LED linear driving circuit and lighting device

Abstract

The utility model provides an LED linear drive circuit and a lighting device, the LED linear drive circuit comprises a rectifier bridge, an energy storage unit and a charging and discharging drive circuit, and the charging and discharging drive circuit drives the rectifier bridge to charge the energy storage unit or drives the rectifier bridge to stop charging the energy storage unit based on the magnitude of direct current voltage. Therefore, the energy storage unit can supply power to the load, charge and discharge control over the energy storage unit is achieved, control over the voltage on the energy storage unit can be achieved, it is guaranteed that charging of the energy storage unit is stopped when the voltage of the energy storage unit is slightly larger than the input voltage threshold value, and therefore the energy loss of the circuit can be reduced, and the energy conversion efficiency can be improved. Meanwhile, the circuit has the advantages of being simple in structure, small in number of components and low in cost.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, and in particular to an LED linear drive circuit and a lighting device. Background Art

[0002] LED (Light-Emitting Diode) lighting is widely used in furniture, office, outdoor, and stage lighting. Dimming technology allows for adjustable brightness of LED loads, expanding the application scenarios and practical experience of LED lighting. In recent years, with the advancement of society, higher requirements have emerged for LED lighting, requiring high PF (Power Factor), no flicker, and high efficiency to reduce damage to the human eye and improve energy efficiency.

[0003] Energy conversion efficiency is a crucial metric in the field of LED lighting. In traditional LED linear dimming solutions, a significant amount of energy is lost in the power transistors. Therefore, reducing power transistor losses and thereby improving the energy conversion efficiency of LED dimming is a pressing issue. Utility Model Content

[0004] The purpose of the present invention is to provide an LED linear drive circuit and an illumination device to solve the problem of how to reduce the energy loss of the drive circuit and thus improve the energy conversion efficiency of LED dimming.

[0005] In order to solve the above technical problems, the present invention provides an LED linear drive circuit, which includes:

[0006] A rectifier bridge, wherein the input end of the rectifier bridge is connected to an AC power supply and the rectifier bridge outputs a DC voltage;

[0007] Energy storage unit;

[0008] A charge-discharge drive circuit is connected to the energy storage unit and then to the output port of the rectifier bridge, and is used to control the rectifier bridge to charge the energy storage unit according to the DC voltage, or to control the rectifier bridge to stop charging the energy storage unit, so that the energy storage unit supplies power to the load.

[0009] Optionally, the charge-discharge drive circuit controls the rectifier bridge to charge the energy storage unit when the voltage sampling signal representing the DC voltage is less than or equal to a threshold voltage, and the charge-discharge drive circuit controls the rectifier bridge to stop charging the energy storage unit when the voltage sampling signal is greater than the threshold voltage, so that the energy storage unit supplies power to the load.

[0010] Optionally, the charge and discharge drive circuit includes a voltage detection circuit, a comparator and a first power switch;

[0011] The voltage detection circuit is used to generate the voltage sampling signal according to the DC voltage;

[0012] The first input terminal of the comparator receives the voltage sampling signal, the second input terminal of the comparator receives the threshold voltage, and the output terminal of the comparator is connected to the control terminal of the first power switch;

[0013] The first power switch is connected to the energy storage unit and then connected to the output port of the rectifier bridge.

[0014] Optionally, the comparator controls the first power switch to turn on when the voltage sampling signal is less than or equal to the threshold voltage, so that the rectifier bridge charges the energy storage unit, and the comparator controls the first power switch to turn off when the voltage sampling signal is greater than the threshold voltage, so that the rectifier bridge stops charging the energy storage unit.

[0015] Optionally, the charge and discharge drive circuit further includes a filter capacitor, a first end of the filter capacitor is connected to the second input end of the comparator, and a second end of the filter capacitor is connected to the second end of the first power switch.

[0016] Optionally, the voltage detection circuit includes a first resistor and a second resistor, one end of the first resistor is connected to the output end of the rectifier bridge, the other end of the first resistor is connected to the second output end of the rectifier bridge through the second resistor, and the other end of the first resistor is connected to the first input end of the comparator.

[0017] Optionally, the maximum voltage on the energy storage unit is not higher than Vref3*(1+R1 / R2);

[0018] Wherein, Vref3 is the threshold voltage, R1 is the resistance value of the first resistor, and R2 is the resistance value of the second resistor.

