CN113763868B - Display device and power supply apparatus - Google Patents
Display device and power supply apparatus Download PDFInfo
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- CN113763868B CN113763868B CN202010483442.1A CN202010483442A CN113763868B CN 113763868 B CN113763868 B CN 113763868B CN 202010483442 A CN202010483442 A CN 202010483442A CN 113763868 B CN113763868 B CN 113763868B
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- 238000005070 sampling Methods 0.000 claims abstract description 6
- 239000003990 capacitor Substances 0.000 claims description 50
- 230000005669 field effect Effects 0.000 claims description 15
- 238000004804 winding Methods 0.000 description 31
- 238000010586 diagram Methods 0.000 description 11
- 238000000034 method Methods 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 230000001965 increasing effect Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
- H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
- H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
- H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/3353—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
- H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
- H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/219—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Dc-Dc Converters (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The application provides a display device and power supply unit, wherein, the sampling point setting of feedback is in the output part of fixed voltage in the power supply unit among the display device, the voltage of the variable voltage part of indirect regulation, accomplish the control to LED drive voltage, thereby realize when the variable voltage sends the fluctuation, can in time feed back and carry out the adjustment of variable voltage, when fixed voltage takes place the fluctuation, also can in time feed back and carry out the regulation of variable voltage, thereby can obtain stable output voltage in multichannel LED drive, improve the shake problem of display screen.
Description
Technical Field
The present application relates to the field of electronic technologies, and in particular, to a display device and a power supply apparatus.
Background
With the development of electronic technology, electronic devices including display devices such as televisions have more and more functions, and users have higher and higher requirements for displaying on display devices such as televisions.
Generally, in some display devices, at least one Light Emitting Diode (LED) Light bar is used to illuminate a display screen.
However, in the prior art, in the screen display, the problem of screen flicker and the like always occurs, which affects the viewing experience of the user.
Disclosure of Invention
The application provides a display device and power supply equipment to solve the screen flashing problem in screen display.
A first aspect of the present application provides a display device comprising:
a display screen configured to display an image picture;
the LED driving circuit is configured to drive at least one path of LED light bar, and the at least one path of LED light bar is used for lightening the display screen;
a power supply circuit configured to supply power to the display screen and the LED driving circuit; the power supply circuit comprises a fixed voltage power supply unit and a variable voltage power supply unit, wherein the fixed voltage power supply unit is superposed on the variable voltage power supply unit to realize step power supply to the LED drive circuit;
a feedback circuit configured to sample an output voltage of the fixed voltage power supply unit and to feed back a variation of the output voltage to a controller of the varying voltage power supply unit;
the controller is configured to control the voltage of the variable voltage power supply unit according to the feedback of the feedback circuit.
In one possible implementation, the feedback circuit includes: a feedback resistance unit and a differential feedback unit;
the feedback resistance unit is respectively connected with the voltage output end of the fixed voltage power supply unit, the LED drive circuit and the controller;
the differential feedback unit is respectively connected with the voltage output end of the fixed voltage power supply unit and the feedback resistance unit.
In one possible implementation, the feedback resistance unit includes: the second resistor, the third resistor, the fourth resistor and the fifth resistor;
one end of the second resistor is connected with a voltage output end of the fixed voltage power supply unit;
the other end of the second resistor is connected with one end of the third resistor and one end of the fifth resistor;
the other end of the third resistor is connected with one end of the fourth resistor and the controller;
the other end of the fourth resistor is grounded;
the other end of the fifth resistor is connected with the LED driving circuit.
In one possible implementation, the differentiating circuit includes: a second capacitor;
one end of the second capacitor is connected with the voltage output end of the fixed voltage power supply unit;
the other end of the second capacitor is connected with one end of the fifth resistor.
In one possible implementation, the differentiating circuit includes: a second capacitor and a first resistor;
one end of the first resistor is connected with a voltage output end of the fixed voltage power supply unit;
the other end of the first resistor is connected with one end of the second capacitor;
the other end of the second capacitor is connected with one end of the fifth resistor.
In one possible implementation, the variable voltage power supply unit includes: the power supply module, the controller, the field effect tube, the diode, the inductor and the first capacitor;
the power supply module is connected with the source end of the field effect tube;
the controller is connected with the grid end of the field effect tube;
the cathode end of the diode and the drain end of the field effect tube are connected with one end of the inductor;
the other end of the inductor is connected with one end of the first capacitor;
and the anode end of the diode and the other end of the first capacitor are grounded.
