Controller for LED display

Abstract

The present invention discloses a controller for an LED display screen, comprising: a decoder, wherein the decoder has a plurality of input terminals and a plurality of output terminals, wherein the decoder receives control data and outputs a driving control signal; and a plurality of driving controllers, wherein each of the plurality of driving controllers is connected to one of the plurality of output terminals of the decoder, wherein each driving controller comprises a driving circuit and an NMOS switch, wherein the output terminal of the driving circuit is connected to the gate of the NMOS switch, the drain of the NMOS switch is connected to a power supply voltage, the source of the NMOS switch serves as the output terminal of the driving controller, and the driving circuit drives the NMOS switch to be turned on or off based on the driving control signal.

Description

Technical Field

[0001] The invention relates to the field of LED display screens, and in particular to a controller for LED display screens. Background Art

[0002] Light-emitting diodes (LEDs) are widely used in lighting, backlighting, display and other fields. The advantages of using LEDs as pixels to achieve large-screen displays include: high brightness, low operating voltage, low power consumption, large-scale, long life, impact resistance and stable performance, so their applications are becoming more and more widespread.

[0003] Figure 1 A circuit diagram of a control circuit of an LED display screen according to the prior art is shown (CN103854598A). Figure 1 As shown, the LED display screen is composed of an LED matrix arrangement of M rows and N columns. The control circuit of the LED display screen includes an LED display screen driving circuit 30, three driving control circuits, a constant current channel group corresponding to the driving control circuit, and a plurality of P-type metal oxide semiconductor (PMOS) switches. The internal architecture of the three driving control circuits is the same, and under the control of the LED display screen driving circuit 30, the LED array is driven to display. Figure 1 The P-MOS switch shown in the figure is controlled by the row power supply control port to realize row-by-row power supply control of the LED array. The anode of a single row of LEDs is interconnected to the drain of the P-MOS, and the common cathode of a single column of LED primary colors is interconnected to the constant current input terminal of the drive control circuit; the source of the P-MOS is connected to the power supply terminal VCC, and the gate is connected to the control port of the LED display screen drive circuit 30; under the control of the display drive circuit 30, the drain of a certain P-MOS is opened to supply power to the anode of this row of LEDs, and at the same time, the constant current control signal output port controls the logic circuit of the LED drive circuit to control the orderly conduction of the constant current array, so as to realize the orderly conduction of the current of this row of LEDs to GND, and realize the orderly lighting of the LEDs.

[0004] At present, with the further development of small-dot-pitch, high-density LED display technology, the technical complexity of the control circuits used in LED displays continues to increase, resulting in challenges to LED displays in terms of integrated circuit technology, drive control, power supply technology and reliability.

[0005] For example, in Figure 1 In the control circuit, the PMOS device used as the power switch has holes as its carriers, low mobility and high on-resistance. When applied to large-screen LED displays, under the same load current conditions, the large on-resistance of the switch tube PMOS will increase the power consumption of the chip, increase the temperature and reduce the reliability of the chip.

[0006] In view of the problem in the prior art that the control circuit of the LED display screen occupies a large area and consumes a large amount of power, no effective solution has been proposed yet. Summary of the invention

[0007] In view of the problem in the prior art that the control circuit of the LED display screen occupies a large area and consumes a large amount of power, no effective solution has been proposed so far. Therefore, the main purpose of the present invention is to provide a control circuit of an LED display screen to solve the above problem.

[0008] NMOS switches are used as row drive power switches for LED display screens. The carriers of NMOS switches are electrons, while the carriers of PMOS switches are holes. Usually, the electron mobility is 2 to 4 times that of the hole mobility. Therefore, under the same load, the NMOS switch has a stronger conductivity.

[0009] On the other hand, under the same on-resistance parameters, the die area of ​​the NMOS switch is much smaller than that of the PMOS switch, and the yield of the same wafer is improved, thereby saving resources and reducing costs.

[0010] According to one aspect of the present invention, there is provided a controller for an LED display screen, comprising: a decoder having a plurality of input terminals and a plurality of output terminals, the decoder receiving control data and outputting a driving control signal; a plurality of driving controllers, each of the plurality of driving controllers being connected to one of the plurality of output terminals of the decoder, wherein each driving controller comprises a driving circuit and an NMOS switch, the output terminal of the driving circuit being connected to the gate of the NMOS switch, the drain of the NMOS switch being connected to a power supply voltage, the source of the NMOS switch being the output terminal of the driving controller, and the driving circuit driving the NMOS switch to be turned on or off based on the driving control signal.

