CN107592704A - A kind of constant-current circuit for LCD TV - Google Patents
A kind of constant-current circuit for LCD TV Download PDFInfo
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- CN107592704A CN107592704A CN201710897090.2A CN201710897090A CN107592704A CN 107592704 A CN107592704 A CN 107592704A CN 201710897090 A CN201710897090 A CN 201710897090A CN 107592704 A CN107592704 A CN 107592704A
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Abstract
The invention discloses a kind of constant-current circuit for LCD TV.The circuit includes：Current rectifying and wave filtering circuit, the first DC voltage is provided for reception exchange input and after carrying out rectifying and wave-filtering；Pfc circuit, for receiving the first DC voltage and carrying out power factor correcting to export the second DC voltage；LLC circuits, for receiving the second DC voltage and exporting corresponding continuous current respectively in multiple output channels under the driving of the second DC voltage；Feedback circuit, for when continuous current fluctuates, the output duty cycle of LLC controller in LLC circuits is adjusted to keep continuous current constant.By the above-mentioned means, the present invention can realize constant-current circuit in a relatively simple manner, be advantageous to improve the productivity effect of LCD TV.
Description
Technical field
The present invention relates to LCD TV field, more particularly to a kind of constant-current circuit for LCD TV.
Background technology
In LCD TV, some drive circuits such as LED drive circuit needs to use constant current to drive, in order to realize constant current
Driving, the way of prior art are：Constant current driving is provided using external constant-current driven chip and its peripheral circuit.
Constant current driving is provided in this way, it is necessary to using extra chip, and circuit is complicated and cost is higher.
The content of the invention
, can be with relatively simple the present invention solves the technical problem of a kind of constant-current circuit for LCD TV is provided
Single mode provides constant current driving.
In order to solve the above technical problems, one aspect of the present invention is：A kind of constant current for liquid crystal is provided
Circuit, the circuit include：Current rectifying and wave filtering circuit, the first direct current is provided for reception exchange input and after carrying out rectifying and wave-filtering
Pressure；Pfc circuit, for receiving the first DC voltage and carrying out power factor correcting to export the second DC voltage；LLC circuits,
For receiving the second DC voltage and exporting corresponding constant current respectively in multiple output channels under the driving of the second DC voltage
Electric current；Feedback circuit, for when continuous current fluctuates, the output duty cycle of LLC controller in LLC circuits is adjusted to protect
It is constant to hold continuous current.
The beneficial effects of the invention are as follows：The constant-current circuit for LCD TV of the present invention passes through on the basis of available circuit
Upper increase feedback circuit, wherein, feedback circuit is used for when continuous current fluctuates, and adjusts LLC controller in LLC circuits
Output duty cycle is to keep continuous current constant.By the above-mentioned means, the present invention can realize constant current in a relatively simple manner
Circuit, circuit is simple, and cost is cheap, is advantageous to improve productivity effect.
Brief description of the drawings
Fig. 1 is the structural representation of the constant-current circuit for LCD TV of the embodiment of the present invention；
Fig. 2 is the circuit theory of current rectifying and wave filtering circuit in Fig. 1；
Fig. 3 is the circuit theory diagrams of pfc circuit in Fig. 1；
Fig. 4 is the circuit theory diagrams of LLC circuits and feedback circuit in Fig. 1.
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, it is clear that described embodiment is only the part of the embodiment of the present invention, rather than whole embodiments.It is based on
Embodiment in the present invention, those of ordinary skill in the art are obtained every other under the premise of creative work is not made
Embodiment, belong to the scope of protection of the invention.
Fig. 1 is the structural representation of the constant-current circuit for LCD TV of the embodiment of the present invention.As shown in figure 1, constant current
Circuit 10 includes current rectifying and wave filtering circuit 11, pfc circuit 12, LLC circuits 13 and feedback circuit 14.
Current rectifying and wave filtering circuit 11 is used to receive exchange input and provides the first DC voltage after carrying out rectifying and wave-filtering；
Pfc circuit 12 is connected with current rectifying and wave filtering circuit 11, for receiving the first DC voltage and carrying out power factor correcting
To export the second DC voltage；
LLC circuits 13 are connected with pfc circuit 12, for receiving the second DC voltage and under the driving of the second DC voltage
Corresponding continuous current is exported respectively in multiple output channels；
Feedback circuit 14 is connected with LLC circuits 13, is controlled for when continuous current fluctuates, adjusting LLC in LLC circuits
The output duty cycle of device processed is to keep continuous current constant.
