CN218214612U

CN218214612U - Display screen power supply circuit and display screen

Info

Publication number: CN218214612U
Application number: CN202222487914.8U
Authority: CN
Inventors: 申远航; 何嘉俊
Original assignee: Qstech Co Ltd
Current assignee: Qstech Co Ltd
Priority date: 2022-09-20
Filing date: 2022-09-20
Publication date: 2023-01-03
Anticipated expiration: 2032-09-20

Abstract

The application provides a display screen power supply circuit and display screen, this power supply circuit is applied to full-color LED display screen, including power module, step-down transform module and constant current drive module, wherein, power module connects red LED's positive pole through step-down transform module, red LED's negative pole passes through constant current drive module and connects power module, power module connects green LED and blue LED's positive pole respectively, green LED and blue LED's negative pole connect power module through constant current drive module respectively, the realization is to red LED, green LED and blue LED's power supply, need not to set up two powers at the source end, two sets of power supply routes are provided, it is great to the present consumption that the power supply exists of static full-color LED display screen to solve, the problem of more wiring etc.

Description

Display screen power supply circuit and display screen

Technical Field

The application relates to the technical field of display screens, in particular to a display screen power supply circuit and a display screen.

Background

With the continuous development of light-emitting diode (LED) display technology, LED display screens gradually replace traditional paper posters to become common commercial propaganda tools, and the switching of dynamic pictures brings new visual experience to people.

In the related art, full-color LED display technology in LED display screens tends to mature, and has been applied to many scenes. The full-color LED display screen is formed by packaging red, green and blue LEDs, the conduction voltage drop of the red LEDs is lower than that of blue and green LEDs due to the design reason of the inner wafer of the three LEDs, and therefore the related art applies a shunt power supply technology to supply power to the full-color LED display screen, namely two power supplies are arranged at the source end, and two power supply paths are provided.

However, for a static full-color LED display screen, especially a high-power static full-color LED display screen, if the above shunt power supply technology is adopted, many problems may occur, such as large power consumption, many wiring lines, and the like.

SUMMERY OF THE UTILITY MODEL

The application provides a display screen power supply circuit and display screen to solve the problem that the consumption that the power supply of static full-color LED display screen exists is great, the wiring is more etc.

In a first aspect, an embodiment of the present application provides a power supply circuit for a display screen, where the display screen includes a red LED, a green LED, and a blue LED, and the power supply circuit includes a power module, a first buck conversion module, and a constant current driving module;

the power module is connected with the anode of the red LED through the first voltage-reducing conversion module, the cathode of the red LED is connected with the power module through the constant current driving module, the power module is respectively connected with the anodes of the green LED and the blue LED, and the cathodes of the green LED and the blue LED are respectively connected with the power module through the constant current driving module.

In the embodiment of the application, the power module provides rated voltages of the green LED and the blue LED, and the first buck conversion module performs buck regulation on the voltage provided by the power module, so that the voltage subjected to buck regulation is the rated voltage of the red LED. Therefore, compared with the prior art, the power supply module outputs relatively high power supply voltage, has lower power supply current under the same power, and reduces line loss heating. In addition, two paths of power supplies do not need to be arranged at the source end, two sets of power supply paths are provided, wiring is less, and the power supply device is suitable for application.

In a possible implementation manner, the power module includes a power supply.

The embodiment of the application designs the power supply mode of being more suitable for the branch circuit of LED drive with power supply all the way, carry out step-down regulation through first step-down transform module to the voltage that power module exported, voltage transmission after will stepping down the regulation is to red LED, normally supply power for red LED, and directly transmit the voltage that above-mentioned power module exported to green LED and blue LED, normally supply power for green LED and blue LED, give red LED through two way power for prior art, the technique of green LED and blue LED power supply, half power supply device and wire rod have been reduced, the line is simple, the cost is saved, the complete machine system has been simplified.

In one possible implementation manner, the power supply circuit further includes a second buck conversion module;

and the power supply module is respectively connected with the anodes of the green LED and the blue LED through the second voltage-reducing conversion module.

Here, the second buck conversion module performs buck regulation on the voltage provided by the power supply module, so that the buck regulated voltage is rated voltage of the green LED and the blue LED. Compared with the first step-down conversion module, the power supply circuit has the advantages that the power supply voltage output by the power supply module is higher, the lower power supply current is provided under the same power, and the line loss heating is further reduced.

