CN113436571B

CN113436571B - Display device and power supply circuit

Info

Publication number: CN113436571B
Application number: CN202110137510.3A
Authority: CN
Inventors: 庞震华
Original assignee: Hisense Visual Technology Co Ltd
Current assignee: Hisense Visual Technology Co Ltd
Priority date: 2020-03-18
Filing date: 2021-02-01
Publication date: 2022-10-18
Anticipated expiration: 2041-02-01
Also published as: CN112785971A; CN112785971B; CN113436571A

Abstract

The application provides a display device and supply circuit, wherein, supply circuit among the display device can be through setting up two different voltages that two different secondary windings exported respectively in a flexible way, and voltage adjustment module only need adjust the voltage of a less secondary winding output of wherein voltage, thereby reduced the requirement to the withstand voltage value of components such as switch tube, electric capacity in the voltage adjustment module, and then reduce the area of supply circuit place PCB board, finally can reduce supply circuit's among the display device cost.

Description

Display device and power supply circuit

The present application claims priority of chinese patent application having application number 202010192086.8 and application name "display and power supply circuit" filed at 18.03.2020 and incorporated herein by reference in its entirety.

Technical Field

The present application relates to the field of electronic technologies, and in particular, to a display device and a power supply circuit.

Background

With the development of electronic technology, the integration level of electronic devices including display devices such as televisions is higher, and the power supply of the display devices is required to be higher. At present, after most display devices receive commercial power alternating current through plugs, a special power supply circuit is adopted to convert the alternating current into direct current, transform the alternating current and the like, and then the power is supplied to loads in the display devices.

In the prior art, a power supply circuit of a display device at least includes the following modules: the circuit comprises a rectifier bridge, a Power Factor Correction (PFC) module and a resonance conversion circuit (LLC) module. In particular, in some display devices, each Light Emitting Diode (LED) Light bar in at least one multiple path for lighting a display screen needs to operate with a certain range of voltage drop to reach a rated current of an LED assembly, so that a secondary winding in the LLC module for supplying power to each multiple path LED Light bar is additionally connected to a voltage adjustment module (e.g., a buck circuit or a boost circuit) and a voltage driving module, and the voltage adjustment module can adjust a voltage directly output by the secondary winding according to a real-time current feedback result of each multiple path LED Light bar and then transmit the adjusted voltage to the voltage driving module, so that the voltage driving module controls the at least one path LED Light bar according to the received voltage, so that the at least one path LED Light bar can operate with the rated current, and damage to components due to an excessive current flowing through the LED assembly in the at least one multiple path LED Light bar is prevented.

In the prior art, the voltage stress of the voltage adjusting module arranged for at least one path of the LED light bar in the power supply Circuit is large, which causes the voltage adjusting module to occupy a large area of a Printed Circuit Board (PCB) Board where the power supply Circuit is located, and thus the cost of the power supply Circuit is high.

Disclosure of Invention

The application provides a display device and a power supply circuit to reduce the voltage stress of a voltage adjusting module in the power supply circuit of the display device, reduce the area size of a PCB (printed circuit board) occupied by the voltage adjusting module, and further reduce the cost of the power supply circuit in the display device.

A first aspect of the present application provides a display device comprising: a display screen configured to display an image picture; a sound reproducing device configured to play sound; at least one LED light bar configured to light the display screen; a power supply circuit configured to supply power to a load of the display device, wherein the load at least comprises the display screen, the sound reproduction device and the at least one LED light bar;

the power supply circuit comprises an LLC primary winding, a first resonant converter LLC secondary winding and a second LLC secondary winding, the first LLC secondary winding is used for converting the voltage of the LLC primary winding into a first voltage and outputting the first voltage to the at least one path of LED light bars, and the second LLC secondary winding is used for converting the voltage of the LLC primary winding into a second voltage and outputting the second voltage to the at least one path of LED light bars; the power supply circuit is specifically configured to adjust a first voltage output by the first LLC secondary winding to a third voltage, and supply power to the at least one LED light bar through a sum of the third voltage and the second voltage.

In an embodiment of the first aspect of the present application, the number of LED light bars is multiple; the power supply circuit further includes: the voltage regulation module and the voltage driving module;

the output end of the second LLC secondary winding is connected with the input end of the first LLC secondary winding, the input end and the output end of the first LLC secondary winding are connected with the voltage adjusting module, and the voltage adjusting module is connected with the voltage driving module;

the first LLC secondary winding is used for outputting a first voltage, and the second LLC secondary winding is used for outputting a second voltage;

the voltage adjusting module is used for adjusting the first voltage into a third voltage and sending the sum of the third voltage and the second voltage to the voltage driving module;

and the voltage driving module is used for respectively supplying power to a plurality of paths of LED lamp bars according to the sum of the third voltage and the second voltage.

In an embodiment of the first aspect of the present application, the voltage driving module is further configured to send a feedback signal to the voltage adjusting module according to the current of the multiple paths of LED light bars; the feedback signal is used for the voltage adjusting module to adjust the first voltage;

the voltage adjusting module is specifically configured to adjust the first voltage to the third voltage according to the feedback signal.

In an embodiment of the first aspect of the present application, the power supply circuit further includes: the optical coupler is respectively connected with the voltage driving module and the voltage adjusting module, and the optical coupler is used for carrying out optical coupler isolation when the voltage driving module sends a feedback signal to the voltage adjusting module.

the output end of the first LLC secondary winding is connected with the input end of the second LLC secondary winding through the voltage adjusting module, and the output end of the second LLC secondary winding is connected with the voltage driving module;

the voltage adjusting module is configured to adjust the first voltage to a third voltage and send the third voltage to the second LLC secondary winding, and the second LLC secondary winding is configured to send a sum of the third voltage and the second voltage to the voltage driving module;

the voltage driving module is used for respectively supplying power to the multiple paths of LED lamp bars according to the sum of the third voltage and the second voltage.