Fig. 2 is the circuit theory diagrams of current rectifying and wave filtering circuit in Fig. 1.As shown in Fig. 2 current rectifying and wave filtering circuit 11 includes the six or two
Pole pipe D6, the 7th diode D7, the 8th diode D8, the 9th diode D9 and the 3rd electric capacity C3.
Wherein, GND, the 6th diode D6 are grounded after the connection of the 6th diode D6 anode and the 7th diode D7 anode
Negative electrode and the 8th diode D8 anode connection after with exchange input AC one end such as zero line be connected, the 7th diode D7
Negative electrode and the 9th diode D9 anode connection after with exchange input AC the other end such as zero line side be connected, the 8th diode
It is connected after the connection of D8 negative electrode and the 9th diode D9 negative electrode with the 3rd electric capacity C3 one end, the 3rd electric capacity C3 another termination
Ground.In the present embodiment, the 3rd electric capacity C3 capacitance is 1uF.
The commonly connected place of 8th diode D8 negative electrode and the 9th diode D9 negative electrode exports the first DC voltage U1.
Please also refer to Fig. 3, Fig. 3 is the circuit theory diagrams of pfc circuit in Fig. 1.As shown in figure 3, pfc circuit 12 includes
Pfc controller PFC IC, common mode inductance LF1, second transistor Q2, the first diode D1 and the first electric capacity C1.
Pfc controller PFC IC include zero current detection input pin ZCD, door driving output pin GATE and current detecting
Input pin CS.
Zero current detection input pin ZCD is connected with common mode inductance LF1 the second Same Name of Ends, door driving output pin GATE
Be connected with second transistor Q2 grid, second transistor Q2 drain electrode respectively with common mode inductance LF1 the first Same Name of Ends and the
One diode D1 anode connection, current detecting input pin CS are connected with second transistor Q2 source electrode, the first diode D1
Negative electrode be connected with the first electric capacity C1 one end, the first electric capacity C1 other end ground connection GND, common mode inductance LF1 the first different name
End is connected to receive the first DC voltage U1, common mode inductance with the common port of the 3rd electric capacity C3 and the 9th diode D9 in Fig. 2
LF1 the second different name end ground connection GND.In the present embodiment, the first electric capacity C1 capacitance is 390uF.
Wherein, the first diode D1 negative electrode exports the second DC voltage U2.
Please also refer to Fig. 4, Fig. 4 is the circuit theory diagrams of LLC circuits and feedback circuit in Fig. 1.As shown in figure 4, LLC is electric
Road 13 includes LLC controller LLC IC, first resistor R1, second resistance R2, the first transistor Q1, third transistor Q3, transformation
Device T1, the second diode D2, the 3rd diode D3, the 4th diode D4, the 5th diode D5, the first inductance L1, the second electric capacity
C2, the 5th electric capacity C5.
LLC controller LLC IC include the first driving pin GATE1, the second driving pin GATE2, delay pin DELAY,
Controlling switch CF and feedback pin FB.
Wherein, the first driving pin GATE1 is connected with the first transistor Q1 grid, and second drives pin GATE2 and the
Three transistor Q3 grid connection, the first transistor Q1 drain electrode receive the second DC voltage U2, the first transistor Q1 source electrode
Drain electrode with third transistor Q3 is connected, third transistor Q3 source ground, and the one of delay pin DELAY and first resistor R1
End connection, the first resistor R1 other end are grounded GND, and controlling switch CF is connected with second resistance R2 one end, second resistance R2
Other end ground connection GND, feedback pin FB is connected with feedback circuit 14.
Transformer T1 includes primary side winding and vice-side winding, and the Same Name of Ends of primary side winding is brilliant by the first inductance L1 and first
Body pipe Q1 source electrode connection, the different name end of primary side winding are grounded GND by the 5th electric capacity C5, and vice-side winding passes through the second electric capacity
Formed between C2, the second diode D2, the 3rd diode D3, the 4th diode D4, the 5th diode D5 and feedback circuit 14 more
Individual output channel.