[0019] Optionally, the LED linear driving circuit further includes a constant current control circuit, and the constant current control circuit is connected to the load and then to both ends of the energy storage unit.

[0020] Optionally, the voltage detection circuit includes a first resistor and a second resistor, one end of the first resistor is connected to the connection point between the load and the constant current control circuit, the other end of the first resistor is connected to the second output end of the rectifier bridge through the second resistor, and the other end of the first resistor is connected to the first input end of the comparator.

[0021] Optionally, the maximum voltage on the energy storage unit is not higher than Vout+Vref1*(1+R1 / R2);

[0022] Wherein, Vout is the voltage across the load, Vref1 is the threshold voltage, R1 is the resistance value of the first resistor, and R2 is the resistance value of the second resistor.

[0023] Optionally, the energy storage unit is used to supply power to the constant current control circuit.

[0024] Optionally, the constant current control circuit includes an operational amplifier, a second power switch and a third resistor, the first input terminal of the operational amplifier is connected to a reference voltage, the second input terminal of the operational amplifier is connected to a reference ground through the third resistor, the output terminal of the operational amplifier is connected to the control terminal of the second power switch, the first terminal of the load is connected to the first output terminal of the rectifier bridge and the first terminal of the energy storage unit, the first terminal of the second power switch is connected to the second terminal of the load, the second terminal of the second power switch is connected to the second input terminal of the operational amplifier, and the end of the third resistor connected to the reference ground is also connected to the second terminal of the energy storage unit.

[0025] Optionally, the constant current control circuit includes an operational amplifier, a second power switch and a third resistor, the first input terminal of the operational amplifier is connected to the reference voltage, the second input terminal of the operational amplifier is connected to the first terminal of the load through the third resistor, the output terminal of the operational amplifier is connected to the control terminal of the second power switch, the first terminal of the second power switch is connected to the first output terminal of the rectifier bridge and the first terminal of the energy storage unit, the second terminal of the second power switch is connected to the second input terminal of the operational amplifier, the second terminal of the load is connected to the reference ground, and the second terminal of the load is also connected to the second terminal of the energy storage unit.

[0026] The LED linear driver circuit described above uses a charging and discharging drive circuit to drive the rectifier bridge to charge the energy storage unit or to stop charging the energy storage unit based on the magnitude of the DC voltage, allowing the energy storage unit to supply power to the load. This controls the charging and discharging of the energy storage unit, and further controls the voltage across the energy storage unit, ensuring that charging stops when the voltage of the energy storage unit is slightly greater than the input voltage threshold. This reduces circuit energy loss and improves energy conversion efficiency. Furthermore, the present invention has the advantages of a simple circuit structure, a small number of components, and low cost.

[0027] The present invention also provides a lighting device, which includes a load and the above-mentioned LED linear drive circuit. It should be noted that since the lighting device includes the LED linear drive circuit, it also has the technical effects of the LED linear drive circuit, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Those skilled in the art will appreciate that the accompanying drawings are provided to better understand the present invention and do not constitute any limitation on the scope of the present invention.

[0029] Figure 1 This is a schematic diagram of an LED linear drive circuit according to a first embodiment of the present invention;

[0030] Figure 2 This is another schematic diagram of the LED linear driving circuit of the first embodiment of the present utility model;

[0031] Figure 3 This is a timing diagram of the alternating current, the output voltage of the rectifier bridge, and the driving signal in the first embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of an LED linear drive circuit according to a second embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of an LED linear drive circuit according to a third embodiment of the present invention.

[0034] In the attached figure:

[0035] 10-rectifier bridge; 20-constant current control circuit; 30-energy storage unit; 40-charge and discharge drive circuit; 41-voltage detection circuit; 50-load;

[0036] U1-comparator; U2-op amp; Q1-first power switch; Q2-second power switch; R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor; C1-energy storage capacitor; C2-filter capacitor. DETAILED DESCRIPTION

[0037] To further clarify the objectives, advantages, and features of the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are highly simplified and not drawn to scale, and are intended solely to facilitate and clearly illustrate the objectives of the embodiments of the present invention. Furthermore, the structures shown in the drawings are often portions of the actual structures. In particular, different drawings may require different emphases and may use different scales.

