CN217936004U

CN217936004U - LED drive circuit, LED straight tube lamp and LED lamps and lanterns system compatible constant current and adjusting luminance

Info

Publication number: CN217936004U
Application number: CN202221376358.0U
Authority: CN
Inventors: 周家明; 蒲纪忠; 赵艺佼; 甘彩英
Original assignee: CH Lighting Technology Co Ltd
Current assignee: CH Lighting Technology Co Ltd
Priority date: 2022-06-02
Filing date: 2022-06-02
Publication date: 2022-11-29
Anticipated expiration: 2032-06-02

Abstract

The application discloses compatible constant current and LED drive circuit who adjusts luminance, LED straight tube lamp and LED lamps and lanterns system, LED drive circuit are including the rectifier unit, the filter unit and the power conversion unit that have alternating current input end, the power conversion unit has and couples alternating current input end's sense terminal to be in two kinds of different mode according to the different input voltage of alternating current input end, be respectively when the input voltage of alternating current input end is greater than first threshold value its output keeps invariable constant current mode of operation and when the input voltage of alternating current input end is less than first threshold value its output follow the mode of adjusting luminance that input voltage changes. The LED driving circuit correspondingly enters a constant-current working mode and a dimming working mode according to the magnitude of input voltage, and meets the requirement of brightness adjustment under the condition that the input voltage is smaller than a first threshold value; and under the condition that the input voltage is greater than the first threshold value, the requirement of maintaining the illumination brightness is met.

Description

LED drive circuit, LED straight tube lamp and LED lamps and lanterns system compatible constant current and adjusting luminance

Technical Field

The application relates to the technical field of lighting, in particular to a constant-current and dimming compatible LED driving circuit, an LED straight-tube lamp and an LED lamp system.

Background

LED lighting technology is rapidly advancing to replace conventional incandescent and fluorescent lamps. The LED lamp tube has the advantages of energy conservation, low energy consumption, environmental protection, long service life and the like, and the LED straight tube lamp is gradually a highly expected illumination option by people accidentally. Thus, taking all factors into account, a LED straight tube lamp would be a cost effective and long life green lighting option.

A conventional fluorescent lamp generally includes an electronic ballast, a fluorescent tube, and a lamp carrier. In order to realize energy conservation, environmental protection and long service life, a common fluorescent lamp is improved to be more energy-saving and environment-friendly, the luminous efficiency is improved, and the service life is prolonged, the traditional fluorescent lamp tube needs to be replaced and modified by an LED lamp tube. The replacement of the fluorescent lamp with the LED lamp tube comprises two schemes: the first kind is not reformed transform the circuit, directly takes off the fluorescent lamp, directly replaces with the LED fluorescent tube, TYPE A replacement TYPE promptly. The second is to bypass the ballast by trimming, and realize single-end or double-end power feeding by wiring, i.e. TYPE B trimming. Besides, the dual-function conversion compatible TYPE of TYPE A + B compatible with the dual-function conversion compatible TYPE of TYPE A + B is also included.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is necessary to provide an LED driving circuit, an LED straight lamp and an LED lamp system that are compatible with constant current and dimming.

The application provides a compatible constant current and LED drive circuit who adjusts luminance, including rectifier unit, filter unit and the power conversion unit that has alternating current input end, the power conversion unit has coupling alternating current input end's sense terminal to be in two kinds of different mode according to the different input voltage of alternating current input end, be respectively when the input voltage of alternating current input end is greater than first threshold value its output keeps invariable constant current mode of operation and when the input voltage of alternating current input end is less than first threshold value its output along with the mode of operation of adjusting luminance that input voltage changes.

Several alternatives are provided below, but not as an additional limitation to the above general solution, but merely as a further addition or preference, each alternative being combinable individually for the above general solution or among several alternatives without technical or logical contradictions.

