WO2019192100A1

WO2019192100A1 - Led drive circuit and led display apparatus

Info

Publication number: WO2019192100A1
Application number: PCT/CN2018/095166
Authority: WO
Inventors: 石昌金; 肖道粲; 刘玲会
Original assignee: 深圳市艾比森光电股份有限公司; 惠州市艾比森光电有限公司
Priority date: 2018-04-02
Filing date: 2018-07-10
Publication date: 2019-10-10
Also published as: WO2019192099A1; CN208029151U

Abstract

Disclosed in the present solution are an LED drive circuit and an LED display apparatus, comprising a first power source and a second power source, a first drive circuit and a second drive circuit, and a first LED lamp group and a second LED lamp group. The first power source drives the first LED lamp group via the first drive circuit; the second power source drives the second LED group via the second drive circuit; the first LED lamp group is a red LED lamp group, and the second LED lamp group is a green and/or blue LED lamp group; and the first drive circuit is a red LED drive circuit, and the second drive circuit is a green and/or blue LED drive circuit. Different voltages are respectively provided to the red LED and the green and/or blue LED by two power sources, and a voltage on the red LED drive circuit is reduced so that the voltage on the red LED drive circuit is consistent with a voltage on the green and/or blue LED drive circuit, facilitating reducing the heating and attenuation of the red LED drive circuit, improving the stability of the red LED drive circuit, and simplifying PCB design, thus having good economic and social benefits.

Description

LED driving circuit and LED display device

Technical field

The solution relates to the field of electronic circuits, and in particular to an LED driving circuit and an LED display device.

Background technique

With the wide application of LED displays in the market, the problem of large power consumption and high energy consumption of LED displays has emerged. At present, in the LED products, as shown in Fig. 1, the driving method is generally that the current flows from the positive pole of the power source to the negative pole of the power supply through the PMOS tube, the LED, and the constant current driving circuit (the driving circuit is the driving chip). Since the physical properties of red, green and blue wafers are different from each other, the forward voltage of the red LED is low. For the same power supply, the voltage Vled across the LED is a fixed forward voltage due to the voltage across the PMOS transistor Vmos. The voltage on the constant current driving circuit of the red LED is higher than the voltage on the constant current driving circuit of the green and/or blue LED, causing serious heat generation of the red LED driving circuit, and the red LED is larger than the green and/or due to the local temperature difference. Or the blue LED decays faster, causing the drive circuit area to turn blue. If used for a long time, there are problems with reliability and stability.

technical problem

The purpose of the solution is to provide an LED driving circuit and an LED display device, aiming at solving the current LED driving technology. The constant current driving circuit of the red LED on the constant current driving circuit is higher than the green and/or blue LED. The high voltage on the LED leads to a serious heat generation in the red LED driving circuit and a blue color in the driving circuit area.

Technical solution

The first aspect of the present invention provides an LED driving circuit, including a first power source and a second power source, a first driving circuit and a second driving circuit, a first LED lamp group and a second LED lamp group;

The first power source drives the first LED light group through the first driving circuit;

The second power source drives the second LED lamp group through the second driving circuit;

The first LED light group is a red LED light group, and the second LED light group is a green and/or blue LED light group;

The first driving circuit is a red LED driving circuit, and the second driving circuit is a green and/or blue LED driving circuit.

Preferably, further comprising a first switching circuit and a second switching circuit;

The first switch circuit is configured to control turning on or off of the first LED light group;

The second switching circuit is configured to control turning on or off of the second LED light group.

As a first implementation manner of the present solution, the first power source is sequentially connected to the first switch circuit, the red LED lamp group, and the red LED drive circuit; the second power source and the second switch circuit, green and/or The blue LED light group, the green and/or blue LED drive circuits are connected in sequence.

As a second preferred embodiment of the present solution, the first power source is sequentially connected to the red LED driving circuit, the red LED lamp group, and the first switching circuit; and the second power source and the green and/or blue LED driving circuit are sequentially connected; The green and/or blue LED light groups and the second switch circuit are sequentially connected.

Preferably, the voltage value of the first power source is 4.3V, and the voltage value of the second power source is 5V.

Preferably, the first switch circuit and the second switch circuit each include a switch controller and a switch transistor, and the switch controller is configured to control on or off of the switch transistor to control a switch state of the corresponding LED light group.

Preferably, the switching transistor is an NMOS transistor.

A second aspect of the present invention provides an LED display device comprising the LED drive circuit as described above.

Beneficial effect

The LED driving circuit and the LED display device provided by the solution provide different voltages for the red LED and the green and/or blue LED respectively by improving the existing LED driving mode, and reducing the voltage. The voltage on the red LED driving circuit makes the voltage on the red LED driving circuit coincide with the voltage on the green and/or blue driving circuit, which overcomes the excessive voltage of the red LED driving circuit existing in the prior art, and the heat is severe and the attenuation is more Fast technical problems, thus reducing heat and energy consumption, improving the stability of red LEDs, and simplifying PCB design, with good economic and social benefits.