[0038] As used in the present invention, the singular forms "a", "an", and "the" include plural referents, the term "or" is generally used to include "and / or", the term "several" is generally used to include "at least one", and the term "at least two" is generally used to include "two or more". In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features specified as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "proximal end" and "distal end" generally refer to two corresponding parts, which not only include endpoints, and the terms "mounted", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal communication between two elements or the interaction relationship between two elements. In addition, as used in this utility model, "one element is disposed on another element" generally only indicates that there is a connection, coupling, cooperation, or transmission relationship between the two elements, and the connection, coupling, cooperation, or transmission between the two elements can be direct or indirect through an intermediate element, and should not be understood as indicating or implying a spatial positional relationship between the two elements, that is, one element can be in any orientation such as inside, outside, above, below, or to the side of another element, unless otherwise explicitly stated. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0039] [Example 1]

[0040] Figure 1 This is a schematic diagram of an LED linear drive circuit according to the first embodiment of the present invention. Figure 2 This is another schematic diagram of the LED linear drive circuit according to the first embodiment of the present invention. Figures 1 to 2 This embodiment provides a LED linear drive circuit, which includes a rectifier bridge 10, an energy storage unit 30, and a charge-discharge drive circuit 40. The input end of the rectifier bridge 10 is connected to an AC power source (AC), thereby ACThe LED linear drive circuit further comprises a constant current control circuit 20, which is connected to both ends of the energy storage unit 30 after being connected to the load 50. The energy storage unit 30 is connected to the output port of the rectifier bridge 10. The charging and discharging drive circuit 40 is connected to the output port of the rectifier bridge 10 and is configured to drive the rectifier bridge 10 to charge the energy storage unit 30 according to the DC voltage Vin, or to drive the rectifier bridge 10 to stop charging the energy storage unit 30, so that the energy storage unit 30 supplies power to the load 50.

[0041] Continue reading Figure 1 and Figure 2 The first end of the load 50 is connected to the first output end of the rectifier bridge 10 and the first end of the energy storage unit 30. The load 50 here is also an LED (Light-Emitting Diode). The second end of the load 50 is connected to the first end of the constant current control circuit 20, and the second end of the constant current control circuit 20 is connected to the second end of the energy storage unit 30. The first end of the charge and discharge drive circuit 40 is connected to the second end of the energy storage unit 30 and the second end of the constant current control circuit 20, and the second end of the charge and discharge drive circuit 40 is connected to the second output end of the rectifier bridge 10, and the second output end of the rectifier bridge 10 is grounded. The charge and discharge drive circuit 40 can drive the rectifier bridge 10 to charge the energy storage unit according to the size of the DC voltage Vin to increase the energy storage voltage of the energy storage unit 30, or drive the rectifier bridge 10 to stop charging the energy storage unit 30, so that the energy storage unit 30 discharges and thus supplies power to the load 50. As will be appreciated, when the DC voltage Vin exceeds the conduction threshold, the DC voltage Vin output by the rectifier bridge 10 supplies power to the load 50, where the conduction threshold is the conduction voltage of the branch where the load 50 is located. The constant current control circuit maintains a constant current through the load 50. Furthermore, the energy storage unit 30 is also used to supply power to the constant current control circuit 20, ensuring normal startup and operation of the constant current control circuit 20.

[0042] In one embodiment, the charge-discharge drive circuit 40 drives the rectifier bridge 10 to charge the energy storage unit when the voltage sampling signal representing the DC voltage is less than or equal to the threshold voltage (Vref1), and the charge-discharge drive circuit 40 drives the rectifier bridge 10 to stop charging the energy storage unit 30 when the voltage sampling signal is greater than the threshold voltage, so that the energy storage unit 30 supplies power to the load 50, and the rectifier bridge 10 stops supplying power to the load 50. Specifically, when the voltage sampling signal is less than or equal to the threshold voltage (Vref1), the rectifier bridge 10, the energy storage unit 30, and the charge-discharge drive circuit 40 form a charging circuit, so that the rectifier bridge 10 charges the energy storage unit 30 and increases the energy storage voltage of the energy storage unit 30; when the DC voltage Vin exceeds the conduction threshold, the rectifier bridge 10, the load 50, and the constant current control circuit 20 form a power supply circuit, so that the rectifier bridge 10 supplies power to the load 50; and, when the sampling voltage is greater than the threshold voltage, the internal circuit of the charge-discharge drive circuit 40 is disconnected, thereby disconnecting the charging circuit. At this time, the energy storage unit 30, the load 50, and the constant current control circuit 20 form a discharge circuit, so that the energy storage unit 30 discharges to the load 50, thereby supplying power to the load 50. It should be noted that when the internal circuit of the charge-discharge drive circuit 40 is disconnected, the rectifier bridge 10 stops supplying power to the load 50.

