CN104253960B - The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption - Google Patents

The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption Download PDF

Info

Publication number
CN104253960B
CN104253960B CN201410476693.1A CN201410476693A CN104253960B CN 104253960 B CN104253960 B CN 104253960B CN 201410476693 A CN201410476693 A CN 201410476693A CN 104253960 B CN104253960 B CN 104253960B
Authority
CN
China
Prior art keywords
voltage
circuit
power supply
resistance
diode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201410476693.1A
Other languages
Chinese (zh)
Other versions
CN104253960A (en
Inventor
吴永芳
刘威河
廖武
杨达富
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangzhou Kun Electronic Technology Co. Ltd.
Original Assignee
Guangzhou Shiyuan Electronics Thecnology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Guangzhou Shiyuan Electronics Thecnology Co Ltd filed Critical Guangzhou Shiyuan Electronics Thecnology Co Ltd
Priority to CN201410476693.1A priority Critical patent/CN104253960B/en
Publication of CN104253960A publication Critical patent/CN104253960A/en
Application granted granted Critical
Publication of CN104253960B publication Critical patent/CN104253960B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

The invention discloses a kind of voltage stabilizing backlight control circuit of low-power consumption, including：Front end power circuit, DC D/C voltages regulation circuit, rear end linear constant current circuit and voltage detecting circuit；Front end power circuit includes power supply circuit, the first power supply output end, the second power supply output end and feedback circuit；Feedback circuit controls the power supply circuit to be adjusted the magnitude of voltage of the first power supply output end and the second power supply output end according to the magnitude of voltage of control signal input；DC D/C voltages adjust circuit and the voltage signal that the second power supply output end is exported are adjusted into fixed voltage signal；Voltage detecting circuit turns off the electric current for flowing through LED string when LED string is closed, and present invention also offers a kind of television set of adaptation power supply regulation.The present invention provides technical scheme can control output voltage according to the voltage change of LED string, the supply voltage of stable mainboard and prevent the LED generations glimmer phenomenon when closing backlight.

