LED drive circuit

Abstract

The utility model relates to an LED driving circuit which comprises a rectifying unit, a filtering unit, a power conversion unit and an LED load which are sequentially coupled, the power conversion unit is provided with a signal input end for receiving a control signal, and the power conversion unit stops working or normally works after the signal input end receives the control signal. The LED driving circuit further comprises a signal generating unit which is coupled with the signal input end, and the signal generating unit is provided with a switch element and can selectively output the control signal. According to the LED driving circuit, the signal generation unit selectively outputs the control signal by using the switch element, and the signal input end of the power conversion unit receives the control signal to realize switching of connection and disconnection of the LED driving circuit, so that the LED load is lightened and extinguished, and finally, the on-off control of the LED load is completed. A switching circuit is not additionally arranged on the high voltage side, and the design of the driving circuit is simplified.

Description

Technical Field

[0001] The present application relates to the field of lighting technology, and in particular to an LED driving circuit. Background Art

[0002] LED driver circuits are widely used in scenarios where LED lamps are connected to AC mains. LED driver circuits usually include a rectifier unit, a filter unit, a power conversion unit, and an LED load, so as to light up the LED lamp.

[0003] At present, the lamps on the market mainly realize the control of the lamp on and off by adding switches on the high voltage side. However, for LED lamps with rich functions, the operation mode of realizing the on and off of the lamps by using switch elements has circuit component redundancy. Utility Model Content

[0004] Based on this, it is necessary to provide an LED driving circuit to address the above technical issues.

[0005] The LED driving circuit of the present application comprises a rectifying unit, a filtering unit, a power conversion unit and an LED load coupled in sequence, wherein the power conversion unit has a signal input terminal for receiving a control signal, and the power conversion unit stops working or works normally after the signal input terminal receives the control signal, thereby disconnecting or connecting the LED driving circuit.

[0006] The LED driving circuit further comprises a signal generating unit coupled to the signal input terminal, wherein the signal generating unit has a switch element and can selectively output the control signal.

[0007] Several optional methods are also provided below, but they are not intended to be additional limitations on the above-mentioned overall solution, but are merely further supplements or preferences. Under the premise that there are no technical or logical contradictions, each optional method can be combined with the above-mentioned overall solution separately, and multiple optional methods can also be combined.

[0008] Optionally, the signal input terminal has a voltage detection function, and the power conversion unit works normally when the input voltage is less than a set value, and stops working when the input voltage is greater than the set value.

[0009] Optionally, the power conversion unit includes an integrated circuit and its peripheral circuits, and the signal input end is an overvoltage protection end of the integrated circuit. The overvoltage protection end stops the integrated circuit from working when the input voltage is higher than a threshold value, and resumes the integrated circuit from working when the input voltage is lower than the threshold value.

[0010] Optionally, the signal generating unit includes a controller and the switch element, the controller has a first input terminal and a first transmitting terminal, and the first input terminal is coupled to the switch element;

[0011] The first transmitting end is coupled to the signal input end, and the first transmitting end is used to selectively output the control signal after the switch element is switched.

[0012] Optionally, the LED driving circuit includes a dimming unit coupled to the LED load for changing the output power of the LED load.

[0013] Optionally, the dimming unit includes a switch tube coupled between the LED load and a ground line, and the dimming unit has a dimming input terminal, and the dimming input terminal is used to receive a dimming signal to change the conduction angle of the switch tube.

[0014] Optionally, the LED load includes a first group of LED lamp beads and a second group of LED lamp beads which are connected in parallel and have different color temperatures, and the switch tube includes a corresponding first switch tube and a second switch tube.

[0015] Optionally, the signal generating unit has a second transmitting end for generating the dimming signal.

[0016] Optionally, the signal generating unit includes the controller and the adjusting element, the controller has a second input terminal coupled to the adjusting element, and the second transmitting terminal, and the second transmitting terminal is used to output the corresponding dimming signal after the adjusting element is switched.

