CN113839570B

CN113839570B - Display device

Info

Publication number: CN113839570B
Application number: CN202111082023.8A
Authority: CN
Inventors: 杨杰; 高宽志; 韩文涛
Original assignee: Hisense Visual Technology Co Ltd
Current assignee: Hisense Visual Technology Co Ltd
Priority date: 2019-03-12
Filing date: 2019-03-12
Publication date: 2024-02-06
Anticipated expiration: 2039-03-12
Also published as: CN113839570A; WO2020181830A1; CN111697848B; CN111697848A

Abstract

The present invention provides a display device including: the device comprises a main controller, a flyback switching power supply module, a resonance conversion power supply module and a power supply control module; when the main controller inputs a first control signal to a first end of the flyback switching power supply module, controlling a voltage output end of the flyback switching power supply module to output a first voltage; the power supply control module receives the first voltage and cuts off power supply to the resonance conversion power supply module; when the main controller inputs a second control signal to the first end of the flyback switching power supply module, controlling the voltage output end of the flyback switching power supply module to output a second voltage; and the power supply control module receives the second voltage and supplies power to the resonance conversion power supply module. The display device provided by the invention has the advantages that the circuit structure is simplified, the production period of the display device is shortened, and meanwhile, the potential safety hazard caused by insufficient primary and secondary isolation voltage resistance is avoided.

Description

Display device

The present application is a divisional application entitled "a display device and a power supply control method" based on 2019, 03, 12, application number 201910183088.8.

Technical Field

The present invention relates to automatic control technologies, and in particular, to a display device and a power supply control method.

Background

As the demand for information is increasing, various types of display devices, such as computers, televisions, projectors, and the like, are being developed. The power supply circuit is one of the most important circuit structures in the display device, and can provide electric energy for the display device, so that the display device can normally operate. Some display devices are provided with independent power boards, and some display devices integrate the power boards and the main boards into one. In general, a power supply circuit of a display device is connected with an alternating current, and then the connected alternating current is processed and converted into a direct current which can be used for a load, and the processing is performed by using a transformer.

In the use of electronic products, in order to ensure the safety of users, a transformer is generally required to convert strong current into weak current, and one end of the transformer connected with the strong current is called a primary end, and the other end connected with the weak current is called a secondary end. In order to enable a user to control the operating state of the primary-side circuit through the secondary side, an optocoupler isolation needs to be provided between the secondary side and the primary side, through which the user's control signals are transmitted. Therefore, the existing power supply circuit may have the following problems: the contained components are more, and the circuit complexity is high; the optical coupler device needs to be subjected to electromagnetic compatibility EMC detection, so that the production period of the product is prolonged; when the optocoupler fails, potential safety hazards may be caused by insufficient primary and secondary isolation voltage resistance.

Disclosure of Invention

The invention provides a display device and a power supply control method, which are used for solving the problem of high circuit complexity of a power supply control module in the existing display device.

The present invention provides a display device including:

a power panel, be provided with on the power panel:

the power supply system comprises a first power supply module, a second power supply module and a power supply control module;

the power supply control module is respectively connected with a voltage output end of the first power supply module and a voltage input end of the second power supply module, wherein the voltage output end is connected with a primary end of a transformer in the first power supply module, and the voltage input end is connected with a primary end of the transformer in the second power supply module;

the power supply control module is used for controlling whether the first power supply module supplies power to the second power supply module according to the voltage value of the voltage output end.

Optionally, the power supply control module includes:

a comparing unit and a switching unit;

the comparison unit is respectively connected with the switch unit and the voltage output end, and the switch unit is respectively connected with the voltage output end, the voltage input end and the ground;

the comparison unit is used for controlling whether the first power supply module supplies power to the second power supply module or not by controlling the conduction state of the switch unit according to the voltage value of the voltage output end.

Optionally, the switching unit includes:

a first switching subunit and a second switching subunit;

the first switch subunit is respectively connected with the comparison unit, the second switch subunit and the ground, the second switch subunit is respectively connected with the voltage output end and the voltage input end, the conduction state of the first switch subunit is controlled by the comparison unit, and the conduction state of the second switch subunit is controlled by the first switch subunit.