Description

The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption
Technical field
The present invention relates to power supply technical field, more particularly to a kind of voltage stabilizing backlight control circuit of low-power consumption and including The television set of the adaptation power supply regulation of the voltage stabilizing backlight control circuit of the low-power consumption.
Background technology
In TV set power control technology field, often realized while to master using one-level linear constant-current modulation circuit The power supply of plate and LED backlight.
Linear constant-current modulation circuit is widely used a kind of element circuit in Analogous Integrated Electronic Circuits, and it is generally interior provided with more Road exports transformer, by the multiple-channel output transformer, draws output all the way as LED backlight power supply output end, then draw another Power supply output end of the output as mainboard all the way.In integration process is carried out to television components, mainboard and backlight lamp bar are usual Need to form a complete production network, and the different backlight LED light bars of quantity will need linear constant-current modulation circuit adaptability to export different electricity Pressure value.In the prior art using a backfeed loop being connected with TV SKD power supply output end, timely monitoring TV mainboard The voltage change for output end of powering.
As shown in figure 1, being a kind of schematic diagram for linear constant-current modulation circuit that prior art provides, pass through power circuit 10 LED power supply signals and main board power supply signal are provided.When the output voltage rise of main board power supply output end, pass through resistance RB135 Be linked into the voltage signal after resistance RB134 partial pressures in voltage-stabiliser tube UB102 reference input R0, and by the voltage signal with Reference voltage (such as 2.5V) inside voltage-stabiliser tube UB102 is made comparisons so that voltage drop between voltage-stabiliser tube UB102 anode and cathodes Low, and then optocoupler diode PCB101A electric current becomes big, the dynamic electric resistor between colelctor electrode and emitter stage diminishes, colelctor electrode with Voltage step-down between emitter stage；The variable quantity of voltage signal is fed back in power circuit 10 by output terminals A DJ/Vs-ON Internal transformer；The internal transformer output voltage in power circuit 10 is reduced to the voltage of setting therewith.Therefore, with electricity The increase of RB134 resistances, the output voltage reduction of LED power supply output ends and main board power supply output end are hindered, otherwise voltage raises.
Due to the difference of application scenario, in the reality of LED (Light Emitting Diode, light emitting diode) television set Linear constant current circuit is generally required in production process and exports different magnitudes of voltage, and is exported to the power supply of TV SKD and backlight End is typically each under the jurisdiction of same transformer, will necessarily be to another when output end of being powered all the way to any of which is modulated The power supply output end on road has an impact.For example, generally require to adjust output extremely according to backlight LED number change in practice The supply voltage of LED string, and the supply voltage of TV SKD is relatively fixed, therefore, prior art can not meet adjusting While the output voltage values of LED power supply output ends, the demand of the voltage stabilization of supply TV SKD is adaptively kept.
In addition, prior art when being improved to linear constant current circuit, often causes the power supply in shut-off backlight LED When, backlight LED one end is still connected with electricity consumption device and weak current be present so that the weak current is played a reversed role to backlight LED So that backlight LED is turned on and sent faint light, this does not allow in television set manufacturing technology field.
The content of the invention
The technical problem to be solved by the invention is to provide a kind of voltage stabilizing backlight control of low-power consumption electricity
Road, backlight of television LED can be complete switched off, avoid unnecessary power consumption penalty and improve backlight LED use Life-span.
To solve above technical problem, on the one hand, the embodiments of the invention provide a kind of voltage stabilizing backlight control of low-power consumption Circuit, including：Front end power circuit, DC-DC voltage regulator circuits, rear end linear constant current circuit and voltage detecting circuit；
The front end power circuit includes power supply circuit, the first power supply output end, the second power supply output end and feedback circuit； The first power supply output end is connected with the anode of LED string, electric for being acted in collusion to make each other's confessions to the LED；
The input of the DC-DC voltage regulator circuits is connected with the described second power supply output end, for by described second After the voltage signal that power supply output end is exported is adjusted to fixed voltage signal, exports to mainboard and be powered；
The rear end linear constant current circuit includes constant-current control circuit and a switching tube (QB1), for controlling output to institute The electric current for stating LED string is constant current signal；When the switching tube (QB1) is triode, the constant-current control circuit passes through institute The colelctor electrode for stating triode is connected with the negative electrode of the LED string；When the switching tube (QB1) is field-effect transistor, institute Constant-current control circuit is stated to be connected with the negative electrode of the LED string by the drain electrode of the field-effect transistor；
Voltage acquisition all the way is drawn in the constant-current control circuit and the LED string junction to export
End, is connected with the voltage detecting circuit；The voltage detecting circuit includes the first diode and the first electricity
Resistance；Wherein, the negative electrode of the first diode is connected on the negative electrode of the LED string；The anode of first diode connects It is connected on one end of first resistor, the other end access high level of first resistor；
When the LED string is opened, the first diode current flow, the voltage detecting circuit passes through the first diode detection Go out the operating voltage of the LED string, so as to control the feedback circuit adjustment the first power supply output end, the second power supply defeated Go out the output voltage at end；When the LED string is closed, the first diode reverse cut-off, shut-off flows through the electricity of the LED string Stream.
Further, the voltage detecting circuit also includes second resistance；One end of second resistance and the first diode Anode connects, and the other end is as the voltage acquisition output end.
Further, the voltage detecting circuit also includes the second diode；
The anode of second diode is connected with the anode of the first diode；The negative electrode of second diode is as institute State voltage acquisition output end.
Preferably, the voltage detecting circuit also includes 3rd resistor；One end ground connection of the 3rd resistor, the other end connect It is connected in the voltage detecting output end.
Further, the voltage detecting circuit also includes voltage-regulator diode (D1), the first electric capacity；And voltage-regulator diode (D1) negative electrode is connected as voltage detecting output end jointly with one end of the first electric capacity；The anode of voltage-regulator diode (D1) and The other end common ground of one electric capacity.
Further, the feedback circuit includes feedback input end, control signal input and feedback signal output；
The feedback input end is connected with the described second power supply output end, the feedback signal output and the power supply electricity Road connects；The feedback circuit is according to the magnitude of voltage of the control signal input, to the power supply circuit output feedback signal, To control the power supply circuit to be adjusted the magnitude of voltage of the described first power supply output end and the second power supply output end.
Further, in the front end power circuit, the feedback circuit is additionally provided with optocoupler
(PCB101), voltage-stablizer (UB102)；
The optocoupler (PCB101) includes the light emitting diode positioned at primary side and the optical signal converter positioned at secondary；
The control signal that the control signal input inputs is accessed to the optocoupler by the voltage-stablizer (UB102) (PCB101) the light emitting diode positioned at primary side；The light emitting diode is transferred to institute after control signal is converted into optical signal State the optical signal converter positioned at secondary of optocoupler (PCB101)；After the optical signal converter converts optical signals to electric signal Export to the feedback signal output.
Preferably, the voltage-stablizer (UB102) uses adjustable precision shunt voltage-stablizer, including negative electrode
(K), anode (A) and reference input (R), and interior have reference voltage；
Wherein, anode (A) ground connection of the adjustable precision shunt voltage-stablizer, negative electrode (K) and the optocoupler (PCB101) Positioned at primary side light emitting diode connect；Reference input (R) is used for the control signal for accessing the control signal input.
Further, the reference input (R) of the adjustable precision shunt voltage-stablizer passes through a divider and the control Signal input part connection processed, it is preferable that the divider is one the 7th resistance.
Yet further, the DC-DC voltage regulator circuits are liter voltage regulator circuit or reduction regulation circuit.
On the other hand, present invention also offers a kind of television set of adaptation power supply regulation, including：Mainboard, LED string, And the voltage stabilizing backlight control circuit of the low-power consumption described in any one as described above；
The voltage stabilizing backlight control circuit is connected respectively with the mainboard and the LED string, for opening the electricity Depending on machine power supply when, according to the operating voltage of the LED string, automatic adjusument supplies the mainboard, the electricity of the LED string Press signal.
Implement technical scheme provided by the invention, can by front end power circuit provide duplex feeding output end, first Output end of powering is used to power to LED backlight；Second power supply output end is connected with DC-DC voltage regulator circuits, and second is supplied After the voltage signal that electricity output end is exported is adjusted to fixed voltage signal, exports to mainboard and be powered, offer is provided Voltage stability to mainboard；It is constant current signal that rear end linear constant current circuit, which is used to control the electric current for flowing through LED string,；Voltage is examined Slowdown monitoring circuit is connect by the first diode and LED series winding, when LED string is opened, the first diode current flow, and voltage detecting circuit The operating voltage of LED string is detected, so as to control the feedback circuit adjustment the first power supply output end, second to supply The output voltage at electricity output end；When the LED string is closed, the cut-off of the first diode reverse, complete switch off and flow through the LED The electric current of lamp string, therefore the present invention can be in backlight open, the operating voltage of normal acquisition LED string, so as to adaptively Adjust the voltage signal values to mainboard and LED statements based on collusion electricity；When receiving the order for closing backlight LED, LED string both ends phase Avoid unnecessary power consumption penalty without glimmer phenomenon when in open circuit, LED and improve backlight LED service life.
Brief description of the drawings
Fig. 1 is a kind of schematic diagram for linear constant-current modulation circuit that prior art provides.
Fig. 2 be low-power consumption provided by the invention constant current and controlling circuit of voltage regulation one embodiment structural representation.
Fig. 3 is a kind of physical circuit schematic diagram of achievable mode of front end power circuit provided by the invention.
Fig. 4 is a kind of physical circuit schematic diagram of front end power circuit provided by the invention.
Fig. 5 is a kind of circuit theory diagrams when DC-DC voltage regulator circuits provided by the invention are liter voltage regulator circuit.
Fig. 6 is a kind of circuit theory diagrams of achievable mode of rear end linear constant current circuit provided by the invention.