In a possible implementation manner, the power supply circuit further includes a third buck conversion module and a fourth buck conversion module;

the power module is connected with the anode of the green LED through the third buck conversion module, the cathode of the green LED is connected with the power module through the constant current driving module, the power module is connected with the anode of the blue LED through the fourth buck conversion module, and the cathode of the blue LED is connected with the power module through the constant current driving module.

This application embodiment adopts two step-down transform modules, third step-down transform module and fourth step-down vary voltage module carry out step-down regulation to the voltage that power module provided respectively promptly, make the voltage after the third step-down transform module step-down regulation be green LED rated voltage, the voltage after the fourth step-down transform module step-down regulation is blue LED rated voltage, for adopting a step-down transform module to carry out the step-down regulation to the voltage that power module provided for the condition of green LED and blue LED power supply, it is more nimble, step-down regulation result is more accurate.

In one possible implementation, the first buck conversion module includes a pulse waveform modulation generator, a logic controller, a first driving unit, and a filter;

the power module is connected with the input end of the first driving unit, the output end of the first driving unit is connected with the input end of the filter, the output end of the filter is respectively connected with the input end of the pulse waveform modulation generator and the anode of the red LED, the output end of the pulse waveform modulation generator is connected with the input end of the logic controller, and the output end of the logic controller is connected with the input end of the first driving unit.

In one possible implementation, the Pulse-shape modulation generator is a Pulse Width Modulation (PWM) generator.

In one possible implementation, the Pulse waveform modulation generator is a Pulse Frequency Modulation (PFM) generator.

In one possible implementation, the Pulse waveform Modulation generator is a Pulse Skip Modulation (PSM) generator.

In the embodiment of the present application, the pulse waveform modulation generator may be a PWM generator, a PFM generator, or a PSM generator, and may be determined specifically according to actual situations, so as to meet application requirements in various application scenarios.

In one possible implementation, the PWM generator is a constant PWM generator.

Here, the constant PWM generator outputs a better voltage ripple and has an excellent dynamic response performance under a pulsed load, which is several times higher than the conventional design. And the constant PWM generator can freely select the number of loaded LEDs according to different designs to design the optimal power supply ripple, solve the problem of severe power supply ripple existing in the existing power supply of the static full-color LED display screen, and reduce ineffective power consumption.

In a possible implementation manner, the power module is connected to an input end of the first driving unit, an output end of the first driving unit is connected to an input end of the pulse waveform modulation generator and an input end of the filter, an output end of the filter is connected to an input end of the pulse waveform modulation generator and an anode of the red LED, an output end of the pulse waveform modulation generator is connected to an input end of the logic controller, and an output end of the logic controller is connected to an input end of the first driving unit.

In a possible implementation manner, the constant current driving module is electrically connected to the power supply module, the voltage provided by the power supply module is greater than the rated voltage of the blue LED, and the voltage provided by the power supply module is greater than the minimum rated voltage of the constant current driving module.

The high voltage output by the power supply module supplies power to the constant current driving module, so that the constant current driving module has low minimum saturation voltage drop, and the ineffective power consumption of a constant current path is reduced.

In one possible implementation, the power module provides 4 to 5.5 volts.

In a possible implementation manner, the power supply module is connected to the constant current driving module through the second buck converter module, and the voltage provided by the power supply module is greater than the rated voltage of the blue LED.

In the embodiment of the application, the power module supplies power to the constant current driving module through the second voltage-reduction conversion module, so that the power module has higher voltage output, lower power supply current under the same power, and line loss heating is further reduced.

In a possible implementation manner, the constant current driving module includes a second driving unit, a third driving unit, and a fourth driving unit;

the cathode of the red LED is connected with the power supply module through the second driving unit, the cathode of the green LED is connected with the power supply module through the third driving unit, and the cathode of the blue LED is connected with the power supply module through the fourth driving unit.

In one possible implementation, the power module is a dc power module.