In a possible implementation manner, the variable voltage power supply unit further includes a sixth resistor;
one end of the sixth resistor is connected with one end of the first capacitor;
the other end of the sixth resistor is connected with the other end of the first capacitor.
In a possible implementation manner, the capacitance value of the first capacitor is smaller than the capacitance value of the second capacitor.
In a possible implementation manner, a difference value between the capacitance value of the first capacitor and the capacitance value of the second capacitor is smaller than a difference threshold.
A second aspect of the present application provides a power supply apparatus, which may include, for example:
the LED driving circuit comprises a fixed voltage power supply unit and a variable voltage power supply unit, wherein the fixed voltage power supply unit and the variable voltage power supply unit are used for superposing the fixed voltage power supply unit on the basis of the variable voltage power supply unit to realize that the LED driving circuit is supplied with power in a stepped manner;
a feedback circuit for sampling an output voltage of the fixed voltage power supply unit and feeding back a variation of the output voltage to a controller of the varying voltage power supply unit;
and the controller is used for controlling the voltage of the variable voltage power supply unit according to the feedback of the feedback circuit.
In summary, the embodiment of the present application provides a display device and a power supply apparatus, and the output end of a fixed voltage power supply unit of a power supply circuit for stepped power supply is sampled and fed back to further adapt to the adjustment of voltage, so that when the variable voltage is sent to fluctuate, the variable voltage can be fed back in time to adjust the variable voltage, and when the fixed voltage fluctuates, the variable voltage can be fed back in time to adjust the variable voltage, so that stable output voltage can be obtained in multi-path LED driving, and the jitter problem of a display screen is improved.
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 structural diagram of a power supply device of a display apparatus according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a possible power supply device provided in an embodiment of the present application;
fig. 5 is a schematic structural diagram of a power supply device of a display apparatus according to an embodiment of the present application;
fig. 6 is a schematic structural diagram of a power supply device of a display apparatus according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the 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 is interchangeable under appropriate circumstances such that the embodiments of the application 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.
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, etc., 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, 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. 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.
In a possible implementation, in order to reduce an area of a Printed Circuit Board (PCB) where a power supply Circuit is located, the power supply Circuit of the display device may be configured to be a sum of voltages output by secondary windings of two different first resonant conversion circuits (LLC) and secondary windings of a second LLC, 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 secondary winding of the first LLC, and to supply the sum of the adjusted voltage and the voltage output by the secondary winding of the second LLC to multiple LED light bars together. The voltage adjusting module only needs to adjust the voltage output by one of the secondary windings, 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, and the cost of a power supply circuit is finally reduced.
For example, fig. 3 is a schematic structural diagram of a power supply circuit of a possible display device, and as shown in fig. 3, the power supply circuit provided in this embodiment includes: the Power supply 11, the filter rectifier module 12, the Power Factor Correction (PFC) module 13, the llc module 14, and the load. Wherein the load includes at least a main board 18 and a plurality of LED light bar drivers 16 as shown.
Specifically, after the LLC module 14 of the power supply circuit 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 main board 18 according to the voltage of the primary winding 141.
Set up two different LLC secondary winding in the LLC module 14 and supply power for multichannel LED lamp strip, include: 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, and send the third voltage output by the voltage adjustment module 15 and the second voltage output by the second LLC secondary winding 143 to the multiple LED drivers 16, and the multiple LED drivers 16 supply 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 secondary winding 143 of the second LLC corresponds to a "fixed voltage" that does not change, and the third voltage output by the voltage adjustment module 15 corresponds to a "variable voltage" that changes, so that the multiple LED light bars are supplied with the superimposed fixed second voltage on the basis of the variable voltage, 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.
It is understood that, as shown in fig. 3, only the 16V/18V voltage of the main board is taken as an exemplary illustration, if the variation range required by the third 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.
However, in the power supply circuit of fig. 3, a problem of cross-adjusting the frequency between different windings may occur in practical applications, and the cross-adjusting the frequency between different windings may cause voltage instability, thereby causing a problem of flicker of the display screen.
In a conceivable feedback design idea, feedback can be set at the output end of the variable voltage, so that the voltage of the power supply circuit can be adjusted based on the voltage output of the variable voltage, and the voltage is stabilized.
For example, fig. 4 shows a circuit diagram of the feedback design concept. However, in the feedback design shown in fig. 4, the stability factor of the system needs to be considered, and the slower the feedback, the more stable the system. The feedback signal of the multi-path LED driving is relatively slow, so when a winding outputting a fixed voltage fluctuates rapidly, for example, the fixed voltage part may cause a change of an output voltage value (such as 12V) due to a load change of other windings, and the change may cause a current jitter in the multi-path LED driving in the circuit, and the feedback of the multi-path LED driving cannot timely adjust the DC-DC output, so that a large fluctuation of the voltage at two ends of the LED light bar may occur, thereby causing abnormal situations such as flicker, protection, and the like.
