WO2013097692A1

WO2013097692A1 - Alternating current direct drive led light-emitting device

Info

Publication number: WO2013097692A1
Application number: PCT/CN2012/087382
Authority: WO
Inventors: 李东明; 杨冕; 封正勇; 龙文涛; 赵昆; 张明
Original assignee: 四川新力光源股份有限公司
Priority date: 2011-12-31
Filing date: 2012-12-25
Publication date: 2013-07-04
Also published as: CN104918387B; CN103188845A; CN104918387A; CN103188845B

Abstract

The present solution relates to an alternating current direct drive technology for an LED light-emitting device. In response to the shortcoming of flickering light caused by an alternating current direct drive LED light-emitting device in the prior art, disclosed is an alternating current direct drive LED light-emitting device, constituted by cascading n number of LED modules (5), where switch-off and switch-on voltages for a switch unit (6) corresponding to each level of the LED modules (5) are preconfigured appropriately via a sampling unit (4), thus preventing flickers from occurring during an alternating current voltage fluctuation. An increase in the number of the LED modules (5), equivalent to a decrease in the conductive voltage of each level of the LED modules (5), increases the utilization rate of a power supply. When multiple levels of the LED modules (5) are used, during the alternating current voltage fluctuation, the impact on each LED module (5) is of a relatively lesser extent than when a single module is used, also, the LED is provided with improved working stability, improved reliability, and enhanced capability in countering the alternating current voltage fluctuation.

Description

Description of the book AC light direct drive LED lighting device

The present invention relates to an LED (Light Emitting Diode) illuminating device, and more particularly to an AC direct driving technique for an LED illuminating device.

Background technique

As a new type of solid-state light source, LED is expected to become a new generation of illumination source with its advantages of energy saving, environmental protection and long life. As we all know, the existing LEDs are almost all driven by DC, and our production and living electricity is AC. Therefore, in the currently used LED products, a power converter is required to convert the alternating current into direct current. The introduction of power converters has many negative effects. First, the life of the power converter is much lower than the life of the LED itself, which shortens the service life of the lighting device. Second, the power converter reduces the efficiency of the lighting device. Third, in low power applications, power conversion The device will cause a drop in power factor and an increase in total harmonic distortion of the current. In order to give full play to the advantages of semiconductor lighting, LED light-emitting devices that can be directly driven by alternating current have become the current research hotspots.

In the existing AC LED disclosure technology, most of the LED components are connected in a reverse parallel or bridge rectified circuit topology to meet the AC power drive requirements. However, the AC power fluctuates periodically according to a certain frequency. Due to the presence of the LED's own turn-on voltage, the LED will turn on and emit light when the instantaneous voltage exceeds the turn-on voltage. Conversely, the LED is off and not illuminated. This circuit makes the LED's luminous efficiency very low, and the illuminating flicker occurs with the AC voltage fluctuation.

In the international patent WO 2004/023568A1 "LIGHT-EMITTING DEVICE HAVING LIGHT-EMITTING ELEMENTS", it is proposed to integrate an LED chip array on a sapphire substrate to provide an AC power driven illumination device, but does not solve the problem of LED illumination and flicker. .

US Patent No. 7,489, 086 B2 "AC LIGHT EITTING DIODE AND AC LED DRIVE METHODS AND APPARATUS" provides an AC LED device, which is a device in which a plurality of LEDs are integrally packaged, utilizing the vision of the human eye. The effect of retention is to compensate for the LED illuminating phenomenon caused by the alternating current. This patent does not fundamentally address the phenomenon of illuminating flicker caused by periodic fluctuations in AC voltage.

It can be seen that in the disclosed LED AC drive technology, there is a disadvantage that the driving current of the LED fluctuates with the fluctuation of the AC voltage, which causes a change in brightness when the LED emits light, and a phenomenon of illuminating and flickering occurs. At the same time, the core of the LED device is a PN junction diode whose I-V characteristic is an approximate exponential function. When the voltage across the LED is greater than the turn-on voltage, the current flowing through the PN junction increases exponentially. The prior art AC drive method may directly damage the LED device when the AC voltage rises unexpectedly.