In an embodiment of the first aspect of the present application, the power supply circuit further includes: a voltage adjustment module; the at least one path of LED lamp strip is respectively connected with one voltage adjusting module;

the output end of the second LLC secondary winding is connected with the input end of the first LLC secondary winding, the output end of the first LLC secondary winding is respectively connected with the input end of each LED light bar in the at least one LED light bar, the output end of each LED light bar is respectively connected with the input end of a voltage adjusting module, and the output end of each voltage adjusting module is connected with the input end of the first LLC secondary winding;

each voltage adjusting module is used for adjusting the first voltage to a third voltage and supplying power to one path of LED light bar connected with the voltage adjusting module according to the sum of the third voltage and the second voltage.

In an embodiment of the first aspect of the present application, the power supply circuit further includes: a voltage adjustment module; the at least one path of LED lamp strip is respectively connected with a second LLC secondary winding and a voltage adjusting module;

for each of the at least one path of LED light bars, the output end of the first LLC secondary winding is connected with the output end of the voltage adjusting module, the input end of the second LLC secondary winding is connected with the input end of the voltage adjusting module, and the output end of the second LLC secondary winding is connected with the input end of the LED light bar;

In an embodiment of the first aspect of the present application, the output voltage of the first LLC secondary winding is further used to supply power to a main board of the display device.

In an embodiment of the first aspect of the present application, the first LLC secondary winding and the second LLC secondary winding are secondary windings of an LLC module in the power supply circuit; or,

the first LLC secondary winding and the second LLC secondary winding are secondary windings of a flyback voltage conversion module in the power supply circuit.

A second aspect of the present application provides a power supply circuit, which may be the power supply circuit in the display device according to any one of the first aspect of the present application, for example, the power supply circuit may include: the first LLC secondary winding is used for converting the voltage of the LLC primary winding into a first voltage and outputting the first voltage to the at least one path of LED light bars, and the second LLC secondary winding is used for converting the voltage of the LLC primary winding into a second voltage and outputting the second voltage to the at least one path of LED light bars;

the power supply circuit is specifically configured to adjust a first voltage output by the first LLC secondary winding to a third voltage, and supply power to the at least one LED light bar through a sum of the third voltage and the second voltage.

In summary, the present application provides a display device and a power supply circuit, where the power supply circuit of the display device is configured to be a sum of voltages output by two different first LLC secondary windings and second LLC secondary windings, respectively, to provide a voltage for supplying power to at least one path of LED light bars, and a voltage adjustment module in the power supply circuit is configured to only need to perform adjustment of boosting or stepping down on the voltage output by the first LLC secondary winding, and to supply power to multiple paths of LED light bars together with the sum of the adjusted voltage and the voltage output by the second LLC secondary winding. The power supply circuit in the display device can respectively output two different voltages through flexibly setting two different secondary windings, and the voltage adjusting module only needs to adjust the voltage output by one secondary winding with smaller voltage, so that the requirement on the withstand voltage value of elements such as a switching tube and a capacitor in the voltage adjusting module is reduced, the area of a PCB (printed circuit board) where the power supply circuit is located is further reduced, and finally the cost of the power supply circuit in the display device can be reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application 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 only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

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

FIG. 2 is a schematic diagram illustrating a connection relationship between a power board and a load;

FIG. 3 is a schematic diagram of a power architecture of a television;

FIG. 4 is a schematic diagram of a power supply circuit for supplying power to a motherboard and an LED light bar;

fig. 5 is a schematic structural diagram of a power supply circuit of a display device according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of a power supply circuit of a display device according to a second embodiment of the present application;

fig. 7 is a schematic structural diagram of a power supply circuit of a display device according to a third embodiment of the present application;

fig. 8 is a schematic structural diagram of a power supply circuit of a display device according to a fourth embodiment of the present application;

FIG. 9 is a schematic diagram of a power supply circuit of a display device according to the prior art;

fig. 10 is a schematic structural diagram of a power supply circuit of a display device according to a fifth embodiment of the present application;

FIG. 11 is a schematic view of the voltage range of the LED light bar of the present application;

fig. 12 is a schematic structural diagram of a power supply circuit of a display device according to a sixth embodiment of the present application;

fig. 13 is a schematic structural diagram of a power supply circuit of a display device according to a seventh embodiment of the present application;

FIG. 14 is a schematic diagram of a power supply circuit of a display device according to the prior art;

fig. 15 is a schematic structural diagram of a power supply circuit of a display device according to an eighth embodiment of the present application;

fig. 16 is a schematic structural diagram of a power supply circuit of a display device according to a ninth embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments. 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 application.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, 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 may be interchanged under appropriate circumstances such that the embodiments of the application described herein may be implemented, for example, in sequences other than those illustrated or 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.

The following first describes a scenario in which the present application is applied and problems that may occur with reference to the drawings. 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.

The structure of the display device is described by taking a display device provided with an independent power board as an example, and referring to fig. 1, fig. 1 is a schematic structural diagram of the display device provided with the independent power board, and as shown in fig. 1, 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 are used for supplying sufficient brightness and light sources with uniform distribution, so that the panel 1 can normally display images, the backlight assembly 2 further comprises a back plate 20, the main plate 3 and the power supply plate 4 are arranged on the back plate 20, usually some convex hull structures are formed on the back plate 20 by pressing, and the main plate 3 and the power supply plate 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. 2 is a schematic diagram of a connection relationship between a power panel and a load, and as shown in fig. 2, 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 figure), where the input end 41 is connected to a mains supply, the output end 42 is connected to the load, for example, the first output end 421 is connected to an LED light bar for lighting a display screen, the second output end 422 is connected to a sound box, and the third output end 423 is connected to a main board. 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.