In one possible implementation, the power module is an ac power module;

the power supply circuit further comprises an Alternating Current-Direct Current (AC-DC) power module, the AC power module is connected with the AC-DC power module, the AC-DC power module is connected with the anode of the red LED through the first buck conversion module, and the AC-DC power module is respectively connected with the anodes of the green LED and the blue LED.

In a second aspect, an embodiment of the present application provides a display screen, which includes a control circuit, a red LED, a green LED, and a blue LED, and a display screen power supply circuit as described in the first aspect.

The embodiment of the application provides a display screen power supply circuit and display screen, this power supply circuit is applied to static full-color LED display screen, including power module, step-down transform module and constant current drive module, wherein, power module connects red LED's positive pole through step-down transform module, red LED's negative pole passes through constant current drive module and connects power module, power module connects green LED and blue LED's positive pole respectively, green LED and blue LED's negative pole passes through constant current drive module respectively and connects power module, the realization is to red LED, green LED and blue LED's power supply, need not to set up two way powers at the source end, two sets of power supply paths are provided, it is great to the present consumption that exists of static full-color LED display screen power supply to solve, the problem of wiring etc.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the description below are only some embodiments of the present application, and for those skilled in the art, other drawings may be obtained according to these drawings without inventive labor.

Fig. 1 is a schematic diagram of a turn-on voltage drop of a rgb LED according to an embodiment of the present disclosure;

fig. 2 is a schematic diagram of a shunt power supply based on a switching power supply according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a display screen power supply circuit according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a buck conversion module according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of another buck conversion module according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of another display screen power supply circuit provided in an embodiment of the present application;

fig. 7 is a schematic structural diagram of a power supply circuit for a display screen according to an embodiment of the present disclosure;

fig. 8a is a schematic diagram of a minimum saturation voltage drop curve of the constant current driving module in 5V power supply according to the embodiment of the present application;

fig. 8b is a schematic diagram of a minimum saturation voltage drop curve of the constant current driving module in the case of supplying power at 3.3V according to the embodiment of the present application;

fig. 9 is a schematic structural diagram of another power supply circuit for a display screen according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of another display screen power supply circuit according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

It should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the description above, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent.

Nowadays, various full-color LED display technologies tend to mature, and due to the design of the internal wafer of the red, green and blue LEDs, the conduction voltage drop of the red LED is lower than that of the blue and green LED, as shown in fig. 1 (in the figure, R represents the red LED, G represents the green LED, and B represents the blue LED). Therefore, a shunt power supply technology is currently applied to supply power to a full-color LED display screen, that is, two power supplies are provided at a source end, and two power supply paths are provided, for example, as shown in fig. 2, two power supply modes of a common anode and a common cathode are achieved by connecting VCC or GND to each other. Fig. 2 illustrates a first power supply and a second power supply, a row driver Integrated Circuit (IC) and three column driver ICs.

However, a static full-color LED display screen, especially a high-power static full-color LED display screen, needs higher brightness, so a static control display mode (i.e. the whole screen is fully bright in a unit time) is usually adopted, and the power consumption is much higher than that of indoor display. This problem is more problematic if the shunt power supply technique described above is used: high wiring loss (low voltage and high current), complicated wiring (two-way power supply), and the like.

Therefore, the embodiment of the application provides a display screen power supply circuit, through power module, step-down transform module and constant current drive module, realize the power supply to red LED, green LED and blue LED, wherein, power module connects red LED's positive pole through step-down transform module, red LED's negative pole passes through constant current drive module and connects power module, power module connects green LED and blue LED's positive pole respectively, green LED and blue LED's negative pole passes through constant current drive module respectively and connects power module, it is great to current consumption that supplies power to static full-color LED display screen, the problem of the more scheduling of wiring.

The technical solutions of the present application are described below with several embodiments as examples, and the same or similar concepts or processes may not be described in detail in some embodiments.

Fig. 3 is a schematic structural diagram of a power supply circuit of a display screen according to an embodiment of the present disclosure, where the display screen includes a red LED, a green LED, and a blue LED. The power supply circuit comprises a power supply module 301, a first step-down conversion module 302 and a constant current driving module 303.

