CN111697848B

CN111697848B - Display device and power supply control method

Info

Publication number: CN111697848B
Application number: CN201910183088.8A
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: 2021-09-07
Anticipated expiration: 2039-03-12
Also published as: CN113839570B; WO2020181830A1; CN113839570A; CN111697848A

Abstract

The present invention provides a display device and a power supply control method. The display device includes: a power supply board, and the power supply board is provided with: a first power supply module, a second power supply module and a power supply control module; wherein, the power supply control module is respectively connected with the voltage output end of the first power supply module and the power supply control module. the voltage input end of the second power supply module is connected, the voltage output end is connected to the primary end of the transformer in the first power supply module, and the voltage input end is connected to the primary end of the transformer in the second power supply module; The power supply control module is configured to control whether the first power supply module supplies power to the second power supply module according to the voltage value of the voltage output terminal. The display device provided by the present invention simplifies the circuit structure, shortens the production cycle of the display device, and simultaneously avoids potential safety hazards due to insufficient withstand voltage of the primary secondary isolation.

Description

Display device and power supply control method

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 obtaining information is continuously 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 the power supply circuit can provide electric energy for the display device, so that the display device can normally operate. Some display devices are provided with independent power panels, and some display devices combine the power panels and the main board into a whole. Generally, a power supply circuit of a display device receives ac power, and then processes the received ac power to convert the ac power into dc power that can be used by a load, and the process is performed by using a transformer.

In order to ensure the safety of the electricity consumption of the user, a transformer is usually used to convert the strong electricity into the weak electricity, one end of the transformer connected with the strong electricity is called a primary end, and one end connected with the weak electricity is called a secondary end. In order to enable a user to control the working state of the primary side circuit through the secondary side, an optical coupling isolation is required to be arranged between the secondary side and the primary side so as to transmit a control signal of the user through the optical coupling isolation. Therefore, the following problems may exist in the conventional power supply circuit: the number of components is large, and the circuit complexity is high; the optical coupler needs to perform electromagnetic compatibility (EMC) detection, so that the production period of the product is increased; when the opto-coupler became invalid, the potential safety hazard may be caused by insufficient withstand voltage of the primary and secondary spacers.

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 conventional display device.

The present invention provides a display device including:

the power strip, be provided with on the power strip:

the power supply control 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, 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 a 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 comparison unit and a switch 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 switch unit includes:

a first switch subunit and a second switch subunit;

wherein, first switch subunit respectively with the comparing unit second switch subunit and ground are connected, second switch subunit respectively with voltage output end and voltage input end are connected, the on-state of first switch subunit by the comparing unit control, the on-state of second switch subunit by first switch subunit control.

Optionally, the first switch subunit includes:

a first triode 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 triode and a second resistor;

the second resistor is connected between the voltage output end and the first switch subunit, the emitting electrode and the base electrode of the second triode are connected to two ends of the second resistor, and the collecting electrode 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 fly box power module, the second power module is a resonant conversion LLC power module, and the comparison unit is a voltage regulator diode.

Optionally, the switch unit further includes:

a third switching subunit;

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

Optionally, the third switching subunit includes:

a third triode 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 triode are connected to two ends of the third resistor, and the emitter electrode of the third triode is connected with 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 so, 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 changes a voltage of a voltage output end of the first power module into a control signal to control whether power is supplied to the second power module or not, so that the circuit structure is simplified, the production period of the display device is shortened, and potential safety hazards caused by insufficient voltage resistance of a primary and secondary insulation are avoided.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1a is a schematic structural diagram of a display device with an independent power panel;

FIG. 1b is a schematic diagram of the connection relationship between the power board and the load;

FIG. 1c is a first schematic diagram of an alternative power board structure;

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

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

FIG. 2 is a second schematic diagram of an alternative power board structure;

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

FIG. 4 is a fourth schematic diagram of an alternative power board structure;

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

FIG. 6 is a schematic diagram of another alternative circuit structure of the FLYBACK module;

FIG. 7 is a sixth schematic diagram of an alternative power board configuration;

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

Description of reference numerals:

1: a panel;

2: a backlight assembly;

20: a back plate;

3: a main board;

4: a power panel;

5: a rear housing;

6: a base;

7: a load;

41: an input end of the power panel 4;

42: an 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 end of the power panel 4;

71: a light bar;

72: sounding;

43: a rectification module;

44: a PFC module;

45: a FLYBACK module;

46: an LLC module;

47: a power supply control module;

450: a transformer of FLYBACK module 45;

451: the primary side of the transformer 450;