[0017] The LED driving circuit of the present application has at least the following technical effects:

[0018] The present application utilizes a switch element to enable the signal generating unit to selectively output a control signal, and the signal input end of the power conversion unit receives the control signal to realize the on-off switching of the LED driving circuit, thereby lighting and extinguishing the LED load, and finally completing the on-off control of the LED load. The present application does not add a switch circuit on the high voltage side, which simplifies the design of the driving circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the module structure of the LED driving circuit in some embodiments of the present application;

[0020] Figure 2 This is a schematic diagram of the module structure of the LED driving circuit in some embodiments of the present application;

[0021] Figure 3 This is a schematic diagram of the module structure of the LED driving circuit in some embodiments of the present application;

[0022] Figure 4 A circuit schematic diagram of an LED driving circuit in some embodiments of the present application;

[0023] The reference numerals in the figures are described as follows:

[0024] 100, rectifier unit; 200, filter unit; 300, power conversion unit; 310, signal input terminal; 400, LED load; 410, first group of LED lamp beads; 420, second group of LED lamp beads; 500, signal generating unit; 510, switch element; 520, controller; 521, first input terminal; 522, first transmitting terminal; 523, second input terminal; 524, second transmitting terminal; 530, adjustment element; 600, dimming unit; 610, dimming input terminal; 700, step-down unit. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] It should be noted that when a component is referred to as being "coupled" to another component, it may be directly connected to the other component or there may be a central component. When a component is considered to be "disposed on" another component, it may be directly disposed on the other component or there may be a central component at the same time.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0028] In this application, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating 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 the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0029] In this application, the terms "comprises" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a system, product or device comprising a series of units is not necessarily limited to those units explicitly listed, but may include other units not explicitly listed or inherent to these products or devices.

[0030] See also Figure 1 and Figure 4 An embodiment of the present application provides an LED driving circuit, which includes a rectifying unit 100, a filtering unit 200, a power conversion unit 300 and an LED load 400 coupled in sequence.

[0031] The rectifier unit 100 may be, for example, a full-wave rectifier bridge, and the filter unit 200 may be, for example, a π-type filter circuit, which includes an inductor L2, a capacitor C1, and a capacitor C2. The inductor L2 may be connected in parallel with a resistor R1. The filter unit outputs a DC bus V_BUS to supply power to the power conversion unit. The power conversion unit 300 has a signal input terminal 310 for receiving a control signal. The power conversion unit 300 stops working or works normally after receiving the control signal at the signal input terminal 310, thereby disconnecting or turning on the LED drive circuit. The signal input terminal 310 has a voltage detection function. The power conversion unit 300 works normally when the input voltage is less than a set value, and stops working when the input voltage is greater than a set value. For example, the power conversion unit 300 includes an integrated circuit U1 and its peripheral circuits, and the signal input terminal 310 is an overvoltage protection terminal ROVP of the integrated circuit. The overvoltage protection terminal ROVP stops the integrated circuit from working when the input voltage is higher than a threshold, and resumes the integrated circuit from working when the input voltage is lower than a threshold.

[0032] Specifically, the integrated circuit U1 has a ground terminal GND at pin 1, an overvoltage protection terminal ROVP at pin 2, a power input terminal HV at pin 4, output terminals DRAIN at pins 5 and 6, and a sampling terminal CS at pin 7. The external circuit of the integrated circuit U1 includes: the overvoltage protection terminal ROVP is grounded via a resistor R2, and the power input terminal HV is connected to the DC bus V_BUS via a resistor. The CS sampling terminal is grounded via parallel sampling resistors RS1 and RS2. The output terminal DRAIN provides power to the LED load via a diode D1. The cathode of the diode D1 is simultaneously coupled to the anode of the LED load and the DC bus V_BUS. The external circuit also includes an inductor T1, one end of the inductor T1 is coupled to the anode of the diode D1, and the other end of the inductor T1 is coupled to the cathode of the diode D1 via a resistor R4. The resistor R4 is connected in parallel with a capacitor C3.

[0033] The LED driving circuit also includes a signal generating unit 500 coupled to the signal input terminal 310. The signal generating unit 500 has a switch element 510, which can selectively output a control signal. The connection relationship between the switch element and the signal transmitting unit includes but is not limited to line connection or electromagnetic connection. The switch element can be a button switch, a dial switch, a touch switch, an induction switch, or other other circuit electronic components that can realize circuit switching.