Specifically, taking a television as an example to introduce a power architecture of a display device, fig. 3 is a schematic diagram of a power architecture of a television, and as shown in fig. 3, the display device may include: power supply circuit 1, load 2, control circuit 3, power 4, wherein, power 4 includes: rectifier bridge 41, power Factor Correction (PFC) block 42, and resonant converter (LLC) block 43, with synchronous rectifier circuitry (not shown in fig. 3) included in LLC block 43. The PFC module 42 is connected to the LLC module 43, and the LLC module 43 is connected to the power supply circuit 1 and the control circuit 3, respectively.

The rectifier bridge 41 is configured to rectify an input ac power and input a full-wave signal to the PFC module 42. An Electromagnetic Interference (EMI) filter (not shown in fig. 3) may be connected before the ac power is input into the PFC module 42 to perform high frequency filtering on the input ac power.

The PFC module 42 generally includes a PFC inductor, a switching power device, and a PFC control chip, and mainly performs power factor correction on an input ac power source to output a stable dc bus voltage (e.g., 380V) to the LLC module 43. The PFC module 41 can effectively improve the power factor of the power supply, and ensure the same phase of the voltage and the current.

The LLC module 43 may employ a double-MOS tube LLC resonant conversion circuit, and a synchronous rectification circuit is usually disposed in the LLC module 43, and the synchronous rectification circuit may mainly include a transformer, a controller, two MOS tubes, and a diode. In addition, the LLC module 43 may further include a Pulse Frequency Modulation (PFM) circuit, a capacitor, an inductor, and other components. The LLC module 43 may specifically step down or step up the dc bus voltage input by the PFC module 42, and output a constant voltage to the load 2. In general, the LLC module 43 is capable of outputting a plurality of different voltages to meet the requirements of the load 2.

The power supply 4 may further include a flyback module (not shown in fig. 3) for providing its own supply voltage and standby power to the PFC module 42 and the LLC module 43.

The control circuit 3 is respectively connected with the power source 4 and the power supply circuit 1, and can control whether the power supply circuit 1 is conducted, that is, whether the electric energy output by the LLC module 43 can supply power to the load 2 through the power supply circuit is controlled, so as to realize the on/off of the load. In general, the control circuit 3 is capable of receiving a control signal from a master chip (not shown in fig. 3), which is controlled by the master chip to control the operating state of the power supply circuit 1.

The power supply circuit 1 is further connected to an LLC module, a load, the LLC module 43 being able to supply power to the load 2 when the power supply circuit 1 is switched on, and the LLC module 43 being unable to supply power to the load 2 when the power supply circuit 1 is switched off. In practice, the power supply circuit 1 usually includes a switching element (not shown in fig. 3), such as a MOS transistor, and the control circuit 3 controls the conducting state of the MOS transistor by controlling the voltage of the source and the gate of the MOS transistor.

The load 2 includes a main board 21, a backlight module 22, a display main body 23, and the like, where the main board 21 includes components such as a control unit, and can receive the voltage output by the LLC module 43, and input the received audio/video signal into the display main body 23 after encoding and decoding, and optionally, the main board 21 generally needs 12V voltage. The backlight assembly 22 can receive the voltage output by the LLC module 43, and realize the display of the display main body 23. The display body 23 may include, but is not limited to, a liquid crystal display, among others.

More specifically, taking the display device as a television as an example, fig. 4 shows a schematic structural diagram of a power supply circuit for supplying power to a motherboard and an LED light bar, wherein after commercial power alternating current (100V-240v, 50-60 Hz) obtained by the power supply circuit sequentially passes through a filtering rectification module (rectifier bridge), a PFC module and an LLC module, power is supplied to the motherboard, multiple paths of LED light bars and other loads of the display device, and other loads are not shown in fig. 4. The first secondary winding in the LLC module provides 12V voltage to the motherboard, the second secondary winding provides 18V voltage to the motherboard, and the third secondary winding provides voltage to multiple LED light bars, where the multiple LED light bars are used to light the display screen of the television, and need to operate with a certain voltage drop to reach the rated current of the LED components, for example, 16 LED light bars, and under the condition of 120mA that each light bar includes 9 LED components, the voltage range required by the multiple LED light bars is 51.3V-58.5V, and the total current is 1.92A.

Because the required voltage range is related to the working environment of the multiple paths of LED lamp strips, the hardware characteristics of the LED components, the service life and other factors, the voltage required by the multiple paths of LED lamp strips has a certain variation range and is limited. Therefore, the secondary winding in the LLC module, which supplies power to the multiple LED light bars, is additionally connected to a voltage adjustment module (e.g., buck circuit or boost circuit, for example, the boost circuit in fig. 4) and a voltage driving module, and the voltage adjustment module can adjust the voltage directly output by the secondary winding according to the real-time current feedback result of the multiple LED light bars and then transmit the adjusted voltage to the voltage driving module, so that the voltage driving module controls the multiple LED light bars to operate at a rated current according to the received voltage, thereby preventing damage to components caused by excessive current flowing through the LED components in the multiple LED light bars.

However, in the power supply circuit shown in fig. 4, the voltage stress of the voltage adjustment module provided for multiple paths of LED light bars in the power supply circuit is large, for example, when the voltage range required by the paths of LED light bars is 51.3V to 58.5V, the voltage adjustment module needs to adjust the voltage of more than 50V to be boosted or reduced, which results in a high voltage withstanding value of the components such as the switching tube and the capacitor in the voltage adjustment module, and further occupies a large area of the PCB where the power supply circuit is located, and finally increases the cost of the power supply circuit.

