LED display screen and double-negative-voltage common-positive-power-supply circuit thereof

Abstract

The utility model provides a kind of LED display screen and its double negative pressure common positive power supply circuit, it is related to LED display screen power supply technical field, the circuit includes drive component, line drive IC, first and second constant current IC, independent negative voltage power module and red green blue lamp tube;Drive component connects line drive IC and two constant current IC input end;Two constant current IC power supply end is connected power module first, second end respectively, and its output end is connected red, green blue lamp tube negative pole respectively;Each lamp tube anode is connected with line drive IC output end;Power module first end output voltage is higher than second end, separate red and green blue voltage.The circuit eliminates redundant voltage drop, inhibits red heat accumulation, improves consistency, reduces power consumption, compatible with existing wiring, suitable for new and old screen modification.

Description

Technical Field

[0001] This utility model relates to the field of LED display power supply technology, specifically to an LED display and its dual negative voltage common anode power supply circuit. Background Technology

[0002] In existing LED display technologies, high brightness and long-term continuous operation have become standard requirements for high-end indoor fixed screens and ultra-high-definition outdoor screens. However, in this scenario, traditional common-anode architectures, in order to balance the luminous efficiency of red, green, and blue LEDs, generally use a uniform forward voltage (typically 4.2 V) for power supply. That is, the anodes of the R, G, and B primary color LEDs are connected in parallel to the same positive terminal of the power supply, and the cathodes are connected to ground through the constant current channel of the driver IC. However, since the forward voltage of red LEDs is only about 2.0 V to 2.2 V, while green and blue LEDs require 2.8 V to 3.2 V and 3.0 V to 3.4 V respectively to emit light normally, the redundant voltage (about 1.2 V to 2.2 V) all drops onto the power switching transistors inside the driver IC and is dissipated as heat. After prolonged operation, the red channel experiences the highest current density and most concentrated heat generation, directly leading to excessively high local temperatures in the driver chip. This results in visible horizontal or vertical color banding, causing display anomalies such as color cast and inconsistent brightness decay, severely weakening the overall visual consistency and color fidelity of the screen. Simultaneously, the sustained high-temperature environment accelerates the light decay of LED chips and packaging materials, shortening the screen's lifespan and increasing customer maintenance costs. Furthermore, a single voltage power supply mode cannot provide precise energy management based on the volt-ampere characteristics of different color chips, resulting in high redundant power consumption across the entire screen, which contradicts the current industry trend towards green, low-carbon, and energy-efficient development.

[0003] To address the aforementioned issues, improved solutions such as a common cathode architecture and independent DC-DC buck modules have emerged on the market, such as the CN117558230A. This solution can, to some extent, resolve display anomalies such as color distortion and inconsistent brightness attenuation. Utility Model Content

[0004] During the implementation of this utility model, the inventors discovered that the aforementioned power supply scheme is prone to display abnormalities such as color distortion and inconsistent brightness decay during prolonged power supply. The inventors further discovered that this is because the common cathode design requires specially made LED chips and driver chips, resulting in high material costs and limited supply chain resources; while the DC-DC external module solution suffers from poor output voltage stability due to input voltage fluctuations, and the conversion chip itself generates significant heat, which also easily leads to display abnormalities.

[0005] This invention provides an LED display screen and its dual negative voltage common anode power supply circuit, which can at least partially improve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A dual negative voltage common anode power supply circuit includes: a driving component, a horizontal driving IC, a first constant current IC, a second constant current IC, an independent negative voltage power supply module, a red lamp, a green lamp, and a blue lamp. The output terminal of the driving component is electrically connected to the input terminals of the horizontal driving IC, the first constant current IC, and the second constant current IC. The power supply terminal of the first constant current IC is electrically connected to the first terminal of the independent negative voltage power supply module, and the power supply terminal of the second constant current IC is electrically connected to the second terminal of the independent negative voltage power supply module. The output terminal of the first constant current IC is electrically connected to the negative terminal of the red lamp, and the output terminal of the second constant current IC is electrically connected to the negative terminals of the green lamp and the blue lamp. The positive terminals of the red lamp, the green lamp, and the blue lamp are all grounded. The negative voltage output from the first terminal of the independent negative voltage power supply module is higher than the negative voltage output from the second terminal of the independent negative voltage power supply module, so as to separate the voltage of the red lamp from that of the green lamp and the blue lamp.