Optionally, the power conversion unit includes a switching tube, the switching tube has a gate, a source and a drain, the drain is coupled to the load via an inductive reactance element, and the source is grounded via a sampling circuit;

in the constant-current working mode, the conduction angle of the switch tube is reduced along with the increase of the input voltage;

and in the dimming working mode, the conduction angle of the switch tube is at the maximum value and is kept unchanged.

Optionally, the power conversion unit includes:

a driver coupled to the gate;

an impedance detector having an input terminal coupled to the detection terminal;

a comparison controller having a sampling input coupled to the output of the impedance detector and a control output coupled to the input of the driver.

Optionally, the power conversion unit includes a main control chip and a peripheral circuit, and the switching tube, the driver, the impedance detector and the comparison controller are integrated in the main control chip.

Optionally, the first threshold is between 108V and 120V.

Optionally, a voltage detection unit coupled between the ac input terminal and the detection terminal is included, and the voltage detection unit includes:

a first diode, the anode of which is coupled to the alternating current input end;

and one end of the first resistor is coupled to the cathode of the first diode, and the other end of the first resistor is coupled to the detection end.

Optionally, the rectifying unit includes a first rectifying unit and a second rectifying unit, the first rectifying unit has a first ac input terminal and a second ac input terminal, and the first ac input terminal and/or the second ac input terminal is coupled to the detecting terminal through a voltage detecting unit.

Optionally, the second rectifying unit has a third ac input terminal and a fourth ac input terminal, and the LED driving circuit includes a frequency detection circuit coupled to the third ac input terminal, the fourth ac input terminal, and the load.

The application still provides a LED straight tube lamp, includes the lamp body of constituteing by the end cover at fluorescent tube and both ends, inside light-emitting component and the drive power supply of being provided with of lamp body, the last LED drive circuit as this application that is provided with of drive power supply, be provided with on the end cover with the electrically conductive piece that AC input end is coupled.

The present application further provides an LED lamp system, comprising the LED straight tube lamp and the dimmer as described in the present application, the dimmer is coupled to the conductive member for adjusting the input voltage.

The LED drive circuit compatible with constant current and dimming at least has the following technical effects:

the LED driving circuit compatible with constant current and dimming correspondingly enters a constant current working mode and a dimming working mode according to the magnitude of input voltage, and the requirement for brightness adjustment is met under the condition that the input voltage is smaller than a first threshold value; and under the condition that the input voltage is greater than the first threshold value, the requirement of maintaining the illumination brightness is met.

Drawings

FIG. 1 is a schematic structural diagram of an LED straight lamp according to an embodiment of the present disclosure;

FIG. 2 is a schematic circuit diagram of a rectifying unit according to an embodiment of the present disclosure;

FIG. 3 is a schematic circuit diagram of a frequency detection circuit according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of an LED lamp system according to an embodiment of the present application;

fig. 5 is a schematic block diagram of an LED driving circuit according to an embodiment of the present application;

fig. 6 is a block diagram of a main control chip according to an embodiment of the present application;

FIG. 7 is a schematic circuit diagram of a rectifying unit and a voltage detecting unit according to an embodiment of the present disclosure;

FIG. 8 is a schematic circuit diagram of a power conversion unit according to an embodiment of the present application;

FIG. 9 is a schematic circuit diagram of an LED driving circuit according to an embodiment of the present application;

FIG. 10 is a schematic diagram of an embodiment of a dimmer;

FIG. 11 is a schematic diagram of the operation of a dimmer according to an embodiment of the present application;

the reference numbers in the figures are as follows:

100. a lamp housing; 101. a lamp tube; 102. an end cap; 110. a conductive member; 111. a first pin; 112. a second pin; 113. a third pin; 114. a fourth pin; 120. a ballast;

200. a rectifying unit; 210. a first rectifying unit; 220. a second rectifying unit; 300. a filtering unit;

400. a power conversion unit; 410. a main control chip; 411. an impedance detector; 412. a comparison controller; 413. a driver; 414. a switching tube; 420. a secondary filtering unit;

500. a frequency detection circuit; 600. a dimmer; 700. a voltage detection unit.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

It is noted that when an element is referred to as being "coupled" to another element, it can be directly connected to the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present.