Based on this, the embodiment of the present application provides a feedback design idea, a sampling point of feedback is set at an output portion of a fixed voltage (which may also be understood as a voltage output end that outputs to an LED, or may be understood as a voltage output end after superposition), a voltage of a variable voltage portion is indirectly adjusted, and control of an LED driving voltage is completed, so that when a variable voltage sends fluctuation, adjustment of the variable voltage can be timely fed back, and when the fixed voltage fluctuates, adjustment of the variable voltage can also be timely fed back, so that stable output voltage can be obtained in multi-path LED driving, and the problem of jitter of a display screen is improved.
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.
Fig. 5 is a schematic structural diagram of a power supply device of a display apparatus according to a second embodiment of the present application, where the power supply device may be applied to the display apparatus shown in any one of fig. 1-2.
As shown in fig. 5, the display device may include: a display screen (not shown in fig. 5), a power supply circuit 51, a feedback circuit 52, and an LED drive circuit 53.
Wherein the display screen is configured to display an image picture.
The LED driving circuit 53 is configured to drive at least one LED light bar, and the at least one LED light bar is used to illuminate the display screen.
A power supply circuit 51 configured to supply power to the display screen and the LED drive circuit; the power supply circuit 51 includes a fixed voltage power supply unit 511 and a variable voltage power supply unit 512, and the fixed voltage power supply unit 511 superimposes on the variable voltage power supply unit 512 to supply power to the LED driving circuit in a stepped manner.
In the embodiment of the present application, the display screen, the power supply circuit 51 and the LED driving circuit 53 may refer to the descriptions in the above embodiments, and are not repeated herein
The feedback circuit 52 in the embodiment of the present application is configured to sample the output voltage of the fixed voltage power supply unit 511, and feed back the variation of the output voltage to the controller 5121 of the varying voltage power supply unit 512. The controller 5121 is configured to control the voltage of the variable voltage power supply unit 512 according to the feedback of the feedback circuit 52.
In the embodiment of the present application, since the sampling point is disposed at the output end of the fixed voltage power supply unit 511, when the voltage fluctuation occurs in the fixed voltage, the voltage fluctuation can be fed back to the controller 5121 of the variable voltage control unit 512 in time, so as to effectively improve the screen flash problem caused by the voltage fluctuation of the fixed voltage power supply unit 511.
On the basis of the corresponding embodiment in fig. 5, in a possible implementation manner, the feedback circuit 52 includes: a feedback resistance unit 521 and a differential feedback unit 522.
The feedback resistance unit 521 is connected to the voltage output terminal of the fixed voltage power supply unit 511, the LED driving circuit 53, and the controller 5121, respectively; the differential feedback unit 522 is connected to the voltage output terminal of the fixed voltage power supply unit 511 and the feedback resistance unit 521, respectively.
In this embodiment of the application, the number of resistors specifically included in the feedback resistor unit 521 and the connection relationship between the resistors may be set according to an actual application scenario, which is not specifically limited in this embodiment of the application.
In the embodiment of the present application, the differential feedback unit 522 may include capacitive devices, and the specific number, type, and the like of the capacitive devices, and the embodiment of the present application is not particularly limited.
In the embodiment of the present application, an implementation manner of the feedback circuit 52 is provided, and a differential feedback unit 522 is provided in the feedback circuit 52, which is equivalent to adding feed-forward, so that output voltage ripple can be reduced, and the voltage stability of the output to the LED driving circuit can be improved.
Illustratively, the feedback resistance unit 521 includes: a second resistor R2, a third resistor R3, a fourth resistor R4 and a fifth resistor R5.
As shown in fig. 5, one end of the second resistor R2 is connected to the voltage output terminal of the fixed voltage supply unit 511; the other end of the second resistor R2 is connected with one end of the third resistor R3 and one end of the fifth resistor R5; the other end of the third resistor R3 is connected to one end of the fourth resistor R4 and the controller 5121; the other end of the fourth resistor R4 is grounded; the other end of the fifth resistor R5 is connected to the LED driving circuit 53.
In one possible implementation, the differentiating circuit 522 includes: a second capacitor C2; one end of the second capacitor C2 is connected to the voltage output end of the fixed voltage power supply unit 511; the other end of the second capacitor C2 is connected to one end of the fifth resistor R5.