Here, the power module 301 is connected to the anode of the red LED through the first step-down conversion module 302, the cathode of the red LED is connected to the power module 301 through the constant current driving module 303, the power module 301 is connected to the anodes of the green LED and the blue LED, respectively, the cathodes of the green LED and the blue LED are connected to the power module 301 through the constant current driving module 303, respectively, and the circuits are common to negative, thereby implementing a power supply scheme for driving the LED display panel with higher voltage output (lower current).

In a specific implementation process, the power module 301 outputs a voltage to the first buck converter module 302, and the first buck converter module 302 performs buck regulation on the voltage output by the power module 301, so that the voltage after the buck regulation is a rated voltage of the red LED. In addition, the power supply module 301 outputs a voltage directly to the green and blue LEDs, providing green and blue LED voltage ratings. The red LED, the green LED and the blue LED are respectively connected with the power supply module 301 through the constant current driving module, wherein the constant current driving module 301 enables current flowing into the LED lamp to have a constant current characteristic, so that the currents of the red LED, the green LED and the blue LED are controlled to be constant, stable luminous intensity of the red LED, the green LED and the blue LED can be ensured to be obtained in the using process, the current of the LED which cannot be constantly controlled is reduced, and the light attenuation condition caused by temperature rise of the LED which cannot be constantly controlled is difficult to control.

Compared with the prior art, the power supply module outputs relatively high power supply voltage, has lower power supply current under the same power, and reduces line loss heating. In addition, two paths of power supplies do not need to be arranged at the source end, two sets of power supply paths are provided, wiring is less, and the power supply device is suitable for application.

In one possible implementation, the power module 301 includes a single power supply.

As shown in fig. 4, the first buck conversion module 302 may include a pulse waveform modulation generator 3021, a logic controller 3022, a first driving unit 3023, and a filter 3024.

The power supply module 301 is connected to an input terminal of the first driving unit 3023, an output terminal of the first driving unit 3023 is connected to an input terminal of the filter 3024, output terminals of the filter 3024 are respectively connected to an input terminal of the pulse-waveform modulation generator 3021 and an anode of the red LED, an output terminal of the pulse-waveform modulation generator 3021 is connected to an input terminal of the logic controller 3022, and an output terminal of the logic controller 3022 is connected to an input terminal of the first driving unit 3023.

Here, the present embodiment performs voltage feedback at the output terminal of the filter 3024, and the pulse waveform modulation generator 3021 constantly adjusts the generated pulse waveform according to the voltage output from the filter and outputs it to the logic controller 3022. The logic controller 3022 generates a corresponding duty ratio to output to the first driving unit 3023. The first driving unit 3023 down-regulates the input voltage based on the duty ratio output from the logic controller 3022 and outputs the down-regulated voltage to the filter 3024, and the filter 3024 filters the input voltage and outputs a stable voltage to the red LED to provide a red LED rated voltage.

In order to increase the dynamic response speed of the buck regulation, as shown in fig. 5, the first buck converter module 302 performs current feedback in addition to the voltage feedback. It should be noted that voltage feedback can be used for voltage reduction regulation, and the addition of current feedback is a further optimization scheme.

The power supply module 301 is connected to an input terminal of the first driving unit 3023, output terminals of the first driving unit 3023 are respectively connected to an input terminal of the pulse waveform modulation generator 3021 and an input terminal of the filter 3024, output terminals of the filter 3024 are respectively connected to an input terminal of the pulse waveform modulation generator 3021 and an anode of the red LED, an output terminal of the pulse waveform modulation generator 3021 is connected to an input terminal of the logic controller 3022, and an output terminal of the logic controller 3022 is connected to an input terminal of the first driving unit 3023.

Here, the present embodiment performs voltage feedback, that is, feedback of a voltage to the pulse-waveform modulation generator 3021 at the output terminal of the filter 3024, and further performs current feedback, that is, feedback of a load current in a feedback circuit to the pulse-waveform modulation generator 3021 at the output terminal of the first driving unit 3023. The pulse waveform modulation generator 3021 superimposes the voltage information and the load current information fed back as described above, generates a corresponding pulse waveform, and outputs the pulse waveform to the logic controller 3022. The logic controller 3022 generates a corresponding duty ratio to output to the first driving unit 3023. The first driving unit 3023 performs voltage reduction adjustment on the voltage output by the power module 301 based on the duty ratio output by the logic controller 3022, and outputs the voltage after voltage reduction adjustment to the filter 3024, and the filter 3024 performs filtering processing on the input voltage, and outputs a stable voltage to the red LED, thereby ensuring that the red LED normally operates.