Optionally, the first switch subunit includes:

a first transistor and a first resistor;

the first resistor is connected between the comparison unit and the ground, the emitter and the base of the first triode are connected to two ends of the first resistor, and the collector of the first triode is connected with the second switch subunit.

Optionally, the first switch subunit further includes:

a first protection resistor;

the first protection resistor is connected between the first resistor and the comparison unit.

Optionally, the second switch subunit includes:

a second transistor and a second resistor;

the second resistor is connected between the voltage output end and the first switch subunit, the emitter and the base of the second triode are connected to two ends of the second resistor, and the collector of the second triode is connected with the voltage input end.

Optionally, the second switch subunit further includes:

a second protection resistor;

the second protection resistor is connected between the second resistor and the first switch subunit.

Optionally, the first power module is a FLYBACK switch FLYBACK power module, the second power module is a resonant conversion LLC power module, and the comparing unit is a zener diode.

Optionally, the switching unit further includes:

a third switch subunit;

the third switch subunit is respectively connected with the second switch subunit and the voltage input end, and the conduction state of the third switch subunit is controlled by the second switch subunit.

Optionally, the third switch subunit includes:

a third transistor and a third resistor;

the third resistor is connected between the second switch subunit and the ground, the base electrode and the collector electrode of the third transistor are connected to two ends of the third resistor, and the emitter electrode of the third transistor is connected to the voltage input end.

The invention also provides a power supply control method, wherein the power supply control module judges whether the voltage value of the voltage output end exceeds a preset value; if yes, the power supply control module controls the first power supply module to supply power to the second power supply module; if not, the power supply control module controls the first power supply module not to supply power to the second power supply module.

The display device provided by the invention comprises a power panel, wherein the power panel is provided with a first power module, a second power module and a power supply control module, and the power supply control module directly uses the voltage change of the voltage output end of the first power module as a control signal to control whether to supply power to the second power module, so that the circuit structure is simplified, the production period of the display device is shortened, and meanwhile, potential safety hazards caused by insufficient primary-secondary isolation pressure resistance are avoided.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it will be obvious that the drawings in the following description are some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art.

FIG. 1a is a schematic diagram of a display device with a separate power panel;

fig. 1b is a schematic diagram of a connection relationship between a power panel and a load;

FIG. 1c is a schematic diagram of an alternative power panel;

FIG. 1d is a schematic diagram of an alternative circuit configuration of the FLYBACK module;

FIG. 1e is a schematic diagram of an alternative circuit configuration of an LLC module;

FIG. 1f is a schematic diagram of an alternative circuit configuration of a power control module;

FIG. 2 is a schematic diagram of an alternative power panel;

FIG. 3 is a schematic diagram of an alternative power panel;

FIG. 4 is a schematic diagram of an alternative power panel;

FIG. 5 is a schematic diagram of an alternative power panel;

FIG. 6 is a schematic diagram of an alternative circuit configuration of the FLYBACK module;

FIG. 7 is a schematic diagram of an alternative power panel;

fig. 8 is a flow chart of an alternative power supply control method.

Reference numerals illustrate:

1: a panel;

2: a backlight assembly;

20: a back plate;

3: a main board;

4: a power panel;

5: a rear case;

6: a base;

7: a load;

41: the input end of the power panel 4;

42: the output end of the power panel 4;

421: a first output terminal of the power panel 4;

422: a second output terminal of the power panel 4;

423: a third output terminal of the power panel 4;

71: a light bar;

72: a sound box;

43: a rectifying module;

44: a PFC module;

45: FLYBACK module;

46: an LLC module;

47: a power supply control module;

450: a transformer of the FLYBACK module 45;

451: a primary side of the transformer 450;

452: a transformer 450 secondary side;

453: the power chip control circuit module of the FLYBACK module 45;

454: MOS tube driving circuit module of FLYBACK module 45;

455: a power supply module;

456: a secondary rectifier circuit module of the FLYBACK module 45;

48: the voltage output of FLYBACK module 45;

49: a voltage input of the LLC module 46;

460: a transformer of the LLC module 46;

461: a primary side of the transformer 460;

462: a transformer 460 secondary side;

463: a power chip control circuit module of the LLC module 46;

464: MOS transistor driving circuit module of LLC module 46;

466: a secondary rectifier circuit module of the LLC module 46;

31: a control signal input;

421': a comparison unit;

422': a switching unit;

4221': a first switch subunit;

4222': a second switch subunit;

423': a first triode;

424': a first resistor;

425': a second triode;

426': a second resistor;

427': a first protection resistor;

428': a second protection resistor;

4223': a third switch subunit;

429': a third triode;

4210': and a third resistor.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented, for example, in sequences other than those illustrated or otherwise described herein.

Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Taking a display device provided with an independent power panel as an example, the structure of the display device will be described, referring to fig. 1a, fig. 1a is a schematic structural diagram of the display device provided with the independent power panel, and as shown in fig. 1a, the display device includes a panel 1, a backlight assembly 2, a main board 3, a power panel 4, a rear case 5, and a base 6. Wherein the panel 1 is used for presenting pictures to a user; the backlight assembly 2 is located below the panel 1, usually some optical assemblies, and is used for providing enough brightness and uniformly distributed light sources to enable the panel 1 to display images normally, the backlight assembly 2 further comprises a back plate 20, the main plate 3 and the power panel 4 are arranged on the back plate 20, some convex hull structures are usually stamped and formed on the back plate 20, and the main plate 3 and the power panel 4 are fixed on the convex hulls through screws or hooks; the rear shell 5 is arranged on the panel 1 in a covering way so as to hide parts of the display device such as the backlight assembly 2, the main board 3, the power panel 4 and the like, thereby having an attractive effect; and a base 6 for supporting the display device.

Further, fig. 1b is a schematic diagram of a connection relationship between a power panel and a load 7, as shown in fig. 1b, the power panel 4 includes an input end 41 and an output end 42 (a first output end 421, a second output end 422, and a third output end 423 are shown in the drawing), where the input end 41 is connected to a mains supply, the output end 42 is connected to the load 7, for example, the first output end 421 is connected to a light bar 71, the second output end 422 is connected to a sound box 72, and the third output end 423 is connected to the main board 3. The power panel 4 needs to convert ac mains to dc power required by a load, and the dc power generally has different specifications, for example, 18V for sound, 12V for a panel, and the like.

Fig. 1c is a schematic structural diagram of an alternative power panel, where the power panel shown in fig. 1c is provided with: the power factor correction (Power Factor Correction, PFC) module 43, FLYBACK switch (Flyback Transformer, FLYBACK) module 45, resonant converter (Resonant Converters, LLC) module 46 and power supply control module 47, wherein the rectifier module 43, FLYBACK module 45 and LLC module 46 are all connected with PFC module 44, and FLYBACK module 45 and LLC module 46 are connected through power supply control module 47.

The rectifying module 43 rectifies and converts ac power provided by the utility power into dc power, and outputs the dc power to the PFC module 44, and an electromagnetic interference (Electromagnetic Interference, EMI) filter (not shown in fig. 1 c) may be connected to the PFC module 44 to perform high-frequency filtering on the input ac power.

The PFC module 44 generally includes a PFC inductor, a switching power device, and a PFC control chip, and is configured to perform power factor correction on an input ac power supply, and perform boost processing on the dc power output from the rectifying module 43 to obtain a stable dc bus voltage (e.g., 380V), and output the dc bus voltage to the FLYBACK module 45 and the LLC module 46, where the PFC module 44 can effectively improve the power factor of the power supply, and ensure that the voltage and the current are in phase.

The FLYBACK module 45 is connected to loads such as the main board 3 and the sound box 72, and is used for supplying power to these components, and in addition, the FLYBACK module is also used for providing power supply voltages and standby power sources of the flb module 44 and the LLC module 46.

LLC module 46 and lamp strip 71 are connected, and LLC module 46 can adopt two MOS pipes, and synchronous rectifier circuit sets up in LLC module 46 generally, and synchronous rectifier circuit mainly can include transformer, controller, two MOS pipes and diode. The LLC module 46 may also include pulse frequency adjustment (Pulse frequency modulation, PFM) circuitry, capacitors, inductors, and other components. The LLC module 46 may specifically step down or step up the dc bus voltage input by the PFC module 44 and output a constant voltage to the load 7 (e.g., the light bar 71). Generally, the LLC module 46 is capable of outputting a variety of different voltages to meet the load requirements.