Specifically, when multiple output channels are two, the Same Name of Ends of vice-side winding and the second electric capacity C2 one end connect
Connect, the negative electrode with the second diode D2, the 3rd diode D3 anode are connected the second electric capacity C2 other end respectively, the three or two pole
Form the first output channel between pipe D3 negative electrode and feedback circuit 14, the second diode D2 plus earth, vice-side winding
The negative electrode with the 4th diode D4, the 5th diode D5 anode are connected respectively at different name end, the 5th diode D5 negative electrode with it is anti-
The second output channel, the 4th diode D4 plus earth are formed between current feed circuit 14.
In the present embodiment, first resistor R1, second resistance R2 resistance are respectively 470R, 10K.First inductance L1 electricity
Inductance value is 150uH.Second electric capacity C2, the 5th electric capacity C5 capacitance are respectively 1uF, 22nF.
Preferably, LLC circuits 13 further comprise the 4th electric capacity C4, the 6th electric capacity C6 and the 7th electric capacity C7, the 4th electric capacity
C4 one end is connected with the 3rd diode D3 negative electrode, the 4th electric capacity C4 other end ground connection GND.6th electric capacity C6 one end with
5th diode D5 negative electrode connection, the 6th electric capacity C6 other end ground connection GND.7th electric capacity C7 one end and delay pin
DELAY connections, the 7th electric capacity C7 other end ground connection.In the present embodiment, the 4th electric capacity C4, the 6th electric capacity C6 and the 7th electric capacity
C7 capacitance is respectively 1uF, 1uF and 0.1uF (104).
Feedback circuit 14 includes operational amplifier IC2, voltage reference chip IC3, optoelectronic isolating element PC1, the 9th electric capacity
C9, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the 11st electricity
Hinder R11 and the 12nd resistance R12.
Wherein, the 9th resistance R9 first end is connected with the 8th resistance R8 one end, the 9th resistance R9 the second end ground connection
GND, the 8th resistance R8 other end are connected with the 9th electric capacity C9 one end and operational amplifier IC2 inverting input respectively,
The 9th electric capacity C9 other end is connected with the 7th resistance R7 one end, the 7th resistance R7 other end respectively with operational amplifier
IC2 output end, the negative electrode connection of the 6th resistance R6 one end, optoelectronic isolating element PC1, the 6th resistance the R6 other end and light
It is connected after being electrically isolated element PC1 anode connection with the 5th resistance R5 one end, the 5th resistance R5 other end is respectively with first
Power supply V0 and the 4th resistance R4 one end are connected, and the 4th resistance R4 other end is connected with voltage reference chip IC3 negative electrode, electricity
Fiducial chip IC3 plus earth GND is pressed, voltage reference chip IC3 adjustable end is connected with the 11st resistance R11 one end,
The 11st resistance R11 other end connects with the 12nd resistance R12 one end and operational amplifier IC2 in-phase input end respectively
Connect, the 12nd resistance R12 other end ground connection GND, optoelectronic isolating element PC1 grounded emitter, optoelectronic isolating element PC1's
Colelctor electrode is connected with LLC controller LLC IC feedback pin FB.
In the present embodiment, the 3rd diode D3 negative electrode and the 9th resistance R9 first end form the first output channel,
The second output channel is formed between 5th diode D5 negative electrode and the 9th resistance R9 first end.In the first output channel and
Two output channels are respectively arranged with the first LED string 15 and the second LED string 16, wherein, the positive pole of the first LED string 15 and
Three diode D3 negative electrode connection, the negative pole of the first LED string 15 are connected with the 9th resistance R9 first end, the second LED string
16 positive pole is connected with the 5th diode D5 negative electrode, and the negative pole of the second LED string 16 is connected with the 9th resistance R9 first end.
Wherein, the first LED string 15 is identical with model with the quantity of LED in the second LED string 16.Flow through the electricity of the first output channel
Stream is designated as the first continuous current I1, and the electric current for flowing through the second output channel is designated as the second continuous current I2.
It will be understood to those skilled in the art that it is only in the first output channel and the second output channel setting LED string
Citing, the present invention are not limited, and in other embodiments, may be arranged as other loads.
In the present embodiment, voltage reference chip IC3 model AZ431, the 9th electric capacity C9 capacitance are 0.1uF, the
Four resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the 11st resistance
R11, the 12nd resistance R12 resistance are 560R, 470R, 1K, 47K, 470R, 2R, 12K, 3K.
