CN110048610B - Self-adaptive backlight power supply circuit applied to LLC resonance framework - Google Patents
Self-adaptive backlight power supply circuit applied to LLC resonance frameworkDownload PDFInfo
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- CN110048610B CN110048610BCN201910270821.XACN201910270821ACN110048610BCN 110048610 BCN110048610 BCN 110048610BCN 201910270821 ACN201910270821 ACN 201910270821ACN 110048610 BCN110048610 BCN 110048610B
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
- H02M1/4241—Arrangements for improving power factor of AC input using a resonant converter
- 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
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
Description
Technical Field
The invention relates to the technical field of switching power supply circuits, in particular to a self-adaptive backlight power supply circuit applied to an LLC resonance framework.
Background
At present, the backlight driving architecture of an LED television with a size of more than 55 inches is generally an LLC (resonant circuit) resonant topology architecture, as shown in fig. 1, the work flow of the existing backlight circuit adopting the LLC resonant architecture is as follows: the input alternating current is rectified into direct current which is input into a PFC (power factor correction) circuit, the direct current is output to an LLC end after being corrected by a power factor, backlight voltage is output by an LLC half-bridge resonant circuit, and the current of one path of light string is sampled to adjust the working frequency, so that constant current output is realized.
However, if the parameters of the backlight module need to be changed during the development process or subsequently developing a new module (for example, the backlight voltage is increased from 130V to 150V, and the current is kept constant), the power supply may need to change the transformer, and in severe cases, even the structure of the transformer needs to be changed, so that the power supply board needs to be redesigned. Namely, the existing backlight circuit adopting the LLC resonant framework has the following defects:
1. the efficiency is low: the backlight parameters are changed to cause that the PCB needs to be changed, and the PCB is tested again after being changed, so that great effort and time of engineers are consumed in the process;
2. the compatibility is low: different transformers need to be adopted for different backlight parameters, which means that the number of sets of backlight modules needs to be matched with the number of transformers, and the circuit cost is increased.
Thus, the prior art has yet to be improved and enhanced.
Disclosure of Invention
In view of the above-mentioned shortcomings in the prior art, an object of the present invention is to provide an adaptive backlight power circuit applied to an LLC resonant architecture, which can adapt to multiple sets of backlight parameters without replacing a backlight transformer, thereby improving circuit compatibility and reducing development cost.
In order to achieve the purpose, the invention adopts the following technical scheme:
a self-adaptive backlight power supply circuit applied to an LLC resonance framework comprises a power factor correction module, an LLC resonance module, a backlight module and a backlight voltage feedback regulation module, wherein direct current input into the power factor correction module outputs power factor correction voltage to the LLC resonance module after power factor correction, the power factor correction voltage outputs backlight voltage to the backlight module after resonance is carried out on the power factor correction voltage through the LLC resonance module, the backlight voltage feedback regulation module samples the value of the backlight voltage and feeds back a regulation signal to the power factor correction module, and the power factor correction module regulates the output power factor correction voltage according to the regulation signal, so that the LLC resonance module regulates the working frequency or duty ratio of the LLC resonance module according to the change of the power factor correction voltage.
The self-adaptive backlight power circuit applied to the LLC resonant framework is characterized in that the power factor correction module comprises a PFC control chip, a PFC inductor, a PFC voltage output unit and a PFC feedback voltage sampling unit, direct current is input to a first end of the PFC inductor, a second end of the PFC inductor is connected with a ZCD end of the PFC control chip, a third end of the PFC inductor is respectively connected with the PFC feedback voltage sampling unit and the PFC voltage output unit, a fourth end of the PFC inductor is grounded, the PFC voltage output unit is further connected with the LLC resonant module, and the PFC feedback voltage sampling unit is further connected with an INV end of the PFC control chip.
In the adaptive backlight power circuit applied to the LLC resonant framework, the backlight voltage feedback regulation module comprises a backlight feedback voltage sampling unit and a feedback regulation unit, the feedback regulation unit is respectively connected with the PFC feedback voltage sampling unit and the backlight feedback voltage sampling unit, and the backlight feedback voltage sampling unit is connected with the backlight module.