The working principle of the power supply control module 47 is as follows: when the display device receives a startup instruction, the power supply control module 47 controls the FLYBACK module 45 to normally supply power to the LLC module 46, so that the display device can normally display images; when the display device receives the standby instruction, the power supply control module 47 controls the FLYBACK module 45 not to supply power to the LLC module 46, so that the LLC module 46 does not operate in the standby state, thereby reducing standby power consumption of the display device.

In the above control process, the power supply control module 47 directly uses the signal triggered by the user at the secondary side of the transformer as the control signal to control whether the FLYBACK module 45 supplies power to the LLC module 46, however, both the voltage output end of the FLYBACK module 45 and the voltage input end of the LLC module 46 are connected to the primary side of the transformer, and the above control method may result in high circuit complexity of the power supply control module 47.

As shown in fig. 1c, fig. 1c is a schematic structural diagram of an alternative power panel, and as can be seen from the foregoing, the power panel shown in fig. 1c includes the following modules: the FLYBACK module 45, the LLC module 46, and the power control module 47.

Referring to fig. 1d, fig. 1d is a schematic diagram of an alternative circuit structure of the FLYBACK module 45, in which a transformer 450 is disposed in the FLYBACK module 45, and the transformer 450 includes a primary side 451 and a secondary side 452.

The primary side 451 is connected to the power chip control circuit module 453, the MOS transistor driving circuit module 454, and the power supply module 455, where the power chip control circuit module 453 is configured to output a reasonable pulse width modulation (Pulse Width Modulation, abbreviated as PWM) control signal to control the switching of the MOS transistor driving circuit module 454 by processing the primary voltage sampling, the current sampling, and the secondary output voltage feedback signal. The MOS transistor driving circuit module 454 generates a voltage and a current which change by opening and closing itself, and transmits energy to the secondary through the transformer 450. The power supply module 455 is configured to output a stable voltage to power the FLYBACK and LLC control chips.

The secondary side 452 is connected to a secondary rectifying circuit module 456, and the secondary rectifying circuit module 456 is configured to convert the rectangular wave into a stable dc output through rectifying diode and output electrolysis.

The voltage output terminal 48 of the flibac module 45 is connected to the power supply module 455, and the control signal input terminal 31 of the main board 3 is connected to the secondary rectifying circuit module 456.

Referring to fig. 1e, fig. 1e is a schematic diagram of an alternative circuit structure of the LLC module 46, wherein a transformer 460 is provided in the LLC module 46, the transformer 460 including a primary side 461 and a secondary side 462.

The primary side 461, the power chip control circuit module 463 and the MOS transistor driving circuit module 464, the power chip control circuit module 463 is configured to output a reasonable pulse width modulation (Pulse Width Modulation, abbreviated as PWM) control signal through processing the primary voltage sampling, the current sampling and the secondary output voltage feedback signal, so as to control the switching of the MOS transistor driving circuit module 464. The MOS transistor driving circuit module 464 generates a voltage and a current which change by opening and closing itself, and transmits energy to the secondary through the transformer 460.

The secondary side 462 is connected to a secondary rectifying circuit module 466, and the secondary rectifying circuit module 466 is configured to convert the rectangular wave into a stable dc output by rectifying diode and output electrolysis.

The voltage input 49 of the LLC module 46 is connected to a power chip control circuit module 463.

Referring to fig. 1f, fig. 1f is a schematic diagram illustrating an alternative circuit configuration of the power supply control module 47. As shown in fig. 1f, the specific control procedure of the power supply control module 47 is:

after a user sends a startup command to the main board 3 through a triggering device such as a remote controller, the main board 3 inputs a high-level signal to the control signal input end 31 according to the startup command, the triode V905 is conducted, the light emitting ends 1 and 2 of the optocoupler N851 are conducted, the optocoupler starts to work, and the V904 is conducted, so that the voltage output end 48 of the FLYBACK module 45 is communicated with the voltage input end 49 of the LLC module 46, the FLYBACK module 45 supplies power to the LLC module 46 normally, the load (the light bar 71) of the LLC module 46 is started, and the user can watch images normally.

