A driving circuit of an LED line lamp

Abstract

The application discloses a driving circuit of an LED line lamp, which comprises a rectifier circuit, a boost circuit, a step-down circuit, a power regulating circuit, a light emitting regulating circuit, a first light emitting module and a second light emitting module; the rectifier circuit converts commercial power into DC output; the boost circuit boosts the DC into high-voltage DC higher than 300V; the step-down circuit comprises a constant current chip and a transformer; the constant current chip controls the output power of the transformer; the power regulating circuit changes the output power of the transformer by changing the sampling resistance of the current sampling pin of the constant current chip; the light emitting regulating circuit controls the light emission of the first light emitting module and the second light emitting module by switching different power supply circuits; and finally the light brightness and color temperature of the lamp are regulated. The application has the advantages of simple circuit, stability, less electromagnetic interference to the power grid, no frequency flicker of the light, durable light source and the like.

Description

Technical Field

[0001] This invention relates to driving circuits for LED lighting fixtures, and more specifically to a driving circuit for an LED linear light. Background Technology

[0002] LED chips are made of semiconductor materials, exhibiting unidirectional conductivity. Furthermore, a single LED chip operates at a relatively low voltage, typically around 3V. Therefore, LED lighting fixtures using LED chips as their light source cannot be directly connected to AC mains power. Additionally, LED chips have non-linear voltage-current characteristics, making them unable to withstand large current surges. They require clean drive current, necessitating a driver circuit to convert AC mains power into clean DC power before connection. Since different applications demand varying brightness and color temperature from LED lighting fixtures, the same LED lighting fixture requires driver circuits with different power ratings and LED chips with different color temperatures. This increases the variety of product specifications available to manufacturers, retailers, and consumers, which is detrimental to production, sales, and user experience. Summary of the Invention

[0003] The purpose of this invention is to provide a driving circuit for LED linear lights that solves the problems existing in the prior art. To achieve this purpose, this invention provides the following technical solution: A driving circuit for an LED linear light includes a rectifier circuit, a boost circuit, a buck circuit, a power regulation circuit, a light emission regulation circuit, a first light-emitting module, and a second light-emitting module. The rectifier circuit converts AC mains power into DC power and outputs it to the boost circuit. The boost circuit includes a constant voltage chip, a boost inductor, and a freewheeling diode. The constant voltage chip drives the boost inductor through the drain of its MOSFET, boosting the DC power input from the rectifier circuit, and then outputting a high-voltage DC power higher than 220V through the high-voltage output terminal of the freewheeling diode. The buck circuit includes a constant current chip and a transformer. The current input terminal of the transformer's primary winding is connected to the high-voltage output terminal of the boost circuit, and its current output terminal is connected to the drain of the built-in MOSFET of the constant current chip. The current sampling pin of the constant current chip is connected to the transformer's current sampling pin through a sampling resistor. The primary winding current is sampled, and the drain of its built-in MOS transistor outputs a low-voltage constant current through the secondary winding of the transformer based on the current sampling pin. The power regulation circuit includes a first power switch and multiple different sampling resistors. The first switch can control the multiple different sampling resistors to conduct with the current sampling pin of the constant current chip. The light emission regulation circuit includes a second switch, the input of which is connected to the primary winding of the transformer, and the output of which includes a first circuit and a second circuit. The second switch can control the first circuit and / or the second circuit to conduct. The first light emission module and the second light emission module each include multiple first LED beads and second LED beads connected in series. The first light emission module and the second light emission module are respectively connected to the first circuit and the second circuit of the light emission regulation circuit.

[0004] As a further improvement to the present invention: The first switch on the power regulation circuit is a first DIP switch. The first DIP switch is provided with a ground pin, a first power pin, and a second power pin. The ground pin is connected to the chip ground pin of the constant current chip. The first power pin and the second power pin are respectively connected to the current sampling pin of the constant current chip through the fourteenth resistor and the fifteenth resistor. The first DIP switch can control the first power pin or the second power pin to be connected to the current sampling pin of the constant current chip.