The self-adaptive backlight power circuit applied to the LLC resonant framework is characterized in that the PFC feedback voltage sampling unit comprises a first resistor, a second resistor, a third resistor and a fourth resistor, one end of the first resistor is respectively connected with a third end of a PFC inductor and the PFC voltage output unit, the other end of the first resistor is connected with one end of the second resistor, the other end of the second resistor is connected with one end of the third resistor, the other end of the third resistor is respectively connected with one end of the fourth resistor and an INV end of a PFC control chip, and the other end of the fourth resistor is connected with the feedback adjusting unit.
The self-adaptive backlight power circuit applied to the LLC resonance framework is characterized in that the feedback adjusting unit comprises a feedback reference chip, a feedback optocoupler, a first capacitor, a fifth resistor and a sixth resistor, wherein the first end of the feedback optocoupler is connected with one end of the fifth resistor and one end of the sixth resistor respectively, the second end of the feedback optocoupler is connected with the other end of the sixth resistor and the cathode of the feedback reference chip respectively, the reference electrode of the feedback reference chip is connected with the backlight feedback voltage sampling unit, the anode of the feedback reference chip is grounded, 12V voltage is input into the other end of the fifth resistor, the third end of the feedback optocoupler is grounded, the fourth end of the feedback optocoupler is connected with one end of the PFC feedback voltage sampling unit and one end of the first capacitor respectively, and the other end of the first capacitor is grounded.
The self-adaptive backlight power circuit applied to the LLC resonant framework is characterized in that the feedback adjusting unit further comprises a second capacitor and a seventh resistor, one end of the seventh resistor is respectively connected with the other end of the sixth resistor, the cathode of the feedback reference chip and the second end of the feedback optocoupler, the other end of the seventh resistor is connected with one end of the second capacitor, and the other end of the second capacitor is respectively connected with the reference electrode of the feedback reference chip and the backlight feedback voltage sampling unit.
In the adaptive backlight power circuit applied to the LLC resonant framework, the feedback reference chip is selected to be a precise controllable voltage regulator TL 431.
The adaptive backlight power supply circuit applied to the LLC resonance framework is characterized in that the backlight feedback voltage sampling unit comprises an eighth resistor, a ninth resistor, a tenth resistor and an eleventh resistor, one end of the eighth resistor is connected with the backlight module, the other end of the eighth resistor is connected with one end of the ninth resistor, the other end of the ninth resistor is connected with one end of the tenth resistor, the other end of the tenth resistor is respectively connected with one end of the eleventh resistor and the feedback regulation unit, and the other end of the eleventh resistor is grounded.
In the adaptive backlight power circuit applied to the LLC resonant framework, the model of the PFC control chip is NCP 1608B.
In the adaptive backlight power circuit applied to the LLC resonant framework, the PFC voltage output unit comprises a third capacitor and a fourth capacitor, and one end of the third capacitor is respectively connected with the third end of the PFC inductor, one end of the fourth capacitor, the PFC feedback voltage sampling unit and the LLC resonant module.
Compared with the prior art, the self-adaptive backlight power supply circuit applied to the LLC resonant framework comprises a power factor correction module, an LLC resonant module, a backlight module and a backlight voltage feedback regulation module, wherein direct current input into the power factor correction module outputs power factor correction voltage to the LLC resonant module after power factor correction, the power factor correction voltage outputs backlight voltage to the backlight module after resonance by the LLC resonant module, the backlight voltage feedback regulation module samples the value of the backlight voltage and feeds back a regulation signal to the power factor correction module, and the power factor correction module regulates the output power factor correction voltage according to the regulation signal, so that the LLC resonant module regulates the working frequency or duty ratio of the LLC resonant module according to the change of the power factor correction voltage. According to the invention, the backlight power supply circuit can adapt to multiple sets of backlight parameters without replacing the backlight transformer through the backlight voltage feedback adjusting module, so that the compatibility of the circuit is improved and the development cost is reduced.
Drawings
Fig. 1 is a schematic circuit diagram of a backlight power circuit applied to an LLC resonant architecture in the prior art;
fig. 2 is a schematic circuit diagram of an adaptive backlight power circuit applied to an LLC resonant architecture according to a preferred embodiment of the present invention.
