Energy-saving LED display screen

Abstract

The utility model provides an energy -conserving type LED display screen, including the LED lamp pearl dot matrix of uniform distribution setting screen, control chip and drive chip, the red light LED, green light LED and blue light LED in LED lamp pearl are lit according to the setting time sequence under the control of control chip by drive chip, the drive chip includes the red light LED drive unit, green light LED and blue light LED drive unit, the red light LED drive unit includes the 2.4V 3.0V power of driving red light LED, the green light LED and blue light LED drive unit includes the 3.7V 4.0V power of driving green light LED and blue light LED, the utility model discloses the drive power of red light LED is reduced to 2.4 3V, has reduced the heat due to the incompatibility of power supply and red light LED, has reduced the working temperature of product, has increased its service life.

Description

Technical Field

[0001] This utility model relates to the field of LED display technology, specifically to an energy-saving LED display screen. Background Technology

[0002] Controller-driver separated LED displays are a novel display technology that separates the controller and driver design to improve system flexibility and reliability. This design allows the controller to centrally process image data, while the driver focuses on lighting up and turning off individual pixels, resulting in higher display quality and a longer lifespan. With its unique advantages, controller-driver separated LED displays will play a vital role in the future display field and become a significant force driving industry development.

[0003] like Figure 1 The diagram shows a driver circuit for an LED display with separate control and driver. The two ends of the RGB LEDs are connected to the anode and cathode of the driver power supply, respectively. The control chip generates control signals to control whether the LEDs are connected to the power supply. Figure 1 As shown, the control signal generated by the control chip controls the LED's on / off state through the electronic switch located on the LED power line. In practice, the control signal generated by the control chip generally has three types of control signals: row, column, red, green, and blue. If it is necessary to control the red LED in row K and column J to light up, then row control signals and column control signals are generated to control the intersecting LEDs to light up, controlling the R, G, and B LEDs in the LEDs respectively.

[0004] like Figure 1 As shown, the current power supply for LED beads is 3.8V. Red (R), green (G), and blue (B) LEDs are all connected to the power supply through row and column switches. However, red LEDs only require a driving voltage of 2.6V to light up. If a 3.8V power supply is used, there will be a 1.2V voltage drop on the line, which will cause the resistor to heat up. This will cause the LED screen to heat up and affect the lifespan of the LED screen. Utility Model Content

[0005] This invention addresses the shortcomings of current LED displays where a uniform 3.8V power supply is provided to red, blue, and green LEDs, resulting in low utilization and heat generation that affects the lifespan of the LED display. The invention provides an energy-saving LED display where a 2.8V power supply is provided to the red LEDs to reduce the voltage drop that generates heat.

[0006] The technical solution for achieving the technical objective of this utility model is as follows: an energy-saving LED display screen, comprising an LED lamp bead matrix evenly distributed on the screen, a control chip and a driver chip, wherein the driver chip, under the control of the control chip, illuminates red LEDs, green LEDs and blue LEDs among the LED lamp beads according to a set timing sequence; the driver chip includes a red LED driver unit, a green LED and a blue LED driver unit; the red LED driver unit includes a 2.4V-3.0V power supply for driving the red LEDs; the green LED and blue LED driver units include a 3.7V-4.0V power supply for driving the green LEDs and blue LEDs.

[0007] Furthermore, in the aforementioned energy-saving LED display screen: the red LED driving unit includes two electronic switches controlled by row lighting control signals and column lighting control signals generated by the control chip, respectively. These two electronic switches are connected in series in the power supply circuit of the red LED.

[0008] Furthermore, in the aforementioned energy-saving LED display screen: the electronic switch adopts a MOSFET power transistor.

[0009] Furthermore, in the aforementioned energy-saving LED display screen: the MOSFET power transistor is a type with a junction area ≥ 500μm. 2 Power MOSFETs.

[0010] Furthermore, in the aforementioned energy-saving LED display screen: in the MOSFET power transistor, at a temperature T = 25℃, the red light conduction current I = 20mA, and the conduction voltage drop satisfies:

[0011] 0.1V≤Vd_S≤0.3V.

