WO2008067750A1

WO2008067750A1 - A serial led groups lighting device

Info

Publication number: WO2008067750A1
Application number: PCT/CN2007/071138
Authority: WO
Inventors: Jung-Hsiang Yao
Original assignee: Jung-Hsiang Yao
Priority date: 2006-12-07
Filing date: 2007-11-28
Publication date: 2008-06-12
Also published as: CN200979092Y

Abstract

A serial LED groups lighting device (2) includes a source circuit (21), an LED array (23) which is formed by connecting in series, a LED group controlling unit (28) and a switching circuit. The serial LED groups lighting device (2) can control respective LED group to operate separately via the switching circuit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved series type LED lamp group light-emitting device. The present invention is based on a Chinese utility model patent application filed on Dec. 7, 2006, the application number of which is incorporated herein by reference. BACKGROUND OF THE INVENTION With the advancement of semiconductor LED (Light Emitting Diode) fabrication technology, the widespread use of LED lighting devices has become a reality. Most typically, LED light-emitting devices assembled from three primary color LEDs of red, green, and blue have been widely used. Since the LED itself has the advantages of saving electric energy and long service life, the LED light group illuminating device composed of the three primary color LEDs can generate various color changes through the combined illuminating of the three primary colors, and therefore, the colored light has rich colors and functions. Diversification and other advantages. These advantages make LED lighting technology a mainstream trend in the market. In general, in order to achieve the color change effect of the lantern, it is necessary to connect the LEDs of the three primary colors (red, green, and blue) in parallel, and then appropriately control the combined illumination by the switch. On the other hand, the power of the single LED is small, often reaching It does not have the brightness required for illumination. Therefore, in the case where higher brightness is required, it is necessary to connect a plurality of LEDs of the same color in series. For example, a conventional LED lamp group illumination device 1 disclosed in FIG. 1 includes a power supply circuit 10, an LED array 11, an LED lamp group control unit 12, an anti-backflow diode D1, a Zener diode Z1, and a filter capacitor C2. , band-stop transistor (base with bias and bleeder resistance) Ql, Q2, Q3 and current limiting resistors Rl, R2, R3. Among them, the LED array 11 includes three LED lamps (typically, red, green, and blue primary colors), and each of the branches includes several same-color LEDs (typically, eight LEDs are connected in series). The power circuit 10 uses a capacitor buck current-limiting power supply because the LED requires a low-voltage DC drive.

The LED lighting device is limited by volume, cost and safety factors. It is not suitable for voltage reduction with a transformer. AC AC (for example, 220V mains) is stepped down by the step-down capacitor C11 and then rectified by the bridge rectifier BRG1. The DC power supply (V+) is used by the LED array 11, the resistor R12 is the bleeder resistor of the step-down capacitor C11, and the resistor R11 is the instantaneous current protection resistor, and the capacitor is step-down current limiting type. The source is a well-known prior art and will not be described here. The Zener diode Z1 is connected between the common anode terminal of the LED array 11 and the ground, and functions as a voltage regulator; the filter capacitor C2 is also connected between the common anode terminal of the LED array 11 and the ground to filter; the anti-backflow diode D1 is connected. Between the common anode terminal of the LED array 11 and the power supply circuit 10, the function is to prevent the electric energy stored in the filter capacitor C2 from being released into the LED lamp group control unit 12 (the capacitor generally has the function of storing electric energy), which affects its normal operation. The band-resistance transistors Q1, Q2, and Q3 respectively control the conduction and disconnection of the three branches at a specific timing according to the control signal of the LED lamp group control unit 12, so that the LED lamp group illumination device 1 produces a color change. With regard to the circuit principle in FIG. 1, reference may be made to the description of the Chinese Patent Application No. 2, 200610035871. In particular, the internal structure and principle of the LED lamp group control unit 12 are described in detail in Chinese Patent Application No. 200610035871. I will not repeat them here. The following focuses on the defects of the LED lamp group illumination device 1 in Fig. 1: As described above, in order to have various colors of the lantern, the LED array 11 must include three primary color monochrome lamps, assuming three parallel branches, each of which The normal working current of the branch is 15mA (this current is the normal working current of the LED), then the sum of the currents of the three parallel branches at the same time is 45mA (the LED light group emits white light), but, in most In this case, only two of the colors need to be combined or only one of the colors is used, at least one of the branches is disconnected, and the current of the power supply circuit 10 is used because the capacitor is used in the circuit. The output is basically a fixed value. Therefore, the current in the disconnected branch is consumed by the Zener Z1. This is also the reason why the Zener Z1 must be used. Otherwise, the balance current will burn out the LED branch under working condition. Road, in this case, there may be 15mA ~ 30mA current is wasted on the Zener Z1, the Zener Z1 will generate a lot of heat, these waste heat makes the LED light unit 1 work In the process, the temperature is higher; on the other hand, the current limiting resistors R1, R2, and R3 connected to the collectors of the transistors Q1, Q2, and Q3 are connected in series in the working branch of the LED, and there is also a certain amount of heat. To a certain extent, the heat generation of the LED lamp group illuminating device 1 is intensified, so that the service life of the LED lamp group illuminating device 1 is greatly reduced, and the work stability is not high. If the LED light group illumination device that needs to control the brightness (the LEDs in the three branches are all white LEDs, the brightness can be controlled by the above circuit), the same problem still exists. The invention is to solve the above technical problems, and under the premise of ensuring the luminous effect and function, reducing The generation of waste heat in the circuit improves the luminous efficiency of the circuit and makes the working performance more stable. SUMMARY OF THE INVENTION An object of the present invention is to provide a tandem LED light group light-emitting device capable of reducing waste heat generation and improving luminous efficiency. In order to achieve the above object, the LED light emitting device of the series type LED lamp of the present invention comprises: a power circuit;