[0007] This utility model also provides an LED display screen, which includes: a display screen body and a plurality of dual negative voltage common anode power supply circuits as described in any one of the claims, wherein the dual negative voltage common anode power supply circuits are configured on the LED display screen.

[0008] In summary, this dual-negative-voltage common-anode power supply circuit for common-anode LED displays introduces a dual-negative-voltage architecture at the power supply end: using 0V as the common anode, two independent negative voltages are directly output from the power supply itself, feeding the red and green / blue chips respectively, ensuring that the driving voltage of each light-emitting channel matches its conduction characteristics. This design eliminates redundant voltage drop at the power source without replacing conventional LEDs or driver chips, suppresses heat buildup in the red channel, reduces chip temperature rise and power consumption, eliminates color banding deviation, and achieves energy-saving effects similar to common-cathode solutions. Simultaneously, it retains existing power wiring and material systems, making it suitable for new screen designs or direct upgrades of existing screens.

[0009] In simple terms, the dual negative voltage common anode power supply circuit uses 0V as the positive input and VCR / VCBG as the negative terminal to form a power supply loop. This achieves voltage separation between the red and blue / green LEDs. Through a negative voltage design circuit, the power signals of the red chip are wired separately from those of the blue and green chips, ensuring voltage stability and accuracy. This technological breakthrough is achieved through differentiated power supply design. The main principle is that the red chip and the green / blue chips are each configured with an independent negative voltage power supply, precisely matching their voltage-current characteristics and reducing heat accumulation at the source. It is expected to reduce color banding abnormalities by more than 30% and extend device lifespan; simultaneously, it can reduce overall energy consumption by 10%-15%, helping customers achieve cost reduction and efficiency improvement. Attached Figure Description

[0010] Figure 1This is a schematic diagram of the dual negative voltage common anode power supply circuit provided in the first embodiment of this utility model.

[0011] Figure 2 This is a schematic diagram showing the transmission directions of the negative voltages -3.2V and -4V in the dual negative voltage common anode power supply circuit provided in the first embodiment of this utility model.

[0012] Figure 3 This is a temperature detection comparison diagram of the dual negative voltage common anode power supply circuit provided in the first embodiment of this utility model. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0014] refer to Figure 1 , Figure 2 As shown, the first embodiment of this utility model discloses a dual negative voltage common anode power supply circuit, which includes: a driving component, a horizontal driving IC, a first constant current IC, a second constant current IC, an independent negative voltage power supply module, a red lamp, a green lamp, and a blue lamp. The output terminal of the driving component is electrically connected to the input terminals of the horizontal driving IC, the first constant current IC, and the second constant current IC. The power supply terminal of the first constant current IC is electrically connected to the first terminal of the independent negative voltage power supply module. The power supply terminal of the second constant current IC is electrically connected to the second terminal of the independent negative voltage power supply module. The output terminal of the first constant current IC is electrically connected to the negative terminal of the red lamp. The output terminal of the second constant current IC is electrically connected to the negative terminals of the green lamp and the blue lamp. The positive terminals of the red lamp, the green lamp, and the blue lamp are all grounded. The negative voltage output from the first terminal of the independent negative voltage power supply module is higher than the negative voltage output from the second terminal of the independent negative voltage power supply module, so as to separate the voltage of the red lamp from that of the green lamp and the blue lamp.

[0015] Preferably, in this embodiment, the driving component includes a control card and a driving IC, wherein the power supply terminal of the control card and the power supply terminal of the driving IC are electrically connected to the second terminal of the independent negative voltage power supply module, the data terminal of the control card is connected to the data terminal of the driving IC, the first terminal of the driving IC is electrically connected to the input terminal of the first constant current IC, and the second terminal of the driving IC is electrically connected to the input terminal of the second constant current IC.

[0016] Preferably, in this embodiment, the driver IC chip model can be DP32020. It is understood that in other embodiments, other models of driver ICs can also be used, which are not specifically limited here, but these solutions are all within the protection scope of this utility model.