After the user sends a standby command to the main board 3 through a triggering device such as a remote controller, the main board 3 inputs a low-level signal to the control signal input end 31 according to the standby command, the triode V905 is not conducted, the light emitting ends 1 and 2 pins of the optocoupler N851 are not conducted, and the optocoupler does not work, so that V904 is also not conducted, the voltage output end 48 of the FLYBACK module 45 and the voltage input end 49 of the LLC module 46 are separated, the FLYBACK module 45 cannot normally supply power to the LLC module 46, the load (light bar 71) of the LLC module 46 is turned off, and the display device is switched to a standby state.

As can be seen from a combination of fig. 1d and 1e, the control signal input terminal 31 is connected to the secondary side of the transformer 450, the voltage output terminal 48 is connected to the primary side of the transformer 450, and the voltage input terminal 49 is connected to the primary side of the transformer 460. As shown in fig. 1f, when the power supply control module 47 directly uses the signal of the control signal input terminal 31 as a control signal to control whether the FLYBACK module 45 supplies power to the LLC module 46, in order to isolate the high voltage risk of the primary side of the transformer and realize the transmission of the control signal, an optocoupler isolation N851 needs to be set in the power supply control module 47.

Fig. 2 is a schematic diagram of an alternative power panel structure, as shown in fig. 2. The power panel 4 shown in fig. 2 is provided with: FLYBACK module 45, LLC module 46 and power control module 47; the power supply control module 47 is connected to a voltage output terminal 48 of the fliyback module 45 and a voltage input terminal 49 of the LLC module 46, wherein the voltage output terminal 48 is connected to a primary terminal 451 of a transformer 450 in the fliyback module 45, and the voltage input terminal 49 is connected to a primary terminal 461 of a transformer 460 in the LLC module 46.

The power supply control module 47 is configured to control whether the FLYBACK module 45 supplies power to the LLC module 46 according to the voltage value of the voltage output terminal 48.

As shown in fig. 3, fig. 3 is a schematic diagram of an alternative power panel structure, and as shown in fig. 3, the power supply control module 47 may include: a comparison unit 421 'and a switching unit 422'.

The comparison unit 421' is connected to the switching unit 422' and the voltage output 48, and the switching unit 422' is connected to the voltage output 48, the voltage input 49, and ground. The comparison unit 421 'is configured to control whether the FLYBACK module 45 supplies power to the LLC module 46 by controlling the on state of the switching unit 422' according to the voltage value of the voltage output terminal 48.

The control principle of the power supply control module 47 shown in fig. 3 is:

when the user sends a standby command to the motherboard 3 through a triggering device such as a remote controller, the motherboard 3 inputs a low-level signal to the FLYBACK module 45 according to the standby command, after the FLYBACK module 45 receives the low-level signal, the voltage value output by the voltage output terminal 48 is controlled to be smaller than a preset value, the comparison unit 421' controls the switch unit 422' to be turned off under the condition that the voltage value output by the voltage output terminal 48 is smaller than the preset voltage value, and the FLYBACK module 45 cannot supply power to the LLC module 46 under the condition that the switch unit 422' is turned off.

After a user sends a startup command to the main board 3 through a triggering device such as a remote controller, the main board 3 inputs a high-level signal to the FLYBACK module 45 according to the startup command, the FLYBACK module 45 controls the voltage value output by the voltage output end 48 to be greater than a preset value, the comparison unit 421 'controls the switch unit 422' to be turned on under the condition that the voltage value output by the voltage output end 48 is greater than the preset voltage value, and then the voltage output end 48 and the voltage input end 49 are turned on, and the FLYBACK module 45 starts to supply power to the LLC module 46.

It should be noted that: the correspondence between the command and the level signal sent from the user to the main board 3 is not limited to the above correspondence, and may be a high level signal corresponding to the standby command and a low level signal corresponding to the power-on command.

Alternatively, the comparing unit 421' may be a zener diode, where the preset voltage value is a reverse breakdown voltage value of the zener diode.

In the power panel shown in fig. 3, the power supply control module 47 directly uses the voltage change of the voltage output end 48 of the FLYBACK module 45 as a control signal to control whether to supply power to the LLC module 46, so that the circuit structure is simplified, the production period of the display device is shortened, and meanwhile, potential safety hazards caused by insufficient primary and secondary voltage isolation and withstanding are avoided.

As shown in fig. 4, fig. 4 is a schematic diagram of an alternative power panel structure, and based on the circuit structure shown in fig. 3, in the power panel shown in fig. 4, the switch unit 422' includes: a first switching sub-unit 4221 'and a second switching sub-unit 4222'.