[0011] The controller also includes a boost converter, which increases the power supply voltage to a converter voltage and provides it to a drive circuit, and the drive circuit drives the NMOS switch to turn on or off based on the drive control signal and using the converter voltage. The boost converter can be a charge pump. The boost converter can also be a switching power supply.

[0012] Furthermore, the output voltage of the boost converter voltage is at least the power supply voltage plus a threshold value V th .

[0013] Furthermore, the output voltage of the boost converter voltage is twice the power supply voltage.

[0014] Furthermore, the output end of each of the driving controllers is connected to one or more rows of the LED display panel.

[0015] Furthermore, the NMOS switch is a plurality of NMOS transistor switches connected in parallel, the gate of each NMOS transistor switch is connected to the output end of the drive circuit, the drain of each NMOS transistor switch is connected to the power supply voltage, and the source of each NMOS transistor switch serves as the output end of the drive controller.

[0016] Furthermore, the drive controller also includes a protection circuit.

[0017] Further, the drive circuit includes: a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor and an inverter, wherein the sources of the first transistor, the second transistor and the third transistor are respectively connected to the converter voltage output by the boost converter, wherein the sources of the fourth transistor, the fifth transistor and the sixth transistor are respectively grounded, wherein the drains of the first transistor and the sixth transistor are respectively connected to the output end of the drive circuit, wherein the gates of the first transistor and the sixth transistor are connected to a node, wherein the drain of the second transistor, the gate of the third transistor and the drain of the fifth transistor are interconnected and connected to the node, wherein the gate of the second transistor, the drain of the third transistor and the drain of the fourth transistor are interconnected, wherein the input end of the drive circuit is connected to the input end of the inverter and the gate of the fourth transistor, the output end of the inverter is connected to the gate of the fifth transistor, wherein the first output end of the drive circuit is connected to the gate of the NMOS switch.

[0018] Furthermore, the first transistor, the second transistor and the third transistor are P-type metal oxide semiconductor transistors; the fourth transistor, the fifth transistor and the sixth transistor are N-type metal oxide semiconductor transistors.

[0019] Further, the decoder is a 3-8 decoder, which receives three binary codes and outputs eight output level signals at eight output terminals to the corresponding drive controller.

[0020] Further, the decoder is a 2-4 decoder, which receives two binary codes and outputs four output level signals at four output terminals to the corresponding drive controller.

[0021] Further, the decoder is a 4-16 decoder, which receives four binary codes and outputs sixteen output level signals at sixteen output terminals to the corresponding drive controller.

[0022] Furthermore, the controller also includes a blanking control circuit and a controllable discharge circuit, wherein the controllable discharge circuit is connected between the source of the NMOS switch and the pull-down power supply, and the blanking control circuit is connected between the gate of the NMOS switch and the controllable discharge circuit.

[0023] Compared with using a PMOS switch as a row drive power switch, the present invention uses an NMOS switch as a row drive power switch of an LED display screen, which has the following advantages: 1) Since the NMOS switch uses electrons as carriers, has high mobility and strong conductivity, the NMOS switch formed on the same semiconductor chip area can reduce the on-resistance of the power switch; 2) Since the die area occupied by an NMOS switch with the same performance is much smaller than the chip area occupied by a PMOS switch, the chip area required for the NMOS switch to achieve the same on-current is small, and the same wafer yield is improved, thereby reducing the cost of the LED drive circuit and facilitating further miniaturization of the control circuit of the LED display screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to further illustrate the above and other advantages and features of various embodiments of the present invention, a more specific description of various embodiments of the present invention will be presented with reference to the accompanying drawings. It will be understood that these drawings only depict typical embodiments of the present invention and are therefore not to be considered as limiting the scope thereof. In the accompanying drawings, for clarity, identical or corresponding parts will be represented by identical or similar reference numerals.

[0025] Figure 1 The invention is a circuit diagram of a control circuit of an LED display screen according to the prior art.