[0017] Preferably, in this embodiment, the chip model of the first constant current IC and the second constant current IC can be DP3264. It is understood that in other embodiments, other models of driver ICs and constant current ICs can also be used. No specific limitation is made here, but these solutions are all within the protection scope of this utility model.

[0018] Preferably, in this embodiment, the negative voltage output from the first terminal of the independent negative voltage power supply module is -3.2V.

[0019] Preferably, in this embodiment, the negative voltage output from the second terminal of the independent negative voltage power supply module is -4V.

[0020] Please see Figure 3 Specifically, in this embodiment, the dual negative voltage common anode power supply circuit is described using a conventional 2828 or 3535 three-in-one LED as an example. The circuit board wiring retains the traditional "common anode, independent cathode" routing method. The only change in this circuit occurs at the interface between the power layer and the driver layer. The independent negative voltage power module is directly attached to the back of the module. Its input is taken from the existing 4.2V~5V main bus. Internally, two sets of synchronous Buck circuits first invert the positive voltage to negative voltage, and then regulate it to -3.2V (first terminal, denoted as VCR) and -4V (second terminal, denoted as VCGB), respectively. Since the two negative voltages share a common ground wire, and the ground wire also serves as the common anode for the R, G, and B three-color LEDs, the front of the LED still shows a "0V" pad, making it fully compatible with the old stencil and surface mount technology. The production line does not need to adjust any machine parameters.

[0021] The VCC pin of the first constant current IC is directly connected to the VCR, and its 16 constant current outputs are connected to the cathodes of the red LEDs. The VCC pin of the second constant current IC is connected to the VCGB, and 16 of its 32 outputs are connected to the cathodes of the green LEDs, while the other 16 are connected to the cathodes of the blue LEDs. Because the red LEDs have the lowest turn-on voltage, -3.2V is sufficient to leave a reasonable linear adjustment margin on the constant current transistor; while the green and blue LEDs have higher turn-on voltages, -4V is used to ensure that the voltage drop of the constant current transistor is not less than 0.5V at maximum brightness, thus avoiding current drift caused by entering the saturation region. The driver IC is responsible for horizontal scanning and data latching, and its power supply pin is also connected to the VCGB, so that the horizontal drive signal and the green and blue channels are kept on the same reference plane, reducing common-mode interference. The control card sends the A, B, and C horizontal selection signals and grayscale data to the driver IC via a ribbon cable, and the scanning frequency can still be maintained above 1920 Hz, with no flickering during screen refresh.

[0022] Since all LED anodes are grounded, the modules are still connected using the traditional "VCC (ground) + signal" four-core ribbon cable. When upgrading an old screen, you only need to change the original 4.2V female connector to the input of the independent negative voltage power supply module, and then plug the original GND female connector into the "0V" pad of the module. The upgrade of one cabinet can be completed in ten minutes, without the need to re-lay copper busbars or replace the receiver card. The negative voltage power supply module itself has synchronous rectification with an efficiency of over 90%, and its own heat generation is much lower than that of an external DC-DC solution. Therefore, the temperature on the back of the module is actually lower than before, and the plastic package of the driver IC no longer yellows due to high temperature, extending the service life of the screen under direct sunlight outdoors.

[0023] Through the specific connection method described above, this embodiment, while maintaining conventional LEDs, conventional PCBs, and conventional signal protocols, changes the power supply of the red channel from "4.2V forward series" to "-3.2V negative common anode," and the green and blue channels to "-4V negative common anode." This eliminates redundant voltage drop at the power source, distributing the heat accumulation area across the two constant current ICs, resulting in a more uniform surface temperature distribution. The assembly, aging, and maintenance processes remain completely consistent with the old solution, yet achieve multiple benefits such as reduced energy consumption, suppressed temperature rise, and elimination of color banding. This provides a plug-and-play, extremely low-cost, and highly compatible energy-saving upgrade path.