The first switching subunit 4221 'is connected to the comparing unit 421', the second switching subunit 4222 'and the ground, the second switching subunit 4222' is connected to the voltage output terminal 48 and the voltage input terminal 49, the on state of the first switching subunit 4221 'is controlled by the comparing unit 421', and the on state of the second switching subunit 4222 'is controlled by the first switching subunit 4221'.

The control principle of the power supply control module 47 shown in fig. 4 is:

when the user sends a standby command to the motherboard 3 through a triggering device such as a remote controller, the motherboard 3 inputs a low-level signal to the FLYBACK module 45 according to the standby command, the FLYBACK module 45 controls the voltage value output by the voltage output terminal 48 to be smaller than a preset value, the comparing unit 421 'controls the first switching subunit 4221' to be turned off under the condition that the voltage value output by the voltage output terminal 48 is smaller than the preset voltage value, the first switching subunit 4221 'further controls the second switching subunit 4222' to be turned off, the voltage output terminal 48 and the voltage input terminal 49 cannot be turned on, and the FLYBACK module 45 cannot supply power to the LLC module 46.

After a user sends a startup command to the main board 3 through a triggering device such as a remote controller, the main board 3 inputs a high-level signal to the FLYBACK module 45 according to the startup command, the FLYBACK module 45 controls the voltage value output by the voltage output end 48 to be greater than a preset value, the comparison unit 421 'controls the first switch subunit 4221' to be turned on under the condition that the voltage value output by the voltage output end 48 is greater than the preset voltage value, the first switch subunit 4221 'cuts off to further control the second switch subunit 4222' to be turned on, and then the connection between the voltage output end 48 and the voltage input end 49 is made, and the FLYBACK module 45 starts to supply power to the LLC module 46.

As shown in fig. 5, fig. 5 is a schematic diagram of an alternative power panel structure, and the first switch subunit 4221' may include:

a first transistor 423 'and a first resistor 424'; the first resistor 424 'is connected between the comparing unit 421' and the ground, the emitter and the base of the first triode 423 'are connected at two ends of the first resistor 424', and the collector of the first triode 423 'is connected with the second switching subunit 4222'. The second switching sub-unit 4222' may comprise: a second transistor 425 'and a second resistor 426'; the second resistor 426' is connected between the voltage output terminal 48 and the first switching subunit 4221', an emitter and a base of the second triode 425' are connected to two ends of the second resistor 426', and a collector of the second triode 425' is connected to the voltage input terminal 49.

Optionally, the first switching subunit 4221' may further comprise: a first protection resistor 427'; the first protection resistor 427' is connected between the first resistor 424' and the comparison unit 421 '. The second switching sub-unit 4222' may further comprise: a second protection resistor 428'; the second protection resistor 428' is connected between the second resistor 426' and the first switching subunit 4221 '.

Fig. 6 is a schematic diagram of an alternative circuit configuration of the fliyback module 45. The control principle of the power supply control module 47 in fig. 5 will be described below with reference to fig. 5 and 6, taking the comparison unit as a zener diode as an example:

when a user sends a standby command to the main board 3 through a triggering device such as a remote controller, the main board 3 inputs a low-level signal to the STB1 in fig. 6 according to the standby command, and when the signal of the STB1 in fig. 6 is the low-level signal, the base voltage and the emitter voltage of the triode V915 are both zero and cannot be turned on, so that R935 and R936 form a feedback resistor, the 2-pin reference of the reference source N922 is 2.5V, and at this time, the original output voltage of the LYBACK module 45 is (R936/2.5) × (r936+r935) =9v. Assuming that the turns ratio of the winding number of the voltage output terminal 48 and the original winding number of the LYBACK module 45 is 6:4, the voltage of the voltage output terminal 48 is 13.5V, the reverse breakdown voltage of the selected zener diode is 15V, the voltage of the voltage output terminal 48 is smaller than the reverse breakdown voltage of the zener diode, the first triode 423', the first resistor 424' and the first protection resistor 427 'are not conducted, the second triode 425' is also not conducted, the voltage output terminal 48 and the voltage input terminal 49 are separated, and the FLYBACK module 45 can not supply power to the LLC module 46.