[0026] Figure 2 is a block diagram of a control system 200 for an LED display screen according to an embodiment of the present invention.

[0027] Figure 3 is a block diagram of a row controller 300 for an LED display screen according to an embodiment of the present invention.

[0028] Figure 4 According to the present invention Figure 3 A block diagram of one embodiment 400 of a driver controller in a row controller is shown.

[0029] Figure 5 According to the present invention Figure 3 A block diagram of another embodiment 500 of a driver controller in a row controller is shown.

[0030] Figure 6 A block diagram of a circuit 600 in which a driving controller is connected to a boost converter according to an embodiment of the present invention is shown.

[0031] Figure 7 Show Figure 5 An embodiment of a specific circuit diagram of a driving circuit 501 in a driving controller is shown.

[0032] Figure 8A block diagram of a charge pump 800 according to one embodiment of the present invention is shown.

[0033] Fig. 9 A block diagram of a row control circuit 900 in which a boost converter is combined with a row controller according to an embodiment of the present invention is shown.

[0034] Fig.10 A partial circuit block diagram of a driving controller including a blanking control circuit 1003 and a controllable discharge circuit 1004 according to an embodiment of the present invention is shown.

[0035] Fig.11 The structure block diagram of the controller for LED display screen of the present invention is shown. DETAILED DESCRIPTION

[0036] In the following description, the present invention is described with reference to various embodiments. However, those skilled in the art will recognize that various embodiments may be implemented without one or more specific details or with other replacement and / or additional methods, materials or components. In other cases, well-known structures, materials or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the present invention. Similarly, for the purpose of explanation, specific quantities, materials and configurations are set forth to provide a comprehensive understanding of embodiments of the present invention. However, the present invention may be implemented without specific details. In addition, it should be understood that the various embodiments shown in the drawings are illustrative representations and are not necessarily drawn to scale.

[0037] In this specification, reference to "one embodiment" or "the embodiment" means that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing in various places in this specification does not necessarily all refer to the same embodiment.

[0038] The basic components of LED display screens are LED display panels, control systems, power systems, frames, etc. The LED display screen control system is the core component of the LED graphic display screen. The LED display screen control system receives the image display information from the input port, puts it into the frame memory, and generates the serial display data and scanning control timing required by the LED display screen according to the partition drive mode.

[0039] Figure 2 FIG. 2 is a block diagram of a control system 200 for an LED display screen according to an embodiment of the present invention. Figure 2As shown, the control system 200 includes an image processing device 201, one or more row controllers 202-1 to 202-N (N≥1) and one or more column controllers 203-1 to 203-M (M≥1). The image processing device 201 receives image information through an input port, processes it to form row control data and column control data that match each other, and outputs them to one or more row controllers 202-1 to 202-N and one or more column controllers 203-1 to 203-M respectively. One or more row controllers 202-1 to 202-N and one or more column controllers 203-1 to 203-M respectively decode the row control data and column control data and form row and column drive control signals based on the decoded control data to drive the rows and columns of the LED display panel 204, thereby forming an image on the LED display panel.

[0040] Figure 3 FIG. 3 is a block diagram of a row controller 300 for an LED display screen according to an embodiment of the present invention. Figure 3 As shown, the row controller 300 may include a decoder 301, a drive controller 302-1 to a drive controller 302-L. The decoder 301 receives the row control data and decodes it to output a drive control signal at its output terminal. The drive controller 302-1 to the drive controller 302-L are respectively connected to an output terminal of the decoder 301. The internal circuit structures of the drive controller 302-1 to the drive controller 302-L are basically the same, and their output terminals 305-1 to 305-L are respectively connected to one or more rows of the LED display panel. The drive controller 302-1 to the drive controller 302-L controls whether to supply power to one or more rows of the LED display panel connected to its output terminals 305-1 to 305-L based on the drive control signal received from the decoder.

[0041] In one embodiment of the present invention, the row controller 300 may further include a bias circuit 303. The bias circuit 303 is connected to each of the driving controllers 302-1 to 302-L and provides a required bias current or bias voltage to the driving controllers 302-1 to 302-L.