Preferably, feedback circuit 14 further comprises the 3rd electric capacity C3, the tenth electric capacity C10 and the 11st electric capacity C11, the 3rd
Electric capacity C3 both ends are connected with being electrically isolated element PC1 emitter and collector respectively, and the tenth electric capacity C10 one end is put with computing
Big device IC2 positive input connection, the tenth electric capacity C10 other end ground connection, the 11st electric capacity C11 one end and the 8th resistance
R8, the 9th resistance R9 public connecting end connection, the 11st electric capacity C11 other end ground connection GND.In the present embodiment, the 3rd
Electric capacity C3, the tenth electric capacity C10 and the 11st electric capacity C11 capacitance are respectively 1uF (105), 1uF (105), 1uF.
The operation principle of constant-current circuit is illustrated with reference to circuit theory diagrams, it is specific as follows shown：
After exchange input AC access current rectifying and wave filtering circuits, current rectifying and wave filtering circuit 11 receives exchange input AC and carries out rectification
First DC voltage U1, the first DC voltage U1 is provided after filtering and exports second after pfc circuit 12 carries out power factor correcting
DC voltage U2.
After LLC circuits 13 receive the second DC voltage U2, LLC controller LLC IC control the first transistor Q1 and the 3rd are brilliant
Body pipe Q3 service time to form primary current Ip in transformer T1 primary side winding, wherein, primary current Ip is positive and negative half
Axle amplitude is identical, and frequency respectively accounts for 50% sine wave, and then secondary current Is is formed on vice-side winding.Those skilled in the art
Member is it is appreciated that because primary current Ip and secondary current Is relation meet：Is=Ip*N, wherein, N is primary side winding and pair
The turn ratio of side winding, therefore the secondary current Is on vice-side winding is also identical for frequency, positive and negative semiaxis amplitude identical is just
String ripple.
When secondary current Is flows through vice-side winding so that when the Same Name of Ends of vice-side winding is high level, secondary current Is
The first continuous current I1, which is formed, after the 3rd diode D3 rectifications, the 4th electric capacity C4 filtering flows through the first of the first output channel
LED string 15, and pass through the different name end of the 4th diode D4 return vice-side windings.Similarly, when secondary current Is flow through secondary around
Group is so that when the different name end of vice-side winding is high level, and secondary current Is is by the 5th diode D5 rectifications, the 6th electric capacity
The second continuous current I2 is formed after C6 filtering and flows through the second LED string 16 of the second output channel, and passes through the second diode D2
Return to the Same Name of Ends of vice-side winding.
Wherein, the first continuous current I1 is the electric current of secondary current Is positive axis, and the second continuous current I2 is secondary current
Is bears the electric current of semiaxis, and therefore, the first continuous current I1 size is equal to the second continuous current I2 size, is designated as continuous current
I0。
In the present embodiment, as the first continuous current I1, the second continuous current I2 is equal in magnitude and remains continuous current
During I0, the voltage of operational amplifier IC2 inverting input is equal to the voltage of positive input.
Wherein, the voltage of operational amplifier IC2 positive input meets equation below：
Ua=VREF/ (r11+r12) * r12；
Wherein, Ua is the voltage of the positive input of operational amplifier, and VREF is the reference voltage of voltage reference chip,
R11 is the 11st resistance R11 resistance, and r12 is the 12nd resistance R12 resistance.
Wherein, the voltage of operational amplifier IC2 inverting input meets equation below：
Ub=I0*r9；
Wherein, Ub is the voltage of the reverse input end of operational amplifier, and I0 is to flow through the first perseverance in the first output channel
Stream electric current flows through the second continuous current in the second output channel, and r9 is the 9th resistance R9 resistance.
Change for an angle, because operational amplifier IC2 is operated in closed loop states, and operational amplifier IC2's is positive defeated
The voltage Ua for entering end is a reference voltage, so that the voltage Ub of inverting input is fixed on the reference voltage, and then is caused
First continuous current I1, the second continuous current I2 are fixed on same continuous current I0.