Fig. 7 is the structural representation of one embodiment of the voltage stabilizing backlight control circuit of low-power consumption provided by the invention.
Fig. 8 is a kind of physical circuit figure of achievable mode of voltage detecting circuit provided by the invention.
Fig. 9 is that the physical circuit figure of mode can be achieved in the another kind of voltage detecting circuit provided by the invention.
Figure 10 is the structural representation of another embodiment of the voltage stabilizing backlight control circuit of low-power consumption provided by the invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Site preparation describes.
The present invention is by LED television mainboard with specific embodiment being described exemplified by LED backlight, it is necessary to illustrate , the present invention provides or improved various circuits are applicable to various mainboards to be powered and LED in itself.
It is that the constant current of low-power consumption provided by the invention and the structure of one embodiment of controlling circuit of voltage regulation are shown referring to Fig. 2 It is intended to.
In the present embodiment, the constant current of described low-power consumption includes front end power circuit 101, DC- with controlling circuit of voltage regulation D/C voltage adjusts circuit 102 and rear end linear constant current circuit 103.
The front end power circuit 101 includes the power supply output end of power supply circuit 1011, first OUT1, the second power supply output end OUT2 and feedback circuit 1012；
Wherein, the feedback circuit 1012 includes feedback input end A_in, control signal input Cont and feedback signal Output end B_out；The feedback input end A_in is connected with the described second power supply output end OUT2, the feedback signal output B_out is connected with the power supply circuit 1011；The feedback circuit 1012 is according to the voltage of the control signal input Cont Value, to the output feedback signal of power supply circuit 1011, to control the power supply circuit 1011 to the described first power supply output end OUT1 and the second power supply output end OUT2 magnitude of voltage are adjusted.
When it is implemented, the LED string that the present embodiment provides is preferably backlight of television LED string, and supplied by first Electricity output end OUT1 is powered；The mainboard is preferably TV SKD, and is supplied by the second power supply output end OUT2 Electricity.
It is a kind of physical circuit schematic diagram of achievable mode of front end power circuit provided by the invention referring to Fig. 3.
In a kind of achievable mode, as shown in figure 3, feedback circuit 1012 can be provided with optocoupler PCB101, voltage-stablizer UB102 And its peripheral circuit.Wherein, the optocoupler PCB101 includes light emitting diode (the i.e. He of pin 1 of optocoupler PCB101 positioned at primary side The component of pin 2) and optical signal converter (i.e. the component of optocoupler PCB101 pin 3 and pin 4) positioned at secondary.
Voltage-stablizer UB102 by the control signal that the control signal input inputs access to optocoupler PCB101 positioned at original The light emitting diode on side；The light emitting diode is converted to control signal the position that the optocoupler PCB101 is transferred to after optical signal In the optical signal converter of secondary；The optical signal converter is exported to the feedback signal after converting optical signals to electric signal Output end.
Further, the feedback circuit 1012 is additionally provided with the 5th resistance RB131 and the 6th resistance RB132；Described 5th Resistance RB131 one end is the feedback input end, the sun of the other end and the optocoupler PCB101 light emitting diode positioned at primary side Pole connects；One end of the 6th resistance RB132 is connected to the anode of the light emitting diode, and the other end is connected to described luminous On the negative electrode of diode.
Wherein, the input (pin 1) positioned at the light emitting diode of primary side is used as feedback input end by the 5th resistance RB131 A_in is connected with the second power supply output end OUT2, and optocoupler PCB101 primary side both ends (pin 1 and pin 2) and the 6th resistance RB132 It is in parallel；Output end (pin 4) connection positioned at the optical signal converter of optocoupler PCB101 secondary is used as feedback signal output B_ Out is connected with the feedback control end feedback of power supply circuit 1011, the other end (pin 3) ground connection of optical signal converter.Need Illustrate, the 6th resistance RB132 is not the necessary electronic component in the feedback circuit in the present embodiment.
Voltage-stablizer UB102 preferably uses adjustable precision shunt voltage-stablizer, including negative electrode K, anode A and reference input R, And the reference voltage of built-in 2.5V (volt), it is preferable that can be realized using model TL431 voltage-stablizer.Wherein, it is described can The anode A ground connection of precision shunt voltage-stablizer is debugged, the negative electrode K and optocoupler PCB101 light emitting diode positioned at primary side connects Connect；Reference input R is used for the control signal for accessing the control signal input Cont.
Further, the feedback circuit 1012 is additionally provided with voltage stabilizing feedback circuit.
In a kind of achievable mode, the voltage stabilizing feedback circuit includes the second electric capacity CB109 and the 4th resistance RB133；One end of the second electric capacity CB109 is connected on the negative electrode K of the adjustable precision shunt voltage-stablizer, the other end with 4th resistance RB133 one end series connection；The 4th resistance RB133 other end is connected to the adjustable precision shunt voltage-stablizer On reference input R.
In another achievable mode, the voltage stabilizing feedback circuit includes the 3rd electric capacity CB110；3rd electric capacity CB110 one end is connected on the negative electrode K of the adjustable precision shunt voltage-stablizer, and it is accurate that the other end is connected to the adjustable On the reference input R of shunt regulator.
Further, both the above implementation can be combined by the present embodiment, to realize the voltage stabilizing feedback electricity Road.I.e. described voltage stabilizing feedback circuit is provided with the second electric capacity CB109, the 4th resistance RB133 and the 3rd electric capacity CB110 simultaneously.
As shown in figure 3, voltage-stablizer UB102 negative electrode K is connected with the pin of light emitting diode 2 of optocoupler PCB101 primary sides, voltage stabilizing Device UB102 anode A ground connection；Resistance RB134 one end is connected with voltage-stablizer UB102 reference input R, other end ground connection； Second electric capacity CB109 one end is connected on the negative electrode K of the adjustable precision shunt voltage-stablizer, the other end and the 4th resistance RB133 one end series connection；The 4th resistance RB133 other end is connected to the reference input of the adjustable precision shunt voltage-stablizer Hold on R；One end of the 3rd electric capacity CB110 is connected on the negative electrode K of the adjustable precision shunt voltage-stablizer, and the other end connects It is connected on the reference input R of the adjustable precision shunt voltage-stablizer.
Further, the reference input R of the adjustable precision shunt voltage-stablizer passes through a divider and the control Signal input part connects.In this embodiment, it is preferred that the divider is one the 7th resistance RB150.
As shown in figure 3, second electric capacity CB109 one end is connected with optocoupler PCB101 2 pin, the other end and the 4th resistance It is connected after RB133 series connection with the 7th resistance RB150 one end, the 7th resistance RB150 other end is defeated as the control signal Enter to hold Cont；3rd electric capacity CB110 one end is connected with voltage-stablizer UB102 negative electrode K, the ginseng of the other end and voltage-stablizer UB102 Examine input R connections；Resistance RB135 one end is connected with feedback input end A_in, and the reference of the other end and voltage-stablizer UB102 is defeated Enter to hold R to connect.Thus, a kind of specific embodiment of feedback circuit 1012 is constituted.
In the present embodiment, increase by one the 7th resistance RB150 on voltage-stablizer UB102 reference input R, pass through simultaneously Control signal input Cont introduces a control signal and carries out automation control to voltage-stablizer UB102 negative electrode K output voltage values System, so as to which the regulation to power supply circuit 1011 and its output voltage can be realized.
It is a kind of physical circuit schematic diagram of front end power circuit provided by the invention referring to Fig. 4.
Wherein, the power supply circuit 1011 includes power supply input circuit 11, switching power circuit 12, multiple-channel output transformer TB101, LED power supply output circuit 13 and main board power supply output circuit 14.
The power supply input circuit 11 under the control of the switching power circuit 12 by the power supply signal of access transmit to The multiple-channel output transformer TB101；As shown in figure 4, the multiple-channel output transformer TB101 includes main winding and auxiliary winding. Wherein, the coil of the pin of multiple-channel output transformer TB101 9 pin~11 forms primary main winding, multiple-channel output transformer TB101's The coil of the pin of 1 pin~2 forms secondary main winding；The coil of the pin of multiple-channel output transformer TB101 7 pin~8 formed it is primary it is secondary around Group, the coil of the pin of multiple-channel output transformer TB101 1 pin~6 form secondary auxiliary winding, wherein, based on the coil of the pin of 1 pin~2 The shared winding of winding and time winding, can be with common sparing winding between secondary main winding and auxiliary winding, it is necessary to explanation, can also Using independent winding.When it is implemented, the main winding will be transmitted after the power supply signal transformation it is defeated to the main board power supply Go out circuit 14, and exported by the described second power supply output end OUT2；The auxiliary winding synchronously becomes the power supply signal Transmit after pressure to LED power supply output circuits 13, and exported by the described first power supply output end OUT1；Therefore, Fig. 4 In multiple-channel output transformer TB101 there is two output voltage.
Especially, in technical field of television sets, the first power supply output end OUT1 is preferably the power supply for supplying LED backlight Output end, the second power supply output end OUT2 is preferably the power supply output end for supplying TV SKD.
In the present embodiment, output voltages of the multiple-channel output transformer TB101 per circle coil is identical, when changing wherein Output voltage all the way, then the output voltage of another way also will synchronously follow change.For example, the coil of main winding is 2 circles, Output voltage is 12V, i.e., is 6V per the output voltage of circle coil；Assuming that the output voltage of auxiliary winding is 120V, then auxiliary winding Coil turn is 20 circles.And the coil turn of main winding and auxiliary winding can be adjusted according to practical application, i.e., described master The coil ratio of winding and the auxiliary winding is 1：N, N ＞ 0, i.e., when the output voltage of main winding is V1, auxiliary winding it is defeated It is V2=N*V1 to go out voltage.
It should be noted that the feedback input end A_in of feedback circuit 1012 can connect the first of the power supply circuit 1011 Power the power supply output end OUT2 of output end OUT1 or second, has no effect on the implementation of the present embodiment.
The outside control letter that the present invention can be accessed by the control signal input Cont of linear regulation feedback circuit 1012 Number size, so as to control the first power supply output end OUT1 or second to power output end OUT2 magnitude of voltage.Specifically, with described The feedback input end A_in of feedback circuit 1012 is connected to exemplified by the second power supply output end OUT2 of the power supply circuit 1011, this The basic functional principle of embodiment is mainly：