Therefore, the application provides a display device and a power supply circuit, the power supply circuit of the display device is configured to be the sum of voltages respectively output by two different first LLC secondary windings and second LLC secondary windings, and is the voltage for supplying power to at least one path of LED light bars, and a voltage adjustment module in the power supply circuit is configured to only need to adjust the voltage output by the first LLC secondary winding to be boosted or stepped down, and the sum of the adjusted voltage and the voltage output by the second LLC secondary winding is used together to supply power to multiple paths of LED light bars. The application provides a display device and supply circuit can be through the voltage range that sets up two different secondary windings outputs in a flexible way for voltage adjustment module only need adjust the voltage of one of them secondary winding output, thereby reduced the requirement to the withstand voltage value of components such as switch tube, electric capacity in the voltage adjustment module, and then reduced the area of supply circuit place PCB board, finally reduced supply circuit's cost.

The technical solution of the present application will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

Example one

Fig. 5 is a schematic structural diagram of a power supply circuit of a display device according to an embodiment of the present application, where the power supply circuit may be applied to the display device shown in any one of fig. 1 to 3, and as shown in fig. 5, the power supply circuit provided in this embodiment includes: the system comprises a power supply 11, a filter rectification module 12, a PFC module 13, an LLC module 14 and a load. Wherein the load comprises at least a main board 18 and a plurality of LED light bars shown in the figure.

Specifically, after the LLC module 14 of the power supply circuit provided in this embodiment receives the dc voltage sent by the PFC module 13 through the primary winding 141, different secondary windings output different voltages according to the voltage of the primary winding 141 to supply power to different loads, for example, the secondary winding 144 outputs a voltage of 12V to the motherboard 18 according to the voltage of the primary winding 141, and the secondary winding 145 outputs a voltage of 16V to the motherboard 18 according to the voltage of the primary winding 141.

In particular, in this embodiment, two different LLC secondary windings are disposed in the LLC module 14 to supply power to multiple LED light bars, including: a first LLC secondary winding 142 and a second LLC secondary winding 143; wherein, the output end a of the first secondary winding 142 outputs a first voltage, and the output end c of the second secondary winding 143 outputs a second voltage; the output end a of the second secondary winding 143 is connected to the input end b of the first secondary winding 142; meanwhile, the input end b and the output end c of the first LLC secondary winding 142 are both connected to the voltage adjustment module 15, the voltage adjustment module 15 may be configured to adjust the first voltage output by the first LLC secondary winding 142, note that the voltage adjusted by the voltage adjustment module 15 is a third voltage, the voltage adjustment module 15 may send the third voltage and the second voltage output by the second LLC secondary winding 142 to the voltage driving module 16, and the voltage driving module 16 supplies power to the multiple LED light bars according to the sum of the second voltage and the third voltage.

At this time, the second voltage output by the second LLC secondary winding 143 is equivalent to a "fixed voltage" that does not change, and the first voltage output by the first LLC secondary winding 142 is equivalent to a "variable voltage" that changes, so an adjustable variable voltage output is added on the basis of the fixed second voltage, and the fixed voltage and the variable voltage output by the two secondary windings jointly supply power to the multiple LED light bars, which may also be referred to as "step power supply".

Optionally, the first voltage output by the first LLC secondary winding is less than the second voltage output by the second LLC secondary winding.

For example, if the multi-path LED light bar in fig. 5 is a 16-path LED light bar, and each light bar includes 9 LED assemblies, under the condition of 120mA, the voltage range required by the multi-path LED light bar is 51.3V-58.5V, and the total current is 1.92A. For the step power supply implemented by the buck structure, the fixed second voltage output by the second LLC secondary winding may be set to 48V, the first voltage output by the first LLC secondary winding may be set to 12V, and the voltage range adjusted by the voltage adjustment module may be set to 3.3V to 10.5V. At this time, the DC-DC parameters for the buck topology are: the input voltage is 12V, the output voltage range is 3.3V-10.5V, and the output current is 1.92A. For the step power supply implemented by adopting the boost structure, the second voltage can be set to 40V, the first voltage floating output can be set to 10V, and then the DC-DC parameters for the boost topology structure are: the input voltage is 12V, the output voltage range is 11.3V-18.5V, and the output current is 1.92A. The buck topology and the boost topology can be selected according to engineering requirements, for example, the buck topology structure has the advantage of low cost, but the output voltage range is narrow; while the boost topology has the advantage of a wider output voltage range, but its cost is relatively high.

In contrast, the DC-DC parameters of the boost topology for supplying power to multiple LED light bars after adjustment by only one secondary winding as shown in fig. 4 are: the input voltage is 45V, the output voltage range is 51.3V-58.5V, and the output current is 1.92A. Obviously, the power supply circuit provided by the embodiment can respectively output two different voltages through flexibly setting two different secondary windings, and the voltage adjustment module only needs to adjust the voltage output by one secondary winding with a smaller voltage, so that the requirement on the withstand voltage value of elements such as a switching tube and a capacitor in the voltage adjustment module is reduced, the area of a PCB (printed circuit board) where the power supply circuit is located is further reduced, and finally the cost of the power supply circuit is reduced.

When measured from the conversion efficiency of DC-DC, the DC-DC loss of the power supply circuit of this embodiment using buck topology can be calculated by 7v 1.92a 0.05/0.95+0.5v 1.92a =1.67w, and the total efficiency is 98.5%; the DC-DC loss for the supply circuit as shown in fig. 4 can be calculated by 55v 1.92a 0.05/0.95=5.55w, where the total efficiency is 95%; therefore, the power supply circuit of the embodiment also improves the conversion efficiency of DC-DC by 3.5%.

Further, in the embodiment shown in fig. 5, the voltage driving module 16 may also send a feedback signal to the voltage adjusting module 15 according to the real-time current of the multiple paths of LED light bars when supplying power to the multiple paths of LED light bars, so that the voltage adjusting module 15 adjusts the first voltage to a new third voltage according to the feedback signal, thereby implementing timely and effective adjustment of the voltage by the voltage adjusting module.

