the signal input terminal and coupled to the ground line via a sampling resistor.

[0019] Optionally, the adjustment unit includes a plurality of resistors connected in parallel with the sampling resistor, and a switching assembly that enables different resistors to conduct.

[0020] Optionally, the switching component is a DIP switch.

[0021] Optionally, the LED driving circuit includes a leakage protection unit coupled between the sampling resistor and the ground wire.

[0022] The present application provides an LED lamp, including a lamp housing, which includes a lamp tube and a first end cap and a second end cap located at both ends of the lamp tube. The first end cap is provided with a first pin and a second pin, and the second end cap is provided with a third pin and a fourth pin.

[0023] The lamp housing has an LED driving circuit as described in this application, characterized in that the first pin is electrically connected to the first AC input terminal, and the second pin is electrically connected to the second AC input terminal.

[0024] Optionally, the AC input terminal includes a third AC input terminal, and the third pin is electrically connected to the third AC input terminal;

[0025] The LED driving circuit includes a second step-down unit, which is coupled between the first AC input terminal and the third AC input terminal.

[0026] The LED driver circuit of this application has at least the following technical advantages:

[0027] In the Type B operating mode, where the circuit is directly connected to mains power, the first step-down unit has no effect on the LED driver circuit. In this mode, the output power of the constant current unit is changed via the adjustment unit. In the Type A operating mode, where the circuit is connected to a ballast, the first step-down unit counteracts the high-frequency, high-voltage current generated by the ballast, reducing the voltage of the high-frequency, high-voltage AC power to allow the subsequent constant current unit to operate normally. In this mode, the adjustment unit can still change the output power of the constant current unit. Therefore, this application, while compatible with both the mains Type B operating mode and the ballast Type A operating mode, can also achieve adjustment of the LED driver circuit's output power in both operating modes. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the module structure of an LED driving circuit in one embodiment of this application;

[0029] Figure 2 This is a schematic diagram of the module structure of an LED driving circuit in one embodiment of this application;

[0030] Figure 3 This is a schematic diagram of the working principle of the constant current unit in the LED driving circuit in one embodiment of this application;

[0031] Figure 4 This is a schematic diagram illustrating the working principle of the adjustment unit in an LED driver circuit according to one embodiment of this application.

[0032] Figure 5 This is a schematic diagram of the structure of an LED lamp in one embodiment of this application;

[0033] The annotations in the figure are explained as follows:

[0034] 101. First AC input terminal; 102. Second AC input terminal; 103. Third AC input terminal;

[0035] 210. First step-down unit; 220. Second step-down unit;

[0036] 300. Rectifier and filter unit;

[0037] 400, Constant current unit; 401, Signal input terminal; 410, Switching transistor; 411, First terminal; 412, Second terminal; 413, Control terminal; 420, Sampling resistor;

[0038] 500, Adjustment unit; 501, Signal output terminal; 510, Switch assembly; 520, First resistor; 530, Second resistor;

[0039] 600, LED load; 700, leakage protection unit;

[0040] 800, LED light fixture; 810, first end cap; 820, second end cap; 830, lamp tube; 811, first pin; 812, second pin; 813, third pin; 814, fourth pin. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] It should be noted that when a component is said to be "coupled" to another component, it can be directly connected to the other component or it can be interposed in another component. When a component is said to be "set on" another component, it can be directly set on the other component or it may be interposed in another component.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0044] In this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number or order of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] In this application, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a system, product, or device that includes a series of units is not necessarily limited to those units that are explicitly listed, but may include other units that are not explicitly listed or that are inherent to such products or devices.

[0046] In this application, the terms "corresponding," "matching," "adapted," such as "B corresponding to A," "B corresponding to A," "A and B corresponding," or "B and A corresponding," indicate that B and A have a corresponding relationship in shape, position, or function, and that B can be determined based on A. Determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information.

[0047] See Figure 1 One embodiment of this application provides an LED driving circuit, which includes an AC input terminal, a step-down unit, a rectifier and filter unit 300, a constant current unit 400, and an adjustment unit 500.