Detailed Description
The invention provides a self-adaptive backlight power supply circuit applied to an LLC resonance framework, which can adapt to multiple sets of backlight parameters without replacing a backlight transformer, thereby improving the compatibility of the circuit and reducing the development cost. In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention will be described in further detail below with reference to the accompanying drawings by way of examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 2, a schematic circuit diagram of a preferred embodiment of the adaptive backlight circuit applied to the LLC resonant architecture provided in the present invention includes a powerfactor correction module 100, anLLC resonant module 200, abacklight module 300, and a backlight voltagefeedback adjustment module 400, wherein direct current input to the powerfactor correction module 100 is power factor corrected and then outputs a power factor correction voltage to theLLC resonant module 200, the power factor correction voltage resonates through theLLC resonant module 200 and then outputs a backlight voltage to thebacklight module 300, the backlight voltagefeedback adjustment module 400 samples a value of the backlight voltage and feeds back an adjustment signal to the powerfactor correction module 100, the powerfactor correction module 100 adjusts the output power factor correction voltage according to the adjustment signal, so that theLLC resonant module 200 adjusts its own operating frequency or duty ratio according to a change in the power factor correction voltage, thereby stably operating in the resonance state.
Thebacklight module 300 is an LED backlight, and the adaptive adjustment process of the adaptive backlight circuit applied to the LLC resonant architecture is as follows: when the backlight voltage is increased, the backlight voltagefeedback adjustment module 400 samples the backlight voltage and feeds back an adjustment signal to the powerfactor correction module 100, so that the power factor correction voltage (hereinafter, PFC voltage is used for replacement) output by the powerfactor correction module 100 is increased, and after the PFC voltage input by theLLC resonance module 200 is increased, the gain required by theLLC resonance module 200 is reduced, and the working frequency of theLLC resonance module 200 is increased;
when the backlight voltage decreases, the backlight voltagefeedback adjustment module 400 samples the backlight voltage and feeds back an adjustment signal to the powerfactor correction module 100, so that the PFC voltage (power factor correction voltage) output by the powerfactor correction module 100 decreases, and after the PFC voltage input by theLLC resonant module 200 decreases, the gain required by theLLC resonant module 200 increases, and the operating frequency of theLLC resonant module 200 decreases.
Therefore, the present invention adds the backlight voltagefeedback adjustment module 400 on the basis of the existing powerfactor correction module 100, theLLC resonant module 200 and thebacklight module 300, thereby realizing the self-adaptive adjustment of the PFC voltage according to the backlight voltage, enabling theLLC resonant module 200 to constantly work near the resonant point, and finally realizing the self-adaptive adjustment of the backlight circuit.
In a specific embodiment, the powerfactor correction module 100 includes a PFC control chip U1, a PFC inductor L1, a PFCvoltage output unit 110, and a PFC feedbackvoltage sampling unit 120, wherein a first end of the PFC inductor L1 inputs a direct current, a second end of the PFC inductor L1 is connected to a ZCD end of the PFC control chip U1, a third end of the PFC inductor L1 is connected to the PFC feedbackvoltage sampling unit 120 and the PFCvoltage output unit 110, a fourth end of the PFC inductor L1 is grounded, the PFCvoltage output unit 110 is further connected to thebacklight module 300, and the PFC feedbackvoltage sampling unit 120 is further connected to an INV end of the PFC control chip U1.
The PFC inductor L1 is configured to provide energy to the PFCvoltage output unit 110, the PFC feedbackvoltage sampling unit 120 is configured to sample the PFC voltage output by the PFCvoltage output unit 110 and feed back the PFC voltage to the PFC control chip U1, and the PFC control chip U1 adjusts the operating frequency of the driving signal (or adjusts the duty ratio of the driving signal), so that the PFC voltage output by the PFCvoltage output unit 110 is a constant value when the powerfactor correction module 100 normally operates. Preferably, the model of the PFC control chip U1 is NCP1608B, but in other embodiments, other PFC control chips with different signals but the same function may be selected.