Optionally, at least two connection relationships of power supply and feedback are included between the voltage adjustment module 15 and the voltage driving module 16, but when the voltage adjustment module 15 performs DC-DC adjustment, its ground point is connected to the output end of the second secondary winding, and its voltage value is not 0V of ground, but is equivalent to adjusting the output voltage of the first secondary winding based on the output voltage value of the second secondary winding, therefore, the feedback signal sent by the voltage driving module 16 to the voltage adjustment module needs to pass through the optical coupler 17, so that the feedback signal is transformed into floating ground voltage by the optical coupler, and the feedback signal sent by the voltage driving module to the voltage adjustment module is optically coupled and isolated, so that the floating ground voltage of the voltage adjustment module 15 at two sides of the optical coupler and the actual ground voltage of the voltage driving module 16 are unified, and mutual influence between them is prevented.

Example two

Fig. 6 is a schematic structural diagram of a power supply circuit of a display device according to a second embodiment of the present disclosure, where the power supply circuit may be applied to the display device shown in any one of fig. 1 to 3, and the power supply circuit shown in fig. 6 and the power supply circuit shown in fig. 5 both adopt an idea that two different voltages output by two different secondary windings are set, and a voltage adjustment module only needs to adjust a voltage output by one secondary winding with a smaller voltage. The only difference is that the power supply circuit in the embodiment shown in fig. 6 adopts a single-flyback structure, the first secondary winding and the second secondary winding are arranged to output voltage through the primary winding in the single-flyback structure, and the first secondary winding and the second secondary winding are arranged in the embodiment shown in fig. 5 to output voltage through the primary winding in the LLC-based module. The principle of the other modules and the power supply circuit shown in fig. 6 is the same as that of the embodiment shown in fig. 5, and are not repeated.

EXAMPLE III

Fig. 7 is a schematic structural diagram of a power supply circuit of a display device according to a third embodiment of the present application, where the power supply circuit may also be applied to the display device shown in any one of fig. 1 to 3, and in the power supply circuit shown in fig. 7, on the basis of the power supply circuit shown in fig. 5, an output end of a first secondary winding is connected to an input end of a second secondary winding, and the multiple LED light bars are supplied with power through an output end of the second secondary winding, at this time, as for an output voltage of the first secondary winding adjusted by a voltage adjustment module, an input end of the first secondary winding is grounded rather than floating, so that in the embodiment shown in fig. 7, an optical coupler may not be provided to optically couple and isolate a feedback signal.

Specifically, the LLC module of the power supply circuit shown in fig. 7 is provided with a first LLC secondary winding 142 and a second LLC secondary winding 143; the input end a of the first secondary winding 142 is grounded, the output end b of the first secondary winding 142 is connected to the input end c of the second secondary winding 143 through the voltage adjusting module 15, and the output end d of the second LLC secondary winding 143 is connected to the voltage driving module; the output end b of the first secondary winding 142 is configured to output a first voltage, the voltage adjustment module 15 is configured to adjust the first voltage output by the first LLC secondary winding 142, and record the voltage adjusted by the voltage adjustment module 15 as a third voltage, and the voltage adjustment module 15 is configured to send the third voltage to the input end c of the second LLC secondary winding 143. The second LLC secondary winding 143 is configured to output a second voltage, an input end c of the second LLC secondary winding 143 is equivalent to a third voltage with a floating ground, an output end d of the second LLC secondary winding 143 sends a sum of the third voltage and the second voltage to the voltage driving module 16, and the voltage driving module 16 supplies power to the multiple LED light bars according to the sum of the second voltage and the third voltage.

At this time, for the second voltage output by the secondary winding 143 of the second LLC corresponds to a "fixed voltage" that does not change, and the first voltage output by the secondary winding 142 of the first LLC corresponds to a "variable voltage" that changes, so that an adjustable variable voltage output is added on the basis of the fixed second voltage, and the fixed voltage and the variable voltage output by the two secondary windings jointly supply power to multiple LED light bars, which may also be referred to as "step power supply". Optionally, the first voltage output by the first LLC secondary winding is less than the second voltage output by the second LLC secondary winding.

Therefore, the power supply circuit provided by the embodiment can respectively output two different voltages through flexibly setting two different secondary windings, and the voltage adjustment module only needs to adjust the voltage output by one secondary winding with a smaller voltage, so that the requirement on the withstand voltage value of elements such as a switching tube and a capacitor in the voltage adjustment module is reduced, the area of a PCB board where the power supply circuit is located is further reduced, and finally the cost of the power supply circuit is reduced. In addition, the optocoupler is not required to be arranged in the embodiment, the complexity of the power supply circuit is reduced, and the cost of the power supply circuit is further reduced.

Example four

Fig. 8 is a schematic structural diagram of a power supply circuit of a display device according to a fourth embodiment of the present invention, where the power supply circuit may also be applied to the display device as shown in any one of fig. 1 to 3, and as shown in fig. 8, in the power supply circuit shown in fig. 5, if a required variation range of the first voltage output by the first LLC secondary winding may be 16V/18V, a secondary winding that provides 16V/18V voltage for the main board may be used as the first LLC secondary winding, and at this time, the first LLC secondary winding does not need to be separately provided. It is understood that, as shown in fig. 8, only the 16V/18V voltage of the main board is taken as an exemplary illustration, if the required variation range of the first voltage is within 12V, the secondary winding providing 12V voltage for the main board may be taken as the first LLC secondary winding; or, in other possible implementations, the secondary winding that provides a certain voltage for other loads may also be used as the first LLC secondary winding, and the like, which are implemented in the same manner as the principle and are not described again.