452: the secondary side of the transformer 450;

453: a power chip control circuit module of the FLYBACK module 45; 454: an MOS tube driving circuit module of the FLYBACK module 45; 455: a power supply module;

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

48: a voltage output of FLYBACK module 45;

49: a voltage input of LLC module 46;

460: a transformer of the LLC module 46;

461: a primary side of a transformer 460;

462: a secondary side of the transformer 460;

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

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

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

31: a control signal input terminal;

421': a comparison unit;

422': a switch 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 switching subunit;

429': a third triode;

4210': and a third resistor.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation 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 board as an example, a structure of the display device is described, referring to fig. 1a, fig. 1a is a schematic structural diagram of the display device provided with the independent power board, and as shown in fig. 1a, the display device includes a panel 1, a backlight assembly 2, a main board 3, a power board 4, a rear case 5 and a base 6. Wherein, the panel 1 is used for presenting pictures for users; the backlight assembly 2 is located below the panel 1, usually some optical assemblies, and is used for supplying sufficient light sources with uniform brightness and distribution, so that the panel 1 can normally display images, the backlight assembly 2 further includes a back plate 20, the main board 3 and the power board 4 are arranged on the back plate 20, usually some convex hull structures are formed by punching on the back plate 20, and the main board 3 and the power board 4 are fixed on the convex hulls through screws or hooks; the rear shell 5 is covered on the panel 1 to hide the parts of the display device such as the backlight assembly 2, the main board 3 and the power panel 4, and the like, thereby achieving the effect of beautiful appearance; and a base 6 for supporting the display device.

Further, fig. 1b is a schematic diagram of a connection relationship between the power board and the load 7, as shown in fig. 1b, the power board 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 figure), where the input end 41 is connected to the commercial power, the output end 42 is connected to the load 7, for example, the first output end 421 is connected to the light bar 71, the second output end 422 is connected to the speaker 72, and the third output end 423 is connected to the main board 3. The power panel 4 needs to convert ac power into dc power required by the load, and the dc power is usually in different specifications, for example, 18V is required for sound, 12V is required for panel, etc.

Fig. 1c is a schematic diagram of an alternative power board structure, in which: the Power Factor Correction circuit comprises a rectifier module 43, a Power Factor Correction (PFC) module 44, a Flyback switch (Flyback converter, abbreviated as "LLC") module 45, a Resonant converter (Resonant Converters, abbreviated as "LLC") module 46, and a Power supply control module 47, wherein the rectifier module 43, the Flyback converter module 45, and the LLC module 46 are all connected to the PFC module 44, and the Flyback converter module 45 and the LLC module 46 are connected to the Power supply control module 47.

The rectifying module 43 is used for rectifying the ac power provided by the utility power into dc power and outputting the dc power to the PFC module 44, and an Electromagnetic Interference (EMI) filter (not shown in fig. 1 c) may be connected in front of 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, obtain a stable dc bus voltage (e.g., 380V) by performing boost processing on a dc power output by the rectifier module 43, and output the dc bus voltage to the FLYBACK module 45 and the LLC module 46, where the PFC module 44 can effectively improve a power factor of the power supply, and ensure that the voltage and the current have the same phase.

The FLYBACK module 45 is connected to loads such as the main board 3 and the audio 72, and is configured to supply power to these components, and in addition, the FLYBACK module is further configured to provide a supply voltage and a standby power supply to the PFC module 44 and the LLC module 46.

The LLC module 46 is connected to the light bar 71, the LLC module 46 can adopt dual MOS transistors, and a synchronous rectification circuit is usually disposed in the LLC module 46, and the synchronous rectification circuit mainly includes a transformer, a controller, two MOS transistors, and a diode. In addition, the LLC module 46 may further include a Pulse Frequency Modulation (PFM) circuit, a capacitor, an inductor, 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). In general, the LLC module 46 is capable of outputting a plurality of different voltages in order to meet the demands of the load.

The working principle of the power supply control module 47 is as follows: when the display device receives a starting 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 work in the standby state, thereby reducing the standby power consumption of the display device.

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

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

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

The primary end 451 is connected to the power chip control circuit module 453, the MOS transistor driving circuit module 454, and the power supply module 455, and the power chip control circuit module 453 is configured to output a reasonable Pulse Width Modulation (PWM) control signal through processing of primary voltage sampling, current sampling, and a secondary output voltage feedback signal, so as to control switching of the MOS transistor driving circuit module 454. The MOS transistor driving circuit 454 generates a variable voltage and current by its own on/off, and transfers energy to the secondary side through the transformer 450. The power supply module 455 is configured to output a stable voltage to supply power to the FLYBACK and LLC control chips.