When a user sends a starting command to the main board 3 through a triggering device such as a remote controller, the main board 3 inputs a high-level signal to STB1 in fig. 6 according to the starting command, under the condition that the signal of STB1 in fig. 6 is a high-level signal, the base voltage of the triode V915 is about 0.7V higher than the emitter voltage, the triode V915 is turned on, thus, after parallel connection of R936 and R996 and R935, a feedback resistor is formed, the reference 2 pin reference of the reference source N922 is 2.5V, the resistor after parallel connection of R936 and R996 is assumed to be R, at this time, the original output voltage of the LYBACK module 45 is (R/2.5) (r+r935) =12v, and the winding turns ratio of the voltage output end 48 and the original output winding turns of the LYBACK module 45 is assumed to be 6:4, at this time, the voltage output end 48 is assumed to be 18V, the reverse breakdown voltage of the selected zener diode is assumed to be 15V, the voltage output end 48 is greater than the reverse breakdown voltage of the zener diode, at this time, the first resistor 423', the first resistor 427' and the first protection resistor 427 'and the second protection resistor 425' are also normally turned on to the triode 46.

The power panel shown in fig. 5 provides a possible implementation manner of the switching unit, so that the display device provided in this embodiment can control whether the LLC module 46 works by using the voltage change of the voltage output terminal of the FLYBACK module 45 as a control signal, without setting an optocoupler isolation, and greatly simplifying a circuit.

Fig. 7 is a schematic diagram of an alternative power panel structure, as shown in fig. 7. On the basis of the circuit structure shown in fig. 5, the power panel shown in fig. 7 further includes: a third switching subunit 4223'.

The third switching subunit 4223 'is connected to the second switching subunit 4222' and the voltage input terminal 49, and the on state of the third switching subunit 4223 'is controlled by the second switching subunit 4222'.

Optionally, the third switching sub-unit 4223' may comprise: third transistor 429 'and third resistor 4210'.

The third resistor 4210' is connected between the second switch subunit 4222' and ground, the base and collector of the third transistor 429' are connected to two ends of the third resistor 4210', and the emitter of the third transistor 429' is connected to the voltage input end 49.

The control principle of the power supply control module 47 shown in fig. 7 is explained as follows:

when the user sends a standby command to the main board 3 through a triggering device such as a remote controller, the main board 3 inputs a low-level signal to the STB1 in fig. 6 according to the standby command, and in the case that the signal of the STB1 in fig. 6 is the low-level signal, the voltage value of the voltage output terminal 48 is smaller than the reverse breakdown voltage of the voltage regulator, the first switching sub-unit 4221', the second switching sub-unit 4222' and the third switching sub-unit 4223' cannot be conducted, the voltage output terminal 48 and the voltage input terminal 49 are separated, and the FLYBACK module 45 cannot supply power to the LLC module 46.

After the user sends a start-up command to the main board 3 through a triggering device such as a remote controller, the main board 3 inputs a high-level signal to the STB1 in fig. 6 according to the start-up command, and in the case that the signal of the STB1 in fig. 6 is the high-level signal, the voltage value of the voltage output end 48 is greater than the reverse breakdown voltage of the voltage regulator tube, the first switch subunit 4221' is turned on, so that the second switch subunit 4222' is turned on, and further, the third switch subunit 4223' is turned on, and the FLYBACK module 45 can normally supply power to the LLC module 46.

In order to ensure unidirectional conduction between the voltage output 48 and the voltage input 49, a first diode and a second diode may also be provided in the power supply control module 47; the first diode is connected between the second switching sub-unit 4222' and the third switching sub-unit 4223', and the second diode is connected between the third switching sub-unit 4223' and the voltage input terminal 49.

To stabilize the voltage at the base of third transistor 429', a voltage regulator may be provided between third transistor 429' and ground. In order to filter the interference in the circuit, a filter capacitor or the like may be provided in the circuit.

The power supply control module 47 in the power panel shown in fig. 7 directly uses the voltage output by the FLYBACK module 45 as a control signal, and controls whether the LLC module 46 works by controlling the on states of the first switch subunit, the second switch subunit and the third switch subunit, so that the circuit structure is simplified, the production period of the display device is shortened, and meanwhile, potential safety hazards caused by insufficient primary isolation and voltage resistance are avoided.