[0005] The step-down circuit includes a positive output terminal and a negative output terminal. A first electrolytic capacitor and a seventh resistor are connected in parallel between the positive and negative output terminals. The current inflow terminal of the secondary winding of the transformer is directly connected to the negative output terminal of the step-down circuit, and its current outflow terminal is connected to the positive output terminal of the step-down circuit through a fourth diode.

[0006] The second switch on the light-emitting adjustment circuit is a second DIP switch. The input terminal of the second DIP switch is connected to the positive and negative output terminals of the buck circuit. Its output terminal includes a first positive terminal, a second positive terminal, and a negative terminal. The negative terminal of the second DIP switch is directly connected to the negative output terminal of the buck circuit, and its first and second positive terminals can be connected to the positive output terminal of the buck circuit, either individually or simultaneously.

[0007] The current inflow terminal of the primary winding of the transformer is connected to its current outflow terminal via a third diode and a resistor-capacitor filter module connected in series.

[0008] The transformer also includes a power-taking winding. The current-in-flow end of the power-taking winding is connected to the chip grounding pin of the constant current chip, and its current-out-flow end is connected to the positive terminal of the constant voltage chip through a fifth diode and also through a sixth diode.

[0009] The constant current chip also includes a feedback voltage sampling pin and a loop compensation pin. A second electrolytic capacitor is provided between the chip power supply pin and the chip ground pin of the constant current chip. The chip power supply pin is also connected to the high voltage output terminal of the boost circuit through a ninth capacitor. The chip ground pin is connected to the high voltage output terminal of the boost circuit through a third electrolytic capacitor. The loop compensation pin is connected to its chip ground pin through a tenth capacitor. The feedback voltage sampling pin is connected to the chip ground pin through an eleventh resistor and to the current output terminal of the power extraction winding through a twelfth resistor. Its current sampling pin is connected to the chip ground pin through a thirteenth resistor.

[0010] The two input terminals of the rectifier bridge are respectively connected to a live wire circuit and a neutral wire circuit. A fuse is installed on the live wire circuit. A varistor and a first capacitor are connected in parallel between the live and neutral wire circuits. The neutral wire circuit is connected to the input terminal of the rectifier bridge through a first inductor and to the negative output terminal of the rectifier bridge through a first resistor. The positive output terminal of the rectifier bridge is connected to the high voltage output terminal through a second capacitor and a first diode connected in parallel.

[0011] The constant voltage chip also includes a chip positive terminal, a chip negative terminal, and a voltage sampling pin. The chip positive terminal is connected to the negative output terminal of the rectifier bridge through a third capacitor, and the chip negative terminal is connected to the negative output terminal of the rectifier bridge. The voltage sampling pin is connected to the negative output terminal of the rectifier bridge through a second resistor and a fourth capacitor in parallel, and is connected to the high voltage output terminal through a third resistor. The current sampling pin is connected to the chip negative terminal through a fourth resistor. The drain pin of the MOS transistor is connected to the positive output terminal of the rectifier bridge through a boost inductor, and is connected to the high voltage output terminal through a freewheeling diode.

[0012] The beneficial effects of this invention are as follows: Because this invention adopts constant current output, it uses a power adjustment circuit to adjust the output current, i.e., the brightness of the lamp, and sets a light emission adjustment circuit to switch between different color temperature light emission modules. Consumers can set different light brightness and color temperature according to the needs of the scene when installing the lamp. The lamp has wide applicability, and only one drive circuit is needed for the same lamp, which greatly reduces the variety of product specifications and is beneficial to production, sales and consumer purchase. Attached Figure Description

[0013] Figure 1 This is a circuit block diagram of the present invention.

[0014] Figure 2 This is a schematic diagram of the rectifier circuit and boost circuit of the present invention.

[0015] Figure 3 This is a schematic diagram of the step-down circuit, power regulation circuit, and light emission regulation circuit of the present invention.