The secondary terminal 452 is connected to a secondary rectifier circuit module 456, and the secondary rectifier circuit module 456 is used to convert the rectangular wave into a stable dc output by means of rectifier diodes and output electrolysis.

The voltage output terminal 48 of the FLYBACK 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 rectification 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 disposed in the LLC module 46, and the transformer 460 includes a primary end 461 and a secondary end 462.

The primary terminal 461, the power chip control circuit 463 and the MOS transistor driving circuit 464, where the power chip control circuit 463 is configured to output a reasonable Pulse Width Modulation (PWM) control signal through processing of primary voltage sampling, current sampling and a secondary output voltage feedback signal, so as to control a switch of the MOS transistor driving circuit 464. The MOS transistor driving circuit 464 generates a voltage and a current varying by its own on/off, and transfers energy to the secondary side through the transformer 460.

The secondary terminal 462 is connected to a secondary rectifier circuit module 466, and the secondary rectifier circuit module 466 is configured to convert the rectangular wave into a stable dc output by means of rectifier diodes and output electrolysis.

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

Referring to fig. 1f, fig. 1f is a schematic diagram of an alternative circuit structure of the power supply control module 47. As shown in fig. 1f, the specific control process of the power supply control module 47 is as follows:

after a user sends a start-up instruction to the main board 3 through trigger equipment such as a remote controller, the main board 3 inputs a high-level signal to the control signal input end 31 according to the start-up instruction, the triode V905 is conducted, the optocoupler N851 light emitting end 1 and the optocoupler 2 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 normally supplies power to the LLC module 46, a load (a light bar 71) of the LLC module 46 is started, and the user can normally watch images.

After the user sends standby instruction to mainboard 3 through trigger equipment such as remote controller, mainboard 3 inputs low level signal to control signal input 31 according to this standby instruction, triode V905 does not switch on, the luminous end 1 of opto-coupler N851, 2 feet do not switch on, the opto-coupler is out of work, consequently, V904 also can not switch on, make and cut off between FLYBACK module 45's voltage output end 48 and LLC module 46's voltage input end 49, thereby FLYBACK module 45 can't give LLC module 46 normal power supply, LLC module 46's load (lamp strip 71) is closed, display device is switched to standby state.

As can be seen from 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 hazard at the primary side of the transformer and implement transmission of the control signal, an optical coupling isolation N851 needs to be set in the power supply control module 47.

As shown in fig. 2, fig. 2 is a schematic diagram of an alternative power board structure. The power supply board 4 shown in fig. 2 is provided with: FLYBACK module 45, LLC module 46 and power supply control module 47; the power supply control module 47 is respectively connected to a voltage output terminal 48 of the FLYBACK 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 FLYBACK 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 board structure, and as shown in fig. 3, the power supply control module 47 may include: a comparison unit 421 'and a switch unit 422'.

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

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

after a user sends a standby instruction to the motherboard 3 through a trigger device such as a remote controller, the motherboard 3 inputs a low level signal to the FLYBACK module 45 according to the standby instruction, after the FLYBACK module 45 receives the low level signal, the voltage value output by the voltage output end 48 is controlled to be smaller than a preset value, the comparison unit 421 ' controls the switch unit 422 ' to be switched off under the condition that the voltage value output by the voltage output end 48 is smaller than the preset voltage value, the voltage output end 48 and the voltage input end 49 cannot be conducted under the condition that the switch unit 422 ' is switched off, and the FLYBACK module 45 cannot supply power to the LLC module 46.

After a user sends a power-on instruction to the motherboard 3 through a triggering device such as a remote controller, the motherboard 3 inputs a high level signal to the FLYBACK module 45 according to the power-on instruction, after the FLYBACK module 45 receives the high level signal, the voltage value output by the voltage output end 48 is controlled to be greater than a preset value, the comparison unit 421 'controls the switch unit 422' to be switched on under the condition that the voltage value output by the voltage output end 48 is greater than the preset voltage value, so that the voltage output end 48 and the voltage input end 49 are switched 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 by the user to the motherboard 3 is not limited to the above correspondence, and the standby command may correspond to a high level signal and the power-on command may correspond to a low level signal.

Alternatively, the comparing unit 421' may be a zener diode, and 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 changes the voltage of the voltage output terminal 48 of the FLYBACK module 45 into a control signal to control whether to supply power to the LLC module 46, so that the circuit structure is simplified, the production cycle of the display device is shortened, and potential safety hazards caused by insufficient voltage resistance of the primary and secondary isolation are avoided.