The red, green and blue LEDs are continuously flickered, the load is changed constantly, the voltage on the red, green and blue LEDs is jittered, the current feedback reflects the change of the load current, and if the current feedback is added on the basis of the voltage feedback, the phenomenon can be relieved.

Optionally, the pulse waveform modulation generator 3021 may be a PWM generator, a PFM generator, or a PSM generator, and may be determined according to actual situations, so as to meet application requirements in various application scenarios.

In the prior art, two power supplies are arranged at a source end as shown in fig. 2, and two power supply paths are provided, so that when a static full-color LED display screen is powered, severe power supply ripples exist in addition to the problems of high wiring loss (low voltage and large current) and mixed and disorderly wiring (two power supplies). The severe power supply ripple is caused by that the output voltages of the two power supplies shown in fig. 2 fluctuate greatly, and the two power supplies are connected with long wires, so that a large resistor is formed on a current transmission path, and the resistor and the output voltages of the two power supplies fluctuate, and finally the severe power supply ripple is caused. (when the ripple is great, except the filter circuit that needs bigger specification, still need to improve the supply voltage of lamp pearl for energy-conserving effect is discounted greatly). Moreover, the conventional LED display screen is driven by a constant current, and the on-state current of the circuit does not change with the difference of devices only when the whole LED driving circuit needs to make the LED driving module (such as the driving IC) work stably in the constant current region. However, in order to stably operate the LED driving IC in the constant current region, at least the minimum saturation voltage drop thereof needs to be reached, and considering the influence of the power supply ripple, the minimum value of the voltage swing is generally used as a basis for determining whether to operate in the constant current region, that is, the difference between the minimum value Vmin of the ripple and the LED on voltage drop Vf is greater than or equal to the minimum saturation voltage drop Vds. If the ripple is large, the higher the source terminal voltage needs to be set, and the more useless power consumption is wasted.

In order to solve the above problem, in the embodiment of the present application, the pulse-waveform modulation generator 3021 may be configured as a constant PWM generator, a constant PFM generator, or a constant PSM generator, and the output voltage ripple is better and has excellent dynamic response performance under a pulse load, which is improved by several times compared with the conventional design. And the constant PWM generator, the constant PFM generator or the constant PSM generator can freely select the number of loaded LEDs according to different designs so as to design the optimal power supply ripple, solve the problem of severe power supply ripple existing in the existing power supply of the static full-color LED display screen, and reduce the invalid power consumption. In addition, the constant current driving module is supplied by the higher voltage directly output by the power module, and the reflected conduction voltage drop is reduced compared with the conduction voltage drop when the constant current driving module is supplied by the lower voltage, so that the invalid power consumption is further reduced. Among them, since the constant PWM generator is low in cost, easy to implement, and high in conversion efficiency when the load is heavy (the LED display generally has a heavy load), the pulse waveform modulation generator 3021 may be preferably provided as the constant PWM generator. The PFM and the PSM have high power saving efficiency under light load.

In a possible implementation manner, as shown in fig. 6, taking the power supply circuit shown in fig. 3 as an example that the power supply circuit includes a power module 301, a first step-down conversion module 302, and a constant current driving module 303, the constant current driving module 303 may include a second driving unit, a third driving unit, and a fourth driving unit.

Here, compared with fig. 3, the different driving units corresponding to the LEDs with different colors in fig. 6 can better drive the LEDs with different colors, and are suitable for practical application.

In addition, since the second driving means may be the first column driver IC, the third driving means may be the second column driver IC, and the fourth driving means may be the third column driver IC, LEDs of different colors are preferably driven by different column driver ICs corresponding to LEDs of different colors in fig. 6, as compared to fig. 3.