[0012] Furthermore, in the aforementioned energy-saving LED display screen: the ion implantation dose in the source and drain regions of the MOSFET power transistor is ≥5×10⁻⁶. 15 cm - .

[0013] Furthermore, in the aforementioned energy-saving LED display screen: in the MOSFET power transistor, the contact hole metal stack Ti / Al / TiN has a thickness ratio of 1:8:0.5.

[0014] This invention reduces the driving power supply of the red LED to 2.7-3V, thereby reducing the heat generated by the mismatch between the power supply and the red LED, lowering the operating temperature of the product, and increasing its service life.

[0015] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Appendix Figure 1 This is a schematic diagram of the current LED screen LED chip control and drive circuit.

[0017] Appendix Figure 2 This is a schematic diagram (I) of the energy-saving LED screen lamp bead control and driving circuit of Embodiment 1 of this utility model;

[0018] Appendix Figure 3 This is a simplified diagram of the power management of the LED screen beads in Embodiment 1 of this utility model;

[0019] Appendix Figure 4 This is the schematic diagram (II) of the energy-saving LED screen lamp bead control and driving circuit of Embodiment 1 of this utility model. Detailed Implementation

[0020] This embodiment is an energy-saving LED display screen, including an LED bead matrix evenly distributed on the screen, a control chip, and a driver chip. Under the control of the control chip, the driver chip illuminates red, green, and blue LEDs according to a set timing sequence. The driver chip includes a red LED driver unit, and green and blue LED driver units. The red LED driver unit includes a 2.4V-3.0V power supply for driving the red LEDs; the green and blue LED driver units include a 3.7V-4.0V power supply for driving the green and blue LEDs. Figure 2 , 3 As shown in Figure 4, in this embodiment of the LED display screen, the power supply section is equipped with two voltage power supplies that supply each LED bead on the screen through wires. One power supply is 2.4V-3.0V. In practice, we provide a 2.8V power supply, which is used to drive the red LED. That is to say, a power supply of about 2.8V is provided separately for the red LED. Other circuits are not modified. For example, the power supply for the green LED and the blue LED still uses the original 3.7V-4V. We actually use the original 3.8V power supply. Of course, the other connection methods of the driver chip and the control chip have not changed.

[0021] In fact, traditional LED display drivers have two major energy efficiency bottlenecks:

[0022] The difference in conduction voltage between red, green, and blue LEDs is approximately Vf_R ≈ 1.8-2.0V and Vf_BG ≈ 2.7-3.0V. The driver chip's own conduction voltage drop (Vd ≈ 0.7-1.0V) necessitates a system power supply voltage designed for maximum demand (typically ≥ 4.0V), resulting in a voltage margin loss of 1.5-2.0V in the red channel, leading to an overall energy efficiency of less than 40%. The display module contains red, green, and blue LEDs. The conduction voltage of red LEDs is approximately 1.8-2 volts. The conduction voltage of blue and green LEDs is around 2.7 volts. In this embodiment, the energy-saving principle is achieved by increasing the junction area of ​​the red LED's control chip, which normally has a conduction voltage drop of around 0.7-1 volt. Through chip manufacturing processes, the conduction voltage can be reduced to between 0.1-0.3 volts. The red chip's driver power supply voltage is approximately 2.7-3 volts. The driver chips for blue and green LEDs are powered by voltages between 3.7 volts and 4 volts. This results in very high overall utilization and energy savings of around 60%.

[0023] Mathematical model for energy efficiency optimization:

[0024] The system power consumption optimization rate η can be expressed as:

[0025] η=1-[(VDD_R×I_R)+(VDD_BG×I_BG)] / (VDD_std×I_total);

[0026] Actual measurement data shows that when VDD_R = 2.8V and VDD_BG = 3.8V:

[0027] The voltage drop loss of the red light branch has been reduced to 0.2V (from 1.2V).

[0028] The system energy efficiency is improved to 78-82% (traditional solutions ≤45%).