EXAMPLE five

In the first to fourth embodiments of the present application, the power supply circuit provides the voltage for the step power supply to the driving modules of the multiple LED light bars, and in other possible implementation scenarios, the power supply circuit may also provide the voltage for the step power supply to each of the at least one LED light bar separately.

Fig. 9 is a schematic structural diagram of a power supply circuit of a display device in the prior art, wherein commercial power alternating current (100V-240v, 50-60 Hz) obtained by the power supply circuit sequentially passes through a filtering and rectifying module (rectifying bridge), a PFC module and an LLC module, and then supplies power to a main board of the display device, at least one LED light bar, and other loads, which is illustrated in fig. 9 by taking as an example that the at least one LED light bar includes two LED light bars numbered as (1) and (2), and other loads are not shown in fig. 9. The first secondary winding in the LLC module provides 12V voltage for the main board, the second secondary winding provides 18V voltage for the main board, and the third secondary winding provides voltage for the LED lamp bars (1) and (2). For the same reason as that of the power supply circuit shown in fig. 4, each of the at least one LED light bar needs to operate with a voltage drop within a certain range to achieve a rated current of the LED assembly, so that a voltage adjusting module implemented based on a buck circuit is respectively connected to the output ends of the LED light bars (1) and (2) in fig. 9, and the voltage adjusting module adjusts the voltage output from the secondary winding to the corresponding LED light bar, so that the LED light bars operate with the rated current, and damage to components due to an excessive current flowing through the LED assembly in the LED light bars is prevented.

However, the voltage stress of the voltage adjustment module connected to each LED light bar in the power supply circuit is large, for example, when the voltage range required by each LED light bar is 5.7V to 6.5V, the voltage adjustment module needs to adjust the voltage of more than 5V by boosting or stepping down, which results in a high withstand voltage value of the components such as the switching tube and the capacitor in the voltage adjustment module, and further occupies a large area of the PCB where the power supply circuit is located, thereby increasing the cost of the power supply circuit.

In order to solve the above problem, fig. 10 is a schematic structural diagram of a power supply circuit of a display device according to a fifth embodiment of the present application, where the power supply circuit includes: the power supply 11, the smoothing and rectifying module 12, the PFC module 13, the LLC module 14 and the load. The load at least comprises a main board 18, an LED light bar (1) and an LED light bar (2) shown in the figure, the secondary winding 144 provides 12V voltage to the main board 18 according to the voltage of the primary winding 141, and the secondary winding 145 provides 18V voltage to the main board 18 according to the voltage of the primary winding 141.

In particular, in this embodiment, two different LLC secondary windings are disposed in the LLC module 14 to supply power to at least one LED light bar, where the two different LLC secondary windings include: a first LLC secondary winding 142 and a second LLC secondary winding 143; the input end a of the first secondary winding 142 is grounded, the output end b of the first secondary winding 142 is connected with the input end c of the second secondary winding 143, and the output end d of the second LLC secondary winding 143 is connected with the anodes of the LED light bars (1) and (2), respectively; the output end b of the first secondary winding 142 is configured to output a first voltage, and then the voltage adjustment module 15, which is connected to the LED light bar (1) and implemented based on a buck circuit, may be configured to adjust the first voltage output by the first LLC secondary winding 142, and record the adjusted voltage as a third voltage, and the voltage adjustment module 15 may send the third voltage to the input end c of the second secondary winding 143. The second LLC secondary winding 143 is used for outputting a second voltage, and an output end d of the second LLC secondary winding 143 sends the sum of the third voltage and the second voltage to the LED light bar (1) for power supply. Similarly, for the voltage adjustment module 16 implemented based on a buck circuit and connected to the LED light bar (2), the voltage adjustment module 16 can be configured to adjust the first voltage output by the first LLC secondary winding 142, and record that the adjusted voltage is the fourth voltage, the voltage adjustment module 15 can send the fourth voltage to the input end c of the second secondary winding 143. The second LLC secondary winding 143 is configured to output a second voltage, and an output end d of the second LLC secondary winding 143 sends a sum of the fourth voltage and the second voltage to the LED light bar (2) for power supply.

At this time, the second voltage output by the second LLC secondary winding 143 is equivalent to a "fixed voltage" that does not change, and the first voltage output by the first LLC secondary winding 142 is equivalent to a "variable voltage" that changes, so an adjustable variable voltage output is added on the basis of the fixed second voltage, and the fixed voltage and the variable voltage output by the two secondary windings jointly supply power to the LED light bar, which may also be referred to as "step power supply". In particular, each path of LED light bar can be connected with an independent voltage adjusting module, so that each voltage adjusting module can more effectively adjust the voltage of the connected LED light bar.

It should be noted that, as shown in the embodiment shown in fig. 10, two LED light bars are taken as an example, the power supply circuit may further include any other number of LED light bars, which is only a simple increase or decrease in the number, and the principle is the same and is not repeated.

Optionally, the first voltage output by the first LLC secondary winding is less than the second voltage output by the second LLC secondary winding. The voltage of the fixed voltage part and the voltage of the variable voltage part are about the whole voltage drop required by the LED lamp strip, otherwise, the circuit cannot work normally; meanwhile, the voltage drop of the fixed voltage part cannot be larger than the minimum voltage required by the lighting of the LED lamp, otherwise, the LED lamp strip can be lighted uncontrollably.

For example, fig. 11 is a schematic diagram of a voltage range of an LED light bar of the present application, wherein a voltage drop of the LED light bar in the display device is within a range under a constant current due to a process factor. Assuming that the voltage of the LED light bar is 6V, the voltage range can be 5.7-6.5V. Therefore, in the present embodiment, in order to achieve the output voltage range of the power supply to the LED light bar of 5.7 to 6.5V, the fixed second voltage output by the second secondary winding may be set to 5.7V, and the variable first voltage output by the first secondary winding may be set to about 0.8V. 5.7V ~ 6.5V's scope, the variable voltage is only 0.8V, and the fixed voltage is 5.7V, can realize the driven demand of LED lamp strip.