An LED array comprising a plurality of sets of LEDs, wherein the plurality of sets of LEDs are connected in series with each other, wherein each set includes at least one LED;

The LED lamp group control unit is connected to the power source and separately controls the plurality of groups of LEDs; the switch circuit is connected between the LED array and the LED lamp group control unit, and controls the plurality of groups of LEDs in the circuit according to the control signal of the LED lamp group control unit The working state in the middle. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of a conventional LED lamp group illuminating device; FIG. 2 is an electrical schematic diagram of a preferred embodiment of a series LED lamp group illuminating device according to the present invention; FIG. 3 is a circuit structure of FIG. A specific circuit diagram. The present invention will be further described below in conjunction with the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the block diagram shown in FIG. 2, FIG. 2 generally discloses an electrical schematic diagram of a preferred embodiment of a series LED light group illumination device 2 of the present invention, which includes a power supply circuit 21, a reverse flow prevention element 22, and an LED array. 23. LED lamp group control unit 28 and switch circuit. The switch circuit includes a plurality of NPN type and PNP type transistors (27A, 26N, 27N, 26Z, etc.), which will be described in detail later. Since Fig. 2 is only an electrical schematic diagram, the components therein are not embodied, and the emphasis is on the connection relationship between the components. The biggest feature of the tandem LED light group illuminating device 2 of the present invention is that the LEDs in the LED array 23 are divided into a plurality of light groups according to different colors, and the light groups are connected in series, and three specific ones are drawn in FIG. The lamp group: the front lamp group 24A, the intermediate lamp group 24N, and the end lamp group 24Z. Obviously, the intermediate lamp group 24N can be further divided into a plurality of lamp groups. Each lamp group includes at least one LED (in order to ensure brightness, generally includes more than 8 LEDs), filter capacitors 25A, 25N, 24Z are respectively connected in parallel at the front end lamp group 24A, the intermediate lamp group 24N, and the end lamp group 24Z. , gp, each lamp group corresponds to a filter capacitor. These lamp groups use independent filter capacitors to ensure that each lamp group is not affected by the instantaneous current generated by the external storage capacitor. Since the series type LED lamp group illuminating device 2 of the present invention adopts the series type LED array 23, the total operating current of the LED is small, and still takes 15 mA as an example. The total operating current of the series type LED lamp group illuminating device 2 of the present invention is 15mA, therefore, only need to limit the output current of the power supply circuit 21 to about 15mA, it can ensure that the LED array always maintains the normal working current, and even if the LED in a certain lamp group needs to stop working, the current of the series circuit is basically It remains unchanged (15 mA), no excess current is absorbed by the energy-consuming components in the circuit, and there is no need to use a Zener tube as in the prior art, resulting in a large amount of waste heat. Since the series type LED lamp group illuminating device 2 of the present invention adopts the series type LED array 23, it is necessary to provide a special switch circuit, which can separately control the working state of each lamp group without affecting the normal working state of other lamp groups. Of course, it can also be seen as setting a separate switch sub-circuit for each lamp group, and then combining or integrating the switch sub-circuits into an integrated circuit (IC). FIG. 2 discloses a switching circuit composed of a switching transistor of PNP and NPN type, and the switching sub-circuits of the three lamp groups are different, wherein the switching sub-circuit of the front-end lamp group 24A adopts a combination of PNP+NPN switching triodes. 27A, the switch sub-circuit of the intermediate lamp group 24N adopts the combination of NPN switch triode 26N and PNP+NPN switch triode combination 27N, and the switch sub-circuit of the end lamp group 24Z adopts NPN switch triode 26Z, the reason and effect of using the above specific circuit and specific The circuit connection method will be described in detail in Figure 3. Referring to FIG. 3 in combination, FIG. 3 is a specific circuit for realizing the circuit structure shown in FIG. 2. The power supply circuit 21 has the same structure as the power supply circuit 10 of FIG. 1, and only the bridge rectifier circuit BRG11 is embodied, and will not be repeatedly described herein. The reverse current preventing element 22 employs a diode D1 to prevent the stored energy of the filter capacitors C1, C2, C3 from being released into the LED lamp group control unit 28. The LED array 23 uses 24 LEDs connected in series and is divided into three lamp groups: LED1—LED8 is a blue LED lamp group (corresponding to the front lamp group 24A), and LED9-LED16 is a red LED LED lamp group (corresponding to the intermediate lamp group 24N, SP, The intermediate lamp group 24N includes only one set of red lights), and the LEDs 17-LEDs 24 are green light groups (corresponding to the end lamp group 24Z).