[0029] In this embodiment, the red LED driving unit includes two electronic switches controlled by row and column lighting control signals generated by a control chip, respectively. These two electronic switches are connected in series in the power supply circuit of the red LED. Figure 2 As shown, the electronic switch is a MOSFET power transistor.

[0030] To further improve system energy efficiency, the manufacturing process of the red LED driving unit was modified in this embodiment: In the red LED driving chip, Cu interconnect technology was used to reduce metal resistance (R_interconnect≤5mΩ), and the temperature compensation circuit was integrated into the driving IC (β=-0.02% / ℃); the voltage conversion module adopted an adaptive red LED driving unit (including junction area ≥500μm). 2 (power MOSFET)

[0031] At room temperature (T = 25℃), when the red LED lighting current I = 20mA, the MOSFET on-state voltage drop in the light driving unit satisfies:

[0032] 0.1V≤Vd_s≤0.3V

[0033] In fact, such as Figure 2 As shown, the MOSFETs in the light driving unit are controlled by either the row control signal (row transistor) or the column control signal (column transistor). The row and column transistors are connected in series in the power supply circuits of the red, blue, and green LEDs. Using MOSFETs with the parameters mentioned above, the maximum voltage drop Vd_s ≤ 0.3V. Even at the maximum, the voltage drop of both the row and column transistors is 0.3V. Taking a red LED as an example, this is 0.3 + 1.8 + 0.3 = 2.4V, meaning our actual operating voltage only needs to reach 2.5V. The semiconductor structure (MOSFET) in the red light driving unit includes:

[0034] Source / drain region ion implantation dose ≥5×10 15 cm -2 The contact hole is a Ti / Al / TiN metal stack with a thickness ratio of 1:8:0.5.

[0035] The energy-saving LED display screen of this embodiment has the following characteristics:

[0036] A pioneering color gamut voltage divider drive architecture solves the voltage mismatch problem of multi-color LEDs;

[0037] A sub-0.3V on-state voltage drop was achieved through carrier mobility optimization techniques;

[0038] An on-chip thermoelectric separation design is adopted to avoid reliability degradation caused by increased junction temperature.

Claims

1. An energy-saving LED display screen, comprising an LED bead matrix evenly distributed on the screen, a control chip and a driver chip, wherein the driver chip, under the control of the control chip, illuminates red LEDs, green LEDs and blue LEDs among the LED beads according to a set timing sequence; characterized in that: The driver chip includes a red LED driver unit, a green LED driver unit, and a blue LED driver unit; the red LED driver unit includes a 2.4V-3.0V power supply for driving the red LED; the green LED and blue LED driver units include a 3.4V-4.0V power supply for driving the green LED and blue LED.

2. The energy-saving LED display screen according to claim 1, characterized in that: The red LED driving unit includes two electronic switches controlled by row lighting control signals and column lighting control signals generated by the control chip, respectively. These two electronic switches are connected in series in the power supply circuit of the red LED.

3. The energy-saving LED display screen according to claim 2, characterized in that: The electronic switch uses a MOSFET power transistor.

4. The energy-saving LED display screen according to claim 3, characterized in that: The MOSFET power transistor has a junction area ≥500μm. 2 Power MOSFETs.

5. The energy-saving LED display screen according to claim 3, characterized in that: In the MOSFET power transistor, at a temperature T = 25℃, the red light conduction current I = 20mA, and the conduction voltage drop satisfies: 0.1V≤Vd_S≤0.3V.

6. The energy-saving LED display screen according to claim 4, characterized in that: The red LED driving unit includes a 2.5V power supply for driving the red LED.

7. The energy-saving LED display screen according to claim 3, characterized in that: In the MOSFET power transistor, the ion implantation dose in the source and drain regions is ≥5×10⁻⁶. 15 cm - .

8. The energy-saving LED display screen according to claim 3, characterized in that: In the MOSFET power transistor, the contact hole metal stacks are Ti / Al / TiN, and their thickness ratio is 1:8:0.5.

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