In the present embodiment, when the first continuous current I1 or the second continuous current I2 such as external load for some reason
When changing and increasing, then the voltage Ub increases of operational amplifier IC2 inverting input, so that operational amplifier
IC2 output voltage is reduced, and then causes the electric current increase that negative electrode is flowed to from optoelectronic isolating element PC1 anode.When photoelectricity every
When anode from element PC1 flows to the electric current increase of negative electrode, optoelectronic isolating element PC1 luminosity strengthens so that photoelectricity
Isolation element PC1 colelctor electrode flows to the electric current increase of emitter stage, so that feedback pin FB voltage rise.When LLC is controlled
After device LLC IC processed detect feedback pin FB voltage rise, the first driving pin GATE1, the second driving pin are reduced
The dutycycle of the pulse signal of GATE2 outputs is so as to reduce the first transistor Q1, third transistor Q3 service time causes just
Level electric current Ip diminishes, and then suppresses the first continuous current I1 or the second continuous current I2 increase, keeps the first Constant Electric Current
Flow I1, the second continuous current I2 constant effect.
Similarly, when the first continuous current I1 or the second continuous current I2 reduce for some reason, then operation amplifier
The voltage Ub of device IC2 inverting input reduces so that operational amplifier IC2 output voltage increase, and then cause from
The electric current that the anode of optoelectronic isolating element flows to negative electrode reduces.The electric current that negative electrode is flowed to when the anode of optoelectronic isolating element reduces
When, the luminosity of optoelectronic isolating element weakens so that the electric current that the colelctor electrode of optoelectronic isolating element flows to emitter stage subtracts
It is small, so that feedback pin FB voltage reduces.Feedback pin FB voltage is detected as LLC controller LLC IC to be reduced
Afterwards, the driving of increase by first pin GATE1, the second driving pin GATE2 outputs pulse signal dutycycle so as to increasing by first
Transistor Q1, third transistor Q3 service time cause primary current Ip to increase, and then suppress the first continuous current I1
Or second continuous current I2 reduction, keep the first continuous current I1, the second continuous current I2 constant effect.
It will be understood to those skilled in the art that multiple output channels are defeated including two output channels namely first in Fig. 4
Go out passage and the second output channel is only for example, present invention could apply to multiple output channels different from two.
Specifically, when multiple output channels include four output channels namely the first output channel, the second output channel,
3rd output channel and the 4th output channel, wherein, the first output channel sets the first LED string, the second output channel to set
Second LED string, the 3rd output channel set the 3rd LED string, the 4th output channel to set the 4th LED string, wherein, first
The positive pole of LED string is connected with the negative electrode of the 3rd diode, and the negative pole of the first LED string is connected with the positive pole of the second LED string
The first end with the 9th resistance is connected afterwards, and the negative pole of the second LED string is connected with the anode of the second diode, the 3rd LED string
Positive pole be connected with the negative electrode of the 5th diode, the negative pole of the 3rd LED string be connected with the positive pole of the 4th LED string after with the 9th
The first end connection of resistance, the negative pole of the 4th LED string are connected with the anode of the 4th diode, now, the sun of the second diode
Pole, the anode of the 4th diode are earth-free, the negative pole of the first LED string, the negative pole ground connection of the 3rd LED string.That is, the
One output channel and the second output channel are in a current loop, and the 3rd output channel and the 4th output channel are in another electricity
Flow back in road.It will be understood to those skilled in the art that when multiple output channels include three output channels, by the 4th LED
Lamp string is taken away, and the anode of the negative pole of the 3rd LED string directly with the 4th diode is connected, now, the first output channel and
Second output channel is in a current loop, and the 3rd output channel is in another current loop.
The beneficial effects of the invention are as follows：The constant-current circuit for LCD TV of the present invention passes through on the basis of available circuit
Upper increase feedback circuit, wherein, feedback circuit is used for when continuous current fluctuates, and adjusts LLC controller in LLC circuits
Output duty cycle is to keep continuous current constant.By the above-mentioned means, the present invention can realize constant current in a relatively simple manner
Circuit, circuit is simple, and cost is cheap, is advantageous to improve productivity effect.
Embodiments of the present invention are the foregoing is only, are not intended to limit the scope of the invention, it is every to utilize this
The equivalent structure or equivalent flow conversion that description of the invention and accompanying drawing content are made, or directly or indirectly it is used in other correlations
Technical field, it is included within the scope of the present invention.