When the output voltage of power supply circuit 1011 raises, (the first power supply output end OUT1 and the second power supply output end OUT2 are same When Shi Shenggao), control signal input Cont control signal passes through resistance RB135 and resistance RB134, the 7th resistance RB150 Voltage after partial pressure is transmitted to voltage-stablizer UB102 reference input R, voltage-stablizer UB102 by reference input R signal value with Its internal reference voltage is compared.When reference input R signal value is more than reference voltage, voltage-stablizer UB102 anode and cathodes Between voltage reduce, and then optocoupler PCB101 electric current increase, dynamic electric resistor between optocoupler PCB101 colelctor electrodes and emitter stage Diminish (4 pin of optocoupler PCB101 current collection extremely optocoupler, 3 pin of transmitting extremely optocoupler), the electricity between colelctor electrode and emitter stage Buckling is low；PWM (Pulse Width Modulation, pulse width modulation) the control chip UB101 connected therewith feedback Pin COMP level step-down, pwm chip UB101 output duty cycles reduce, so that multiple-channel output transformer TB101 Output voltage reduces.Conversely, when reference input R signal value is less than reference voltage, multiple-channel output transformer may be such that TB101 output voltage (including the first power supply output end OUT1 and the second power supply output end OUT2 output voltage) rise.Cause This, voltage-stablizer UB102 reference input R magnitude of voltage determines multiple-channel output transformer TB101 output voltage.
Therefore, based on principles above, to reach the voltage signal of regulation voltage-stablizer UB102 reference input R accesses Size is so as to control the purpose of transformer TB101 output voltage, and the present invention is by increasing by the 7th resistance RB150 and in the 7th electricity The side incoming control signal for hindering RB150 is realized.Specifically, when the output electricity for needing the power supply output end of modulation second OUT2 Pressure, and when voltage-stablizer UB102 internal reference voltage be 2.5V, the second output voltage values calculation formula for powering output end is： Vout2=reference voltages * (1+R135/R134), wherein, reference voltage is preferably 2.5V.Preferably, core can be controlled by outside Piece exports a PWM_12V signal to the control signal input Cont, via the 7th resistance RB150 by PWM_12V signals Transmit to series connection point between resistance RB134 and resistance RB135 (i.e. voltage-stablizer UB102 reference input R).
When it is implemented, control signal input Cont PWM_12V signals can use any one perseverance in 0-3.3V Determine magnitude of voltage, or, using PWM (Pulse Width Modulation, pulse width modulation) ripple of certain waveform.According to The output voltage values calculation formula of two power supply output ends：Vout2=reference voltages * (1+R135/R134), under any circumstance, When by control signal input Cont from outside control chip to feedback circuit 1012 input control signal for 3.3V (most When greatly), the second power supply output end OUT2 output voltage is minimum, because control signal input Cont input voltage (3.3V) more than voltage-stablizer UB102 reference voltage 2.5V (when circuit stability works voltage-stablizer UB102 1 pin voltage and Reference voltage is almost equal), so be the equal of now that the 7th resistance RB150 is connected on 3.3V power supply, that is, equivalent to 7th resistance RB150 is connected in parallel on resistance RB135, it can be seen from Vout2 voltage equation, because resistance RB135 is in parallel 7th resistance RB150, the equivalent resistance equivalent to resistance RB135 is reduced, so that output voltage Vout2 is reduced.When passing through When the control signal of control signal input Cont input of the outside control chip to feedback circuit 1012 is 0V (minimum), second Output end of powering OUT2 output voltage is maximum, because the control signal of control signal input Cont inputs is suitable when being 0V In ground connection, at this moment it has been connected in parallel on equivalent to by the 7th resistance RB150 on resistance RB134, according to above-mentioned voltage computing formula, due to Resistance RB134 7th resistance RB150 in parallel, the equivalent resistance equivalent to resistance RB135 diminishes, so that output voltage Vout2 is raised.
It can be seen that by the control signal of the control signal input Cont of linear regulation feedback circuit 1012 input (such as Above-mentioned 0V~3.3V constant voltage signal or PWM ripples), it may be such that the second power supply output end OUT2 output voltage in reality (Vout2_max=12.5V, Vout2_min=11.5V) is adjusted between common voltage scope 11.5V~12.5V, so as to Realize fine setting；Similarly, in the presence of multiple-channel output transformer TB101, the first power supply output end OUT1 output voltage also will Synchronous automatic adaptation regulation is realized, especially, the output voltage of supply TV motherboard circuit often changes 0.01V, supplies LED string Output voltage will change 0.1V.
In concrete application occasion, under product ideal case (power supply circuit output reduce), can be by linear regulation outside The control signal of control signal input Cont input of portion's control chip to feedback circuit 1012 is high level (such as 3.3V), from And the second of power supply circuit 1011 voltage for powering output end OUT2 outputs can be made to be minimum output voltage, it is possible to reduce television set The stand-by power consumption of mainboard.
In addition, the LED string to be powered is in series by multiple LEDs, with the quantity of LED string to be powered Increase, the supply voltage required for after multiple LED strip connection constantly increases, it is therefore desirable to the first power supply output end OUT1 output Voltage can adaptively respond LED number change, automatically adjust its output voltage values.
The the first power supply output end OUT1 and the second power supply output end OUT2 provided due to the present embodiment belongs to a change Depressor TB101, will necessarily be to the second power supply output end when the output voltage to the first power supply output end OUT1 is adjusted OUT2 output voltage has an impact, and vice versa.And the supply voltage of TV SKD is typically more fixed (about 12V), if Second power supply output end OUT2 output voltage amplitude fluctuation is excessive, it will the overall performance of TV SKD is influenceed, and it is too high Supply voltage possibly even burn TV SKD.
As shown in Fig. 2 the constant current of low-power consumption provided by the invention is additionally provided with DC-DC voltage-regulations electricity with controlling circuit of voltage regulation Road 102.Specifically, the input of the DC-DC voltage regulator circuits 102 is connected with the described second power supply output end OUT2, is used After the voltage signal for being exported the described second power supply output end OUT2 is adjusted to fixed voltage signal, export to television set Mainboard is powered.
So that supply voltage needed for TV SKD is 12V as an example, the present embodiment is in front end power circuit 101 and TV owner Increase one-level DC-DC voltage regulator circuits 102 between plate, pass through the response of DC-DC voltage regulator circuits 102 second power supply output end The change of OUT2 output voltage, output is automatically adjusted to the voltage value of TV SKD.DC-DC voltage regulator circuits 102 can be more than or less than 12V situation according to the second power supply output end OUT2 output voltage, using reduction regulation circuit Or rise voltage regulator circuit.
It is a kind of circuit theory when DC-DC voltage regulator circuits provided by the invention are liter voltage regulator circuit referring to Fig. 5 Figure.Specifically, when the DC-DC voltage regulator circuits 102 is rise voltage regulator circuit, including：Exported with the described second power supply Inductor LB801, on-off circuit 1021, voltage conversion chip UB801 and its peripheral circuit 1022 of OUT2 connections are held, and it is defeated Go out filter circuit 1023.In the present embodiment, by the way that the second power supply output end OUT2 output voltage is adjusted using Fig. 5 boosting Economize on electricity road obtains 12.5Vout after being boosted and is powered to TV SKD.
The on-off circuit 1021 is connected with inductor LB801 output ends, by the described second power supply output end OUT2 electricity Pressure signal, which is transmitted into voltage conversion chip UB801, is adjusted to stable voltage signal；Again will by the on-off circuit 1021 The voltage signal of stabilization after regulation is transmitted to the output filter circuit 1023 filtered after, there is provided enter to TV SKD Row power supply.
In order to realize the power supply output end of automatic adjusument first OUT1 output voltage, while ensure to supply TV SKD Voltage signal stability, it is defeated then to realize the second power supply after it with the addition of DC-DC voltage regulator circuits 102 the present embodiment Go out to hold the adjustability of OUT2 output voltage.The operating voltage range that TV SKD allows is usually 11.5V~12.5V, then After DC-DC voltage regulator circuits 102 start effect be after the second power supply output end OUT2 output voltage is adjusted 12.5Vout output ends export 11.5V~12.5V voltage signal, so that the first power supply connect with LED series winding exports Holding OUT1 output voltage can be adjusted according to the LED light bar quantity of reality, improve the control electricity that the present embodiment provides The scope of application on road and flexibility.
Described constant current is additionally provided with rear end linear constant current circuit 103 with controlling circuit of voltage regulation, specifically, as shown in Fig. 2 institute Stating rear end linear constant current circuit 103 includes comparison circuit 1031 and constant-current control circuit 1032；The comparison circuit 1031 is provided with Reference signal input PWM_REF, to access constant current reference voltage VREF；The constant-current control circuit 1032 is electric in the comparison One end LED- under the regulation on road 1031 with LED string to be powered is connected, the other end LED+ of the LED string to be powered and institute State the first power supply output end OUT1 connections；
Voltage acquisition all the way is drawn in the constant-current control circuit 1032 with the LED string junction P to be powered to export Hold (the output terminals A DC_12V in such as Fig. 2), with the voltage change according to the LED string to be powered, the front end power circuit The magnitude of voltage of the control signal input Cont is adjusted, so as to control the first power supply output end OUT1, the second power supply defeated Go out to hold OUT2 output voltage.
It is a kind of circuit theory diagrams of achievable mode of rear end linear constant current circuit provided by the invention referring to Fig. 6.
When it is implemented, in the rear in linear constant-current circuit 103, the comparison circuit 1031 also includes operation amplifier Device UB1A, the operational amplifier UB1A inverting input pass through a resistance RB12 and the reference signal input PWM_ REF connections；The normal phase input end of the operational amplifier UB1A is connected with current feedback circuit.Specifically, as shown in fig. 6, should Current feedback circuit includes multiple constant current detection resistances, respectively the 9th resistance RB5, the tenth resistance RB6, the 11st resistance RB7, 12nd resistance RB8, the 13rd resistance RB9；Wherein, the tenth resistance RB6, the 11st resistance RB7, the 12nd resistance RB8 and 13 resistance RB9 form parallel circuit, and one end of the parallel circuit is connected on the 9th resistance RB5 one end, the parallel connection The other end ground connection of circuit；The 9th resistance RB5 other end is connected on the normal phase input end of the operational amplifier.Further Ground, the current feedback circuit also include the 4th electric capacity CB5；One end ground connection of the 4th electric capacity CB5, the other end are connected to institute State on the normal phase input end of operational amplifier.The circuit of wherein the 9th resistance RB5 and the 4th electric capacity CB5 compositions can be to being input to The signal of operational amplifier UB1A normal phase input end is filtered.
Preferably, the comparison circuit 1031 also includes a clamp diode DB1, to protect the comparison circuit 1031 Normal work.
The rear end linear constant current circuit 103 also includes a switching tube QB1.Switching tube QB1 can be triode or MOS (Metal-Oxid-Semiconductor, metal-oxide semiconductor (MOS)) field-effect transistor, abbreviation metal-oxide-semiconductor or field effect transistor Pipe.Wherein, switching tube QB1 conduction and cut-off state is associated with the physical characteristic of its own.For example, when switching tube QB1 is three During pole pipe, according to the VA characteristic curve of triode, there is saturation region, amplification region and cut-off region, respectively to the hair of triode Voltage signal between emitter-base bandgap grading and colelctor electrode produces different influences, such as when triode operation is in saturation region, the hair of triode Equivalent to short-circuit (conducting state) between emitter-base bandgap grading and colelctor electrode.