[0043] Furthermore, the charge and discharge drive circuit 40 includes a voltage detection circuit 41, a comparator U1, and a first power switch Q1. The voltage detection circuit 41 samples the DC voltage to obtain a voltage sampling signal. The first input terminal (e.g., the inverting input terminal) of the comparator U1 is connected to the voltage detection circuit 41 to receive the voltage sampling signal. The second input terminal (e.g., the non-inverting input terminal) of the comparator U1 is connected to the threshold voltage. The output terminal of the comparator U1 is connected to the gate terminal (control terminal) of the first power switch Q1. The first power switch Q1 is connected to the energy storage unit 30 and then connected to the output port of the rectifier bridge 10. Specifically, the first terminal of the energy storage unit 30 is connected to the first output terminal of the rectifier bridge 10, the drain terminal (first terminal) of the first power switch Q1 is connected to the second terminal of the energy storage unit 30, and the source terminal (second terminal) of the first power switch Q1 is connected to the second output terminal of the rectifier bridge 10. In other embodiments, the drain end (first end) of the first power switch Q1 is connected to the first output end of the rectifier bridge 10, the source end (second end) of the first power switch Q1 is connected to the first end of the energy storage unit 30, and the second end of the energy storage unit 30 is connected to the second output end of the rectifier bridge 10.

[0044] The comparator U1 controls the on / off switching of the first power switch Q1 based on the comparison result between the voltage sampling signal and the threshold voltage. Specifically, the comparator U1 outputs a drive signal VG to the first power switch Q1, driving the first power switch Q1 to conduct or shut down. When the voltage sampling signal is less than or equal to the threshold voltage, the drive signal VG output by the comparator U1 is high, driving the first power switch Q1 to conduct, so that the rectifier bridge 10, the energy storage unit 30, and the first power switch Q1 form a charging circuit, charging the energy storage unit 30. When the sampling voltage is greater than the threshold voltage, the drive signal VG output by the comparator U1 is low, driving the first power switch Q1 to turn off. At this time, the energy storage unit 30, the constant current control circuit 20, and the load 50 form a discharge circuit, causing the energy storage unit 30 to discharge to the load 50, providing power to the load 50.

[0045] As an example, the first power switch Q1 is an NMOS transistor, wherein the first terminal of the first power switch Q1 is a drain, the second terminal is a source, and the control terminal is a gate. In another example, the first power switch Q1 is an NPN transistor, wherein the first terminal of the first power switch Q1 is a collector, the second terminal is an emitter, and the control terminal is a base.

[0046] Preferably, see Figure 2 The charge and discharge drive circuit 40 further includes a filter capacitor C2 and a fourth resistor R4. One end of the fourth resistor R4 is connected to the threshold voltage. The other end of the fourth resistor R4 is connected to one end of the filter capacitor C2 and then connected to the second input end of the comparator U1. The other end of the filter capacitor C2 is grounded. In this way, the threshold voltage is filtered to ensure that the threshold voltage received by the second input end of the comparator U1 is more stable, making the drive signal it outputs more accurate.

[0047] As an example, the voltage detection circuit 41 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the connection point between the load 50 and the constant current control circuit 20, the other end of the first resistor R1 is connected to the second output end of the rectifier bridge 10 through the second resistor R2, and the other end of the first resistor R1 is connected to the first input end of the comparator U1 of the charge and discharge drive circuit 40. In this way, the voltage at the connection point between the load 50 and the constant current control circuit 20 is sampled by the voltage divider of the first resistor R1 and the second resistor R2, thereby sampling the DC voltage Vin to obtain a voltage sampling signal.