Claims (10)
1. a kind of constant-current circuit for LCD TV, it is characterised in that the circuit includes：
Current rectifying and wave filtering circuit, the first DC voltage is provided for reception exchange input and after carrying out rectifying and wave-filtering；
Pfc circuit, for receiving first DC voltage and carrying out power factor correcting to export the second DC voltage；
LLC circuits, for receiving second DC voltage and leading under the driving of second DC voltage in multiple outputs
Road exports corresponding continuous current respectively；
Feedback circuit, for when the continuous current fluctuates, the output for adjusting LLC controller in the LLC circuits to account for
It is empty than to keep the continuous current constant.
2. the circuit according to right wants 1, it is characterised in that the feedback circuit includes operational amplifier, voltage reference core
Piece, optoelectronic isolating element, the 9th electric capacity, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the 9th electricity
Resistance, the 11st resistance and the 12nd resistance；
The first end of 9th resistance is connected with one end of the 8th resistance and the LLC circuits respectively, the 9th electricity
The second end ground connection of resistance, the other end of the 8th resistance are anti-phase with one end of the 9th electric capacity and the operational amplifier respectively
Input connects, and the other end of the 9th electric capacity is connected with one end of the 7th resistance, the other end of the 7th resistance respectively with institute
State the negative electrode connection of the output end of operational amplifier, one end of the 6th resistance, the optoelectronic isolating element, the 6th electricity
It is connected after the connection of the anode of the other end of resistance and the optoelectronic isolating element with one end of the 5th resistance, the 5th resistance
One end respectively with the first power supply and the 4th resistance of the other end be connected, the other end and the voltage of the 4th resistance
The negative electrode connection of fiducial chip, the plus earth of the voltage reference chip, the adjustable end and the tenth of the voltage reference chip
One end connection of one resistance, the other end of the 11st resistance are put with one end of the 12nd resistance and the computing respectively
The in-phase input end connection of big device, the other end ground connection of the 12nd resistance, the grounded emitter of the optoelectronic isolating element,
The colelctor electrode of the optoelectronic isolating element is connected with the LLC circuits.
3. circuit according to claim 2, it is characterised in that the LLC circuits include LLC controller, first resistor, the
Two resistance, the first transistor, third transistor, transformer, the second diode, the 3rd diode, the 4th diode, the five or two pole
Pipe, the first inductance, the second electric capacity, the 5th electric capacity, wherein, the LLC controller includes the first driving pin, the second driving is drawn
Pin, delay pin, controlling switch and feedback pin；
The grid of the first driving pin and the first transistor connects, the second driving pin and the third transistor
Grid connects, and the drain electrode of the first transistor receives second DC voltage, the source electrode of the first transistor with it is described
The drain electrode connection of third transistor, the source ground of the third transistor, the delay pin and the one of the first resistor
End connection, the other end ground connection of the first resistor, the controlling switch are connected with one end of the second resistance, and described second
The other end ground connection of resistance, the feedback pin are connected with the colelctor electrode of the optoelectronic isolating element；
The transformer includes primary side winding and vice-side winding, and the Same Name of Ends of the primary side winding passes through first inductance and institute
The source electrode connection of the first transistor is stated, the different name end of the primary side winding passes through the 5th capacity earth, the vice-side winding
Pass through second electric capacity, second diode, the 3rd diode, the 4th diode, the 5th diode
Multiple output channels are formed with the feedback circuit.
4. circuit according to claim 3, it is characterised in that when multiple output channels are two, the secondary
The Same Name of Ends of winding is connected with one end of the second electric capacity, the other end of second electric capacity the moon with second diode respectively
Pole, the anode connection of the 3rd diode, the first end of the negative electrode of the 3rd diode and the 9th resistance form the
One output channel, the plus earth of second diode, the different name end of the vice-side winding respectively with the 4th diode
Negative electrode, the 5th diode anode connection, the negative electrode of the 5th diode and the first end shape of the 9th resistance
Into the second output channel, the plus earth of the 4th diode,
Wherein, the electric current for flowing through first output channel is designated as the first continuous current, flows through the electricity of second output channel
Stream is designated as the second continuous current.
5. circuit according to claim 4, it is characterised in that flow through first continuous current of first output channel etc.
In the second continuous current for flowing through second output channel.