[0042] In one embodiment of the present invention, decoder 301 can be a 3-8 decoder. In this case, decoder 301 can receive three binary codes and convert them into eight output level signals for output. Eight output level signals are provided to drive controller 302-1 to 302-8 respectively. Under normal working state, based on the value of three input terminals, one of the eight output level signals of 3-8 decoder is a high level. In another embodiment of the present invention, decoder 301 can be a 2-4 decoder or a 4-16 decoder. However, the decoder used in the present invention is not limited to the above-mentioned decoder type, as long as the decoder can be used for controlling the LED display panel, it can be used as the decoder of the present invention.

[0043] In one embodiment of the present invention, the controller 300 may further include a logic unit 304, which serves as an internal signal control terminal of the controller 300 and performs internal logic processing so as to shut down all outputs of the drive controllers 302-1 to 302-N under a specific state.

[0044] Figure 4 It shows that according to the present invention Figure 3 FIG. 4 is a block diagram of an embodiment of a drive controller 400 in a row controller 300. Figure 4 As shown, the driving controller 400 includes a driving circuit 401 and an NMOS switch 402. The output terminal 411 of the driving circuit 401 is connected to the gate of the NMOS switch 402. The source S of the NMOS switch 402 serves as the output terminal 405, and the drain D of the NMOS switch 402 is connected to the power supply voltage VDD. The driving circuit 401 receives a driving control signal from the decoder 301 at a first input terminal 406, and determines whether to provide a driving voltage to the gate of the NMOS switch 402 based on the level of the driving control signal, thereby controlling the conduction or cutoff of the NMOS switch 402. When the NMOS switch 402 is turned on, the power supply VDD supplies power to one or more rows of the LED display panel through the NMOS switch 402. When the NMOS switch 402 is turned off, the power supply VDD cannot supply power to one or more rows of the LED display panel through the NMOS switch 402.

[0045] The driving circuit 401 may have a second input terminal 407 for receiving a driving voltage required to drive the NMOS switch 402 . The driving voltage of the NMOS switch 402 and the second input terminal 407 of the driving circuit 401 will be described in detail below.

[0046] In the embodiment of the present invention, an NMOS switch 402 is used as a row drive power switch of an LED display screen. The carriers of an NMOS switch are electrons, while the carriers of a PMOS switch are holes. Generally, the electron mobility is 2 to 4 times that of the hole mobility. Therefore, under the same load current, the NMOS switch has a stronger conductivity.

[0047] Compared with the driving controller using PMOS switch as the row driving power switch, using NMOS switch as the row driving power switch of LED display screen has the following advantages: 1) Since NMOS switch uses electrons as carriers, has high mobility and strong conductivity, the NMOS switch formed on the same semiconductor chip area can reduce the on-resistance of the power switch; 2) Since the die area occupied by NMOS switch of the same performance is much smaller than the chip area occupied by PMOS switch, the chip area required for NMOS switch to achieve the same on-current is small, and the yield of the same wafer is improved, thereby reducing the cost of LED driving circuit and facilitating the further miniaturization of the control circuit of LED display screen.

[0048] Figure 5 According to the present invention Figure 3 FIG. 5 is a block diagram of another embodiment of a drive controller 500 in a row controller 300. Figure 5 As shown, the driving controller 500 includes a driving circuit 501, one or more NMOS switches 502, and a protection circuit 503. The protection circuit 503 receives a driving control signal output from the decoder 301 at a first input terminal 506 and monitors an output terminal 511 of the driving circuit 501 and an output terminal 505 of the driving controller 500. When the protection circuit 503 detects that the voltage and / or current at the input terminal 506, the output terminal 511, and the output terminal 505 is greater than a specific threshold, the protection circuit 503 performs a protection function. The driving circuit 501 may have a second input terminal 507 for receiving a driving voltage required to drive the NMOS switch 502. The second input terminal 507 of the driving voltage of the driving circuit 501 will be described in detail below.