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

In this application, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number, order of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In this application, the terms "comprises" and "comprising," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a system, article, or apparatus that comprises a list of elements is not necessarily limited to those elements explicitly listed, but may include other elements not expressly listed or inherent to such product or apparatus.

Referring to fig. 1 and 2, an embodiment of the present application provides an LED straight tube lamp, which includes a lamp housing 100 composed of a lamp tube 101 and end caps 102 at two ends of the lamp tube, a light emitting assembly and a driving power supply are disposed inside the lamp housing 100, an LED driving circuit is disposed on the driving power supply, and a conductive member 110 coupled to an ac input end is disposed on the end cap 102. The conductive member 110 includes a first pin 111 and a second pin 112 provided on one end cap 102, and a third pin 113 and a fourth pin 114 provided on the other end cap 102, wherein the third pin 113 and the fourth pin 114 are shorted.

The LED driving circuit includes a rectifying unit 200 with an ac input terminal, a filtering unit, and a power converting unit, the rectifying unit 200 includes a first rectifying unit 210 and a second rectifying unit 220, the first rectifying unit 210 may be, for example, a rectifier bridge BD1, and the second rectifying unit 220 may be, for example, a rectifier bridge BD2. The rectifying unit 200 outputs a dc bus Vbus +, and a voltage dependent resistor RV1 is connected between the dc bus Vbus + and a ground.

The AC input terminals include a first AC input terminal L1 and a second AC input terminal N1 that the first rectifying unit 210 has, and a third AC input terminal AC2 and a fourth AC input terminal AC3 that the second rectifying unit 220 has. The third AC input terminal AC2 and the fourth AC input terminal AC3 are short-circuited and coupled to the short-circuited third pin 113 and the short-circuited fourth pin 114 via the fuse F3, and the fuse F3 is used for monitoring the working state of the varistor RV1 and protecting the abnormal state. A capacitor CX1 is coupled between the first AC input terminal L1 and the second AC input terminal N1, a capacitor CX2 is coupled between the third AC input terminal AC2 and the second AC input terminal N1, and the capacitor CX1 and the capacitor CX2 form a step-down protection.

Referring to fig. 3, the led driving circuit includes a frequency detection circuit 500, and the frequency detection circuit 500 is coupled between a load, which may be, for example, a light emitting assembly, and the third and fourth AC input terminals AC2 and AC3. The frequency detection circuit 500 specifically includes a circuit topology structure composed of a capacitor C8, a capacitor C9, a diode D6, a diode D7, a zener diode Z1, a resistor R15, and a switching tube Q1, and is used for performing switching determination between a mains supply mode and a ballast mode, where the switching tube may be, for example, a MOSFET tube. The commercial power mode is that the input voltage is 120-277V, and the frequency is 50-60Hz; the ballast mode is that the input voltage is 800-1200V and the frequency is 25K-80KHz.

In the TYPE a replacement mode, the conductive members 110 at the two ends of the lamp housing 100 are coupled to the ballast 120, the frequency detection circuit 500 receives AC signals through the third AC input terminal AC2 and the fourth AC input terminal AC3, specifically, the HIF pins in the figure, high-frequency 25K-100KHz high-frequency AC power enters through the AC input terminals, the frequency detection circuit 500 enters a working state, the capacitor C8 performs high-frequency voltage and current sampling, the diode D6 and the diode D7 perform rectification and filtering, so that the switching tube Q1 is turned on, and the drain of the switching tube Q1 is coupled to the load through the Q1-D pins in the figure, so as to supply power to the load. In the TYPE A mode, as long as the ballast 120 has a dimming function, dimming can be realized by directly replacing a fluorescent tube with an LED straight tube lamp, such as silicon controlled dimming, 0-10V dimming and the like, so that the energy-saving and environment-friendly functions are realized, and the requirements of DLC5.1 are met.