[0024] In summary, this circuit separates the voltage of the red LED from that of the blue and green LEDs. Through a negative voltage design, the power signals of the red chip are wired separately from those of the blue and green chips. The VCC electrical input of the R / G / B chip is connected to the power supply GND as an input, and the GND input of the chip is connected to the power supply VCR / VCGB respectively. A constant current driver IC and its peripheral circuits are designed to ensure that each output port can be correctly connected to the LED, and a constant current adjustment module and a switching transistor are configured for each port. Based on the conduction characteristics of the red LED, the operating voltage of the red chip is reduced, thereby reducing chip power consumption and heat generation. The dual negative voltage common anode power supply circuit provides independent negative voltage power supplies for the red, green, and blue chips, precisely matching their characteristics, reducing red IC heat generation and color banding abnormalities, extending lifespan, and reducing power consumption; it is also compatible with conventional LED chips, eliminating the need for customization, reducing the types of materials controlled, lowering costs, facilitating promotion, and also compatible with old power supply systems, enhancing practicality.

[0025] Compared with existing technologies, this circuit has the following advantages: 1. Effectively reduces the surface and chip temperature of the product, with a 17% temperature reduction compared to conventional solutions; 2. Compared with conventional solutions, under the same current and brightness conditions, the power consumption per square meter is reduced by 11.5%; 3. Compared with conventional common cathode solutions on the market, the dual negative voltage solution can achieve 80% of the energy-saving effect of the common cathode solution, and is compatible with existing conventional lamp tube and chip solutions, reducing material costs by 80% compared to the common cathode solution; 4. Dual negative voltage eliminates the need for customized lamp tubes and chips, allowing the use of conventional materials to achieve energy-saving and cooling effects, reducing the types of materials controlled; 5. The dual negative voltage solution is compatible with conventional power supply solutions; 6. By outputting two independent modules internally to power the red and green / blue lamp tubes separately, the output stability is higher; the redesigned dual-output voltage results in better display effects.

[0026] The second embodiment of this utility model provides an LED display screen, which includes: a display screen body and a plurality of dual negative voltage common anode power supply circuits as described in any one of the claims, wherein the dual negative voltage common anode power supply circuits are configured on the LED display screen.

[0027] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A dual negative voltage common anode power supply circuit, characterized in that, include: The system includes a driving component, a horizontal driving IC, a first constant current IC, a second constant current IC, an independent negative voltage power supply module, a red lamp, a green lamp, and a blue lamp. The output terminal of the driving component is electrically connected to the input terminals of the horizontal driving IC, the first constant current IC, and the second constant current IC. The power supply terminal of the first constant current IC is electrically connected to the first terminal of the independent negative voltage power supply module, and the power supply terminal of the second constant current IC is electrically connected to the second terminal of the independent negative voltage power supply module. The output terminal of the first constant current IC is electrically connected to the negative terminal of the red lamp, and the output terminal of the second constant current IC is electrically connected to the negative terminals of the green lamp and the blue lamp. The positive terminals of the red lamp, the green lamp, and the blue lamp are all electrically connected to the output terminal of the horizontal driving IC. The negative voltage output from the first terminal of the independent negative voltage power supply module is higher than the negative voltage output from the second terminal of the independent negative voltage power supply module, so as to separate the voltage of the red lamp from that of the green lamp and the blue lamp.

2. The dual negative voltage common positive supply circuit of claim 1, wherein, The driving component includes a control card and a driving IC. The power supply terminals of the control card and the driving IC are electrically connected to the second terminal of the independent negative voltage power supply module. The data terminal of the control card is connected to the data terminal of the driving IC. The first terminal of the driving IC is electrically connected to the input terminal of the first constant current IC, and the second terminal of the driving IC is electrically connected to the input terminal of the second constant current IC.

3. The dual negative voltage common anode power supply circuit according to claim 2, characterized in that, The driver IC has a chip model of DP32020.

4. The dual negative voltage common positive supply circuit of claim 1, wherein, The chip model of the first constant current IC and the second constant current IC is DP3264.

5. The dual negative voltage common positive supply circuit of claim 1, wherein, The negative voltage output from the first terminal of the independent negative voltage power supply module is -3.2V.

6. The dual negative voltage common anode power supply circuit according to claim 1, characterized in that, The negative voltage output from the second terminal of the independent negative voltage power supply module is -4V.

7. An LED display screen, characterized by It includes a display screen body and multiple dual negative voltage common anode power supply circuits as described in any one of claims 1 to 6, wherein the dual negative voltage common anode power supply circuits are configured on the LED display screen.

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