[0048] Figure 3 This is a timing diagram of the AC power, the output voltage of the rectifier bridge 10 and the driving signal of the first embodiment of the present invention. Figure 1 and Figure 3, defining the voltage sampling coefficient of the voltage detection circuit 41 at the connection point between the load 50 and the constant current control circuit 20 as k. Based on the structural configuration of the voltage detection circuit 41, where K = R2 / (R1+R2), the threshold voltage is Vref1, and the voltage across the load 50 is Vout, then the maximum energy storage voltage on the energy storage unit 30 will not exceed the input voltage threshold Vth1, where Vth1 = Vout+Vref1 / k. In other words, the maximum energy storage voltage on the energy storage unit 30 will not exceed Vout+Vref1*(1+R1 / R2). It should be noted that as long as the first power switch Q1 is controlled to be off when the input voltage threshold Vth1 is slightly greater than the load voltage Vout, high efficiency of the LED linear drive circuit can be achieved. In this way, when the DC voltage Vin output by the rectifier bridge 10 is less than or equal to the input voltage threshold Vth1, the drive signal VG is at a high level, the first power switch Q1 is turned on, and the rectifier bridge 10 charges the energy storage unit 30. When the output voltage Vin of the rectifier bridge 10 is greater than the input voltage threshold Vth1, the drive signal VG is at a low level, the first power switch Q1 is turned off, and the energy storage unit 30 discharges to the load 50.

[0049] For example, see Figure 1 and Figure 2 The constant current control circuit 20 includes an operational amplifier U2 (operational amplifier), a second power switch Q2, and a third resistor R3. The first input terminal (e.g., the non-inverting input terminal) of the operational amplifier U2 is connected to a reference voltage (Vref2). The second input terminal (e.g., the inverting input terminal) of the operational amplifier U2 is connected to the reference ground GND via the third resistor R3. The output terminal of the operational amplifier U2 is connected to the gate terminal (control terminal) of the second power switch Q2. The first terminal of the load 50 is connected to the first output terminal of the rectifier bridge 10 and the first terminal of the energy storage unit 30. The second terminal of the load 50 is connected to the drain terminal (first terminal) of the second power switch Q2. The source terminal (second terminal) of the second power switch Q2 is connected to the second input terminal of the operational amplifier U2. One terminal of the third resistor R3 connected to the reference ground GND is also connected to the second terminal of the energy storage unit 30. Thus, the operational amplifier U2 converts the input voltage signal (reference voltage Vref2) into a current signal. The converted current signal is equivalent to a simple constant current source with an adjustable output. The current is the quotient of the reference voltage Vref2 and the third resistor R3.

[0050] In one embodiment, the second power switch Q2 is an NMOS transistor, wherein the first terminal of the second power switch Q2 is a drain, the second terminal is a source, and the control terminal is a gate. In another example, the second power switch Q2 is an NPN transistor, wherein the first terminal of the second power switch Q2 is a collector, the second terminal is an emitter, and the control terminal is a base.

[0051] See Figures 1 to 2The energy storage unit 30 is used to supply power to the constant current control circuit 20. Specifically, a first end of the energy storage capacitor is connected to a power supply terminal (not shown) of the operational amplifier U2 to provide an operating voltage to the operational amplifier U2.

[0052] [Example 2]

[0053] This embodiment only describes the technical features that are different from the first embodiment. The same technical features can be understood by referring to the description of the first embodiment, which will not be repeated here.

[0054] Figure 4 This is a schematic diagram of the LED linear drive circuit of the second embodiment of the present invention. Figure 4 The voltage detection circuit 41 is connected to the first output terminal of the rectifier bridge 10 and samples the DC voltage Vin output by the rectifier bridge 10 to obtain a voltage sampling signal. Specifically, one end of the first resistor R1 is connected to the first output terminal of the first rectifier bridge 10, and the other end of the first resistor R1 is connected to the second output terminal of the rectifier bridge 10 through the second resistor R2. The other end of the first resistor R1 is also connected to the first input terminal of the comparator U1.