Under the commercial power mode, the industrial power voltage is 277V, and the household power voltage is 120V. In household use, a dimmer is generally used to adjust the brightness of a lamp, and meanwhile, the requirement of maintaining the brightness when the voltage fluctuates and the requirement of maintaining the brightness of the lamp under the condition of industrial power utilization exist.

Referring to fig. 4 and 5, in an embodiment, an LED lamp system is provided, which includes a dimmer 600, and a LED straight tube lamp in the previous embodiment, the dimmer 600 is coupled to the conductive member 110 for adjusting an input voltage, and the dimmer 600 may adjust the input voltage AC by, for example, a front-cut or a back-cut mode.

The LED driving circuit in this embodiment is compatible with constant current and dimming, and includes a rectifying unit 200 having an ac input terminal, a filtering unit 300, and a power converting unit 400, where the power converting unit 400 has a detection terminal DET coupled to the ac input terminal, and is in two different operating modes according to different input voltages of the ac input terminal, which are a constant current operating mode in which the output power of the ac input terminal is kept constant when the input voltage of the ac input terminal is greater than a first threshold value, and a dimming operating mode in which the output power of the ac input terminal changes with the input voltage when the input voltage of the ac input terminal is less than the first threshold value. The first threshold is between 108 and 120V, which may be 110V, for example, to avoid entering dimming fluctuations due to voltage fluctuations. It can be understood that in the TYPE B mode, the power conversion unit 400 normally operates, realizes the constant current mode and the dimming mode, realizes the advantage of multiple functions, and meets the requirements of UL safety regulations and DLC 5.1.

Referring to fig. 5 and 6, the power conversion unit 400 includes a switch tube 414, the switch tube 414 has a gate, a source and a drain, the drain of the switch tube 414 is coupled to the load via an inductive reactance element, and the source is grounded via a sampling circuit. The inductive reactance element may be, for example, a transformer or an inductor, and the sampling circuit may be, for example, a sampling resistor RS. In the constant current operating mode, the conduction angle of the switching tube 414 decreases as the input voltage increases; in the dimming operation mode, the conduction angle of the switching tube 414 is at the maximum value and remains unchanged.

In this embodiment, the power conversion unit 400 includes an impedance detector 411, a comparison controller 412, a driver 413, and a switching tube 414. The input terminal of the impedance detector 411 is coupled to the detection terminal DET. The comparison controller 412 has a sampling input coupled to the output of the impedance detector 411 and a control output coupled to the input of the driver 413. The output terminal of the driver 413 is coupled to the gate of the switching tube 414 for adjusting the conduction angle of the switching tube 414. The power conversion unit 400 includes a main control chip 410 and peripheral circuits, and the switching tube 414, the driver 413, the impedance detector 411 and the comparison controller 412 are integrated in the main control chip 410. The drain of the switching tube 414 is specifically the output Dra of the main control chip, and the source is specifically the sampling end ISP of the main control chip.

The switching between the constant current mode and the dimming mode is realized by driving the switching tube in a self-adaptive manner, and the requirements of stable illumination brightness in factories and household illumination dimming can be met simultaneously. And the characteristics of one switching tube are utilized, and different circuit elements are controlled and driven by logic judgment instead of the characteristics, so that the use of the circuit elements is reduced, the control mode is simplified, and the control stability is ensured.

Under the constant current working mode, the conduction angle is self-adaptively changed between 1 degree and 360 degrees, and the output power is kept unchanged. Certainly, the conduction angle is limited by the self-limit of the switching tube, and the interval of the self-adaptive change of the conduction angle is limited, for example, the conduction time of the switching tube is adjustable within 0.9-11 mus. Under the dimming working mode, the conduction angle of the switch tube reaches the limit state, self-adaptive change cannot be carried out, the constant-current working mode exits, the dimming working mode is entered, and at the moment, the output power of the power conversion unit is only influenced by external input voltage.

Examples are as follows: in the initial state, the input voltage may be 277V, for example. The input voltage decreases from 277V, and the conduction angle of the switch tube 414 gradually increases, keeping the output power constant. The input voltage reaches a first threshold value, for example 110V, and the conduction angle of the switching tube 414 reaches a maximum adjustable value. The input voltage continues to drop from 110V and the output power begins to drop concomitantly.