[0048] The AC input terminals include a first AC input terminal 101 and a second AC input terminal 102. The step-down unit includes a first step-down unit 210 coupled between the AC input terminals 101 and 102. A rectifier-filter unit 300 is coupled to both AC input terminals 101 and 102 to convert AC to DC. A constant current unit 400 is coupled to the rectifier-filter unit 300 (specifically, the output DC bus) and is used to power the LED load. The constant current unit has a signal input terminal 401, which may be constructed, for example, based on an integrated circuit. An adjustment unit 500 has a signal output terminal 501 coupled to the signal input terminal 401. The signal input terminal 401 receives an adjustment signal from the signal output terminal 501, causing the constant current unit 400 to change its output power accordingly.

[0049] When the first step-down unit 210 is connected to high-frequency high-voltage AC power at the AC input terminal 101, it is used to step down the high-frequency high-voltage AC power so that it does not affect the normal operation of the downstream circuit equipment and approaches or reaches the power frequency specified by local regulations. The term "high-frequency high-voltage AC power" refers to the AC power of the LED driver circuit in Type A mode, specifically the AC power after the ballast frequency and voltage are increased relative to the power frequency mains power, usually with a frequency of 35-45Hz and a voltage range of 200-400V.

[0050] In Type B operating mode, where the circuit is directly connected to the mains power, the first step-down unit 210 has no effect on the LED driver circuit. In this mode, the output power of the constant current unit 400 is changed by the adjustment unit 500, thereby altering the luminous power. In Type A operating mode, where the circuit is connected to the ballast, the first step-down unit 210 counteracts the high-frequency, high-voltage current generated by the ballast, stepping down the high-frequency, high-voltage AC power to allow the subsequent constant current unit 400 to operate normally. In this mode, the adjustment unit 500 can still change the output power of the constant current unit 400. Therefore, while compatible with both Type A and Type B operating modes, it can achieve power regulation not only in Type B operating mode but also in Type A operating mode.

[0051] See Figure 2 The AC input terminal includes a third AC input terminal 103. The LED driving circuit includes a second step-down unit 220, which is coupled between the first AC input terminal 101 and the third AC input terminal 103. Further, the step-down unit includes a capacitor, for example, capacitors with different resistance values. When a capacitor is used in the step-down unit, the capacitive reactance of the first step-down unit 210 is 1.5–1.8 nF, and the capacitive reactance of the second step-down unit 220 is 15–18 nF. The rectifier-filter unit 300 may include a rectifier module and a filter module coupled in sequence. The rectifier module may be configured with rectifier diodes for each AC input terminal, achieving full-wave rectification when any two AC input terminals are powered. The filter module may be implemented using a π-type filter circuit, etc.

[0052] See Figure 3 The constant current unit 400 includes a switching transistor 410, which has a first electrode 411, a second electrode 412, and a control electrode 413 for controlling the conduction of the first electrode 411 and the second electrode 412. The control electrode 413 is used to receive PWM signals. The second electrode 412 is connected to the LED load 600 to supply power to the LED load 600. The first electrode 411 is coupled to the signal input terminal 401 and coupled to the ground wire via the sampling resistor 420. The LED driving circuit includes a leakage protection unit 700 coupled between the sampling resistor 420 and the ground wire. The adjustment unit 500 has a signal output terminal 501 and a ground terminal 502 coupled to the ground wire. When the leakage protection unit 700 is present, the ground terminal 502 can be grounded through the leakage protection unit 700.

[0053] The constant current unit 400 includes an integrated circuit U1 and peripheral circuits. The peripheral circuits include a switching transistor 410 and a sampling resistor 420. The integrated circuit U1 has a signal input terminal CS and a signal driving terminal DRV. The signal driving terminal DRV is used to output a PWM signal and is connected to the control electrode 413 of the switching transistor 410.

[0054] The switching transistor 410 can be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The first terminal 411 of the switching transistor 410 is the drain of the MOSFET, the second terminal 412 is the source of the MOSFET, and the control terminal 413 is the gate of the MOSFET. Correspondingly, a freewheeling diode is configured between the source of the MOSFET and the bus output of the rectifier-filter unit 300. The positive terminal of the freewheeling diode is coupled to the source of the MOSFET, and the negative terminal of the freewheeling diode is coupled to the bus. The positive terminal of the LED load is coupled to the bus, and the negative terminal of the LED load is coupled to the source of the MOSFET via an inductor, thus realizing the basic function of the BUCK circuit. In use, power regulation is achieved by controlling the conduction angle of the switching transistor 410. Changing the conduction angle can be achieved by changing the resistance value of the sampling resistor 420, thereby changing the reference.