Summary of the invention The technical problem to be solved by the present invention is to address the shortcomings of the flashing light caused by the direct driving of the LED lighting device by the alternating current in the prior art, and to provide an LED lighting device directly driven by the alternating current, overcome the LED flicker phenomenon caused by the alternating current, and improve the LED lighting. The efficiency of the device extends the life of the LED.

The present invention solves the technical problem, and adopts a technical solution that an AC direct-drive LED lighting device includes an AC input terminal, a protection unit, and a rectifying unit, wherein the first output end of the rectifying unit passes through n LEDs. The module and a switch unit are connected to the second output end, wherein nl is an integer; when ₁ 2, a channel formed by the switch unit between each two LED modules is connected with the second output end, and each switch The unit is connected to the sampling unit; the AC input terminal is used for connecting an alternating current to provide an operating current for the device;

The protection unit is connected to the AC input terminal to provide a protection function for the device;

The rectifying unit is connected to the protection unit, and rectifies the alternating current output by the protection unit;

The sampling unit is configured to sample an output voltage of the rectifying unit, and output a control signal to each switching unit; the switching unit is connected to the sampling unit, and is turned off or on according to a control signal output by the sampling unit.

The LED light-emitting device circuit of the invention is composed of a cascade of n-level LED modules, and the turn-off and turn-on voltage of the corresponding switch unit of each level of the LED module is appropriately preset by the sampling unit, so that flickering occurs when the AC voltage fluctuates phenomenon. Increasing the number of LED modules is equivalent to reducing the turn-on voltage of each stage of the LED module and improving the utilization of the power supply. When multi-level LED module is applied, when the AC voltage fluctuates, each LED module is affected less by the influence of a single module, and the stability of LED operation is better, more reliable, and the ability to withstand AC voltage fluctuation. Stronger.

Specifically, the n LED modules are composed of an LED array.

LED arrays can be used to form high-power LED modules.

Further, the LED array is composed of at least one LED disposed on the same printed circuit board; or at least one LED integrally packaged on the same substrate; or at least one LED integrated on the same semiconductor substrate Composition.

Arranging all the LEDs in the LED module on the same printed circuit board is the simplest and most economical packaging method under the current process conditions; or all the LEDs in the LED module are integrally packaged on the same substrate, that is, the LED module All of the LEDs are secondarily packaged and integrated on the same heat sink substrate; or integrated on the same semiconductor substrate, which is a semiconductor integrated circuit process that integrates LEDs on the same semiconductor substrate. These technologies can also interleave the LEDs in each LED module to improve the uniformity of the illumination brightness of the illumination device, and to overcome the flicker phenomenon, and the LED package wiring is also more convenient.

Specifically, the LEDs are connected in parallel and/or in series.

The appropriate combination of LEDs in the LED module, such as parallel, series or hybrid, can adapt to the AC direct drive environment, and easily adjust the current and voltage parameters of each LED module.

Specifically, the protection unit includes a fuse and/or a varistor, and the fuse is connected in series at an AC input end, The varistor is connected in parallel to the AC input.

Fuses are commonly used current-limiting protection components, and varistors are commonly used voltage-limiting protection components. Their combination can achieve the most basic current limiting and voltage limiting protection, and the cost is low, the installation is convenient, and secondary integration is facilitated.

Further, the protection unit further includes a common mode choke coil and/or a gas discharge tube, the common mode choke coil is connected in series at the AC input end, and the gas discharge tube is connected in parallel at the AC input end.

The common mode choke can suppress common mode interference, and the gas discharge tube can protect the lighting device from being damaged by lightning.

Specifically, the rectifying unit is configured by a full-wave rectification or a half-wave rectifying circuit composed of a rectifying diode.