More specifically, the PFCvoltage output unit 110 includes a third capacitor C3 and a fourth capacitor C4, and one end of the third capacitor C3 is respectively connected to the third terminal of the PFC inductor L1, one end of the fourth capacitor C4, the PFC feedbackvoltage sampling unit 120, and theLLC resonant module 200. The third capacitor C3 and the fourth capacitor C4 are both large electrolytic capacitors, and can realize the storage and the release of energy. Meanwhile, thepfc module 100 further includes a driving MOS transistor Q1, a freewheeling diode D1, and other peripheral components and circuits, which are not described herein again because those skilled in the art can design the pfc module according to actual requirements.
Further, the backlight voltagefeedback adjustment module 400 includes a backlight feedbackvoltage sampling unit 410 and afeedback adjustment unit 420, thefeedback adjustment unit 420 is respectively connected to the PFC feedbackvoltage sampling unit 120 and the backlight feedbackvoltage sampling unit 410, and the backlight feedbackvoltage sampling unit 410 is connected to thebacklight module 300. The backlight feedbackvoltage sampling unit 410 may sample the backlight voltage output by thebacklight module 300, and thefeedback adjusting unit 420 may perform reference judgment on the sampled backlight voltage and adjust the PFC voltage value sampled by the PFC feedbackvoltage sampling unit 120, so as to adjust the PFC voltage value output by the powerfactor correction module 100.
More specifically, the PFC feedbackvoltage sampling unit 120 includes a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, wherein one end of the first resistor R1 is respectively connected to the third end of the PFC inductor L1 and the PFC voltage output unit 110 (i.e., one end of the third capacitor C3 and one end of the fourth capacitor C4), the other end of the first resistor R1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is respectively connected to one end of the fourth resistor R4 and the INV end of the PFC control chip U1, and the other end of the fourth resistor R4 is connected to thefeedback adjustment unit 420. The PFC voltage output by the powerfactor correction module 100 may be sampled by sampling and dividing sampling resistors such as the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4. Of course, other numbers of sampling resistors are also selected for PFC voltage sampling in other embodiments.
The backlight feedbackvoltage sampling unit 410 includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10 and an eleventh resistor R11, one end of the eighth resistor R8 is connected to thebacklight module 300, the other end of the eighth resistor R8 is connected to one end of the ninth resistor R9, the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10, the other end of the tenth resistor R10 is connected to one end of the eleventh resistor R11 and thefeedback adjustment unit 420, and the other end of the eleventh resistor R11 is grounded. The sampling voltage of the sampling resistors such as the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11 can sample the backlight voltage output by theLLC resonant module 200. Of course, other numbers of sampling resistors are selected for backlight voltage sampling in other embodiments.
In a further embodiment, thefeedback adjusting unit 420 includes a feedback reference chip U2, a feedback optical coupler OC, a first capacitor C1, a fifth resistor R5, and a sixth resistor R6, a first end of the feedback optical coupler OC is connected to one end of the fifth resistor R5 and one end of the sixth resistor R6, a second end of the feedback optical coupler OC is connected to the other end of the sixth resistor R6 and a cathode of the feedback reference chip U2, a reference electrode of the feedback reference chip U2 is connected to the backlight feedbackvoltage sampling unit 410, an anode of the feedback reference chip U2 is grounded, the other end of the fifth resistor R5 is input with 12V voltage, a third end of the feedback optical coupler OC is grounded, a fourth end of the feedback optical coupler OC is connected to one end of the PFC feedbackvoltage sampling unit 120 and one end of the first capacitor C1, and the other end of the first capacitor C1 is grounded.
Preferably, thefeedback adjusting unit 420 further includes a second capacitor C2 and a seventh resistor R7, one end of the seventh resistor R7 is connected to the other end of the sixth resistor R6, the cathode of the feedback reference chip U2 and the second end of the feedback optical coupler OC, the other end of the seventh resistor R7 is connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is connected to the reference electrode of the feedback reference chip U2 and the backlight feedbackvoltage sampling unit 410. Through the second capacitor C2 and the seventh resistor R7, a feedback loop can be compensated, interference is reduced, and the circuit works more stably.