In this embodiment, the detection terminal DET detects the input voltage at the ac input terminal, and the impedance detector 411 samples the input current and voltage through the internal sampling resistor to obtain the detection result, which is generally an isometric reduction of the detection result relative to the input voltage at the ac input terminal. The comparison controller 412 has a reference voltage, which may be, for example, 200mV. The comparison controller 412 compares the detection result with the reference voltage, and controls the driver 413 to adjust the conduction angle of the switching tube 414 according to the comparison result. The comparison controller 412 may, for example, implement its function through an operational amplifier, and the driver 413 may, for example, control the PWM signal accordingly by the comparison controller 412 to complete the driving control of the gate. Further, the grounded source of a sampling circuit is also coupled to the comparison controller 412, so as to form output feedback control and ensure control accuracy.

Referring to fig. 7, the led driving circuit further includes a voltage detection unit 700 coupled between the ac input terminal and the detection terminal DET, and the voltage detection unit 700 includes a first diode D1 and a first resistor R1. Wherein, the anode of the first diode D1 is coupled to the AC input end; one end of the first resistor R1 is coupled to the cathode of the first diode D1, and the other end is coupled to the detection terminal DET.

Further, the first ac input terminal L1 and/or the second ac input terminal N1 are coupled to the detection terminal DET through the voltage detection unit 700. When the LED driving circuit is built in the LED straight-tube lamp provided by each embodiment, the detection of the input voltage can be realized no matter whether the power is fed in a single end or double ends. Specifically, the voltage detection unit disposed between the second ac input terminal N1 and the detection terminal DET includes a diode D2 and a resistor R2. The anode of the diode D2 is coupled to the second ac input terminal N1, one end of the resistor R2 is coupled to the cathode of the diode D2, and the other end is coupled to the detection terminal DET.

Referring to fig. 3, 6 to 8, the filtering unit 300 and the power converting unit 400 may be arranged as shown. The filtering unit 300 includes an EMI anti-interference circuit including an inductor L1, a capacitor C1, and a capacitor C2. The power conversion unit 400 includes a main control chip 410 having a power input terminal VIN, a power supply terminal VCC, an output terminal Dra, a ground terminal GND, a sampling terminal ISP, and a detection terminal REC. The power-in terminal VIN is coupled to the dc bus Vbus + via a resistor R8. The power supply terminal VCC is coupled to the power input terminal VIN to provide a chip operating voltage, and is grounded via the capacitor C3, and the capacitor C3 is charged when in use. The output Dra is coupled to the drain of the built-in switch 414. The sampling terminal ISP is grounded via the resistor RS1 and the resistor RS 2. The detection terminal REC is coupled to the detection terminal DET. The output Dra is coupled to the load via a transformer T1, of which only the input V1+ and the output V1-are shown. A secondary filter unit 420 is arranged between the input end V1+ and the output end V1-of the load, and comprises a topological circuit consisting of a capacitor CD1, a capacitor CD2 and a resistor R14. In each embodiment, the internal or peripheral circuit of the main control chip is also provided with a leakage detection circuit, and if the leakage detection circuit detects an electric shock risk, the whole loop is disconnected, so that the use risk and the potential safety hazard are reduced. Details and operation principles of the leakage protection circuit are not described herein, and reference may be made to the prior art.

This embodiment is compatible with TYPE a and TYPE B operating modes. In TYPE a mode, the frequency detection circuit 500 enters a working state, the ac input terminal is rectified by the diode D6 and the diode D7, and the switching tube Q1 is coupled to the secondary filter unit 420 by the pins Q1 to D to supply power to the load, at this time, the main control chip stops working. In the TYPE B mode, low-frequency AC50-60Hz alternating current enters through the alternating current input end, and the switching tube Q1 does not work. The alternating current passes through the rectifying unit 200, the filtering unit 300 and the power conversion unit in sequence, and the selection of the constant current working mode and the dimming working mode is completed.