In the present embodiment, when the switching tube QB1 is triode, the constant-current control circuit 1032 passes through described three The colelctor electrode of pole pipe is connected with one end (LED-) of the LED string to be powered；The emitter stage of the triode and the clamper Diode DB1 anode connection；When the switching tube QB1 is field-effect transistor, the constant-current control circuit 1032 passes through The drain electrode of the field-effect transistor is connected with one end (LED-) of the LED string to be powered；The field-effect transistor Source electrode is connected with the anode of the clamp diode DB1.
When it is implemented, clamp diode DB1 minus earth, anode is connected to operation amplifier by the 9th resistance RB5 Device UB1A normal phase input end.After the startup of rear end linear constant current circuit 103, by operational amplifier UB1A adjustment, it is just Phase input connects the magnitude of voltage and its constant current reference voltage V that reversely input accesses that constant current detection resistance is gotREFPhase Deng then as constant current reference voltage VREFDuring turn-on voltage (about 0.7V) higher than clamp diode DB1, clamp diode DB1 will Ground connection can be turned on, i.e., is composed in parallel by the tenth resistance RB6, the 11st resistance RB7, the 12nd resistance RB8 and the 13rd resistance RB9 The magnitude of voltage at constant current detection resistance both ends be clamped diode DB1 and limited, therefore, clamp diode DB1 is served necessarily Protective effect.
Also, due to switching tube QB1 emitter stage (switching tube QB1 is triode) or source electrode (switching tube QB1 is metal-oxide-semiconductor) It is connected with clamp diode DB1 anode, therefore the constant current value for the switching tube QB1 that circulates can be calculated by below equation：
As constant current reference voltage VREFDuring turn-on voltage higher than clamp diode DB1, circulation switching tube QB1 constant current Signal is：IConstant currentThe resistance of=DB1 turn-on voltage/constant current detection resistance；As constant current reference voltage VREFLess than the pole of clamper two During pipe DB1 turn-on voltage, circulation switching tube QB1 constant current signal is：IConstant current=constant current reference voltage VREF/ constant current detection electricity The resistance of resistance.Generally, clamp diode DB1 turn-on voltage is 0.7V, and the resistance of constant current detection resistance is the tenth resistance Equivalent resistance after RB6, the 11st resistance RB7, the 12nd resistance RB8 and the 13rd resistance RB9 parallel connections.
In the present embodiment, the first power supply output end is connected to the positive pole LED+ of LED string, passes through switching tube QB1 perseverance Flow control, then concatenate constant current detection resistance (the tenth resistance RB6, the 11st resistance RB7, the 12nd resistance RB8 and the 13rd resistance RB9 parallel resistance) to ground, the size of current of LED string is converted into voltage signal and is linked into computing putting by constant current detection resistance Big device UB1A and constant current reference voltage VREF(it is controlled by outside master chip, or access fixed voltage, if fixed voltage The constant current value I then exportedConstant currentIt is then fixed value, it is impossible to carry out the regulation of constant current size) it is compared and amplifies, so as to control out Close the constant current hold of pipe QB1 adjustment LED strings.
The plurality of LEDs lamp when it is implemented, LED string can typically connect, wherein the operating voltage of single LEDs is generally 2.8V ~3.4V, the operating voltage after plurality of LEDs lamp string joins will accordingly increase.So that switching tube QB1 is metal-oxide-semiconductor as an example, switching tube QB1's Drain source electrode between voltage be：VDS=VOUT1- LED string operating voltage-constant current reference voltage VREF.Therefore, back end of line Property constant-current circuit 103 enter working condition after, the voltage V between switching tube QB1 drain electrode and source electrodeDSWill be by LED string Operating voltage size influence, may also be subjected to multiple-channel output transformer TB101 crossmodulation in addition, (general range is 7%) influence.
With the change of LED string voltage, switching tube QB1 drain-source voltage VDSVoltage also synchronously changes, switching tube QB1 this Partial Power (VDS* constant current value IConstant current) form that will be converted into heat comes out, VDSVoltage is bigger, switching tube QB1 power consumption is bigger, and temperature is higher.Therefore the excessive switching tube QB1 of power consumption can reduce power-efficient and cause switching tube QB1 Overheat and be easily damaged.In order to reduce switching tube QB1 power consumption and temperature, multiple metal-oxide-semiconductors or triode work in parallel can be used Used for switching tube QB1, but this technical scheme result in the increase of cost.Therefore, the present embodiment is to the linear Constant Electric Current in rear end Make further improvement in road 103.
Combination of embodiment of the present invention Fig. 2~Fig. 6, there is provided a kind of constant current of low-power consumption and controlling circuit of voltage regulation, can solve Above-described switching tube QB1 power problemses.Specifically, the present embodiment by the constant-current control circuit 1032 with it is described LED string junction P to be powered draws voltage acquisition output terminals A DC_12V all the way, to detect the electricity of LED string to be powered in real time Buckling, the pressure drop between voltage acquisition output terminals A DC_12V and reference signal input PWM_REF set a threshold value, Or for voltage acquisition output terminals A DC_12V output voltage set steady state value (reference signal input PWM_REF's Voltage VREFIt is typically small), when the pressure drop between voltage acquisition output terminals A DC_12V and reference signal input PWM_REF is more than The threshold value, or when voltage acquisition output terminals A DC_12V output voltage is more than the steady state value, by adjusting front end power supply The control signal PWM_12V of control signal input Cont in circuit 101, optocoupler PCB101 is controlled by the work of LED string The situation of change (the i.e. first power supply output end OUT1 voltage change situation) of voltage feeds back to pwm chip UB101, PWM Control chip UB101 controlling switch pipes QB101 changes dutycycle, so that voltage acquisition output terminals A DC_12V magnitude of voltage Reference signal input PWM_REF magnitude of voltage is subtracted equal or close to the default threshold value (or voltage acquisition output end ADC_12V magnitude of voltage is equal or close to the steady state value), therefore, the present embodiment can pass through control signal input Cont Control signal PWM_12V, stop voltage collection output terminals A DC_12V and reference signal input PWM_REF between pressure drop, So as to reduce switching tube QB1 drain-source voltage VDSInfluenceed by the voltage change of LED string, reduce switching tube QB1 power consumption With ensure that power-efficient.
In the present embodiment, due to the first power supply output end OUT1 and the second power supply output end OUT2 output voltage by Multiple-channel output transformer TB101 is exported, then is reduced above by control signal input Cont control signal PWM_12V While switching tube QB1 power consumption, the voltage of multiple-channel output transformer TB101 all output windings will necessarily be caused to change Become (output voltage i.e. to the second power supply output end OUT2 of TV SKD power supply will also change), still, due to this Embodiment is provided with DC-DC voltage regulator circuits 102, therefore this implementation between the second power supply output end OUT2 and TV SKD Example can prevent the change model for causing TV SKD power supply because excessive to the adjustment of the output voltage of front end power circuit Excessive situation is enclosed to occur, and DC-DC voltage regulator circuits 102 can be according to actual conditions using decompression or booster circuit.
A kind of constant current of low-power consumption provided by the invention and controlling circuit of voltage regulation, it is provided with front end power circuit, DC-DC electricity Voltage regulator circuit and rear end linear constant current circuit, using the supply voltage of front end power circuit regulation two-way output, and in front end Feedback circuit is established in power circuit, and is provided with control signal input in a feedback circuit, front end power supply is controlled to realize Voltage of the circuit in the first power supply output end and the second power supply output end；Because the voltage signal of control signal input will be same When influence first power supply output end and the second output end output voltage, therefore the present invention further pass through DC-DC voltage-regulations Circuit come ensure output to motherboard circuit voltage signal stabilization；And adapt to go here and there automatically by setting up rear end linear constant current circuit The change of the LED backlight quantity of connection, the magnitude of voltage after being connected according to LED backlight adjust the control signal input Magnitude of voltage, control the first power supply output end, the second power supply output so as to pass through front end power circuit and its feedback circuit The output voltage at end, and the first power supply output end is connected to LED backlight and is powered, and realizes and LED backlight quantity phase The voltage automation regulation of adaptation, reduces the power consumption of circuit switch element, and ensure that the stabilization of the supply voltage of motherboard circuit Property.
In the present embodiment, because the voltage acquisition that the tie point of backlight LED light string and constant-current control circuit is drawn exports When the LED operation voltage (analog signal) collected is delivered to external control devices such as analog-digital converter by end ADC_12V, electricity Pressure collection output terminals A DC voltage is often higher (being more than 3.3V), and being mismatched with the voltage of analog-digital converter can not be directly Connection.Therefore, one or more resistance are generally serially connected between voltage acquisition output terminals A DC_12V and analog-digital converter to big Ground, the voltage signal after partial pressure export to the input port of analog-digital converter again.But when closing television machine backlight electric power When, voltage acquisition output terminals A DC_12V magnitude of voltage will make its resistance concatenated produce current signal, and the current signal is by electricity Pressure collection output terminals A DC_12V is moved back in LED string, because LED string is very sensitive to electric current, as long as there is faint electric current It is luminous with regard to that can turn on, therefore, prevent backlight LED to send faint light from complete switching off by the way of big resistance is concatenated, This phenomenon does not allow for television set manufacture index request.Therefore need to do backlight of television control circuit into The improvement of one step.
Therefore, the embodiment of the present invention enters one on the basis of the constant current of previously described low-power consumption and controlling circuit of voltage regulation Step ground, by setting up a kind of voltage detecting circuit 104 being connected with rear end linear constant current circuit 103, to set up into a kind of low work( The voltage stabilizing backlight control circuit of consumption.
It is a kind of structure of one embodiment of the voltage stabilizing backlight control circuit of low-power consumption provided by the invention referring to Fig. 7 Schematic diagram.
The present embodiment provide low-power consumption voltage stabilizing backlight control circuit, above-described low-power consumption constant current with stably On the basis of control circuit, further, voltage detecting circuit 104 is additionally provided with, that is, is included：Front end power circuit 101, DC-DC Voltage regulator circuit 102, rear end linear constant current circuit 103 and voltage detecting circuit 104.