[0034] In this embodiment, the signal generating unit selectively outputs a control signal by using a switch element, and the signal input end of the power conversion unit receives the control signal to realize the on-off switching of the LED driving circuit, thereby lighting and extinguishing the LED load, and finally completing the on-off control of the LED load. In this embodiment, no switch circuit is added on the high voltage side, which simplifies the design of the driving circuit.

[0035] See also Figure 2 and Figure 4 The signal generating unit 500 includes a controller 520 and a switch element 510. The controller 520 has a first input terminal 521 and a first transmitting terminal 522. The first input terminal 521 is coupled to the switch element 510. The first transmitting terminal 522 is coupled to the signal input terminal 310. The first transmitting terminal 522 is used to selectively output a control signal after the switch element 510 is switched.

[0036] Since the mechanical switch has limited gears, usually 2 or 3 gears, only 2 or 3 color temperatures can be mixed, and the color temperature gear options are limited. When multiple lamps are used in series or installed in a position that is inconvenient to adjust, it will take time to switch the color temperature.

[0037] See also Figure 3 and Figure 4 The LED driving circuit includes a dimming unit 600 coupled to the LED load 400 to change the output power of the LED load 400. The dimming unit 600 includes a switch tube coupled between the LED load 400 and the ground line, and the dimming unit 600 has a dimming input terminal 610, and the dimming input terminal 610 is used to receive a dimming signal to change the conduction angle of the switch tube.

[0038] The signal generating unit 500 has a second transmitting terminal 524 for generating a dimming signal. Specifically, the signal generating unit 500 includes a controller 520 and an adjusting element 530, wherein the controller 520 has a second input terminal 523 coupled to the adjusting element 530, and a second transmitting terminal 524, wherein the second transmitting terminal 524 is used to output a corresponding dimming signal after the adjusting element 530 is switched.

[0039] The controller 520 may be, for example, an MCU (Microcontroller Unit, Figure 4The controller 520 has a 2-pin TP2 terminal (i.e., a second input terminal 523), a 3-pin CCT terminal (i.e., a second transmitting terminal 524), a 4-pin TP1 terminal (i.e., a first input terminal 521), a 5-pin VCC power supply terminal, a 6-pin PWM terminal (i.e., a first transmitting terminal 522), and an 8-pin ground terminal GND. The LED driving circuit also includes a buck unit 700 coupled between the DC bus V_BUS and the VCC power supply terminal. The buck unit 700 obtains the VCC power supply terminal by a linear buck plus voltage regulation method. From V_BUS, the voltage is first stabilized to 5.1V through the resistor R5 and the voltage regulator D4, and then the voltage is further reduced to 3.3V through the linear regulator LDO of U4 for use by the power supply terminals VCC of U2 and U3. This circuit can eliminate the power supply circuit of a conventional switching power supply.

[0040] The switch element 510 changes the input of the TP1 terminal by switching, and the PWM terminal outputs a control signal, such as a PWM signal, accordingly through the programming logic of the MCU. For example, the TP1 terminal receives an OFF signal, so that the PWM terminal outputs a PWM signal higher than the threshold, so that the integrated circuit U1 stops working. The TP1 terminal receives an ON signal, and outputs a PWM signal lower than the threshold of the overvoltage protection terminal, so that the integrated circuit U1 resumes working.

[0041] This embodiment detects the output of the switching element through the MCU, and uses the overvoltage protection terminal to directly control the switch. When U3 detects the switch (ON / OFF) touch signal, the 6-pin signal of U3 will invert the current signal and connect to the 2-pin of U1. The ROVP overvoltage protection function controls the power input of the LED load to realize the switching of the light. The high level turns on the light, and the low level turns off the light. By controlling the switch of the light through the overvoltage protection function, there is no need for the U1 chip to have a special dimming interface. It can be understood that the so-called overvoltage protection means that the circuit is broken when the voltage becomes high. Then the high level turns on the light, which obviously refers to the input signal of the MCU. If the MCU inputs a high level, the output PWM is inverted to a low level, and the OVP is not triggered to light up normally. Otherwise it is turned off.

[0042] After the adjustment element 530 is switched, the input of the TP2 terminal is changed, and the CCT terminal is made to output a dimming signal, such as a PWM signal, accordingly through the editing logic of the MCU. The dimming unit adopts, for example, an integrated circuit chip U2 of model BP5936D. The dimming unit has a VS terminal at pin 1, a VH terminal at pin 2, a PWM terminal at pin 6 (i.e., a dimming input terminal 610), a VCC power supply terminal at pin 7, and a GND ground terminal at pin 8.