Alternatively, the power module 301 may be a dc power module or an ac power module. When the power module 301 is a DC power module, the DC power module may be directly connected to the anode of the red LED through a first step-down converter module to supply power to the red LED, and the first step-down converter module may be a DC-DC (DC-DC) converter module; when the power module 301 is an AC power module, the power supply circuit may further include an AC-DC power module, the AC power module is connected to the AC-DC power module, and the AC-DC power module is connected to the anode of the red LED through the first step-down conversion module, so as to supply power to the red LED, and meet different application requirements in different application scenarios. In a general scenario, communication is used; in the experimental scenario, direct current was used. For the green LED and the blue LED, when the power module 301 is a DC power module, the DC power module may be directly connected to anodes of the green LED and the blue LED to implement power supply to the green LED and the blue LED, and when the power module 301 is an AC power module, the power supply circuit may further include an AC-DC power module, the AC power module is connected to the AC-DC power module, and the AC-DC power module is connected to anodes of the green LED and the blue LED to implement power supply to the green LED and the blue LED.

In the embodiment of the present application, in order to further reduce the problem of large power consumption in supplying power to the static LED display screen, as shown in fig. 7, the power supply circuit may further include a second step-down converting module 304 in addition to the power supply module 301, the first step-down converting module 302, and the constant current driving module 303.

The power module 301 is connected to the anode of the red LED through a first buck converter module 302, the cathode of the red LED is connected to the power module 301 through a constant current driver module 303, the power module 301 is connected to the anodes of the green LED and the blue LED through a second buck converter module 304, and the cathodes of the green LED and the blue LED are connected to the power module 301 through the constant current driver module 303.

As shown in fig. 7, the constant current driving module 303 is electrically connected to the power supply module 301, the voltage provided by the power supply module 301 is greater than the rated voltage of the blue LED, and the power supply module 301 is greater than the minimum rated voltage of the constant current driving module 303, so as to ensure that the constant current driving module 303 can normally operate.

In an alternative embodiment, the power module may provide 4 to 5.5 volts. Since 4V is the rated voltage of the blue LED and 5.5V is the maximum rated voltage of the constant current driving module, the power supply module can provide 4V to 5.5V.

The first buck conversion module 302 performs buck regulation on the voltage provided by the power module 301, so that the voltage subjected to buck regulation is the rated voltage of the red LED, and the second buck conversion module 304 performs buck regulation on the voltage provided by the power module 301, so that the voltage subjected to buck regulation is the rated voltage of the green LED and the blue LED.

In the embodiment of the application, compared with the case that only the first buck conversion module is provided, the power supply module outputs a higher power supply voltage, and has a lower power supply current under the same power, so that the line loss heat generation is further reduced.

The second buck conversion module 304 may include a pulse waveform modulation generator, a logic controller, a fifth driving unit, and a filter, similar to the first buck conversion module 302.

The power module 301 is connected to an input terminal of the fifth driving unit, an output terminal of the fifth driving unit is connected to an input terminal of the filter, output terminals of the filter are respectively connected to an input terminal of the pulse waveform modulation generator and anodes of the blue LED and the green LED, an output terminal of the pulse waveform modulation generator is connected to an input terminal of the logic controller, and an output terminal of the logic controller 3022 is connected to an input terminal of the fifth driving unit.

Optionally, the power module 301 may further be connected to an input end of a fifth driving unit, an output end of the fifth driving unit is respectively connected to an input end of the pulse waveform modulation generator and an input end of the filter, an output end of the filter is respectively connected to an input end of the pulse waveform modulation generator and anodes of the blue LED and the green LED, an output end of the pulse waveform modulation generator is connected to an input end of the logic controller, and an output end of the logic controller is connected to an input end of the fifth driving unit.

In an alternative embodiment, the pulse waveform modulation generator may be a PWM generator, a PFM generator, or a PSM generator. The PWM generator can be a constant PWM generator, the PFM generator can be a constant PFM generator, and the PSM generator can be a constant PSM generator, so that the number of loaded LEDs can be freely selected according to different designs to design optimal power supply ripples, the problem of severe power supply ripples existing in the existing power supply of a static full-color LED display screen is solved, and invalid power consumption is reduced. In addition, the constant current driving module is supplied by the higher voltage directly output by the power supply module, and the reflected conduction voltage drop is reduced compared with the conduction voltage drop when the power supply is supplied by the low voltage, so that the invalid power consumption is further reduced. As shown in fig. 8a and 8b, the minimum saturation voltage drop curve of the constant current driving module when supplying 5V and 3.3V power obviously requires lower voltage for constant current when supplying 5V power, and the ineffective power consumption of the constant current path is also lower. In the figure, the abscissa represents voltage, and the ordinate represents current. Therefore, the power module of the embodiment provides a voltage of 4 to 5.5 volts, and the voltage is adopted to supply power, so that the voltage required by the constant current is lower, and the invalid power consumption of the constant current path is also lower.