[0055] See Figure 4 The adjustment unit 500 includes multiple resistors connected in parallel with the sampling resistor 420, and a switching assembly 510 that enables different resistors to conduct. The switching assembly 510 is a DIP switch. Specifically, the adjustment unit 500 includes a first resistor 520 and a second resistor 530 connected in parallel with the sampling resistor 420, and the first resistor 520 and the second resistor 530 share a single DIP switch. When the DIP switch is adjusted to different positions, it selects to conduct the first resistor 520, the second resistor 530, or neither resistor is conducting.

[0056] See Figure 5 One embodiment of this application provides an LED lamp 800, which includes a lamp housing. The lamp housing includes a lamp tube 830 and a first end cover 810 and a second end cover 820 located at both ends of the lamp tube 830. The first end cover 810 is provided with a first pin 811 and a second pin 812, and the second end cover 820 is provided with a third pin 813 and a fourth pin 814. The lamp housing has an internal LED driving circuit as provided in various embodiments. The first pin 811 is electrically connected to a first AC input terminal 101, the second pin 812 is electrically connected to a second AC input terminal 102, and the third pin 813 is electrically connected to a third AC input terminal 103. The fourth pin 814 can be idle. When the first pin 811 and the second pin 812 are powered, the LED lamp 800 can be powered at one end. When the first pin 811 and the third pin 813 are powered, the LED lamp 800 can be powered at both ends.

[0057] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered to be within the scope of this specification. When technical features of different embodiments are embodied in the same drawing, it can be regarded as the drawing also disclosing examples of combinations of the various embodiments involved.

[0058] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. An LED driver circuit, characterized in that, include: The AC input terminals include a first AC input terminal and a second AC input terminal; The first step-down unit is coupled between the first AC input terminal and the second AC input terminal; The rectifier and filter unit is simultaneously coupled to the first AC input terminal and the second AC input terminal, and is used to convert AC power into DC power. A constant current unit, coupled to the rectifier and filter unit, is used to supply power to the LED load and has a signal input terminal; The adjustment unit has a signal output terminal coupled to the signal input terminal, wherein the signal input terminal receives the adjustment signal from the signal output terminal, causing the constant current unit to change its output power accordingly.

2. The LED driving circuit according to claim 1, characterized in that, The step-down unit includes a capacitor.

3. The LED driving circuit according to claim 2, characterized in that, The AC input terminal includes a third AC input terminal; The second step-down unit of the LED driving circuit is coupled between the first AC input terminal and the third AC input terminal.

4. The LED driving circuit according to claim 3, characterized in that, The capacitive reactance of the first step-down unit is 1 to 2 nF, and the capacitive reactance of the second step-down unit is 10 to 20 nF.

5. The LED driving circuit according to claim 1, characterized in that, The constant current unit includes a switching transistor with a first terminal, a second terminal, and a control terminal for controlling the conduction of the first and second terminals. The control terminal is used to receive PWM signals, the second terminal is used to supply power to the LED load, and the first terminal is coupled to the signal input terminal and coupled to the ground line through a sampling resistor.

6. The LED driving circuit according to claim 5, characterized in that, The adjustment unit includes multiple resistors connected in parallel with the sampling resistor, and a switching assembly that enables different resistors to conduct.

7. The LED driving circuit according to claim 6, characterized in that, The switching assembly is a DIP switch.

8. The LED driving circuit according to claim 5, characterized in that, The LED driving circuit includes a leakage protection unit coupled between the sampling resistor and the ground wire.

9. An LED lamp, comprising a lamp housing, the lamp housing comprising a lamp tube and a first end cap and a second end cap located at both ends of the lamp tube, the first end cap being provided with a first pin and a second pin, and the second end cap being provided with a third pin and a fourth pin; The lamp housing has a built-in LED driving circuit as described in any one of claims 1 to 8, characterized in that... The first pin is electrically connected to the first AC input terminal, and the second pin is electrically connected to the second AC input terminal.

10. The LED lamp according to claim 9, characterized in that, The AC input terminal includes a third AC input terminal, and the third pin is electrically connected to the third AC input terminal; The LED driving circuit includes a second step-down unit, which is coupled between the first AC input terminal and the third AC input terminal.

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