At this time, in the backlight voltagefeedback adjustment module 400, the first end of the feedback optical coupler OC is respectively connected to one end of the fifth resistor R5 and one end of the sixth resistor R6, the second end of the feedback optical coupler OC is respectively connected with the other end of the sixth resistor R6, one end of the seventh resistor R7 and the cathode of the feedback reference chip U2, the reference electrode of the feedback reference chip U2 is respectively connected with the other end of the second capacitor C2, the other end of the tenth resistor R10 and one end of the eleventh resistor R11, the anode of the feedback reference chip U2 is grounded, the other end of the fifth resistor R5 is inputted with 12V voltage, the other end of the seventh resistor R7 is connected with one end of a second capacitor C2, the third end of the feedback optical coupler OC is grounded, and the fourth end of the feedback optical coupler OC is respectively connected with the other end of the fourth resistor R4 and one end of the first capacitor C1, and the other end of the first capacitor C1 is grounded.
Preferably, the feedback reference chip U2 is a precisely controllable voltage regulator TL431, and the TL431 is continuously adjustable from 2.5V to 36V, and has the characteristics of good temperature characteristic in the whole temperature range, fast response and low leakage current. In addition, the first capacitor C1 is used for filtering, the fifth resistor R5 is used for limiting current, and the sixth resistor R6 is used for preventing a light emitting diode in the feedback optical coupler OC from being conducted by mistake.
The working process of the backlight voltagefeedback adjustment module 400 is as follows:
when the backlight voltage is increased, the voltage sampled by the eighth resistor R8, the ninth resistor R9, the tenth resistor R10 and the eleventh resistor R11 is greater than the reference voltage 2.5V of the TL431, so that the feedback optocoupler OC is turned on, and further the sampling value of the PFC voltage sampled by the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 is reduced, so that the PFC control chip U1 increases the working frequency of the driving signal or increases the duty ratio of the driving signal, and further the PFC control chip U1 adjusts the voltage increase of the large electrolytic capacitor (the third capacitor C3 and the fourth capacitor C4); when the voltage of the large electrolytic capacitor is increased, the PFC voltage value input by theLLC resonance module 200 is increased, the gain required by theLLC resonance module 200 is reduced, and the working frequency of the LLC resonance module is increased;
when the backlight voltage is reduced, the voltage sampled by the eighth resistor R8, the ninth resistor R9, the tenth resistor R10 and the eleventh resistor R11 is less than the reference voltage 2.5V of the TL431, so that the feedback optocoupler OC is cut off, further the sampling value of the PFC voltage sampled by the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 is increased, the PFC control chip U1 is caused to reduce the working frequency of the driving signal or reduce the duty ratio of the driving signal, and further the PFC control chip U1 adjusts the voltage reduction of the large electrolytic capacitor; when the voltage of the large electrolytic capacitor is reduced, the PFC voltage value input by theLLC resonance module 200 is reduced, the gain required by theLLC resonance module 200 is increased, and the working frequency of theLLC resonance module 200 is reduced; therefore, the backlight voltagefeedback adjustment module 400 realizes the self-adaptive adjustment of the large electrolytic voltage according to the backlight voltage, and finally theLLC resonance module 200 can work around the resonance point constantly.
Therefore, through the design of the innovative circuit, the circuit is self-adaptive to multiple sets of backlight parameters without replacing a backlight transformer, the compatibility is improved compared with the traditional power supply circuit, the development cost is reduced, and the novel power supply circuit is suitable for the switching power supply which has large backlight parameter variation and adopts an LLC framework as an LED backlight circuit.
In summary, the present invention provides an adaptive backlight power circuit applied to an LLC resonant architecture, which includes a power factor correction module, an LLC resonant module, a backlight module, and a backlight voltage feedback adjustment module, wherein a direct current input to the power factor correction module is power factor corrected and then outputs a power factor correction voltage to the LLC resonant module, the power factor correction voltage resonates through the LLC resonant module and then outputs a backlight voltage to the backlight module, the backlight voltage feedback adjustment module samples a value of the backlight voltage and feeds back an adjustment signal to the power factor correction module, and the power factor correction module adjusts the output power factor correction voltage according to the adjustment signal, so that the LLC resonant module stably operates in a resonant state according to a change in the power factor correction voltage. According to the invention, the backlight power supply circuit can adapt to multiple sets of backlight parameters without replacing the backlight transformer through the backlight voltage feedback adjusting module, so that the compatibility of the circuit is improved and the development cost is reduced.