[0016] Figure 4 This is a circuit diagram of the first and second light-emitting modules of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] refer to Figure 1A driving circuit for an LED linear light includes a rectifier circuit 1, a boost circuit 2, a buck circuit 3, a power regulation circuit 4, a light emission regulation circuit 5, a first light emission module 61, and a second light emission module 62 connected in sequence.

[0019] refer to Figure 2 The rectifier circuit 1 includes a neutral wire circuit N, a live wire circuit L, a rectifier bridge DB1, and an EMI filter module connected to the input terminal of the rectifier bridge DB1. The EMI filter module includes a fuse F0 connected to the live wire L, a varistor RV and a first capacitor C1 connected between the neutral and live wires, a first inductor L1 connected to the neutral wire, and a first resistor R1 connected between the neutral wire N and the negative output terminal of the rectifier bridge DB1. The positive output terminal of the rectifier bridge DB1 is connected to the high-voltage output terminal HV+ through a capacitor C2 connected in parallel and a first diode D1.

[0020] refer to Figure 2 The input terminal of the boost circuit 2 is connected to the rectifier circuit 1, and its output terminal is the high-voltage output terminal HV+. Its function is to convert the 220V DC power processed by the rectifier circuit 1 into 380V high-voltage DC power to provide to the buck circuit 3. The boost circuit 2 includes a constant voltage chip U1, a boost inductor L2, and a freewheeling diode D2. The constant voltage chip U1 includes a positive terminal VCC, a negative terminal GND, a voltage sampling pin FB, a current sampling pin CS, and a MOSFET drain pin DRAIN. The positive terminal VCC is connected to the negative output terminal of the rectifier bridge DB1 through a third capacitor C3. The third capacitor C3 serves as the start-up capacitor for the constant voltage chip U1 and also as the filter capacitor after the constant voltage chip U1 starts up. The negative terminal GND is connected to the negative output terminal of the rectifier bridge DB1. The voltage sampling pin FB is connected to the negative output terminal of the rectifier bridge DB1 through a fourth capacitor C4 in parallel and a second resistor R2, and is connected to the high-voltage output terminal HV+ through a third resistor R3. The current sampling pin CS is connected to the chip's negative terminal GND via the fourth sampling resistor R4. The MOSFET drain pin DRAIN is connected to the positive output terminal of the rectifier bridge DB1 via the boost inductor L2, and to the high-voltage output terminal HV+ via the freewheeling diode D2. To improve the output current carrying capacity of the boost circuit, the constant voltage chip includes multiple parallel-connected MOSFET drain pins DRAIN. This boost circuit 2 can improve the power factor of the circuit and the stability of subsequent circuits, and reduce electromagnetic interference from the lighting fixtures to the power grid.

[0021] refer to Figure 3The input terminal of the step-down circuit 3 is connected to the high-voltage output terminal HV+ of the boost circuit 2. Its output terminal includes a positive terminal V+ and a negative terminal V-, responsible for outputting a 36V constant current DC power supply to the light-emitting module. The step-down circuit 3 includes a constant current chip U2 and a transformer T2. The constant current chip U2 includes a chip power supply pin VCC, a chip ground pin GND, a feedback voltage sampling pin FB, a current sampling pin CS, a loop compensation pin COMP, and a built-in MOSFET drain DRAIN. The transformer T2 includes a primary winding T1, a secondary winding T2, and a power-taking winding T3. The primary winding T1, secondary winding T2, and power-taking winding T3 each have current inflow terminals T11, T21, and T31, and current outflow terminals T12, T22, and T32, respectively. The transformer T2 steps down the voltage through the winding ratio of the primary winding T1 and the secondary winding T2.

[0022] The current inflow terminal T11 of the primary winding T1 is connected to the high-voltage output terminal HV+ of the boost circuit 2, and its current outflow terminal T12 is connected to the drain DRAIN of the built-in MOS transistor of the constant current chip U2. The current inflow terminal T11 of the primary winding T1 is connected to the current outflow terminal T12 through a series connection of the third diode D3, the sixth resistor R6, and the RC filter module. The RC filter module includes a fifth capacitor C5 and a fifth resistor R5 connected in parallel.