[0049] In one embodiment of the present invention, one or more NMOS switches 502 may be a plurality of NMOS switches connected in parallel, and the output terminal 511 of the driving circuit 501 is connected to the gate of each of these NMOS switches 502 and provides a gate drive voltage thereto. The source S of each of the NMOS switches 502 is connected to the output terminal 505, and the drain D of each of the NMOS switches 502 is connected to the power supply voltage VDD. Based on the voltage level at the gate of the NMOS switch 502, whether the NMOS switch 502 is turned on is controlled, thereby controlling whether to supply power to one or more rows of the LED display panel. In one embodiment, one or more NMOS switches 502 may be 800 NMOS switches connected in parallel, thereby allowing the current required to drive one or more rows of the LED display panel to flow. In another embodiment, one or more NMOS switches 502 may also be 400, 600 or 1000 NMOS switches connected in parallel. The number of one or more NMOS switches 502 depends on the current required to drive one or more rows of the LED display panel and the characteristics of each NMOS switch transistor. As long as the NMOS switch can allow the current required by one or more rows of the LED display panel to flow, it can be used as the NMOS switch 502 of the present invention without being limited in number.

[0050] like Figure 4 and Figure 5 As shown, for NMOS switch 402 or 502, when the gate voltage V G The source voltage of the NMOS switch is higher than a certain threshold V th When the source voltage of the NMOS switch is the power supply voltage VDD, the gate voltage of the NMOS switch needs to satisfy V G ≥VDD+V th Therefore, in order to drive the NMOS switch to turn on, a sufficiently high gate voltage V is required at the gate of the NMOS switch. G In one embodiment, the gate voltage can be set to: V G =2VDD.

[0051] In an embodiment of the present invention, in order to provide the required gate voltage V G , a boost converter can be provided. The boost converter is used to boost the power supply voltage VDD to a converter voltage VPPI, so that VPPI ≥ VDD + V thIn one embodiment, VPPI=2VDD. The boost converter provides the converter voltage VPPI to the second input terminal 407 or 507 of the driving circuit 401 or 501. The driving circuit 401 or 501 determines whether to provide the converter voltage VPPI to the gate of the NMOS switch based on the level of the driving control signal, thereby controlling the conduction or cutoff of the NMOS switch.

[0052] Figure 6 FIG. 6 shows a circuit block diagram of integrating boost conversion into a drive controller 600 according to an embodiment of the present invention. Figure 6 As shown, the boost converter 601 boosts the power supply voltage to form a converter voltage VPPI, and provides the converter voltage VPPI to the drive circuit 401 or 501. The drive circuit 401 or 501 drives the gate of the NMOS switch using the converter voltage VPPI.

[0053] In an embodiment of the present invention, the boost converter may be integrated with the drive controller on the same die as a part of the row controller, or the boost converter may be integrated into the drive controller as a part of the drive controller. In another embodiment of the present invention, the boost converter is a separately formed integrated circuit chip, separated from the drive controller or the row controller, and provides the converter voltage to the drive circuit in the drive controller through a specific interface. In another embodiment of the present invention, the boost converter may not be included, and the row controller receives the required drive voltage from an external power supply through a specific interface.

[0054] Figure 7 Show Figure 5 FIG. 5 is an embodiment of a specific circuit diagram of a driving circuit 501 in a driving controller. Figure 7As shown, the driving circuit 501 includes a first transistor 701, a second transistor 702 and a third transistor 703 located at the upper part, and a fourth transistor 704, a fifth transistor 705 and a sixth transistor 706 located at the lower part. The driving circuit 501 also includes an inverter 708. The first transistor 701, the second transistor 702 and the third transistor 703 are P-type metal oxide semiconductor transistors. The sources of the first transistor 701, the second transistor 702 and the third transistor 703 are respectively connected to the converter voltage VPPI output by the boost converter. The fourth transistor 704, the fifth transistor 705 and the sixth transistor 706 are N-type metal oxide semiconductor transistors. The sources of the fourth transistor 704, the fifth transistor 705 and the sixth transistor 706 are respectively connected to the ground node GND. The drains of the first transistor 701 and the sixth transistor 706 are respectively connected to the output terminal 511 of the driving circuit 501. The gates of the first transistor 701 and the sixth transistor 706 are connected to the node 707. The node 707 can be used as the second output terminal 512 of the driving circuit 501. The second output terminal 512 provides an inverted signal opposite to the output signal of the output terminal 511. The drain of the second transistor 702, the gate of the third transistor 703 and the drain of the fifth transistor 705 are connected to each other and to the node 707. The gate of the second transistor 702, the drain of the third transistor 703 and the drain of the fourth transistor 704 are connected to each other. The input terminal of the driving circuit 501 is connected to the input terminal of the inverter 708 and the gate of the fourth transistor 704, and the output terminal of the inverter 708 is connected to the gate of the fifth transistor 705.