DRAWINGS

1 is a schematic view showing a driving method of an LED in the prior art;

2 is a schematic diagram of a circuit structure of a basic concept of the present solution;

3a and 3b are schematic circuit diagrams of a first embodiment of the present solution;

4a and 4b are schematic circuit diagrams of a second embodiment of the present solution.

Embodiments of the invention

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present solution more clear, the present embodiment will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to be limiting.

The first core of the solution provides an LED driver circuit that provides two sets of power supplies to provide different voltages to the red LED and the green and/or blue LED, respectively, by improving the existing LED driving method. The voltage on the red LED driving circuit makes the voltage on the red LED driving circuit coincide with the voltage on the green and/or blue driving circuit, which overcomes the excessive voltage of the red LED driving circuit existing in the prior art, and the heat is severely attenuated. Faster technical issues. The second core of the solution is to provide an LED display device comprising the above LED drive circuit.

In order to enable a person skilled in the art to better understand the technical solutions of the present solution, the present solution will be further described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, in the current LED products, the driving method is generally that the current flows from the positive pole of the power supply to the negative pole of the power supply through the PMOS transistor, the LED, and the constant current driving circuit. Since the physical properties of the red, green and blue wafers are different from each other, the forward voltage of the red LED is low. When the same power supply VCC is supplied, the voltage Vled across the LED is a fixed forward conduction due to the voltage Vmos across the PMOS transistor. The voltage causes the voltage on the constant current driving circuit of the red LED to be higher than the voltage on the constant current driving circuit of the green and/or blue LED, causing the red LED driving circuit to generate heat seriously, and the red LED has a larger local temperature difference than the green and / or the blue LED decays faster, causing the drive circuit area to be blue.

For example, when using a power supply VCC with a voltage of 5V, the forward voltage Vled1 of the red LED is 1.8V, the forward voltage Vled2 of the green and/or blue LED is 2.5V, and the fixed voltage Vmos of the PMOS transistor is 1V. , the voltage on the red LED drive circuit is VCC-Vmos-Vled1=5V-1.8V-1V=2.2V, and the voltage on the green and/or blue LED drive circuit is VCC-Vmos-Vled2=5V-2.5V- 1V = 1.5V. That is, the voltage on the red LED driving circuit is higher than the voltage on the green and/or blue LED driving circuit, causing the red LED driving circuit to have serious heat generation, faster attenuation, and problems in long-term use safety and reliability.

As shown in FIG. 2, the basic idea of the present invention is to provide an LED driving circuit including a first power source and a second power source, a first driving circuit and a second driving circuit, a first LED lamp group and a second LED lamp group. The first power source drives the first LED light group through the first driving circuit; the second power source drives the second LED light group through the second driving circuit; the first LED light group is a red LED light group, and the second LED light group is green and / or blue LED light group; the first drive circuit is a red LED drive circuit, and the second drive circuit is a green and / or blue LED drive circuit.

3a and 3b are schematic circuit diagrams of a first embodiment of the present solution, including a first power supply VCC1, a second power supply VCC2, a first switching circuit, a second switching circuit, a red LED light group, green and/or Blue LED light set, red LED drive circuit, green and / or blue LED drive circuit.

As shown in FIG. 3a, the first power supply VCC1 is sequentially connected to the first switch circuit, the red LED lamp group, and the red LED drive circuit. The first switch circuit includes an NMOS transistor and a controller, and the controller is used to control the NMOS. Turning on and off the tube to control the opening and closing of the red LED group; as shown in Figure 3b, the second source VCC2 and the second switching circuit, the green and/or blue LED group, green and/or blue The LED driving circuit is sequentially connected. The second switching circuit includes an NMOS transistor and a controller. The controller is used to control the on and off of the NMOS transistor, thereby controlling the opening and closing of the green and/or blue LED group.

Further, the drain of the NMOS transistor is connected to the first power source VCC1, the source is connected to the anode of the red LED lamp group, and the gate is connected to the controller.

Compared with PMOS, NMOS has less self-heating, so that more power is used for LED illumination. Therefore, in this embodiment, an NMOS transistor is selected as the switching circuit.

Since the forward voltage value of the red LED is lower than the forward voltage value of the green and/or blue LED, if the voltages on the two driving circuits are the same, the voltage of the first power source VCC1 should be less than the second value. The voltage value of the power supply VCC2. In this embodiment, the voltage value of the power supply VCC1 is set to 4.3V, the voltage value of the power supply VCC2 is 5V, the forward voltage of the red LED is 1.8V, and the forward voltage of the green and/or blue LED is 2.5V. The fixed voltage of the NMOS transistor is 1V, the voltage on the red LED driving circuit is 4.3V-1.8V-1V=1.5V, and the voltage on the green and/or blue LED driving circuit is 5V-2.5V-1V=1.5V. . Compared to the prior art, the voltage on the red LED drive circuit is reduced such that the voltage on the red LED drive circuit is consistent with the voltage on the green and/or blue LED drive circuit.