In one possible implementation, the differentiating circuit 522 includes: a second capacitor C2 and a first resistor R1; one end of the first resistor R1 is connected to the voltage output end of the fixed voltage power supply unit 511; the other end of the first resistor R1 is connected with one end of the second capacitor C2; the other end of the second capacitor C2 is connected to one end of the fifth resistor R5.
In addition to the corresponding embodiment in fig. 5, in a possible implementation manner, the variable voltage power supply unit 512 includes: the power supply module 5122, the controller 5121, the fet 5123, the diode 5124, the inductor L, and the first capacitor C1.
Illustratively, as shown in fig. 5, the power supply module 5122 is connected to a source terminal of the fet 5123; the controller 5121 is connected with the gate end of the field effect tube 5123; the cathode end of the diode 5124 and the drain end of the field effect tube 5123 are connected with one end of the inductor L; the other end of the inductor L is connected with one end of the first capacitor C1; the positive terminal of the diode 5124 and the other terminal of the first capacitor C1 are grounded.
In a possible implementation manner, the capacitance value of the first capacitor C1 is smaller than that of the second capacitor C2. Alternatively, the difference between the capacitance value of the first capacitor C1 and the capacitance value of the second capacitor C2 is smaller than the difference threshold.
Because R1 and C2 form differential feedback, the response speed of the DC-DC is increased. However, if the capacity of C1 is too large, the charge cannot be released after shutdown, the residual voltage is high, and a fixed voltage output is superimposed when the LED light bar is turned on next time, which causes a phenomenon that the LED light bar flickers, therefore, in the embodiment of the present application, the capacity of C2 is equal to the capacity of C1 or the capacity of C1 is smaller than C2, so that the problem of flickering of the LED light bar when the LED light bar is turned on can be solved, and because the capacity of C2 is equal to the capacity of C1 or the capacity of C1 is smaller than C2, C1 can be a capacitor with a smaller capacity, which can reduce the cost.
In a possible implementation manner, as shown in fig. 6, the variable voltage power supply unit further includes a sixth resistor R6; one end of the sixth resistor R6 is connected with one end of the first capacitor C1; the other end of the sixth resistor R6 is connected to the other end of the first capacitor C1.
In the embodiment of the application, load resistance R6 can be increased, when the display device is turned off, the R6 is used for consuming the circuit in C1, the C1 residual voltage is high when the power is off, and therefore the problem of flickering of the LED lamp strip when the power is on can be solved.
It should be noted that the resistor according to the embodiment of the present application may be a single resistor, or may be a resistive device, or may be a module composed of multiple resistors or multiple resistive devices; the capacitor related to the embodiment of the present application may be a single capacitor, a capacitive device, or a module formed by a plurality of capacitors or a plurality of capacitive devices; the inductor according to the embodiments of the present application may be a single inductor, an inductive device, or a module composed of a plurality of inductors or a plurality of inductive devices. The embodiment of the present application is not particularly limited thereto; the field effect transistor according to the embodiment of the present application may be a single field effect transistor, a field effect device, or a module formed by a plurality of field effect transistors or a plurality of field effect devices. The embodiment of the present application is not particularly limited to this.
The embodiment of the application also provides power supply equipment, which comprises a fixed voltage power supply unit and a variable voltage power supply unit, wherein the fixed voltage power supply unit is superposed on the variable voltage power supply unit to realize that the LED drive circuit is supplied with power in a stepped manner; a feedback circuit for sampling an output voltage of the fixed voltage supply unit and feeding back a variation of the output voltage to a controller of the varying voltage supply unit; and the controller is used for controlling the voltage of the variable voltage power supply unit according to the feedback of the feedback circuit. Reference may be made to the description of the above embodiments, which are not repeated herein.
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 (9)
1. A display device, comprising:
a display screen configured to display an image screen;
the LED driving circuit is configured to drive at least one LED light bar, and the at least one LED light bar is used for lighting the display screen;
a power supply circuit configured to supply power to the display screen and the LED driving circuit; the power supply circuit comprises a fixed voltage power supply unit and a variable voltage power supply unit, wherein the fixed voltage power supply unit is superposed on the variable voltage power supply unit to realize step power supply to the LED drive circuit;
a feedback circuit configured to sample an output voltage of the fixed voltage power supply unit and to feed back a variation of the output voltage to a controller of the varying voltage power supply unit;
the controller is configured to control the voltage of the variable voltage power supply unit according to the feedback of the feedback circuit;
the feedback circuit includes: a feedback resistance unit and a differential feedback unit;
the feedback resistance unit is respectively connected with the voltage output end of the fixed voltage power supply unit, the LED drive circuit and the controller;
the differential feedback unit is respectively connected with the voltage output end of the fixed voltage power supply unit and the feedback resistance unit.