[0055] The first output terminal 511 of the driving circuit 501 is connected to the gate of the NMOS switch 402 or 502. The driving circuit 501 determines whether to provide the voltage VPPI to the first output terminal 511 based on the level of the input signal, thereby turning the NMOS switch 402 or 502 on or off.

[0056] Now back to Figure 6 In one embodiment of the present invention, the boost converter 601 may be a charge pump. In another embodiment of the present invention, the boost converter 601 may also be a switching power supply. However, the scope of the boost converter of the present invention is not limited to the examples listed herein, and any boost converter that can boost the power supply voltage to the required high driving voltage may be used as the boost converter of the present invention.

[0057] Figure 8 A block diagram of a charge pump 800 according to an embodiment of the present invention is shown. The charge pump 800 includes an oscillator 801, a pump capacitor 802, a logic controller 803, and an output voltage controller 804. The charge pump 800 performs voltage conversion by powering on or off the pump capacitor through a controller.

[0058] Fig. 9 FIG. 8 is a block diagram of a row control circuit 900 in which a boost converter and a row controller are combined according to an embodiment of the present invention. Fig. 9 As shown, first, the power supply voltage is provided to the boost converter 901 through the filter voltage regulator circuit 903, and the boost converter 901 boosts the power supply voltage to the required converter voltage VPPI and provides the converter voltage VPPI to the drive circuit in the row controller 902, and the drive circuit drives the gate of the NMOS switch using the converter voltage VPPI. The circuit 900 also includes an electrostatic protection circuit 904 arranged at the input and output pins of the row control circuit 900, and the row control data output from the image processor is transmitted to the row controller 902 through the electrostatic protection circuit 904, and after being decoded by the row controller 902, the power switch is driven to control the LED display panel.

[0059] In practical applications, each output terminal of the row controller can be connected to one or more rows of the LED display panel. According to the decoder model in the row controller, a specific row controller can control a specific number of rows of the LED display panel. For example, in the case where the decoder is a 3-8 decoder, a row controller may have eight output terminals, each of which controls one or more rows of the LED display panel; in the case where the decoder is a 2-4 decoder, a row controller has four output terminals, each of which controls one or more rows of the LED display panel. According to the actual size of the LED display panel, multiple row controllers can be cascaded through external control to realize the drive control of the LED large-screen display.

[0060] Fig.10 FIG. 1 shows a partial circuit block diagram of a driving controller including a blanking control circuit 1003 and a controllable discharge circuit 1004 according to an embodiment of the present invention. Fig.10As shown, the output end of the driving circuit 1001 is connected to the gate of the NMOS switch 1002. The source S of the NMOS switch 1002 is connected to the output end 1005, and the drain of the NMOS switch 1002 is connected to the power supply voltage VDD. The controllable discharge circuit 1004 is connected between the source S of the NMOS switch 1002 and the pull-down power supply Vdc. The controllable discharge circuit 1004 is used to connect the source S of the NMOS switch 1002 to the pull-down power supply when the NMOS switch 1002 is turned off, so as to discharge the source S of the NMOS switch 1002. The blanking control circuit 1003 is connected between the gate of the NMOS switch 1002 and the controllable discharge circuit 1004. When the control signal of the gate of the NMOS switch 1002 is in the off state, the blanking control circuit 1003 outputs a pull-down pulse to the controllable discharge circuit 1004. When receiving a pull-down pulse, the controllable discharge circuit 1004 connects the source S of the NMOS switch 1002 to the pull-down power supply to discharge the source S of the NMOS switch 1002. When not receiving a pull-down pulse, the controllable discharge circuit 1004 sets the source S of the NMOS switch 1002 to a high impedance state to stop discharging the source S of the NMOS switch 1002.

[0061] Although various embodiments of the present invention are described above, it should be understood that they are presented as examples only and not as limitations. It is obvious to those skilled in the relevant art that various combinations, modifications and changes can be made thereto without departing from the spirit and scope of the present invention. Therefore, the breadth and scope of the present invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should only be defined according to the attached claims and their equivalents.