4a and 4b are schematic circuit diagrams of a second embodiment of the present invention, including a first power supply VCC1, a second power supply VCC2, a red LED drive circuit, a green and/or blue LED drive circuit, and a red LED light group. , green and / or blue LED light group, first switching circuit, second switching circuit.

As shown in FIG. 4a, the first power source VCC1 is sequentially connected to the red LED driving circuit, the red LED lamp group, and the first switching circuit. The first switching circuit includes an NMOS transistor and a controller, and the controller is used to control the NMOS. Turning on and off the tube to control the opening and closing of the red LED group; as shown in Figure 4b, the second source VCC2 and the green and/or blue LED driver circuit, the green and/or blue LED group, The two switch circuits are sequentially connected, and the second switch circuit includes an NMOS transistor and a controller, and the controller is used to control the on and off of the NMOS transistor, thereby controlling the on and off of the green and/or blue LED group.

Further, the drain of the NMOS transistor is connected to the cathode of the red LED lamp group, the source is grounded, and the gate is connected to the controller.

In addition, the solution can also supply power to the red LED, the green LED, and the blue LED by three sets of power supplies, wherein the power supply voltage for the red LED is lower than the power supply voltage for the green LED and the blue LED, for the green LED and blue The power supply voltages supplied by the color LEDs are equal. In this way, the voltage on the red LED driving circuit can be reduced to reduce the heat generation.

The present solution also provides an LED display device including the LED drive circuit as described above. The above LED display device includes a billboard, a television screen, a splicing screen, and the like.

Compared with the prior art of FIG. 1, on the one hand, the solution improves the existing LED driving mode, and increases the voltage of the red LED and the green and/or blue LED by the two sets of power sources respectively, thereby reducing The voltage on the red LED driving circuit makes the voltage on the red LED driving circuit coincide with the voltage on the green and/or blue LED driving circuit, which is beneficial to reduce the heat of the red LED driving circuit, and the voltage on the red LED driving circuit The reduction and the stability of the red LED driving circuit are improved, and the ghosting and caterpillar phenomenon of the LED display screen are effectively solved. At the same time, the same cost of LED is used to achieve the same brightness, and the lower the voltage, the lower the power of the LED display. On the other hand, this solution uses two sets of power supplies to supply power. It does not require twice the MOS tube to use two voltages to drive the LEDs, simplifying the PCB design.

The above is a detailed description of the preferred implementation of the present solution, but the present invention is not limited to the embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present solution. Such equivalent modifications or alternatives are intended to be included within the scope of the claims.

The principle and implementation of the solution are described in the following examples. The description of the above embodiments is only used to help understand the method and core idea of the solution. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention. These modifications and modifications are also within the scope of the claims of the present invention.

The above description is only for the preferred embodiment of the present solution, and is not intended to limit the present solution. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present solution should be included in the protection of the present solution. Within the scope.

Claims

An LED driving circuit, comprising: a first power source and a second power source, a first driving circuit and a second driving circuit, a first LED lamp group and a second LED lamp group;

The first power source drives the first LED light group through the first driving circuit;

The second power source drives the second LED lamp group through the second driving circuit;

The first LED light group is a red LED light group, and the second LED light group is a green and/or blue LED light group;

The first driving circuit is a red LED driving circuit, and the second driving circuit is a green and/or blue LED driving circuit.
An LED driving circuit according to claim 1, further comprising a first switching circuit and a second switching circuit;

The first switch circuit is configured to control turning on or off of the first LED light group;

The second switching circuit is configured to control turning on or off of the second LED light group.
The LED driving circuit according to claim 2, wherein the first power source is sequentially connected to the first switch circuit, the red LED lamp group, and the red LED driving circuit; the second power source and the second switch circuit The green and/or blue LED light groups, green and/or blue LED drive circuits are connected in sequence.
The LED driving circuit according to claim 2, wherein the first power source is sequentially connected to the red LED driving circuit, the red LED lamp group, and the first switching circuit; and the second power source is green and/or The blue LED driving circuit, the green and/or blue LED lamp group, and the second switching circuit are sequentially connected.
The LED driving circuit according to any one of claims 1 to 4, wherein a voltage value of the first power source is 4.3V, and a voltage value of the second power source is 5V.
The LED driving circuit according to claim 2, wherein the first switching circuit and the second switching circuit each comprise a switching controller and a switching transistor, and the switching controller is configured to control conduction of the switching transistor or Turn off to control the switch state of the corresponding LED light group.
The LED driving circuit according to claim 6, wherein the switching transistor is an NMOS transistor.
An LED display device, characterized in that the LED display device comprises the LED drive circuit according to any one of claims 1-7.