Specifically, the front end power circuit 101, DC-DC voltage regulator circuits 102, rear end linear constant current circuit 103 with Above and the front end power circuit 101 of embodiment described in Fig. 2~Fig. 6, DC-DC voltage regulator circuits 102, rear end linear constant current Basic structure and the principle one-to-one corresponding of circuit 103 are identical, and detailed content refer to above, will not be repeated here.
Preferably, the first power supply output end OUT1 is connected with the anode of LED string, for television set LED backlight Lamp is powered；The input of the DC-DC voltage regulator circuits 102 is connected with the described second power supply output end OUT2, for by institute State after the voltage signal that the second power supply output end OUT2 is exported is adjusted to fixed voltage signal, export to TV SKD Row power supply；When it is implemented, adding DC-DC voltage regulator circuits 102 causes the voltage adjustable extent of supply backlight LED light string more Width, but still output to the voltage signal of TV SKD can be kept to be relatively fixed, therefore the present embodiment need not can repaiied Change and match use with the television set of the 32 cun~scopes such as 42 cun in the case of hardware circuit.
The rear end linear constant current circuit 103 includes the switching tube QB1 of constant-current control circuit 1032 and one, is exported for controlling Electric current to the LED string is constant current signal；When the switching tube QB1 is triode, the constant-current control circuit 1032 It is connected by the colelctor electrode of the triode with the negative electrode of the LED string；When the switching tube QB1 is field-effect transistor When, the constant-current control circuit 1032 is connected by the drain electrode of the field-effect transistor with the negative electrode of the LED string；
Drawn in the constant-current control circuit 1032 and LED string junction (i.e. switching tube QB1 and LED string) electric all the way Collection voltages output terminals A DC_12V is pressed, is connected with the voltage detecting circuit 104；The voltage detecting circuit 104 includes first Diode DB2 and first resistor RB18；Wherein, the first diode DB2 negative electrode is connected on the negative electrode of the LED string；The One diode DB2 anode is connected on first resistor RB18 one end, first resistor RB18 other end access high level VCC (being preferably 3.3V).When it is implemented, high level VCC can be by the current constant control that is controlled with switching tube QB1 identicals control terminal Circuit 1032 is provided.
When the LED string is opened, the first diode DB2 conductings, the voltage detecting circuit 104 passes through the one or two pole Pipe DB2 detects the operating voltage of the LED string, so as to control the feedback circuit 1012 to adjust the first power supply output Hold OUT1, the second power supply output end OUT2 output voltage；When the LED string is closed, the first diode DB2 is reversely cut Only, shut-off flows through the electric current of the LED string.
The present embodiment is further provided with detector 1041, for exporting voltage acquisition output terminals A DC_12V voltage signal. Wherein, the input of the detector 1041 is connected with the first diode DB2 anode, and the output end of the detector 1041 is made For " new voltage acquisition output terminals A DC_12V " (now or being voltage detecting output terminals A DC).
As shown in fig. 7, draw output terminals A DC_ all the way in the junction P of constant-current control circuit 1032 and LED string negative electrode 12V is connected with the first diode DB2 negative electrodes, when the LED string is opened, the first diode DB2 conductings, and the voltage detecting Circuit 104 detects the operating voltage of the LED string by the first diode DB2, so as to control the feedback circuit 1012 Adjust the first power supply output end OUT1, the second power supply output end OUT2 output voltage；When the LED string is closed, First diode DB2 reversely ends, and shut-off flows through the electric current of the LED string.
Specifically, the main operational principle of the voltage stabilizing backlight control circuit for the low-power consumption that the present embodiment provides is：
When opening backlight of television power supply, switching tube QB1 conductings enter working condition, the P points that will be connect with LED series winding Voltage be limited in colelctor electrode (when switching tube QB1 is triode) or drain electrode (when switching tube QB1 is field-effect transistor) Magnitude of voltage (typically smaller than 3.3V) on, meanwhile, high level VCC access causes the first diode DB2 and first resistor RB18 Tie point voltage VAHigher than the voltage of P points, therefore, the first diode DB2 conductings, circuit passes through first resistor RB18, the One diode DB2 and switching tube QB1 loops are operated.Now, the first diode DB2 and first resistor RB18 tie point Voltage VA=VDB2+VQB1；In closing television machine backlight electric power, switching tube QB1 enters cut-off state, and LED string both ends are kept Constant pressure and the high level much larger than 3.3V be present at LED- ends, therefore the first diode DB2 reversely ends, LED string and voltage Open circuit is equivalent between detection circuit 104, i.e., LED string will be without weak current by that thus will not produce glimmer phenomenon.
Preferably, the voltage detecting circuit 104 that the present embodiment provides also includes a filter circuit of pressure-stabilizing 1042；It is described Filter circuit of pressure-stabilizing 1042 is connected with the output end of detector 1041, for when the first diode DB2 is turned on, by the inspection The output signal of survey device 1041 exports after being filtered.
Specifically, the voltage detecting circuit 104 is in the filter circuit of pressure-stabilizing 1042, in addition to 3rd resistor RB17；One end ground connection of the 3rd resistor RB17, the other end are connected on the voltage detecting output terminals A DC.
Further, the voltage detecting circuit 104 also includes voltage-regulator diode D1, the first electric capacity CB7；And the pole of voltage stabilizing two Pipe D1 negative electrode is connected as voltage detecting output terminals A DC jointly with the first electric capacity CB7 one end；Voltage-regulator diode D1 anode With the first electric capacity CB7 other end common ground.Wherein, voltage-regulator diode D1 main function is to prevent voltage detecting circuit 104 cause port ADC output in operation irregularity or when switching tube QB1 turns off because high level VCC voltages are more than 3.3V Voltage is excessive, occurs so as to burn the situation for the device that voltage detecting output terminals A DC is connected.
It is a kind of physical circuit figure of achievable mode of voltage detecting circuit provided by the invention referring to Fig. 8.
In a kind of achievable mode, the voltage detecting circuit 104 also includes second resistance RB16；Second resistance RB16 one end is connected with the first diode DB2 anode, and the other end is as the voltage detecting output terminals A DC.Now, voltage Collection output terminals A DC output voltage is：VADC=VA*RB17/(RB16+RB17)。
It is that the physical circuit figure of mode can be achieved in the another kind of voltage detecting circuit provided by the invention referring to Fig. 9.
In another achievable mode, it is (i.e. described that the voltage detecting circuit 104 also includes the second diode DB3 Detector 1041 is the second diode DB3), the anode of the second diode DB3 is connected with the first diode DB2 anode； The negative electrode of the second diode DB3 is as the voltage acquisition output terminals A DC, now, voltage acquisition output terminals A DC output Voltage is：VADC=VA-VDB3。
Voltage detecting output terminals A DC output voltage VADCIt will be transmitted to external control devices and carry out Treatment Analysis, with basis Analysis result controls the working condition of front end power circuit 101, defeated so as to control the first power supply output end OUT1 and second to power Go out to hold OUT2 output voltage.
It is the structural representation of the another embodiment of the voltage stabilizing backlight control circuit of low-power consumption provided by the invention referring to Figure 10 Figure.
The present embodiment and the distinctive points of previously described embodiment are, on the basis of previously described embodiment, enter One step, the present embodiment also includes a control master chip 105.Wherein, front end power circuit 101, DC-DC voltage regulator circuits 102nd, the essential structure of rear end linear constant current circuit 103 and voltage detecting circuit 104 and operation principle and previously described implementation Example is identical, will not be repeated here.
Control master chip 105 and the control signal input Cont, the reference signal input PWM_REF with And the voltage acquisition output terminals A DC_12V is (when control circuit includes voltage detecting circuit 104, for through Zenith tracking electricity Voltage detecting output terminals A DC after the detection of road 104) connect respectively.
The control master chip 105 adjusts the output to the control according to the voltage change of the voltage detecting output terminals A DC Signal input part Cont processed signal magnitude, to control the first of the front end power circuit 101 the power supply output end OUT1, second Output end of powering OUT2 output voltage values；And by the reference signal input PWM_REF to the rear end linear constant current Circuit 103 inputs the constant current reference voltage VREF。
Specifically, when the control master chip 105 detects that the voltage detecting output terminals A DC and the reference signal are defeated When entering to hold PWM_REF voltage difference to be more than default threshold value, the control master chip 105 will export defeated to the control signal Enter to hold Cont voltage signal dutycycle to reduce.When it is implemented, the control master chip 105 is built-in with analog-digital converter, use Data signal is converted in the voltage signal for accessing the control master chip 105.Obtained from voltage detecting output terminals A DC collections Voltage signal first pass around the conversion of analog-digital converter after, obtain corresponding data signal, then by controlling in master chip 105 Other processing units processing.Because too high input voltage value can influence the normal work of analog-digital converter, and closing The magnitude of voltage of P points easily causes the resistance between the connection analog-digital converter in original technology to produce weak current during LED string Signal, so that LED backlight produces glimmer phenomenon.Because the present embodiment is provided with voltage detecting circuit 104, can close During brokeback photoelectric source, by controlling the first diode DB2 to be played a reversed role so as to effectively separate the current signal of voltage detecting circuit 104 Into LED string, the generation of " glimmer phenomenon " is avoided.
The present embodiment is defeated to control signal input Cont, the reference signal as a result of same control master chip Enter to hold the signal of tri- terminals of PWM_REF and the voltage detecting output terminals A DC to be handled, therefore have previously described , further can be in real time according to reference signal input PWM_REF and voltage acquisition output terminals A DC on the basis of imitating effect Signal intensity, and send corresponding control signal to control signal input Cont, therefore can reach rapidly to LED string The beneficial effect that the change of operating voltage is responded.
Further, the embodiment of the present invention additionally provides a kind of television set of adaptation power supply regulation, including：Mainboard, LED Lamp string, and the voltage stabilizing backlight control circuit of the low-power consumption described in any of the above item.
The voltage stabilizing backlight control circuit is connected respectively with the mainboard and the LED string, for opening the electricity Depending on machine power supply when, according to the operating voltage of the LED string, automatic adjusument supplies the mainboard, the electricity of the LED string Press signal；When closing the power supply of the television set, shut-off flows through the electric current of the LED string.Wherein, voltage stabilizing backlight control electricity The basic composition on road and operation principle with it is described previously identical, will not be repeated here.
Described above is the preferred embodiment of the present invention, it is noted that for those skilled in the art For, under the premise without departing from the principles of the invention, some improvements and modifications can also be made, these improvements and modifications are also considered as Protection scope of the present invention.