[0023] The current-out terminal T22 of the secondary winding T2 is connected to the positive output terminal V+ through the fourth diode D4, and to the negative terminal GND of the constant current chip U2 through the sixth capacitor C6. The current-in terminal T21 of the secondary winding T2 is directly connected to the negative output terminal V-, and to the current-in terminal T11 of the primary winding T1 through the seventh capacitor C7. A seventh resistor R7 and a first electrolytic capacitor CE1 are connected in parallel between the positive output terminal V+ and the negative output terminal V-.

[0024] The current inflow terminal T31 of the power-taking winding T3 is connected to the chip ground pin GND of the constant current chip U2, and its current outflow terminal T32 is connected to the positive terminal VCC of the constant voltage chip U1 through a series connection of the fifth diode D5 and the eighth resistor R8. The current outflow terminal T32 is also connected to the positive terminal VCC of the constant voltage chip U1 through a series connection of the sixth diode D6 and the ninth resistor R9. The power-taking winding T3 provides power to the constant voltage chip U1 and the constant current chip U2 after startup. Using the power-taking winding T3 to power the constant voltage chip U1 and the constant current chip U2 simplifies the circuit.

[0025] A second electrolytic capacitor CE2, a tenth resistor R10, and an eighth capacitor C8 are connected in parallel between the chip power supply pin VCC and the chip ground pin GND of the constant current chip U2. The chip power supply pin VCC is also connected to the high-voltage output terminal HV+ of the boost circuit 2 through the ninth capacitor C9, which serves as the startup capacitor and the filtering capacitor after startup of the constant current chip U2. The chip ground pin GND is connected to the high-voltage output terminal HV+ of the boost circuit 2 through the third electrolytic capacitor CE3. The loop compensation pin COMP is connected to its chip ground pin GND through the tenth capacitor C10, providing frequency compensation for the feedback loop. The feedback voltage sampling pin FB is connected to the chip ground pin GND through the eleventh capacitor C11 and the eleventh resistor R11 in parallel, and is connected to the current output terminal T32 of the power extraction winding T3 through the twelfth resistor R12. The current sampling pin CS of the constant current chip U2 is connected to the chip ground pin GND through the thirteenth resistor R13, used to set the output current and output power of the positive terminal V+ and the negative terminal V- of the buck circuit. This step-down circuit uses low-voltage constant current power supply, which can improve current stability, reduce light flicker, and extend the life of the light-emitting module.

[0026] The power regulation circuit 4 includes a first DIP switch DIP1, which has a ground pin GND, a first power pin P1, and a second power pin P2. The ground pin GND is connected to the chip ground pin GND of the constant current chip U2. The first power pin P1 and the second power pin P2 are respectively connected to the current sampling pin CS of the constant current chip U2 through the fourteenth resistor R14 and the fifteenth resistor R15. The first DIP switch DIP1 can control the first power pin P1, the second power pin P2, and the current sampling pin CS of the constant current chip U2 to be connected respectively. When DIP1 is in position 0, the current sampling pin CS of the constant current chip U2 is sampled through the thirteenth resistor R13, resulting in minimum power output. When DIP1 is in position 1, the first power pin P1 is connected to the current sampling pin CS, and the current sampling pin CS is sampled through the fourteenth resistor R14, resulting in the second highest power output. When DIP1 is in position 2, the second power pin P2 is connected to the current sampling pin CS, and the current sampling pin CS is sampled through the fifteenth resistor R15, resulting in maximum power output.

[0027] The light-emitting adjustment circuit 5 includes a second DIP switch DIP2. The input terminal of the second DIP switch DIP2 is connected to the positive output terminal V+ and the negative output terminal V- of the buck circuit 3. Its output terminal includes a first positive terminal V1+, a second positive terminal V2+, and a negative terminal V-. The negative terminal V- of the second DIP switch DIP2 is directly connected to the negative output terminal V- of the buck circuit 3, and its first positive terminal V1+ and second positive terminal V2+ can be connected to the positive output terminal V+ of the buck circuit 3, either individually or simultaneously.