EXAMPLE six

Fig. 12 is a schematic structural diagram of a power supply circuit of a display device according to a sixth embodiment of the present application, where the power supply circuit shown in fig. 12 and the power supply circuit shown in fig. 10 both adopt an idea that two different voltages respectively output by two different secondary windings are set to supply power to an LED light bar together, and a voltage adjustment module only needs to adjust a voltage output by one secondary winding with a smaller voltage. The only difference is that the power supply circuit in the embodiment shown in fig. 12 adopts a single-flyback structure, the first secondary winding and the second secondary winding are arranged to output voltage through the primary winding in the single-flyback structure, and the first secondary winding and the second secondary winding are arranged in the embodiment shown in fig. 10 to output voltage through the primary winding in the LLC-based module. The principle of the other modules and the power supply circuit shown in fig. 12 is the same as that of the embodiment shown in fig. 10, and are not repeated.

EXAMPLE seven

Fig. 13 is a schematic structural diagram of a power supply circuit of a display device according to a seventh embodiment of the present application, where in the power supply circuit shown in fig. 13, if a variation range required by a first voltage output by a first LLC secondary winding can be 18V on the basis of the power supply circuit shown in fig. 10, a secondary winding that provides 18V voltage for a motherboard can be used as the first LLC secondary winding, and at this time, the first LLC secondary winding does not need to be separately provided, which can further reduce complexity of the power supply circuit and further reduce cost compared with the embodiment shown in fig. 10. It is understood that, as shown in fig. 13, only the 18V voltage of the main board is taken as an exemplary illustration, if the variation range required by the first voltage is within 12V, the secondary winding providing 12V voltage for the main board may be taken as the first LLC secondary winding; or, in other possible implementations, a secondary winding that provides a certain voltage for other loads may also be used as the first LLC secondary winding, and the like, which are implemented in the same manner as the principle and are not described again.

Example eight

Fig. 14 is a schematic structural diagram of a power supply circuit of a display device in the prior art, wherein in the fourth to seventh embodiments, a voltage adjustment module implemented based on a buck circuit is taken as an example, and in other possible implementations, the voltage adjustment module may also be implemented based on a boost circuit. Fig. 14 shows that in the conventional power supply circuit, the first secondary winding in the LLC module provides 12V to the main board, the second secondary winding provides 18V to the main board, and the third secondary winding provides voltage to the LED light bars (1) and (2). Similarly, in order to solve the technical problem that in the power supply module shown in fig. 14, voltage-withstanding values of components such as a switching tube and a capacitor of the voltage adjustment module are high, and further an area of a PCB where the power supply circuit is located is large, and finally a cost of the power supply circuit is increased, fig. 15 is a schematic structural diagram of the power supply circuit of the display device provided in the eighth embodiment of the present application, where the power supply circuit is used as an example for supplying power to two LED light bars (1) and (2), three different LLC secondary windings are provided in the LLC module 14 to supply power to the LED light bars (1) and (2), and the LLC secondary windings include: a first LLC secondary winding 142, and two second LLC secondary windings 143 and 146; the input end a of the first secondary winding 142 is grounded, the output end b of the first secondary winding 142 is connected with the voltage adjusting module 15 and the voltage adjusting module 16, the input end c of the second LLC secondary winding 143 is connected with the voltage adjusting module 15, the output end d is connected with the LED light bar (1), the input end e of the second LLC secondary winding 146 is connected with the voltage adjusting module 16, and the output end f is connected with the LED light bar (2). It can be understood that, when the power supply circuit supplies power to more LED light bars, a second secondary winding and a voltage adjustment module can be respectively provided for each LED light bar, and the LED light bars are connected in the same manner as in fig. 15, and the implementation manner is the same as the principle, and is not described again.

Then, for the voltage adjustment module 15 implemented based on the boost circuit and connected to the LED light bar (1), the voltage adjustment module 15 may be configured to adjust the first voltage output by the first LLC secondary winding 142, and record the adjusted voltage as a third voltage, and the voltage adjustment module 15 may send the third voltage to the input end c of the second secondary winding 143. The second LLC secondary winding 143 is used for outputting a second voltage, and an output end d of the second LLC secondary winding 143 sends the sum of the third voltage and the second voltage to the LED light bar (1) for power supply. Similarly, the boost-circuit-based voltage adjustment module 16 connected to the LED light bar (2) may be configured to adjust the first voltage output by the first LLC secondary winding 142, and the adjusted voltage is recorded as a fourth voltage, and the voltage adjustment module 15 may send the fourth voltage to the input end e of the second secondary winding 146. The second LLC secondary winding 146 is configured to output a fifth voltage, and an output end f of the second LLC secondary winding 143 sends a sum of the fourth voltage and the fifth voltage to the LED light bar (2) together for power supply.

At this time, the second voltage output by the second LLC secondary winding 143 and the fifth voltage output by the third LLC secondary winding 146 are equivalent to "fixed voltages" that do not change, and the first voltage output by the first LLC secondary winding 142 is equivalent to "variable voltages" that change, so that an adjustable variable voltage output is added on the basis of the fixed second voltage, and the fixed voltages and the variable voltages output by the two secondary windings together supply power to the LED light bar, which may also be referred to as "step power supply". In particular, each of the LED light bars can be connected to a separate voltage regulation module and a separate LLC secondary winding, so that each voltage regulation module can more effectively regulate the voltage of the LED light bar to which it is connected.