The rectifier diode is used as the rectifying component, which is small in size and light in weight, and is convenient for secondary integrated packaging.

Specifically, the sampling unit is composed of a resistor network.

The resistor network is ideal for collecting DC parameters and is easy to set the switching unit operating point.

Specifically, the switch unit is composed of a transistor, and the transistor control pole is connected to the sampling unit.

As a switching element, the transistor has the characteristics of easy control, no contact, and long life.

More specifically, the transistor is a field effect transistor or a bipolar transistor, and the control is the gate of a field effect transistor or the base of a bipolar transistor.

Transistor switching elements, mature technology, responsive, reliable operation.

The invention has the beneficial effects that the LED module is directly driven by the alternating current power, the circuit is simple, the volume is small, the weight is light, and the cost is low. By presetting the appropriate turn-off voltage, the AC power directly drives the LED device without flickering when the AC voltage fluctuates. Moreover, when the instantaneous voltage of the alternating current is too high, the switch unit is turned off, and the LED module does not emit light, thereby improving the utilization efficiency of the power source and reducing the power loss. At the same time, the LED module is also prevented from being burnt due to excessive current, which prolongs the service life of the device.

DRAWINGS

1 is a block diagram showing the structure of Embodiment 1;

Figure 2 is a circuit schematic diagram of Embodiment 1;

Figure 3 is a block diagram showing the structure of Embodiment 2;

Figure 4 is a block diagram showing the structure of Embodiment 3;

Fig. 5 is a circuit diagram of the third embodiment.

detailed description

The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

The AC direct-drive LED lighting device of the present invention comprises an AC input terminal, a protection unit, a rectifying unit, a sampling unit, a switching unit and n LED modules, wherein _η 1, and is an integer. In the illuminating device of the present invention, the first output end of the rectifying unit (generally the positive end of the direct current output) is connected to the second output end through n LED modules and a switching unit (straight Description Book stream output negative end). When the number of LED modules exceeds two, a channel formed by a switch unit between each two LED modules is connected to the second output end. Each switching unit is connected to and controlled by the sampling unit. The LED light-emitting device circuit of the invention is composed of a cascade of n-level LED modules, and the turn-off and turn-on voltage of the corresponding switch unit of each level of the LED module is appropriately preset by the sampling unit, so that flickering occurs when the AC voltage fluctuates phenomenon. Increasing the number of LED modules is equivalent to reducing the turn-on voltage of each stage of the LED module and improving the utilization of the power supply. When multi-level LED module is applied, when the AC voltage fluctuates, each LED module is affected less by the influence of a single module, and the stability of LED operation is better, more reliable, and the ability to withstand AC voltage fluctuation. Stronger.

Example 1

Referring to FIG. 1 and FIG. 2, the illuminating device of the present embodiment includes an AC input terminal 1, a protection unit 2, a rectifying unit 3, a sampling unit 4, a switch unit 6, and an LED module 5. The number of LED modules 5 in this example is 1 (ie, n = l ). The first output end of the rectifying unit of this example is a DC output positive terminal 31, and the positive terminal 31 is connected to the second output DC output negative terminal 32 through the LED module 5 switching unit 6. See Figure 1. The AC input terminal 1 is connected to the AC L terminal (phase line) and N terminal (neutral line) to introduce AC power into the protection unit 2. The protection unit 2 provides a basic protection function for the entire device, consisting of a varistor VR and a fuse F. The fuse F is connected in series on the phase line, and the varistor is connected in parallel between the phase line and the neutral line, as shown in Fig. 2. For application to a particular environment, the protection unit 2 may also include a common mode choke and a gas discharge tube. The common mode choke is connected in series on the phase line and the neutral line, and the gas discharge tube is generally connected in parallel between the phase line and the neutral line. The rectifying unit 3 of this example is composed of a full-wave rectifying circuit D composed of a rectifying diode, and performs full-wave rectification on the alternating current. The voltage sampling unit 4 of this example is composed of a resistor network composed of sampling resistors R1 and R2, and the switching unit 6 is controlled by the DC voltage output from the sampling rectifier circuit D. as shown in picture 2. The switching unit 6 of this example is composed of M0SFET (Metal Oxide Semiconductor Field Effect Transistor, FET for short) Ml and M2 and Zener diodes DZ1, DZ2, resistors R3, R4 and R5. The LED module 5 of the present example is composed of an array of a plurality of LEDs connected in series, in parallel or in a mixed manner, and may be a plurality of LEDs arranged on the same printed circuit board, or a plurality of LEDs integrated on the same heat dissipation substrate. Or an integrated circuit composed of a plurality of LEDs integrated on the same semiconductor substrate.