[0043] The dimming unit includes a first switch tube and a second switch tube with built-in components, and the drain of the first switch tube (pin 3) and the drain of the second switch tube (pin 4) are exposed. The LED load 400 includes a first group of LED lamp beads 410 (C-LED) and a second group of LED lamp beads 420 (W-LED) in parallel and with different color temperatures. The first switch tube is coupled between the first group of LED lamp beads 410 and the ground wire, and the second switch tube is coupled between the ground wires of the second group of LED lamp beads 420. When the dimming input terminal 610 receives a corresponding PWM signal, the first switch tube and / or the second switch tube are changed to adjust the power of the LED load, and adjust the brightness and color temperature.

[0044] Specifically, when U3 detects a color temperature adjustment (CCT) touch signal, it will output a PWM waveform with different duty cycles at pin 3 of U3 according to the preset color temperature, and connect it to pin 6 of U2. When the level is high, D2 of U2 is turned on and D1 is turned off, corresponding to the C-LED emitting light and the W-LED not emitting light. When the level is low, D1 of U2 is turned on and D2 is turned off, corresponding to the W-LED emitting light and the C-LED not emitting light. By mixing W-LED and C-LED, different color temperatures can be mixed.

[0045] The switch element and the adjustment element in this embodiment may be, for example, a capacitive touch button. The switch (ON / OFF) signal or the color temperature adjustment (CCT, Color Temperature Control) signal is identified through the touch detection function of the MCU.

[0046] The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. When the technical features in different embodiments are embodied in the same figure, it can be regarded that the figure also discloses the combination examples of the various embodiments involved.

[0047] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. An LED driving circuit, comprising a rectifying unit, a filtering unit, a power conversion unit and an LED load coupled in sequence, wherein the power conversion unit has a signal input terminal for receiving a control signal, and the power conversion unit stops working or works normally after the signal input terminal receives the control signal, thereby disconnecting or turning on the LED driving circuit. It is characterized in that The LED driving circuit further comprises a signal generating unit coupled to the signal input terminal, wherein the signal generating unit has a switch element and can selectively output the control signal.

2. The LED driving circuit according to claim 1, characterized in that: The signal input terminal has a voltage detection function. The power conversion unit works normally when the input voltage is less than a set value, and stops working when the input voltage is greater than the set value.

3. The LED driving circuit according to claim 2, characterized in that: The power conversion unit includes an integrated circuit and its peripheral circuits. The signal input terminal is an overvoltage protection terminal of the integrated circuit. The overvoltage protection terminal stops the integrated circuit from working when the input voltage is higher than a threshold value, and resumes the integrated circuit from working when the input voltage is lower than the threshold value.

4. The LED driving circuit according to claim 1, characterized in that: The signal generating unit comprises a controller and the switch element, the controller has a first input terminal and a first transmitting terminal, the first input terminal is coupled to the switch element; The first transmitting end is coupled to the signal input end, and the first transmitting end is used to selectively output the control signal after the switch element is switched.

5. The LED driving circuit according to claim 4, characterized in that: The LED driving circuit includes a dimming unit coupled to the LED load to change the output power of the LED load.

6. The LED driving circuit according to claim 5, characterized in that: The dimming unit includes a switch tube coupled between the LED load and a ground line. The dimming unit has a dimming input terminal, and the dimming input terminal is used to receive a dimming signal to change a conduction angle of the switch tube.

7. The LED driving circuit according to claim 6, characterized in that: The LED load includes a first group of LED lamp beads and a second group of LED lamp beads which are connected in parallel and have different color temperatures, and the switch tube includes a corresponding first switch tube and a second switch tube.

8. The LED driving circuit according to claim 6, characterized in that: The signal generating unit has a second transmitting end for generating the dimming signal.

9. The LED driving circuit according to claim 8, characterized in that: The signal generating unit includes the controller and the adjusting element. The controller has a second input terminal coupled to the adjusting element, and the second transmitting terminal. The second transmitting terminal is used to output the corresponding dimming signal after the adjusting element is switched.

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