The circuit structure of the LED lamp group control unit 28 can be referred to the description in Chinese Patent Application No. 200610035871. No. 2, which is briefly described as follows: The diode D21 is also a reverse current preventing element, and the transistors Q21 and Q22 and the resistors R21, R22 and R23 form a three-terminal structure. The voltage regulator circuit outputs 5V voltage for the single chip U1 to work, and the capacitor C21 is the filter capacitor for the three-terminal voltage regulator circuit. The transistor Q24 and the resistors R26, R27, R29 and the capacitors C25 and C26 form a reset circuit for the single chip U1 to be disconnected. The power supply is reset before the power supply; the resistor R28 and the capacitor C27 form an RC oscillator circuit, which provides an external clock for the single chip U1 to control the color jump period of the color lamp; the transistor Q23, the resistor R24 and the capacitors C22 and C23 form a power failure detecting circuit, which can utilize the lamp The power switch is turned on or off to control the color change or other functions of the lantern. The resistor R25 is the collector load resistance of the transistor Q23; the capacitor C24 is the storage capacitor, and the stored energy can be short-circuited by the microcontroller U1 after the power is turned off. Operation; The single-chip microcomputer U1 contains a preset program for generating control signals and controlling the state of each switch circuit. In summary, the function of the lamp group control unit 28 is to control the plurality of groups of LEDs described above, and the specific structure thereof is not the point of the invention, and will not be described herein. The switch circuit is connected between the LED array 23 and the LED lamp group control unit 28, and controls the conduction of the three groups of different color LED lamp groups in the circuit according to the control signal of the single chip U1 in the LED lamp group control unit 28. Short circuit, short circuit is short circuit, current does not flow through it. In the on state, the LED is in normal working state. In the shorted state, the shorted LED is in non-lighting non-working state. The switch circuit includes band-stop transistors Ql, Q2, Q3, Q4, Q5, Q6, wherein the transistors Ql, Q4 form a switch sub-circuit of the blue front-end lamp group 24A, and control the conduction or short-circuit of the front-end lamp group 24A, the resistor R1 For the current limiting resistor, the base bias resistor of the band-stop transistor Q1 is prevented from being overloaded and damaged; the transistors Q2 and Q6 together form a switch sub-circuit of the red intermediate lamp group 24N, in control The lamp group 24N is turned on or shorted, and the transistor Q5 is used to control the intermediate lamp group 24N and the terminal lamp group 24Z to be simultaneously turned on or shorted; the transistor Q3 is the switch sub-circuit of the green end lamp group 24Z, and the terminal lamp group is controlled. 24Z is turned on or shorted. The following focuses on the working principle of the switching sub-circuit: As shown in Figure 2 and Figure 3, the collectors of the NPN-type switching transistors 26N, 26Z (ie, the transistors Q5, Q3) are connected to the connection points between the lamp groups, and their emitters. Grounding, the base is connected to the corresponding control pin of the single chip U1, and all the light groups after the transistor Q5 or Q3 are shorted by receiving the high potential signal.