Claims (24)

  1. A kind of 1. voltage stabilizing backlight control circuit of low-power consumption, it is characterised in that including：Front end power circuit, DC-DC voltage-regulations Circuit, rear end linear constant current circuit and voltage detecting circuit；
    The front end power circuit includes power supply circuit, the first power supply output end, the second power supply output end and feedback circuit；It is described First power supply output end is connected with the anode of LED string, electric for being acted in collusion to make each other's confessions to the LED；
    The input of the DC-DC voltage regulator circuits is connected with the described second power supply output end, for described second to be powered After the voltage signal that output end is exported is adjusted to fixed voltage signal, exports to mainboard and be powered；
    The rear end linear constant current circuit includes constant-current control circuit and a switching tube (QB1), for controlling output to the LED The electric current of lamp string is constant current signal；When the switching tube (QB1) is triode, the constant-current control circuit passes through three pole The colelctor electrode of pipe is connected with the negative electrode of the LED string；When the switching tube (QB1) is field-effect transistor, the constant current Control circuit is connected by the drain electrode of the field-effect transistor with the negative electrode of the LED string；
    Voltage acquisition output end all the way is drawn in the constant-current control circuit and the LED string junction, is examined with the voltage Slowdown monitoring circuit connects；The voltage detecting circuit includes the first diode and first resistor；Wherein, the negative electrode connection of the first diode On the negative electrode of the LED string；The anode of first diode is connected on one end of first resistor, the other end of first resistor Access high level；
    When the LED string is opened, the first diode current flow, the voltage detecting circuit goes out institute by the first diode detection The operating voltage of LED string is stated, so as to control the feedback circuit adjustment the first power supply output end, the second power supply output end Output voltage；When the LED string is closed, the first diode reverse cut-off, shut-off flows through the electric current of the LED string.
  2. 2. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 1, it is characterised in that the voltage detecting circuit is also Including second resistance；One end of second resistance is connected with the anode of the first diode, and the other end exports as the voltage acquisition End.
  3. 3. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 1, it is characterised in that the voltage detecting circuit is also Including the second diode；
    The anode of second diode is connected with the anode of the first diode；The negative electrode of second diode is as the electricity Pressure collection output end.
  4. 4. the voltage stabilizing backlight control circuit of the low-power consumption as described in any one of claims 1 to 3, it is characterised in that the voltage Detection circuit also includes 3rd resistor；
    One end ground connection of the 3rd resistor, the other end are connected in the voltage detecting output end.
  5. 5. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 4, it is characterised in that the voltage detecting circuit is also Including voltage-regulator diode (D1), the first electric capacity；And the negative electrode of voltage-regulator diode (D1) is connected work jointly with one end of the first electric capacity For voltage detecting output end；The anode of voltage-regulator diode (D1) and the other end common ground of the first electric capacity.
  6. 6. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 5, it is characterised in that the feedback circuit includes anti- Present input, control signal input and feedback signal output；
    The feedback input end is connected with the described second power supply output end, and the feedback signal output connects with the power supply circuit Connect；The feedback circuit is according to the magnitude of voltage of the control signal input, to the power supply circuit output feedback signal, with control The power supply circuit is made to be adjusted the magnitude of voltage of the described first power supply output end and the second power supply output end.
  7. 7. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 6, it is characterised in that in the front end power circuit In, the feedback circuit is additionally provided with optocoupler (PCB101), voltage-stablizer (UB102)；
    The optocoupler (PCB101) includes the light emitting diode positioned at primary side and the optical signal converter positioned at secondary；
    The control signal that the control signal input inputs is accessed to the optocoupler (PCB101) by the voltage-stablizer (UB102) The light emitting diode positioned at primary side；The light emitting diode is transferred to the optocoupler after control signal is converted into optical signal (PCB101) the optical signal converter positioned at secondary；The optical signal converter convert optical signals to export after electric signal to The feedback signal output.
  8. 8. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 7, it is characterised in that the voltage-stablizer (UB102) is adopted With adjustable precision shunt voltage-stablizer, including negative electrode (K), anode (A) and reference input (R), and interior have reference voltage；
    Wherein, anode (A) ground connection of the adjustable precision shunt voltage-stablizer, the position of negative electrode (K) and the optocoupler (PCB101) Connected in the light emitting diode of primary side；Reference input (R) is used for the control signal for accessing the control signal input.
  9. 9. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 8, it is characterised in that the feedback circuit is additionally provided with surely Press feedback circuit.
  10. 10. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 9, it is characterised in that the voltage stabilizing feedback circuit bag Include the second electric capacity and the 4th resistance；
    One end of second electric capacity is connected on the negative electrode (K) of the adjustable precision shunt voltage-stablizer, the other end and the 4th One end series connection of resistance；The other end of 4th resistance is connected to the reference input (R) of the adjustable precision shunt voltage-stablizer On.
  11. 11. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 9, it is characterised in that the voltage stabilizing feedback circuit bag Include the 3rd electric capacity；
    One end of 3rd electric capacity is connected on the negative electrode (K) of the adjustable precision shunt voltage-stablizer, and the other end is connected to On the reference input (R) of the adjustable precision shunt voltage-stablizer.
  12. 12. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 9, it is characterised in that the voltage stabilizing feedback circuit bag Include the second electric capacity, the 4th resistance and the 3rd electric capacity；
    One end of second electric capacity is connected on the negative electrode (K) of the adjustable precision shunt voltage-stablizer, the other end and the 4th One end series connection of resistance；The other end of 4th resistance is connected to the reference input (R) of the adjustable precision shunt voltage-stablizer On；
    One end of 3rd electric capacity is connected on the negative electrode (K) of the adjustable precision shunt voltage-stablizer, and the other end is connected to On the reference input (R) of the adjustable precision shunt voltage-stablizer.
  13. 13. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 9, it is characterised in that the feedback circuit is additionally provided with 5th resistance and the 6th resistance；
    One end of 5th resistance is the feedback input end, and the other end is with optocoupler (PCB101) positioned at luminous the two of primary side The anode connection of pole pipe；One end of 6th resistance is connected to the anode of the light emitting diode, and the other end is connected to described On the negative electrode of light emitting diode.
  14. 14. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 9, it is characterised in that the adjustable precision shunt The reference input (R) of voltage-stablizer is connected by a divider with the control signal input.
  15. 15. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 14, it is characterised in that the divider is one the 7th Resistance.
  16. 16. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 7, it is characterised in that linear perseverance in the rear Comparison circuit is additionally provided with current circuit, the comparison circuit is provided with reference signal input, to access constant current reference voltage；
    The comparison circuit is additionally provided with operational amplifier, and the inverting input of the operational amplifier passes through one the 8th resistance and institute State the connection of reference signal input；The normal phase input end of the operational amplifier is connected with current feedback circuit.
  17. 17. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 16, it is characterised in that the current feedback circuit bag Include multiple constant current detection resistances, respectively the 9th resistance, the tenth resistance, the 11st resistance, the 12nd resistance, the 13rd resistance；
    Wherein, the tenth resistance, the 11st resistance, the 12nd resistance and the 13rd resistance composition parallel circuit, the parallel circuit One end be connected on one end of the 9th resistance, the other end of parallel circuit ground connection；The other end of 9th resistance is connected to On the normal phase input end of the operational amplifier.
  18. 18. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 17, it is characterised in that the current feedback circuit is also Including the 4th electric capacity；One end ground connection of 4th electric capacity, the other end are connected on the normal phase input end of the operational amplifier.
  19. 19. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 16, it is characterised in that the comparison circuit also includes One clamp diode；
    The minus earth of the clamp diode；The anode of the clamp diode is connected with the switching tube (QB1), including： When the switching tube (QB1) is triode, the anode of the clamp diode is connected with the emitter stage of the triode；Work as institute When to state switching tube (QB1) be field-effect transistor, the source electrode of the anode of the clamp diode and the field-effect transistor connects Connect.
  20. 20. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 16, it is characterised in that also including a control main core Piece；
    The control master chip exports with the control signal input, the reference signal input and the voltage acquisition End connects respectively；
    The control master chip adjusts the output to the control signal input according to the voltage change of the voltage acquisition output end The signal magnitude at end, to control the output voltage of the first of the front end power circuit the power supply output end, the second power supply output end Value；And the constant current reference voltage is inputted to the rear end linear constant current circuit by the reference signal input.
  21. 21. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 20, it is characterised in that when the control master chip inspection When measuring the voltage difference of the voltage acquisition output end and the reference signal input and being more than default threshold value, the control Master chip reduces the voltage signal dutycycle exported to the control signal input.
  22. 22. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 21, it is characterised in that the power supply circuit includes electricity Source input circuit, switching power circuit, multiple-channel output transformer, LED power supply output circuits and main board power supply output circuit；
    The power supply input circuit transmits the power supply signal of access to the multichannel under the control of the switching power circuit Export transformer；
    The multiple-channel output transformer includes main winding and auxiliary winding；The main winding will be transmitted after the power supply signal transformation to The main board power supply output circuit, and exported by the described second power supply output end；The auxiliary winding believes the power supply Transmit to the LED and power output circuit after number synchronous transformation, and exported by the described first power supply output end；The master The coil ratio of winding and the auxiliary winding is 1：N, N ＞ 0.
  23. 23. the voltage stabilizing backlight control circuit of low-power consumption as claimed in claim 1, it is characterised in that the DC-DC voltage-regulations electricity Lu Weisheng voltage regulator circuits or reduction regulation circuit.
  24. A kind of 24. television set of adaptation power supply regulation, it is characterised in that including：Mainboard, LED string, and such as claim The voltage stabilizing backlight control circuit of low-power consumption described in 1~23 any one；
    The voltage stabilizing backlight control circuit is connected respectively with the mainboard and the LED string, for opening the television set Power supply when, according to the operating voltage of the LED string, automatic adjusument supplies the voltage letter of the mainboard, the LED string Number；When closing the power supply of the television set, shut-off flows through the electric current of the LED string.
CN201410476693.1A 2014-09-17 2014-09-17 The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption Active CN104253960B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201410476693.1A CN104253960B (en) 2014-09-17 2014-09-17 The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201410476693.1A CN104253960B (en) 2014-09-17 2014-09-17 The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption

Publications (2)

Publication Number Publication Date
CN104253960A CN104253960A (en) 2014-12-31
CN104253960B true CN104253960B (en) 2017-12-19

Family

ID=52188451

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201410476693.1A Active CN104253960B (en) 2014-09-17 2014-09-17 The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption

Country Status (1)

Country Link
CN (1) CN104253960B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106787749A (en) * 2016-12-15 2017-05-31 广州市花都区广尔中电子厂 A kind of constant pressure and flow Switching Power Supply
CN107942821B (en) * 2017-12-20 2020-04-10 武汉瑞纳捷电子技术有限公司 Deep sleep control device and method for battery power supply system
CN109994924B (en) * 2017-12-29 2022-09-06 深圳光峰科技股份有限公司 Solid-state light source driving device and projection apparatus
CN110277911A (en) * 2018-03-15 2019-09-24 深圳市三诺数字科技有限公司 Power supply circuit and sound equipment applied to sound equipment

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102186276A (en) * 2011-03-08 2011-09-14 天利半导体（深圳）有限公司 LED (light emitting diode) constant current driving circuit with current detection and LED backlight system
CN103037597A (en) * 2013-01-06 2013-04-10 深圳创维－Rgb电子有限公司 Multi-channel LED (Light Emitting Diode) constant current control circuit and LED light source control system
CN103384436A (en) * 2013-08-02 2013-11-06 广州视源电子科技股份有限公司 Light-emitting diode (LED) backlight constant-current circuit
CN104009644A (en) * 2014-05-30 2014-08-27 广州视源电子科技股份有限公司 Fly-back power circuit

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102014537B (en) * 2009-09-14 2014-04-02 深圳市航嘉驰源电气股份有限公司 Drive circuit of LED lamp
CN102243854B (en) * 2011-08-18 2013-10-16 深圳市华星光电技术有限公司 LED (light emitting diode) backlight driving method, liquid crystal display device and LED backlight driving circuit

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102186276A (en) * 2011-03-08 2011-09-14 天利半导体（深圳）有限公司 LED (light emitting diode) constant current driving circuit with current detection and LED backlight system
CN103037597A (en) * 2013-01-06 2013-04-10 深圳创维－Rgb电子有限公司 Multi-channel LED (Light Emitting Diode) constant current control circuit and LED light source control system
CN103384436A (en) * 2013-08-02 2013-11-06 广州视源电子科技股份有限公司 Light-emitting diode (LED) backlight constant-current circuit
CN104009644A (en) * 2014-05-30 2014-08-27 广州视源电子科技股份有限公司 Fly-back power circuit

Also Published As

Publication number Publication date
CN104253960A (en) 2014-12-31

Similar Documents

Publication Publication Date Title
CN104253959B (en) The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption
CN104253957B (en) The constant current of low-power consumption and backlight control circuit and television set
CN104243872B (en) The constant current of low-power consumption and backlight control circuit and television set
CN106488607B (en) Switching Power Supply and television set
CN104253954B (en) The constant current of low-power consumption and backlight control circuit and television set
CN105960070B (en) A kind of single feedback direct-push DC dimming LED lamp tube drive circuits
CN103037597B (en) Multi-channel LED (Light Emitting Diode) constant current control circuit and LED light source control system
CN107508465B (en) Constant on-time type boost-voltage regulator
CN104253960B (en) The voltage stabilizing backlight control circuit and television set of a kind of low-power consumption
CN104253956B (en) Low-power-consumption stable voltage backlight control circuit and television
CN103487767A (en) Load driving circuit and electronic load
CN207625849U (en) A kind of backlight circuit and display screen of constant current
CN108123604A (en) Resonant power and electronic equipment
CN110166721A (en) The straight crystal drive circuit of interleaved PFC constant current, driving power and television set
CN203313488U (en) Backlight driving circuit and lamp bar light-adjusting unit
CN104253955B (en) A kind of constant current of low-power consumption and controlling circuit of voltage regulation and television set
CN203645858U (en) Step-down control chip, step-down LED drive circuit and display screen
CN203800802U (en) Large current detection circuit and power source circuit
CN205912292U (en) Straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance
CN104066244A (en) Universal LED simulation dimming circuit
CN104039039B (en) A kind of constant current LED drive circuit exporting two-way
CN104243876B (en) The constant-current control circuit and television set of low-power consumption
CN203748072U (en) Constant-current set-up circuit with adjustable output voltage
CN211792154U (en) Backlight control circuit, television and intelligent panel
CN204046886U (en) Led constant current circuit

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
TR01 Transfer of patent right

Effective date of registration: 20181030

Address after: 510663 3, 310, No. 192, Ke Zhu Road, Guangzhou high tech Industrial Development Zone, Guangdong

Patentee after: Guangzhou Kun Electronic Technology Co. Ltd.

Address before: 510663, 4, No. 192, Ke Zhu Road, science and Technology City, Guangzhou high tech Industrial Development Zone, Guangdong

Patentee before: Guangzhou CVT Electronics Technology Co., Ltd.

TR01 Transfer of patent right