It should be understood that equivalents and modifications of the technical solution and inventive concept thereof may occur to those skilled in the art, and all such modifications and alterations should fall within the scope of the appended claims.
Claims (10)
1. A self-adaptive backlight power supply circuit applied to an LLC resonance framework is characterized by comprising a power factor correction module, an LLC resonance module, a backlight module and a backlight voltage feedback regulation module, wherein direct current input into the power factor correction module outputs power factor correction voltage to the LLC resonance module after power factor correction, the power factor correction voltage outputs backlight voltage to the backlight module after resonance by the LLC resonance module, the backlight voltage feedback regulation module samples the value of the backlight voltage and feeds back a regulation signal to the power factor correction module, and the power factor correction module regulates the output power factor correction voltage according to the regulation signal so that the LLC resonance module regulates the working frequency or duty ratio of the LLC resonance module according to the change of the power factor correction voltage;
when the backlight voltage is increased and the backlight voltage sampled by the backlight voltage feedback adjusting module is greater than the reference voltage, feeding back an adjusting signal to the power factor correction module to enable the power factor correction voltage to rise, and after the power correction factor input by the LLC resonance module rises, reducing the gain of the LLC resonance module and improving the working frequency;
when the backlight voltage is reduced and the backlight voltage sampled by the backlight voltage feedback dimming module is smaller than the reference voltage, the feedback adjusting signal is sent to the power factor correction module, so that the power factor correction voltage is reduced, and after the power correction factor input by the LLC resonance module is reduced, the gain of the LLC resonance module is increased and the working frequency is reduced.
2. The adaptive backlight power supply circuit applied to the LLC resonant architecture of claim 1, wherein the power factor correction module includes a PFC control chip, a PFC inductor, a PFC voltage output unit, and a PFC feedback voltage sampling unit, a first end of the PFC inductor inputs a direct current, a second end of the PFC inductor is connected to a ZCD end of the PFC control chip, a third end of the PFC inductor is connected to the PFC feedback voltage sampling unit and the PFC voltage output unit, respectively, a fourth end of the PFC inductor is grounded, the PFC voltage output unit is further connected to the LLC resonant module, and the PFC feedback voltage sampling unit is further connected to an INV end of the PFC control chip.
3. The adaptive backlight power supply circuit applied to the LLC resonant framework of claim 2, wherein the backlight voltage feedback regulation module includes a backlight feedback voltage sampling unit and a feedback regulation unit, the feedback regulation unit is respectively connected to the PFC feedback voltage sampling unit and the backlight feedback voltage sampling unit, and the backlight feedback voltage sampling unit is connected to the backlight module.
4. The adaptive backlight power supply circuit applied to the LLC resonant architecture of claim 3, wherein the PFC feedback voltage sampling unit includes a first resistor, a second resistor, a third resistor and a fourth resistor, one end of the first resistor is connected to the third terminal of the PFC inductor and the PFC voltage output unit respectively, the other end of the first resistor is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the fourth resistor and the INV terminal of the PFC control chip respectively, and the other end of the fourth resistor is connected to the feedback adjustment unit.
5. The adaptive backlight power supply circuit applied to the LLC resonant architecture according to claim 3, wherein the feedback regulation unit comprises a feedback reference chip, a feedback optocoupler, a first capacitor, a fifth resistor and a sixth resistor, a first end of the feedback optocoupler is connected to one end of the fifth resistor and one end of the sixth resistor respectively, a second end of the feedback optocoupler is connected to the other end of the sixth resistor and a cathode of the feedback reference chip respectively, a reference electrode of the feedback reference chip is connected to the backlight feedback voltage sampling unit, an anode of the feedback reference chip is grounded, a voltage of 12V is input to the other end of the fifth resistor, a third end of the feedback optocoupler is grounded, a fourth end of the feedback optocoupler is connected to one end of the PFC feedback voltage sampling unit and one end of the first capacitor respectively, and the other end of the first capacitor is grounded.