[0055] As an example, the sampling coefficient of the voltage detection circuit 41 for the DC voltage Vin output by the rectifier bridge 10 is defined as k. Based on the structural configuration of the voltage detection circuit 41, K is defined as R2 / (R1+R2), the threshold voltage is Vref3 (Vref3 here can be different from Vref1 in the first embodiment), and the voltage of the load 50 is Vout. Therefore, the maximum energy storage voltage of the energy storage unit 30 will not exceed the input voltage threshold Vth2, where Vth2=Vref3 / k>Vout. In other words, the maximum energy storage voltage of the energy storage unit 30 will not exceed Vref3*(1+R1 / R2). Thus, when the output voltage Vin of the rectifier bridge 10 is less than or equal to the input voltage threshold Vth2, the drive signal VG is high, the first power switch Q1 is turned on, and the rectifier bridge 10 charges the energy storage unit 30. When the output voltage Vin of the rectifier bridge 10 is greater than the input voltage threshold Vth2, the drive signal VG is low, the first power switch Q1 is turned off, and the energy storage unit 30 discharges to the load 50. When the input threshold Vth2 and Vout are close, the energy conversion efficiency of the system is higher.

[0056] [Example 3]

[0057] This embodiment only describes the technical features that are different from the second embodiment. The same technical features can be understood by referring to the description of the first embodiment, which will not be repeated here.

[0058] Figure 5 This is a schematic diagram of the LED linear drive circuit of the third embodiment of the present invention. Figure 5The first end of the constant current control circuit 20 is connected to the first output end of the rectifier bridge 10 and the first end of the energy storage unit 30, the second end of the constant current control circuit 20 is connected to the first end of the load 50 (the anode of the light-emitting diode), and the second end (cathode) of the load 50 is connected to the second end of the energy storage unit 30.

[0059] See also Figure 5 The first end of the second power switch Q2 is connected to the first output end of the rectifier bridge 10 and the first end of the energy storage unit 30. The second end of the second power switch Q2 is connected to the first end of the load 50 via the third resistor. The second end of the load 50 is connected to the reference ground GND, and the second end of the load 50 is connected to the second end of the energy storage unit 30. In this way, the input voltage signal (reference voltage Vref2) is converted into a current signal by the operational amplifier U2. The converted current signal is equivalent to a simple constant current source with an adjustable output. The current is the quotient of the reference voltage Vref2 and the third resistor R3.

[0060] This embodiment provides a lighting device, which includes a load and the above-mentioned LED linear drive circuit. The description of the LED linear drive circuit can be understood by referring to the description of Embodiments 1 to 3, which will not be repeated here.

[0061] In the present invention, the LED driver circuit uses a charging and discharging drive circuit to drive the rectifier bridge to charge the energy storage unit based on the magnitude of the DC voltage, or to drive the rectifier bridge to stop charging the energy storage unit, so that the energy storage unit can supply power to the load, thereby achieving charge and discharge control of the energy storage unit. Furthermore, the voltage on the energy storage unit can be controlled to ensure that charging of the energy storage unit is stopped when the voltage of the energy storage unit is slightly greater than the input voltage threshold. This can reduce energy loss in the circuit and improve energy conversion efficiency. Furthermore, the present invention has the advantages of a simple circuit structure, a small number of components, and low cost.

[0062] Although the present invention is disclosed above with reference to preferred embodiments, the above embodiments are not intended to limit the present invention. Any person skilled in the art can utilize the above-disclosed technical content to make many possible changes and modifications to the present invention without departing from the scope of the present invention, or to modify the present invention into equivalent embodiments with equivalent variations. Therefore, any simple modifications, equivalent variations, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention are still within the scope of protection of the present invention.

Claims

1. An LED linear drive circuit, characterized in that: include: A rectifier bridge, wherein the input end of the rectifier bridge is connected to an AC power supply and the rectifier bridge outputs a DC voltage; Energy storage unit; A charge-discharge drive circuit is connected to the energy storage unit and then to the output port of the rectifier bridge, and is used to drive the rectifier bridge to charge the energy storage unit according to the DC voltage, or drive the rectifier bridge to stop charging the energy storage unit, so that the energy storage unit supplies power to the load.

2. The LED linear driving circuit according to claim 1, characterized in that: The charge-discharge drive circuit controls the rectifier bridge to charge the energy storage unit when the voltage sampling signal representing the DC voltage is less than or equal to a threshold voltage, and controls the rectifier bridge to stop charging the energy storage unit when the voltage sampling signal is greater than the threshold voltage, so that the energy storage unit supplies power to the load.