In a possible implementation manner, the constant current driving module may include a second driving unit, a third driving unit, and a fourth driving unit.

Optionally, the power module may be a dc power module or an ac power module. When the power supply module is a direct current power supply module, the direct current power supply module can be connected with the anode of the red LED through the first voltage-reducing conversion module to supply power to the red LED; the direct current power supply module is connected with the anodes of the green LED and the blue LED through the second voltage reduction conversion module, so that power supply for the green LED and the blue LED is realized. When the power module is an alternating current power module, the power supply circuit can further comprise an AC-DC power module, the alternating current power module is connected with the AC-DC power module, the AC-DC power module is connected with the anode of the red LED through the first step-down conversion module to realize power supply to the red LED, and the AC-DC power module is respectively connected with the anodes of the green LED and the blue LED through the second step-down conversion module to realize power supply to the green LED and the blue LED.

In this embodiment, as shown in fig. 9, on the basis that the power supply circuit further includes a second step-down conversion module 304, a power supply module 301 may be connected to a constant current driving module 303 through the second step-down conversion module 304, and the constant current driving module 303 makes a current flowing into the LED lamp have a constant current characteristic, so as to control currents of the red LED, the green LED, and the blue LED to be constant, where a voltage provided by the power supply module 301 is greater than a rated voltage of the blue LED.

In this embodiment of the application, the power module in fig. 9 outputs the voltage to the second voltage-drop conversion module, and the voltage output by the power module is subjected to voltage-drop adjustment by the second voltage-drop conversion module and then is supplied to the constant current driving module, where compared with fig. 7 in which the source-end power supply is directly used to supply power to the constant current driving module, the power module in fig. 9 has higher voltage output, has lower supply current at the same power, and further reduces line loss heating.

In addition, in order to better perform voltage reduction adjustment on the voltage provided by the power supply module to supply power to the green LED and the blue LED, as shown in fig. 10, the power supply circuit may further include a third voltage-reduction conversion module 305 and a fourth voltage-reduction conversion module 306 in addition to the power supply module 301, the first voltage-reduction conversion module 302 and the constant current driving module 303.

The power module 301 is connected to the anode of the red LED through the first buck converter module 302, and the cathode of the red LED is connected to the power module 301 through the constant current driver module 303. The power module 301 is connected to the anode of the green LED through the third buck conversion module 305, the cathode of the green LED is connected to the power module 301 through the constant current driving module 303, the power module 301 is connected to the anode of the blue LED through the fourth buck conversion module 306, and the cathode of the blue LED is connected to the power module 301 through the constant current driving module 303.

In this embodiment, the parts of the first buck conversion module and the red LED are not described any more, two buck conversion modules are adopted, that is, the voltages provided by the power module 301 are respectively regulated by the third buck conversion module 305 and the fourth buck transformation module 306, so that the voltage regulated by the third buck conversion module 305 is the rated voltage of the green LED, the voltage regulated by the fourth buck conversion module 306 is the rated voltage of the blue LED, and for the voltage regulated by the one buck conversion module to the power module, the voltage regulated by the one buck conversion module is the power supplied to the green LED and the blue LED, which is more flexible and the buck regulation result is more accurate.

The specific components of the third buck conversion module 305 and the fourth buck conversion module 306 refer to the descriptions of the first buck conversion module 302 and the second buck conversion module 304, and are not described herein again.

Alternatively, as shown in fig. 10, the constant current driving module 303 and the power supply module 301 are electrically connected, the voltage supplied by the power supply module 301 is greater than the rated voltage of the blue LED, and the voltage supplied by the power supply module 301 is greater than the minimum rated voltage of the constant current driving module 303.

Optionally, in another embodiment, the power module 301 may be connected to the constant current driving module 303 through the third step-down converting module 305 or the fourth step-down transforming module 306, and the voltage provided by the power module 301 is greater than the rated voltage of the blue LED.