When the instantaneous voltage of the alternating current reaches the turn-on voltage of the LED module 5, the switch unit 6 is turned on by the sampling unit 4, and the LED module 5 starts to emit light; when the instantaneous voltage of the alternating current exceeds the preset turn-off voltage, the switch When unit 6 is turned off, LED module 5 stops emitting light; when AC power fluctuates, within the normal working voltage range, that is, between the turn-on voltage of LED module 5 and the preset turn-off voltage, only the change occurs. At the time when the switching unit 6 is turned on and off, the illumination of the LED module 5 does not blink.

As shown in FIG. 2, the positive terminal of the rectifier circuit D is connected to one end of the resistor R1, and is connected to the positive terminal of the LED module, and the output negative terminal of the rectifier circuit D serves as a ground. The other end of the resistor R1 is connected to one end of the resistor R2, the negative terminal of the Zener diode DZ1, and one end of the resistor R3; the other end of the resistor R3 is connected to the gate of the field effect transistor M1, the drain of the field effect transistor M1, and the resistor R4 One end, one end of the resistor R5, and the negative terminal of the Zener diode DZ2 are connected. The other end of the resistor R5 and the field effect transistor Description

The gate of M2 is connected, the drain of FET M2, the other end of resistor R4, and the negative terminal of LED module are connected. The other end of the resistor R2, the positive terminal of the Zener diode DZ1, the positive terminal of the Zener diode DZ2, the source of the FET M1, and the source of the FET M2 are connected to the ground (DC output negative terminal).

When the AC input terminal 1 is connected to the power grid, the lighting device obtains AC power, passes through the protection unit 2, and is rectified into a DC power by the rectifying unit 3, and is supplied to the sampling unit 4, the switching unit 6, and the LED module 5. In each AC cycle, the output voltage of the rectifier circuit D rises from zero. When the voltage rises to the turn-on voltage of the switch unit, the FET M1 turns off, M2 turns on, and the LED module 5 starts to emit light; When the voltage rises, the current passed by the LED module increases. When the voltage is lower than the preset turn-off voltage, the voltage output by the sampling unit 4 is insufficient to turn on the FET M1, M1 remains turned off, and M2 remains turned on. The LED module 5 continues to emit light; when the voltage rises unexpectedly, when the preset off voltage is exceeded, Ml starts to conduct, M2 turns off, and the LED module does not emit light, protecting the LED module 5 from the impact of a large current.

Example 2

As shown in FIG. 3, there are two LED modules 5 of the present embodiment, and two switching units 6 are also provided. The positive terminal 31 of the rectifying unit 3 passes through two LED modules and a second switching unit 6 (labeled as a switching unit in the figure). 2, other switch units are labeled similarly) connected to the negative terminal 32 of the rectifier unit 3, and there is a channel and a rectification unit formed by the first switch unit 6 between the first LED module 5 and the second LED module 5 3 negative terminal 32 connection. In this example, all of the switching units 6 are connected to the sampling unit 4.