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

The first switch subunit 4221 'is respectively connected to the comparison unit 421', the second switch subunit 4222 'and ground, the second switch subunit 4222' is respectively connected to the voltage output end 48 and the voltage input end 49, an on state of the first switch subunit 4221 'is controlled by the comparison unit 421', and an on state of the second switch subunit 4222 'is controlled by the first switch subunit 4221'.

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

after a user sends a standby instruction to the main board 3 through a trigger device such as a remote controller, the main board 3 inputs a low level signal to the FLYBACK module 45 according to the standby instruction, after the FLYBACK module 45 receives the low level signal, the voltage value output by the voltage output end 48 is controlled to be smaller than a preset value, the comparison unit 421 'controls the first switch subunit 4221' to be switched off under the condition that the voltage value output by the voltage output end 48 is smaller than the preset voltage value, the first switch subunit 4221 'is switched off to further control the second switch subunit 4222' to be switched off, the voltage output end 48 and the voltage input end 49 cannot be conducted, and the FLYBACK module 45 cannot supply power to the LLC module 46.

After a user sends a power-on instruction to the main board 3 through a trigger device such as a remote controller, the main board 3 inputs a high level signal to the FLYBACK module 45 according to the power-on instruction, after the FLYBACK module 45 receives the high level signal, the voltage value output by the voltage output end 48 is controlled to be greater than a preset value, the comparison unit 421 'controls the first switch subunit 4221' to be conducted 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 'is cut off to further control the second switch subunit 4222' to be conducted, so that the voltage output end 48 is conducted with the voltage input end 49, and the FLYBACK module 45 starts to supply power to the LLC module 46.

As shown in fig. 5, fig. 5 is a fifth structural diagram of an optional power board, and the first switch subunit 4221' may include:

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

Optionally, the first switch subunit 4221' may further include: a first protection resistor 427'; the first protection resistor 427 ' is connected between the first resistor 424 ' and the comparing unit 421 '. The second switch subunit 4222' may further include: a second protection resistor 428'; the second protection resistor 428 ' is connected between the second resistor 426 ' and the first switch subunit 4221 '.

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

when a user sends a standby instruction to the main board 3 through a trigger 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 instruction, and when the signal of the STB1 in fig. 6 is a low-level signal, both the base voltage and the emitter voltage of the transistor V915 are zero and are not conducted, so that R935 and R936 form a feedback resistor, the reference of the 2-pin 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 winding turn ratio of the voltage output end 48 and the original output winding turn ratio of the LYBACK module 45 is 6:4, at this time, the voltage of the voltage output end 48 can be calculated to be 13.5V, assuming that the reverse breakdown voltage of the selected Zener diode is 15V, the voltage of the voltage output end 48 is smaller than the reverse breakdown voltage of the Zener diode, at this time, 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 end 48 and the voltage input end 49 are separated, and the FLYBACK module 45 cannot supply power to the LLC module 46.

When a user sends a power-on command to the main board 3 through a trigger device such as a remote controller, the main board 3 inputs a high-level signal to the STB1 in fig. 6 according to the power-on command, and when the signal of the STB1 in fig. 6 is a high-level signal, the base voltage of the transistor V915 is higher than the emitter voltage by about 0.7V, the transistor V915 is turned on, so that R936 and R996 are connected in parallel and R935 form a feedback resistor, the 2-pin reference of the reference source N922 is 2.5V, and the resistor after R936 and R996 are connected in parallel is assumed to be R, at this time, the original output voltage of the LYBACK module 45 is (R/2.5) × (R + R935) 12V, the number-turn ratio of the winding of the voltage output end 48 and the original output winding of the LYBACK module 45 is assumed to be 6:4, at this time, the voltage output end 48 voltage can be calculated to be 18V, the reverse breakdown voltage of the selected zener diode is assumed to be 15V, and the voltage of the voltage output end 48 is greater than the reverse breakdown voltage of the zener diode, at this time, the first transistor 423 ', the first resistor 424' and the first protection resistor 427 'are turned on, the second transistor 425' is also turned on, and the FLYBACK block 45 can normally supply power to the LLC block 46.

The power board shown in fig. 5 provides possible implementation manners of the switch unit, so that the display device provided in this embodiment can change the voltage of the voltage output end of the FLYBACK module 45 into the control signal to control whether the LLC module 46 works, and optical coupling isolation is not required to be set, thereby greatly simplifying the circuit.