[0028] refer to Figure 4 The first light-emitting module 61 includes several first LED beads 6a connected in series, and the second light-emitting module 62 includes several second LED beads 6b connected in series. The first LED beads 6a are cool white LED beads, and the second LED beads 6b are warm white LED beads. The first light-emitting module 61 is connected between the first positive terminal V1+ and the negative terminal V- of the second DIP switch DIP2, and the second light-emitting module 62 is connected between the second positive terminal V2+ and the negative terminal V- of the second DIP switch DIP2. The first light-emitting module 61 and the second light-emitting module 62 should be connected in series with an appropriate number of LED beads so that the operating voltage of the light-emitting module matches the output voltage of the step-down circuit 3. When the output voltage of the step-down circuit 3 is 36V, 12 LED beads can be connected in series; when the output voltage of the step-down circuit 3 is 12 or 24V, 4 or 8 LED beads can be connected in series, and so on. To improve the brightness of the lamps, multiple first light-emitting modules 61 can be connected in parallel between the first positive terminal V1+ and the negative terminal V- of the second DIP switch DIP2, and multiple second light-emitting modules 62 can be connected in parallel between the second positive terminal V2+ and the negative terminal V-.

[0029] The second DIP switch DIP2 can control the first light-emitting module 61 and the second light-emitting module 62 to emit light individually or simultaneously. When the first light-emitting module 61 emits light alone, the light effect of the strip light is pure white light; when the second light-emitting module 62 emits light alone, the light effect of the strip light is warm white light; when the first light-emitting module 61 and the second light-emitting module 62 emit light simultaneously, the light effect of the strip light is neutral light.

[0030] This invention employs constant current output, combined with a power adjustment circuit to regulate the output current, i.e., the brightness of the lamp. It also includes a light emission adjustment circuit for switching between different color temperature light emission modules. Consumers can set different light brightness and color temperature according to their needs during installation. The lamp has wide applicability, and only one driver circuit is required for the same type of lamp, which greatly reduces the variety of product specifications and is beneficial for production, sales, and consumer purchase.

Claims

1. A driving circuit for an LED linear light, characterized in that: It includes a rectifier circuit, a boost circuit, a buck circuit, a power regulation circuit, a light emission regulation circuit, a first light emission module, and a second light emission module; The rectifier circuit converts the mains power into DC power and outputs it to the boost circuit. The boost circuit includes a constant voltage chip, a boost inductor, and a freewheeling diode. The constant voltage chip drives the boost inductor through the drain of its MOSFET to boost the DC power input from the rectifier circuit, and then outputs a high-voltage DC power higher than 220V through the high-voltage output terminal of the freewheeling diode. The step-down circuit includes a constant current chip and a transformer. The current input terminal of the primary winding of the transformer is connected to the high voltage output terminal of the step-up circuit, and its current output terminal is connected to the drain of the built-in MOS transistor of the constant current chip. The current sampling pin of the constant current chip samples the current of the primary winding of the transformer through a sampling resistor. The drain of the built-in MOS transistor outputs a low-voltage constant current through the secondary winding of the transformer according to the sampling of the current sampling pin. The power regulation circuit includes a first power switch and multiple different sampling resistors. The first switch can control the multiple different sampling resistors to conduct with the current sampling pin of the constant current chip. The light-emitting adjustment circuit includes a second switch, the input of which is connected to the primary winding of the transformer, and the output of which includes a first circuit and a second circuit. The second switch can control the first circuit and / or the second circuit to be turned on. The first light-emitting module and the second light-emitting module each include a plurality of first LED beads and second LED beads connected in series. The first light-emitting module and the second light-emitting module are respectively connected to the first circuit and the second circuit of the light-emitting adjustment circuit.