3. The LED linear driving circuit according to claim 2, characterized in that: The charging and discharging driving circuit includes a voltage detection circuit, a comparator and a first power switch; The voltage detection circuit is used to generate the voltage sampling signal according to the DC voltage; The first input terminal of the comparator receives the voltage sampling signal, the second input terminal of the comparator receives the threshold voltage, and the output terminal of the comparator is connected to the control terminal of the first power switch; The first power switch is connected to the energy storage unit and then connected to the output port of the rectifier bridge.

4. The LED linear driving circuit according to claim 3, characterized in that: The comparator controls the first power switch to turn on when the voltage sampling signal is less than or equal to the threshold voltage, so that the rectifier bridge charges the energy storage unit; and the comparator controls the first power switch to turn off when the voltage sampling signal is greater than the threshold voltage, so that the rectifier bridge stops charging the energy storage unit.

5. The LED linear driving circuit according to claim 3, characterized in that: The charge-discharge drive circuit further includes a filter capacitor, a first end of the filter capacitor is connected to the second input end of the comparator, and a second end of the filter capacitor is connected to the second end of the first power switch.

6. The LED linear driving circuit according to claim 3, characterized in that: The voltage detection circuit includes a first resistor and a second resistor, one end of the first resistor is connected to the first output end of the rectifier bridge, the other end of the first resistor is connected to the second output end of the rectifier bridge through the second resistor, and the other end of the first resistor is connected to the first input end of the comparator.

7. The LED linear driving circuit according to claim 6, characterized in that: The maximum voltage on the energy storage unit is not higher than Vref3*(1+R1 / R2); Wherein, Vref3 is the threshold voltage, R1 is the resistance value of the first resistor, and R2 is the resistance value of the second resistor.

8. The LED linear driving circuit according to claim 3, characterized in that: The LED linear drive circuit further includes a constant current control circuit. The constant current control circuit is connected to the load and then to both ends of the energy storage unit.

9. The LED linear driving circuit according to claim 8, characterized in that: The voltage detection circuit includes a first resistor and a second resistor, one end of the first resistor is connected to the connection point between the load and the constant current control circuit, the other end of the first resistor is connected to the second output end of the rectifier bridge through the second resistor, and the other end of the first resistor is connected to the first input end of the comparator.

10. The LED linear driving circuit according to claim 9, characterized in that: The maximum voltage on the energy storage unit is not higher than Vout+Vref1*(1+R1 / R2); Wherein, Vout is the voltage across the load, Vref1 is the threshold voltage, R1 is the resistance value of the first resistor, and R2 is the resistance value of the second resistor.

11. The LED linear driving circuit according to claim 8, characterized in that: The energy storage unit is used to supply power to the constant current control circuit.

12. The LED linear driving circuit according to claim 8, characterized in that: The constant current control circuit includes an operational amplifier, a second power switch, and a third resistor. The first input terminal of the operational amplifier is connected to a reference voltage, the second input terminal of the operational amplifier is connected to a reference ground through the third resistor, the output terminal of the operational amplifier is connected to a control terminal of the second power switch, the first terminal of the load is connected to the first output terminal of the rectifier bridge and the first terminal of the energy storage unit, the first terminal of the second power switch is connected to the second terminal of the load, the second terminal of the second power switch is connected to the second input terminal of the operational amplifier, and the end of the third resistor connected to the reference ground is also connected to the second terminal of the energy storage unit.

13. The LED linear driving circuit according to claim 8, characterized in that: The constant current control circuit includes an operational amplifier, a second power switch, and a third resistor. The first input terminal of the operational amplifier is connected to a reference voltage, the second input terminal of the operational amplifier is connected to the first terminal of the load through the third resistor, the output terminal of the operational amplifier is connected to the control terminal of the second power switch, the first terminal of the second power switch is connected to the first output terminal of the rectifier bridge and the first terminal of the energy storage unit, the second terminal of the second power switch is connected to the second input terminal of the operational amplifier, the second terminal of the load is connected to the reference ground, and the second terminal of the load is also connected to the second terminal of the energy storage unit.

14. A lighting device, characterized in that: The invention comprises a load and the LED linear driving circuit according to any one of claims 1 to 13.

Images