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

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

Alternatively, the third switching sub-unit 4223' may include: a third triode 429 'and a third resistor 4210'.

The third resistor 4210 ' is connected between the second switch subunit 4222 ' and ground, the base and collector of the third triode 429 ' are connected to two ends of the third resistor 4210 ', and the emitter of the third triode 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 below:

after a user sends a standby instruction to the main board 3 through a trigger 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 instruction, and when the signal of the STB1 in fig. 6 is a low level signal, the voltage value of the voltage output end 48 is smaller than the reverse breakdown voltage of the voltage regulator tube, the first switch subunit 4221 ', the second switch subunit 4222 ' and the third switch subunit 4223 ' cannot be conducted, the voltage output end 48 and the voltage input end 49 are isolated, and the FLYBACK module 45 cannot supply power to the LLC module 46.

When a user sends a power-on instruction to the main board 3 through a trigger device such as a remote controller, the main board 3 inputs a high-level signal to the STB1 in fig. 6 according to the power-on instruction, and when 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, the third switch subunit 4223 ' is turned on, and the flick yb 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 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 the third transistor 429 ', a voltage regulator may be provided between the 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 board 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 or not by controlling the conduction states of the first switch subunit, the second switch subunit, and the third switch subunit, thereby simplifying the circuit structure, shortening the production cycle of the display device, and avoiding the potential safety hazard caused by insufficient voltage resistance of the primary and secondary compartments.

Fig. 8 is a flow chart illustrating 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, the comparing unit 421' determines whether the voltage value of the voltage output end 48 exceeds a preset value;

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

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

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

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

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

S802 ', comparing unit 421 ' controls first switch subunit 4221 ' to turn off;

s803 ' and the first switch subunit 4221 ' controls the second switch subunit 4222 ' to turn off;

s804 ' and the second switch subunit 4222 ' control the third switch subunit 4223 ' to cut off, so that the voltage output end 48 and the voltage input end 49 are cut off, 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 the control signal to control the conduction state between the voltage output terminal 48 and the voltage input terminal 49, and further control whether the FLYBACK module 45 supplies power to the LLC module 46. As can be seen from the above, the voltage output end 48 and the voltage input end 49 are both connected to the primary side of the transformer, so that the power supply control method does not need to involve the 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 used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled 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 the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A display device, characterized in that, comprising: a power board, wherein the power board is provided with:

a first power supply module, a second power supply module and a power supply control module;

Wherein, the power supply control module is respectively connected with the voltage output terminal of the first power supply module and the voltage input terminal of the second power supply module; the first power supply module is used for supplying the second power supply module and the display device The first load of the display device supplies power; the second power module is used to supply power to the second load of the display device;

The power supply control module is configured to control whether the first power supply module supplies power to the second power supply module according to the voltage value of the voltage output terminal;

The power supply control module includes:

comparison unit and switching unit;

Wherein, the comparison unit is respectively connected to the switch unit and the voltage output terminal, and the switch unit is respectively connected to the voltage output terminal, the voltage input terminal and the ground;

The comparison unit is configured to control whether the first power supply module supplies power to the second power supply module by controlling the conduction state of the switch unit according to the voltage value of the voltage output terminal;

The switch unit includes:

a first switch subunit and a second switch subunit;

The first switch subunit is respectively connected to the comparison unit, the second switch subunit and the ground, and the second switch subunit is respectively connected to the voltage output terminal and the voltage input terminal, so 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.

2. The display device according to claim 1, wherein the first switch subunit comprises:

a first transistor and a first resistor;

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

3. The display device according to claim 2, wherein the first switch subunit further comprises:

the first protection resistor;

4. The display device according to claim 1, wherein the second switch subunit comprises:

a second transistor and a second resistor;

Wherein, the second resistor is connected between the voltage output terminal and the first switch subunit, and the emitter and base of the second triode are connected to both ends of the second resistor, so The collector of the second triode is connected to the voltage input terminal.

5. The display device according to claim 4, wherein the second switch subunit further comprises:

the second protection resistor;

6. The display device according to any one of claims 1-5, wherein,

The first power supply module is a flyback switch FLYBACK power supply module, the second power supply module is a resonant conversion LLC power supply module, and the comparison unit is a zener diode.

7. The display device according to any one of claims 1-5, wherein the switch unit further comprises:

the third switch subunit;

The third switch subunit is respectively connected to 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.

8. A power supply control method, applied to the display device according to any one of claims 1-7, characterized in that, comprising:

The power supply control module determines whether the voltage value of the voltage output terminal 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.