The LED straight lamp and the LED drive circuit provided in the embodiments of the application are of TYPE A + B dual-function conversion compatible TYPE. The luminous efficiency is high, all have the function of adjusting luminance. Under the TYPE B mode, the self-adaptive adjustment of a constant current working mode and a dimming working mode can be realized according to the input voltage.

Referring to fig. 9 to 11, in one embodiment, an LED driving circuit is provided as shown, the LED driving circuit includes a rectifying unit BD and a power converting unit PC coupled in sequence, the rectifying unit BD may be a full-wave rectifying bridge, for example, and has an AC input terminal and a dc output terminal, the AC input terminal of the rectifying unit BD is coupled to a commercial power via a Dimmer TRIAC Dimmer, for example, the commercial power may be AC120V/60Hz, and the Dimmer may be implemented by a back-cut principle as shown in fig. 10 or a front-cut principle as shown in fig. 11, for example.

The dc output terminal is provided with a filter capacitor, and the power conversion unit PC includes a main control chip 410 and its peripheral circuits. In this embodiment, the connection modes of the power supply terminal VCC, the power input terminal VIN, the ground terminal GND, the sampling terminal ISP, and the detection terminal REC of the main control chip 410 can be referred to the above embodiments. The output end Dra of the main control chip 410 is coupled to a load, i.e., a light emitting diode Dx, via an inductor.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features. When technical features in different embodiments are represented in the same drawing, it can be seen that the drawing also discloses a combination of the embodiments concerned.

The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is specific and detailed, but not construed as limiting the scope of the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, and these are all within the scope of protection of the present application.

Claims

1. The LED driving circuit compatible with constant current and dimming comprises a rectifying unit with an alternating current input end, a filtering unit and a power conversion unit, and is characterized in that the power conversion unit is provided with a detection end coupled with the alternating current input end, and is in two different working modes according to different input voltages of the alternating current input end, namely a constant current working mode in which the output power of the constant current working mode is kept constant when the input voltage of the alternating current input end is greater than a first threshold value and a dimming working mode in which the output power of the constant current working mode changes along with the input voltage when the input voltage of the alternating current input end is less than the first threshold value.

2. The LED driving circuit of claim 1, wherein the power conversion unit comprises a switch tube having a gate, a source and a drain, the drain being coupled to a load via an inductive reactance element, the source being grounded via a sampling circuit;

3. The LED driving circuit according to claim 2, wherein the power conversion unit comprises:

a driver coupled to the gate;

4. The LED driving circuit according to claim 3, wherein the power conversion unit comprises a main control chip and a peripheral circuit, and the switching tube, the driver, the impedance detector and the comparison controller are integrated in the main control chip.

5. The LED driving circuit of claim 1, wherein the first threshold is between 108-120V.

6. The LED driving circuit according to claim 1, comprising a voltage detection unit coupled between the ac input terminal and the detection terminal, the voltage detection unit comprising:

7. The LED driving circuit according to claim 6, wherein the rectifying unit comprises a first rectifying unit and a second rectifying unit, the first rectifying unit has a first AC input end and a second AC input end, and the first AC input end and/or the second AC input end is coupled to the detecting end through a voltage detecting unit.

8. The LED driving circuit according to claim 7, wherein the second rectifying unit has a third AC input terminal and a fourth AC input terminal, the LED driving circuit comprising a frequency detection circuit coupled to the third AC input terminal, the fourth AC input terminal and a load.

The LED straight lamp comprises a lamp shell consisting of a lamp tube and end covers at two ends of the lamp tube, wherein a light-emitting component and a driving power supply are arranged in the lamp shell, and the LED straight lamp is characterized in that the driving power supply is provided with an LED driving circuit according to any one of claims 1-8, and the end covers are provided with conductive pieces coupled with the alternating current input end.

An LED lamp system comprising the LED straight tube lamp of claim 9 and a dimmer coupled to the conductive member for regulating the input voltage.