Fig. 8 is a flow chart of an alternative power supply control method. The power supply control method shown in fig. 8 corresponds to the circuit configuration shown in fig. 7, and includes:

s801, a comparison unit 421' judges whether the voltage value of the voltage output terminal 48 exceeds a preset value;

if the voltage value of the voltage output terminal 48 exceeds the preset value, steps S802-S804 are performed.

S802, the comparing unit 421 'controls the first switch subunit 4221' to be turned on;

s803, the first switching subunit 4221 'controls the second switching subunit 4222' to be turned on;

s804, the second switching subunit 4222 'controls the third switching subunit 4223' to be turned on, so that the voltage output terminal 48 and the voltage input terminal 49 are turned on, and the FLYBACK module 45 may normally supply power to the LLC module 46.

If the voltage value of the voltage output terminal 48 does not exceed the preset value, steps S802'-S804' are performed.

S802', the comparison unit 421' controls the first switching sub-unit 4221' to be turned off;

s803', the first switching subunit 4221' controls the second switching subunit 4222' to be turned off;

s804', the second switching sub-unit 4222' controls the third switching sub-unit 4223' to be turned off, so that the voltage output terminal 48 and the voltage input terminal 49 are blocked, and the FLYBACK module 45 cannot normally supply power to the LLC module 46.

It can be seen that the control method shown in fig. 8 directly uses the voltage value of the voltage output terminal 48 of the FLYBACK module 45 as a control signal to control the conduction state between the voltage output terminal 48 and the voltage input terminal 49, so as to control whether the FLYBACK module 45 supplies power to the LLC module 46. As can be seen from the above, the voltage output terminal 48 and the voltage input terminal 49 are both connected to the primary side of the transformer, so that the power supply control method does not need to involve control of the optocoupler, and the control process is simple and easy to implement.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. A display device, comprising: the device comprises a main controller, a flyback switching power supply module, a resonance conversion power supply module and a power supply control module;

the main controller is connected with the first end of the flyback switching power supply module;

the power supply control module is respectively connected with the voltage output end of the flyback switching power supply module and the voltage input end of the resonance conversion power supply module;

when the main controller inputs a first control signal to a first end of the flyback switching power supply module, controlling a voltage output end of the flyback switching power supply module to output a first voltage; the power supply control module receives the first voltage and cuts off power supply to the resonance conversion power supply module;

when the main controller inputs a second control signal to the first end of the flyback switching power supply module, controlling the voltage output end of the flyback switching power supply module to output a second voltage; and the power supply control module receives the second voltage and supplies power to the resonance conversion power supply module.

2. The display device of claim 1, wherein the display device comprises a display device,

the power supply control module includes: a comparing unit and a switching unit;

the comparison unit is respectively connected with the switch unit and the voltage output end of the flyback switch power supply module, and the switch unit is respectively connected with the voltage output end of the flyback switch power supply module, the voltage input end of the resonant conversion power supply module and the ground;

the comparison unit is used for controlling the conduction state of the switch unit according to the first voltage or the second voltage;

when the switch unit is conducted, the flyback switch power supply module supplies power to the resonance conversion power supply module; when the switch unit is non-conductive, the flyback switch power supply module does not supply power to the resonant conversion power supply module.

3. The display device of claim 2, wherein the display device comprises a display device,

when the comparison unit receives the first voltage, the switching unit is controlled to be switched to a non-conducting state;

and when the comparison unit receives the second voltage, the switching unit is controlled to be switched to a conducting state.

4. The display device of claim 2, wherein the display device comprises a display device,

the switch unit comprises a first switch subunit and a second switch subunit;

5. The display device of claim 4, wherein the first switching subunit comprises:

a first triode and a first resistor;

6. The display device of claim 5, wherein the first switch subunit further comprises:

a first protection resistor;

7. The display device of claim 4, wherein the second switching sub-unit comprises:

a second triode and a second resistor;

8. The display device of claim 7, wherein the second switch subunit further comprises:

a second protection resistor;

9. The display device of claim 4, wherein the display device comprises a display panel,

the switching unit further includes:

a third switch subunit;

10. The display device of claim 2, wherein the display device comprises a display device,

the comparison unit is a zener diode.