Claims

1. A controller for an LED display screen, characterized in that: include: A decoder, the decoder having a plurality of input terminals and a plurality of output terminals, the decoder receiving control data and outputting a driving control signal; A plurality of driving controllers, each of the plurality of driving controllers is connected to one of the plurality of output terminals of the decoder, wherein each driving controller comprises a driving circuit and an NMOS switch, the output terminal of the driving circuit is connected to the gate of the NMOS switch, the drain of the NMOS switch is connected to the power supply voltage, the source of the NMOS switch serves as the output terminal of the driving controller, the driving circuit drives the NMOS switch to be turned on or off based on the driving control signal, when the NMOS switch is turned on, the power supply supplies power to one or more rows of the LED display panel through the NMOS switch, when the NMOS switch is turned off, the power supply cannot supply power to one or more rows of the LED display panel through the NMOS switch; as well as a boost converter, wherein the boost converter boosts the power supply voltage to a boost converter voltage and provides the boost converter voltage to a drive circuit, wherein the drive circuit drives the NMOS switch to turn on or off based on the drive control signal and using the boost converter voltage, The driving circuit includes: a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor and an inverter. The sources of the first transistor, the second transistor and the third transistor are respectively connected to the converter voltage output by the boost converter, The sources of the fourth transistor, the fifth transistor and the sixth transistor are grounded respectively. The drains of the first transistor and the sixth transistor are connected to the output terminals of the driving circuit respectively. The gates of the first transistor and the sixth transistor are connected to a node. wherein the drain of the second transistor, the gate of the third transistor and the drain of the fifth transistor are connected to each other and to the node, The gate of the second transistor, the drain of the third transistor and the drain of the fourth transistor are connected to each other. The input end of the driving circuit is connected to the input end of the inverter and the gate of the fourth transistor, and the output end of the inverter is connected to the gate of the fifth transistor. The first output terminal of the driving circuit is connected to the gate of the NMOS switch.

2. The controller for an LED display screen according to claim 1, characterized in that: The boost converter is a charge pump.

3. The controller for an LED display screen according to claim 1, characterized in that: The boost converter is a switching power supply.

4. The controller for an LED display screen according to claim 1, characterized in that: The output voltage of the boost converter is at least the power supply voltage plus a threshold value V th .

5. The controller for an LED display screen according to claim 1, characterized in that: The boost converter output voltage is twice the power supply voltage.

6. The controller for an LED display screen according to any one of claims 1 to 5, characterized in that: The output end of each driving controller is connected to one or more rows of the LED display panel.

7. The controller for an LED display screen according to any one of claims 1 to 5, characterized in that: The NMOS switch is a plurality of NMOS transistor switches connected in parallel, the gate of each NMOS transistor switch is connected to the output end of the drive circuit, the drain of each NMOS transistor switch is connected to the power supply voltage, and the source of each NMOS transistor switch is connected to the output end of the drive controller.

8. The controller for an LED display screen according to any one of claims 1 to 5, characterized in that: The drive controller also includes a protection circuit.

9. The controller for an LED display screen according to claim 1, characterized in that: The first transistor, the second transistor and the third transistor are P-type metal oxide semiconductor transistors; the fourth transistor, the fifth transistor and the sixth transistor are N-type metal oxide semiconductor transistors.

10. The controller for an LED display screen according to claim 1, characterized in that: The decoder is a 3-8 decoder, which receives three binary codes and outputs eight output level signals at eight output terminals to corresponding drive controllers.

11. The controller for an LED display screen according to claim 1, characterized in that: The decoder is a 2-4 decoder, which receives two binary codes and outputs four output level signals at four output terminals to the corresponding drive controllers.

12. The controller for an LED display screen according to claim 1, characterized in that: The decoder is a 4-16 decoder, which receives four binary codes and outputs sixteen output level signals at sixteen output terminals to the corresponding drive controller.

13. The controller for an LED display screen according to any one of claims 1 to 5, characterized in that: It also includes a blanking control circuit and a controllable discharge circuit, wherein the controllable discharge circuit is connected between the source of the NMOS switch and the pull-down power supply, and the blanking control circuit is connected between the gate of the NMOS switch and the controllable discharge circuit.

Images