The embodiment of the application further provides a display screen, which comprises a display screen power supply circuit, a control circuit, a red LED, a green LED and a blue LED.

The display screen power supply circuit in this embodiment has the same structure as the display screen power supply circuit provided in any of the embodiments described above, and can bring about the same or similar technical effects, and details are not repeated here, and reference may be specifically made to the description of the embodiments described above.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A power supply circuit for a display screen is characterized in that the display screen comprises a red light-emitting diode, a green light-emitting diode and a blue light-emitting diode, and the power supply circuit comprises a power supply module, a first voltage reduction conversion module and a constant current driving module;

the power module is connected with the anode of the red light-emitting diode through the first step-down conversion module, the cathode of the red light-emitting diode is connected with the power module through the constant current driving module, the power module is respectively connected with the anodes of the green light-emitting diode and the blue light-emitting diode, and the cathodes of the green light-emitting diode and the blue light-emitting diode are respectively connected with the power module through the constant current driving module.

2. The circuit of claim 1, wherein the power supply circuit further comprises a second buck converter module;

the power supply module is respectively connected with the anodes of the green light-emitting diode and the blue light-emitting diode through the second voltage-reducing conversion module.

3. The circuit of claim 1, wherein the power supply circuit further comprises a third buck converter module and a fourth buck converter module;

the power module is connected with the anode of the green light-emitting diode through the third buck conversion module, the cathode of the green light-emitting diode is connected with the power module through the constant current driving module, the power module is connected with the anode of the blue light-emitting diode through the fourth buck conversion module, and the cathode of the blue light-emitting diode is connected with the power module through the constant current driving module.

4. The circuit of any one of claims 1 to 3, wherein the first buck conversion module comprises a pulse waveform modulation generator, a logic controller, a first drive unit, and a filter;

the power module is connected with the input end of the first driving unit, the output end of the first driving unit is connected with the input end of the filter, the output end of the filter is respectively connected with the input end of the pulse waveform modulation generator and the anode of the red light-emitting diode, the output end of the pulse waveform modulation generator is connected with the input end of the logic controller, and the output end of the logic controller is connected with the input end of the first driving unit.

5. The circuit of claim 4, wherein the pulse waveform modulation generator is a pulse width modulation generator, a pulse frequency modulation generator, or a pulse over-period modulation generator.

6. The circuit of claim 4, wherein the power module is connected to an input terminal of the first driving unit, an output terminal of the first driving unit is connected to an input terminal of the PWM generator and an input terminal of the filter, an output terminal of the filter is connected to an input terminal of the PWM generator and an anode of the red LED, an output terminal of the PWM generator is connected to an input terminal of the logic controller, and an output terminal of the logic controller is connected to an input terminal of the first driving unit.

7. The circuit according to claim 2, wherein the constant current driving module is electrically connected with the power supply module, the power supply module provides a voltage greater than a rated voltage of the blue light emitting diode, and the power supply module provides a voltage greater than a minimum rated voltage of the constant current driving module.

8. The circuit according to claim 2, wherein the power module is connected to the constant current driving module through the second buck converter module, and the voltage provided by the power module is greater than the rated voltage of the blue light emitting diode.

9. The circuit according to any one of claims 1 to 3, wherein the constant current driving module comprises a second driving unit, a third driving unit and a fourth driving unit;

the cathode of the red light-emitting diode is connected with the power supply module through the second driving unit, the cathode of the green light-emitting diode is connected with the power supply module through the third driving unit, and the cathode of the blue light-emitting diode is connected with the power supply module through the fourth driving unit.

10. The circuit of claim 1, wherein the power module is a dc power module.

11. The circuit of claim 1, wherein the power module is an ac power module;

the power supply circuit further comprises an alternating current-direct current power supply module, the alternating current power supply module is connected with the alternating current-direct current power supply module, the alternating current-direct current power supply module is connected with the anode of the red light-emitting diode through the first step-down conversion module, and the alternating current-direct current power supply module is respectively connected with the anodes of the green light-emitting diode and the blue light-emitting diode.

12. A display panel comprising control circuitry, red, green and blue light emitting diodes, and a display panel power supply circuit as claimed in any one of claims 1 to 11.