Example 3

As shown in FIG. 4, there are three LED modules 5 of the present embodiment, and three switch units 6 are also provided. The positive terminal 31 of the rectifying unit 3 passes through the three LED modules and the third switching unit 6 and the negative terminal of the rectifying unit 3. 32 connection, there is a channel formed by the first switch unit 6 between the first LED module 5 (labeled as LED module 1 in the figure, similar to other LED modules) and the second LED module 5 It is connected to the negative terminal 32 of the rectifying unit 3. A channel formed by the second switching unit 6 between the second LED module 5 and the third LED module 5 is connected to the negative terminal 32 of the rectifying unit 3. In this example, all of the switching units 6 are connected to the sampling unit 4.

The circuit schematic diagram of the device of this example is shown in FIG. 5, and its working principle and specific circuit structure are similar to those of Embodiment 1, and are not described here. The sampling unit 4 of this example is composed of resistors R1, R2, R6, R7, Rl l, R12, three switching units 6, and three LED module groups 5 into three-stage circuits, and three switching units 6 respectively control three LEDs. The module sets the off time of each stage switch through the sampling unit 4, and protects the corresponding LED module 5. As the number of LED modules increases, the turn-on voltage of each LED module is reduced, which improves the utilization of the power supply. When multi-level LED module is applied, when the AC voltage fluctuates, each LED module is affected less by the influence of a single module, and the stability of LED operation is better, more reliable, and the ability to withstand AC voltage fluctuation. Stronger.

From the above detailed explanation, it can be seen that the voltage sampling unit of the present invention monitors the input voltage while also having the pair of LEDs. The protection function of the manual module. When the AC voltage fluctuates greatly, the switch unit can also be disconnected in time to protect the LED module from damage due to excessive current.

It should be noted that, although the above embodiments have described the structure of the present invention in detail, the present invention is not limited to the above embodiments, and any conventional replacement structure performed by those skilled in the art according to the above description belongs to the protection scope of the present invention. .

Claims

Claim

1. An LED light-emitting device directly driven by an alternating current, comprising an alternating current input end, a protection unit and a rectifying unit, wherein the first output end of the rectifying unit is connected to the second output end through n LED modules and a switching unit , where n^ l , and is an integer; when 0 2, a channel formed by a switch unit between each two LED modules is connected to the second output end, and each switch unit is connected to the sampling unit;

The AC input terminal is used for connecting an alternating current to provide an operating current for the device;

2. The alternating current direct drive LED lighting device according to claim 1, wherein the n LED modules are composed of an LED array.

3. The alternating current direct drive LED lighting device according to claim 2, wherein the LED array is composed of at least one LED disposed on the same printed circuit board; or at least integrated on the same substrate. One LED is configured; or at least one LED integrated on the same semiconductor substrate.

4. An alternating current direct drive LED lighting device according to claim 3, wherein the LEDs are connected in parallel and/or in series.

5. The alternating current direct drive LED lighting device of claim 1, wherein the protection unit comprises a fuse and/or a varistor, the fuse being connected in series at an alternating current input, the varistor being connected in parallel AC input.

6. The alternating current direct drive LED lighting device of claim 5, wherein the protection unit further comprises a common mode choke and/or a gas discharge tube, wherein the common mode choke is connected in series to the alternating current input. The gas discharge tube is connected in parallel at the AC input end.

7. The alternating current direct drive LED lighting device according to claim 1, wherein the rectifying unit is constituted by a full-wave rectifying or half-wave rectifying circuit composed of a rectifying diode.

8. The alternating current direct drive LED lighting device according to claim 1, wherein the sampling unit is constituted by a resistor network.

9. The alternating current direct drive LED lighting device according to claim 1, wherein the switching unit is constituted by a transistor, and the transistor control electrode is connected to the sampling unit.

10. The alternating current direct drive LED lighting device according to claim 9, wherein the transistor is a field effect transistor or a bipolar transistor, and the gate of the field effect transistor or the bipolar transistor is controlled. Base.