6. The adaptive backlight power supply circuit applied to the LLC resonant architecture of claim 5, wherein the feedback adjustment unit further includes a second capacitor and a seventh resistor, one end of the seventh resistor is respectively connected to the other end of the sixth resistor, the cathode of the feedback reference chip, and the second end of the feedback optocoupler, the other end of the seventh resistor is connected to one end of the second capacitor, and the other end of the second capacitor is respectively connected to the reference electrode of the feedback reference chip and the backlight feedback voltage sampling unit.
7. The adaptive backlight power supply circuit applied to the LLC resonant architecture of claim 5, wherein the feedback reference chip is selected as a precision controllable voltage regulator TL 431.
8. The adaptive backlight power supply circuit applied to the LLC resonant architecture of claim 3, wherein the backlight feedback voltage sampling unit includes an eighth resistor, a ninth resistor, a tenth resistor and an eleventh resistor, one end of the eighth resistor is connected to the backlight module, the other end of the eighth resistor is connected to one end of the ninth resistor, the other end of the ninth resistor is connected to one end of the tenth resistor, the other end of the tenth resistor is connected to one end of the eleventh resistor and the feedback adjustment unit, respectively, and the other end of the eleventh resistor is grounded.
9. The adaptive backlight power supply circuit applied to the LLC resonant architecture of claim 2, wherein the model of the PFC control chip is NCP 1608B.
10. The adaptive backlight power supply circuit applied to the LLC resonant architecture of claim 2, wherein the PFC voltage output unit includes a third capacitor and a fourth capacitor, one end of the third capacitor is respectively connected to the third terminal of the PFC inductor, one end of the fourth capacitor, the PFC feedback voltage sampling unit, and the LLC resonant module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910270821.XACN110048610B (en) | 2019-04-04 | 2019-04-04 | Self-adaptive backlight power supply circuit applied to LLC resonance framework |
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| CN201910270821.XACN110048610B (en) | 2019-04-04 | 2019-04-04 | Self-adaptive backlight power supply circuit applied to LLC resonance framework |
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| CN110048610Btrue CN110048610B (en) | 2020-11-06 |
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| WO2021185150A1 (en) | 2020-03-18 | 2021-09-23 | 海信视像科技股份有限公司 | Display apparatus and display control method |
| CN111293758A (en)* | 2020-03-30 | 2020-06-16 | 江苏永坤智能科技有限公司 | Charger adaptive to different batteries |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US20070139984A1 (en)* | 2005-12-20 | 2007-06-21 | Yu-Kang Lo | Resonant conversion control method and device with a very low standby power consumption |
| CN101873749B (en)* | 2010-06-25 | 2014-01-15 | 海洋王照明科技股份有限公司 | Power conversion circuit and LED drive circuit |
| CN102523406B (en)* | 2011-12-07 | 2014-01-08 | 青岛海信电器股份有限公司 | Power circuit structure and LED liquid crystal television |
| CN102595739B (en)* | 2012-03-09 | 2014-05-07 | 新视野光电（郑州）有限公司 | LED driving power supply circuit |
| CN103974497A (en)* | 2013-02-05 | 2014-08-06 | 国钰电子(北海)有限公司 | Light emitting diode driving system |
| CN104935841B (en)* | 2015-06-04 | 2018-10-12 | 青岛海信电器股份有限公司 | A kind of power circuit and television set applied to television set |
| CN105848334B (en)* | 2016-03-26 | 2018-03-02 | 中山市德源照明电器有限公司 | L ED constant current control power supply |
| CN206099766U (en)* | 2016-07-18 | 2017-04-12 | 杭州重芯力科技有限公司 | Active PFC+soft switching power converter with adjustable output power |
| CN106059294B (en)* | 2016-07-18 | 2021-03-05 | 杭州重芯力科技有限公司 | Switching power supply and conversion method |
| CN108112127B (en)* | 2018-01-08 | 2019-07-05 | 深圳市崧盛电子股份有限公司 | A kind of constant-current control circuit and power supply that half-bridge resonance Width funtion efficiently exports |
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