2. The driving circuit for an LED linear light according to claim 1, characterized in that: The first switch on the power regulation circuit is a first DIP switch. The first DIP switch is provided with a ground pin, a first power pin, and a second power pin. The ground pin is connected to the chip ground pin of the constant current chip. The first power pin and the second power pin are respectively connected to the current sampling pin of the constant current chip through the fourteenth resistor and the fifteenth resistor. The first DIP switch can control the first power pin or the second power pin to be connected to the current sampling pin of the constant current chip.

3. The driving circuit for an LED linear light according to claim 1, characterized in that: The step-down circuit includes a positive output terminal and a negative output terminal. A first electrolytic capacitor and a seventh resistor are connected in parallel between the positive and negative output terminals. The current inflow terminal of the secondary winding of the transformer is directly connected to the negative output terminal of the step-down circuit, and its current outflow terminal is connected to the positive output terminal of the step-down circuit through a fourth diode.

4. The driving circuit for an LED linear light according to claim 3, characterized in that: The second switch on the light-emitting adjustment circuit is a second DIP switch. The input terminal of the second DIP switch is connected to the positive and negative output terminals of the buck circuit. Its output terminal includes a first positive terminal, a second positive terminal, and a negative terminal. The negative terminal of the second DIP switch is directly connected to the negative output terminal of the buck circuit, and its first and second positive terminals can be connected to the positive output terminal of the buck circuit, either individually or simultaneously.

5. The driving circuit for an LED linear light according to claim 1, characterized in that: The current inflow terminal of the primary winding of the transformer is connected to its current outflow terminal via a third diode and a resistor-capacitor filter module connected in series.

6. The driving circuit for an LED linear light according to claim 1, characterized in that: The transformer also includes a power-taking winding. The current-in-flow end of the power-taking winding is connected to the chip grounding pin of the constant current chip, and its current-out-flow end is connected to the positive terminal of the constant voltage chip through a fifth diode and also through a sixth diode.

7. The driving circuit for an LED linear light according to claim 1, characterized in that: The constant current chip also includes a feedback voltage sampling pin and a loop compensation pin. A second electrolytic capacitor is provided between the chip power supply pin and the chip ground pin of the constant current chip. The chip power supply pin is also connected to the high voltage output terminal of the boost circuit through a ninth capacitor. The chip ground pin is connected to the high voltage output terminal of the boost circuit through a third electrolytic capacitor. The loop compensation pin is connected to its chip ground pin through a tenth capacitor. The feedback voltage sampling pin is connected to the chip ground pin through an eleventh resistor and to the current output terminal of the power extraction winding through a twelfth resistor. Its current sampling pin is connected to the chip's ground pin through the thirteenth resistor.

8. The driving circuit for an LED linear light according to claim 1, characterized in that: The two input terminals of the rectifier bridge are respectively connected to a live wire circuit and a neutral wire circuit. A fuse is installed on the live wire circuit. A varistor and a first capacitor are connected in parallel between the live and neutral wire circuits. The neutral wire circuit is connected to the input terminal of the rectifier bridge through a first inductor and to the negative output terminal of the rectifier bridge through a first resistor. The positive output terminal of the rectifier bridge is connected to the high voltage output terminal through a second capacitor and a first diode connected in parallel.

9. The driving circuit for an LED linear light according to claim 8, characterized in that: The constant voltage chip also includes a chip positive terminal, a chip negative terminal, and a voltage sampling pin. The chip positive terminal is connected to the negative output terminal of the rectifier bridge through a third capacitor, and the chip negative terminal is connected to the negative output terminal of the rectifier bridge. The voltage sampling pin is connected to the negative output terminal of the rectifier bridge through a second resistor and a fourth capacitor in parallel, and is connected to the high voltage output terminal through a third resistor. The current sampling pin is connected to the chip negative terminal through a fourth resistor. The drain pin of the MOS transistor is connected to the positive output terminal of the rectifier bridge through a boost inductor, and is connected to the high voltage output terminal through a freewheeling diode.

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