Alternatively, in the power supply circuit of the embodiment shown in fig. 15, the power supply circuit uses an LLC module to supply power, and a first secondary winding, a second secondary winding, and a third secondary winding are disposed in the LLC module, while in other possible implementations, the power supply circuit may also use the first secondary winding and the second secondary winding disposed in a single flyback structure, and output voltage through the primary winding in the single flyback structure.

Example nine

Fig. 16 is a schematic structural diagram of a power supply circuit of a display device according to a ninth embodiment of the present application, where in the power supply circuit shown in fig. 16, on the basis of the power supply circuit shown in fig. 15, if a variation range required by a first voltage output by a first LLC secondary winding can be 18V, a secondary winding that provides 18V voltage for a motherboard can be used as the first LLC secondary winding, and at this time, the first LLC secondary winding does not need to be separately provided, which can further reduce the complexity of the power supply circuit and further reduce the cost compared with the embodiment shown in fig. 15. It is understood that, as shown in fig. 16, only the 18V voltage of the main board is taken as an exemplary illustration, if the variation range required by the first voltage is within 12V, the secondary winding providing 12V voltage for the main board may be taken as the first LLC secondary winding; or, in other possible implementations, the secondary winding that provides a certain voltage for other loads may also be used as the first LLC secondary winding, and the like, which are implemented in the same manner as the principle and are not described again.

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 these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A display device, comprising:

a display screen configured to display an image screen;

a sound reproducing device configured to play sound;

at least one LED light bar configured to light the display screen;

a power supply circuit configured to supply power to a load of the display device, the load including at least the display screen, the sound reproduction device, and the at least one LED light bar;

the power supply circuit comprises an LLC primary winding, a first resonant converter LLC secondary winding and a second LLC secondary winding, the first resonant converter LLC secondary winding is used for converting the voltage of the LLC primary winding into a first voltage and outputting the first voltage to the at least one path of LED light bars, and the second LLC secondary winding is used for converting the voltage of the LLC primary winding into a second voltage and outputting the second voltage to the at least one path of LED light bars;

the power supply circuit is specifically configured to adjust a first voltage output by the first resonant converter LLC secondary winding to a third voltage, and supply power to the at least one LED light bar through a sum of the third voltage and the second voltage;

the number of the LED lamp strips is multiple; the power supply circuit further includes: the voltage regulation circuit comprises a voltage regulation module and a voltage driving module, wherein the voltage regulation module is a buck circuit;

the voltage driving module is used for sending a feedback signal to the voltage adjusting module according to the current of the multiple paths of LED lamp bars; the feedback signal is used for the voltage adjusting module to adjust the first voltage;

the voltage adjusting module is used for adjusting the first voltage to the third voltage according to the feedback signal.

2. The display device according to claim 1,

the output end of the second LLC secondary winding is connected with the input end of the LLC secondary winding of the first resonant converter, the input end and the output end of the LLC secondary winding of the first resonant converter are connected with the voltage adjusting module, and the voltage adjusting module is connected with the voltage driving module;

the first resonant converter LLC secondary winding is used for outputting a first voltage, and the second LLC secondary winding is used for outputting a second voltage;

3. The display device according to claim 1, wherein the power supply circuit further comprises:

the optical coupler is respectively connected with the voltage driving module and the voltage adjusting module, and the optical coupler is used for carrying out optical coupler isolation when the voltage driving module sends a feedback signal to the voltage adjusting module.

4. The display device of claim 1, wherein the number of LED light bars is multiplexed; the power supply circuit further includes: the voltage regulation module and the voltage driving module;

the output end of the LLC secondary winding of the first resonant converter is connected with the input end of the second LLC secondary winding through the voltage adjusting module, and the output end of the second LLC secondary winding is connected with the voltage driving module;

5. The display device according to claim 1, wherein the power supply circuit further comprises: a voltage adjustment module; the at least one path of LED light bar is respectively connected with a voltage adjusting module;

the output end of the second LLC secondary winding is connected with the input end of the first resonant converter LLC secondary winding, the output end of the first resonant converter LLC secondary winding is respectively connected with the input end of each LED light bar in the at least one LED light bar, the output end of each LED light bar is respectively connected with the input end of a voltage adjusting module, and the output end of each voltage adjusting module is connected with the input end of the first resonant converter LLC secondary winding;

6. The display device according to claim 1, wherein the power supply circuit further comprises: a voltage adjustment module; the at least one path of LED lamp strip is respectively connected with a second LLC secondary winding and a voltage adjusting module;

for each of the at least one path of LED light bars, an output end of the LLC secondary winding of the first resonant converter is connected with an output end of the voltage adjusting module, an input end of the LLC secondary winding of the second resonant converter is connected with an input end of the voltage adjusting module, and an output end of the LLC secondary winding of the second resonant converter is connected with an input end of the LED light bar;

each voltage adjusting module is used for adjusting the first voltage to a third voltage and supplying power to one path of LED lamp strip connected with the voltage adjusting module according to the sum of the third voltage and the second voltage.

7. The display device according to any one of claims 1 to 6,

the output voltage of the first resonant converter LLC secondary winding is also used to power the main board of the display device.

8. The display device according to any one of claims 1 to 6,

the first resonant converter LLC secondary winding and the second LLC secondary winding are secondary windings of an LLC module in the power supply circuit; or,

the first resonant converter LLC secondary winding and the second LLC secondary winding are secondary windings of a flyback voltage conversion module in the power supply circuit.

9. A power supply circuit, comprising:

the LED lamp strip power supply comprises an LLC primary winding, a first resonant converter LLC secondary winding and a second LLC secondary winding, wherein the first resonant converter LLC secondary winding is used for converting the voltage of the LLC primary winding into a first voltage and then outputting the first voltage to at least one LED lamp strip, and the second LLC secondary winding is used for converting the voltage of the LLC primary winding into a second voltage and then outputting the second voltage to at least one LED lamp strip;