The PNP+NPN switch triode combination 27A (ie, triode Q1+transistor Q4) and 27N (triode Q2+ triode Q6) are respectively connected between the respective lamp groups except the end lamp group 24Z and the LED lamp group control unit 28, the triode The connection method of Q1+ transistor Q4 is as follows: The emitter and collector of PNP transistor Q1 are respectively connected to the anode of the first LED of the corresponding lamp group and the cathode of the last LED, and the base is connected to the set of NPN transistor Q4 through the current limiting resistor R1. The electrode, the NPN transistor Q4 emitter is grounded, and the base is connected to the corresponding pin of the single chip U1, the connection relationship of the triode Q2+ transistor Q6 is the same as the connection relationship of the above transistor Q1+ transistor Q4, but the current limiting resistor Rl, the front end lamp is not required. The group 24A and any one of the intermediate lamp groups 24N can be controlled to be turned on or shorted by the above-mentioned PNP+NPN switch triode combination, thereby controlling the working state of the corresponding lamp group, and producing various color change effects. It should be emphasized that if it is necessary to make a certain lamp group and all subsequent lamp groups in a non-operating state, since the bias voltages of the PNP transistors Q1 and Q2 are close to zero, there is not enough bias to drive the PNP transistors Ql and Q2 completely. Closed, it may make the corresponding lamp group in a semi-bright state, affecting the color change effect. In this case, it is necessary to operate with the above-mentioned NPN type switching transistor 26N (corresponding to the transistor Q5) to achieve better technical effects. In summary, the tandem LED lamp group illuminating device 2 of the present invention solves the problem of independent operation of each lamp group while adopting a series of LED arrays. Since the series LED array is used, compared with the prior art, The advantages of less waste heat and high luminous efficiency, and the stability of the circuit is also higher. Of course, the above embodiments are merely preferred embodiments, and the present invention can also be made according to the above embodiments. Some equivalent changes, for example, if a low-power PNP band-stop transistor cannot drive a high-power LED, it can be disassembled into an independent high-power PNP switch transistor and an independent base bias resistor, base bleeder resistor Three components; if the power of the low-power NPN band-stop transistor is insufficient or the flow resistance parameter is not enough, it can be changed to a higher power Darlington dual transistor, and these problems can be solved. Of course, if the cost is not considered The function of the triode can also be replaced by a FET, which can be easily considered by those skilled in the art; the above switching circuit is only a preferred embodiment, and can be independently controlled for each lamp group. Other circuit switching methods are adopted. At the same time, depending on the built-in program, the LED lamp group control unit can also adopt other structures; if high-power LEDs are used, the boosting circuit can be added to the LED lamp group control unit to avoid Some LEDs pull down the low voltage when they are not working, which affects the normal operation of the LED light unit control unit. This is also more common. Technical means, at the same time, in order to avoid the strong transient pulse in the high-power LED destroying the internal structure of the LED, a diode capable of absorbing the surge may be connected in parallel at each end of each group of LEDs; the LEDs included in each group of LEDs may be the above The series relationship disclosed in the embodiment may of course be a parallel relationship or a hybrid relationship, and it is only necessary to ensure that the LEDs of each group are in series relationship. It should be emphasized that although all the above descriptions highlight the application of the present invention in a lantern, if the lamps are all set to one color, for example, all LEDs are white, then the above colors The change control naturally converts to the change control of the color brightness (the more the number of LED groups participating in the illumination, the higher the illumination brightness is naturally), which is also required in some occasions. This application can be directly derived from the above description. For equivalent applications, various equivalents are intended to be included within the scope of the claims. Industrial Applicability The tandem LED lamp group illuminating device of the present invention solves the problem of independent operation of each lamp group through a switching circuit while using a series of LED arrays, and adopts a series LED array, compared with the prior art. In terms of waste heat and high luminous efficiency, the stability of the circuit is also higher.

Claims

Claim

1. Series LED light group illuminating device, including

Power circuit

An LED array comprising a plurality of sets of LEDs, wherein each set includes at least one LED;

LED lamp group control unit, connected to the power source and respectively controlling the plurality of groups of LEDs;

It is characterized by:

The plurality of sets of LEDs are connected in series with each other;

The switch circuit is connected between the LED array and the LED lamp group control unit, and controls the working state of the plurality of groups of LEDs in the circuit according to the control signal of the LED lamp group control unit.

2. The tandem LED light group illuminating device according to claim 1, wherein the LEDs in each group of LEDs are connected in parallel, in series or mixed.

3. The tandem LED light group illuminating device according to claim 2, wherein: the LED array comprises three groups of LEDs having illuminating colors of red, blue and green, wherein each group of LEDs comprises 8 colors of the same color. LED.

4. The tandem LED light group illuminating device according to claim 1, wherein the LEDs of each group of LEDs in the LED array are all white.

The tandem LED light group illuminating device according to claim 1, wherein a front end preventing element is connected in series with the front end of the LED array.

6. The tandem LED light group illuminating device according to claim 1, wherein: a filter capacitor is connected in parallel at both ends of each group of LEDs.

7. The tandem LED light group illuminating device according to claim 1, wherein:

The tandem LED light group illuminating device according to any one of claims 1 to 7, wherein:

A corresponding switch sub-circuit is arranged between each group of LEDs and the LED lamp group control unit.

9. The LED light emitting device of the series type LED lamp according to claim 8, wherein: an NPN type band-resistance switch triode is connected between the connection point between each group of LEDs and the ground, and the set of the NPN type band-resistance triode is connected. The electrodes are connected to the above connection points, the emitters are grounded, and the bases are respectively connected to corresponding control pins of the LED lamp group control unit.

10. The LED light emitting device of the series type according to claim 8, wherein: a PNP and an NPN switch transistor are connected between each group of LEDs other than the last group of LEDs and the LED lamp group control unit. The emitter of the NPN switch transistor is grounded.