2. The display device according to claim 1,
the feedback resistance unit includes: the second resistor, the third resistor, the fourth resistor and the fifth resistor;
one end of the second resistor is connected with a voltage output end of the fixed voltage power supply unit;
the other end of the second resistor is connected with one end of the third resistor and one end of the fifth resistor;
the other end of the third resistor is connected with one end of the fourth resistor and the controller;
the other end of the fourth resistor is grounded;
the other end of the fifth resistor is connected with the LED driving circuit.
3. The display device according to claim 2, wherein the differential feedback unit comprises: a second capacitor;
one end of the second capacitor is connected with the voltage output end of the fixed voltage power supply unit;
the other end of the second capacitor is connected with one end of the fifth resistor.
4. The display device according to claim 2, wherein the differential feedback unit comprises: a second capacitor and a first resistor;
one end of the first resistor is connected with a voltage output end of the fixed voltage power supply unit;
the other end of the first resistor is connected with one end of the second capacitor;
and the other end of the second capacitor is connected with one end of the fifth resistor.
5. The display device according to any one of claims 1 to 4, wherein the variable voltage power supply unit includes: the power supply module, the controller, the field effect tube, the diode, the inductor and the first capacitor;
the power supply module is connected with the source end of the field effect tube;
the controller is connected with the grid end of the field effect tube;
the cathode end of the diode and the drain end of the field effect tube are connected with one end of the inductor;
the other end of the inductor is connected with one end of the first capacitor;
and the positive end of the diode and the other end of the first capacitor are grounded.
6. The display device according to claim 5, wherein the variable voltage power supply unit further comprises a sixth resistor;
one end of the sixth resistor is connected with one end of the first capacitor;
the other end of the sixth resistor is connected with the other end of the first capacitor.
7. The display device according to claim 6, wherein a capacitance value of the first capacitor is smaller than a capacitance value of the second capacitor.
8. The display device according to claim 6, wherein a difference between the capacitance value of the first capacitor and the capacitance value of the second capacitor is smaller than a difference threshold.
9. A power supply apparatus, comprising:
the LED driving circuit comprises a fixed voltage power supply unit and a variable voltage power supply unit, wherein the fixed voltage power supply unit and the variable voltage power supply unit are used for superposing the fixed voltage power supply unit on the basis of the variable voltage power supply unit to realize step power supply to the LED driving circuit;
a feedback circuit for sampling an output voltage of the fixed voltage power supply unit and feeding back a variation of the output voltage to a controller of the varying voltage power supply unit;
the controller is used for controlling the voltage of the variable voltage power supply unit according to the feedback of the feedback circuit;
the feedback circuit includes: a feedback resistance unit and a differential feedback unit;
the feedback resistance unit is respectively connected with the voltage output end of the fixed voltage power supply unit, the LED drive circuit and the controller;
the differential feedback unit is respectively connected with the voltage output end of the fixed voltage power supply unit and the feedback resistance unit.
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| JP5122141B2 (en) * | 2003-11-13 | 2013-01-16 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | Resonant power LED control circuit with brightness and color tone adjustment |
| JP4788133B2 (en) * | 2004-11-30 | 2011-10-05 | カシオ計算機株式会社 | Power circuit |
| KR20130043023A (en) * | 2011-10-19 | 2013-04-29 | 삼성전자주식회사 | Led driving apparatus, method for driving the led and display apparatus using the same |
| CN104025711B (en) * | 2012-02-10 | 2016-08-24 | 皇家飞利浦有限公司 | The drive circuit loaded at least one and the method operated on it |
| CN102821521A (en) * | 2012-08-13 | 2012-12-12 | 江门市联创发展有限公司 | Full-digital proportion integration differentiation (PID) controlled light-emitting diode (LED) light source driver |
| JP2015186337A (en) * | 2014-03-24 | 2015-10-22 | 東芝ライテック株式会社 | Power supply circuit and illumination device |
| CN208444581U (en) * | 2018-06-15 | 2019-01-29 | 深圳Tcl新技术有限公司 | LCD color TV backlight electric power circuit and LCD color TV |
| CN110391751A (en) * | 2019-08-06 | 2019-10-29 | 深圳创维－Rgb电子有限公司 | Double feedback digital power circuits and power supply |
| CN110677042B (en) * | 2019-09-06 | 2021-05-18 | 华为技术有限公司 | Voltage conversion circuit and power supply system |
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