6. circuit according to claim 5, it is characterised in that the voltage of the inverting input of the operational amplifier meets
Equation below：
Ub=I0*r9；
Wherein, Ub is the voltage of the reverse input end of the operational amplifier, and I0 is to flow through the in first output channel
One continuous current flows through the second continuous current in second output channel, and r9 is the resistance of the 9th resistance.
7. circuit according to claim 6, it is characterised in that when first continuous current, second continuous current
When keeping constant, the voltage of the inverting input of the operational amplifier is equal to the voltage of positive input.
8. circuit according to claim 2, it is characterised in that the voltage of the positive input of the operational amplifier meets
Equation below：
Ua=VREF/ (r11+r12) * r12；
Wherein, Ua is the voltage of the positive input of the operational amplifier, and VREF is the benchmark electricity of the voltage reference chip
Pressure, r11 are the resistance of the 11st resistance, and r12 is the resistance of the 12nd resistance.
9. circuit according to claim 1, it is characterised in that the current rectifying and wave filtering circuit includes the 6th diode, the 7th
Diode, the 8th diode, the 9th diode and the 3rd electric capacity, wherein, the anode and the described 7th 2 of the 6th diode
Be grounded after the anode connection of pole pipe, after the anode connection of the negative electrode of the 6th diode and the 8th diode with the friendship
After the anode connection of one end connection of stream input, the negative electrode of the 7th diode and the 9th diode with it is described exchange it is defeated
After the negative electrode connection of the other end connection entered, the negative electrode of the 8th diode and the 9th diode with the 3rd electric capacity
One end connection, the 3rd electric capacity the other end ground connection；
Wherein, the negative electrode of the 8th diode exports first direct current after being connected with the negative electrode of the 9th diode
Pressure.
10. circuit according to claim 1, it is characterised in that the FPC circuits include pfc controller, common mode inductance,
Second transistor, the first diode and the first electric capacity, wherein, the pfc controller includes zero current detection input pin, door drives
Dynamic output pin and current detecting input pin；
The zero current detection input pin is connected with the second Same Name of Ends of the common mode inductance, door driving output pin with
The grid connection of the second transistor, the drain electrode of the second transistor respectively with the first Same Name of Ends of the common mode inductance and
The anode connection of first diode, the current detecting input pin is connected with the source electrode of the second transistor, described
The negative electrode of first diode is connected with one end of first electric capacity, the other end ground connection of first electric capacity, the common mode electricity
First different name end of sense receives first DC voltage, the second different name end ground connection of the common mode inductance；
Wherein, the negative electrode of first diode exports second DC voltage.
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| CN201710897090.2A CN107592704B (en) | 2017-09-29 | 2017-09-29 | A kind of constant-current circuit for LCD TV |
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| CN201710897090.2A CN107592704B (en) | 2017-09-29 | 2017-09-29 | A kind of constant-current circuit for LCD TV |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109151351A (en) * | 2018-09-25 | 2019-01-04 | 深圳创维－Rgb电子有限公司 | A kind of power panel and TV |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103813589A (en) * | 2014-01-24 | 2014-05-21 | 东南大学 | Isolation type high-power light emitting diode (LED) driving power source with multi-output current sharing |
| CN104519637A (en) * | 2013-09-27 | 2015-04-15 | 东芝照明技术株式会社 | Power supply circuit and luminaire |
| US20150351175A1 (en) * | 2014-06-03 | 2015-12-03 | Samsung Electro-Mechanics Co., Ltd. | Feedback circuit, control circuit, and power supply apparatus including the same |
| CN205726567U (en) * | 2016-06-08 | 2016-11-23 | 深圳市志和兴业电子有限公司 | A kind of multiple-channel output constant-current circuit |
| CN106304492A (en) * | 2016-08-30 | 2017-01-04 | 康佳集团股份有限公司 | A kind of two-way constant-current circuit and supply unit |
-
2017
- 2017-09-29 CN CN201710897090.2A patent/CN107592704B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104519637A (en) * | 2013-09-27 | 2015-04-15 | 东芝照明技术株式会社 | Power supply circuit and luminaire |
| CN103813589A (en) * | 2014-01-24 | 2014-05-21 | 东南大学 | Isolation type high-power light emitting diode (LED) driving power source with multi-output current sharing |
| US20150351175A1 (en) * | 2014-06-03 | 2015-12-03 | Samsung Electro-Mechanics Co., Ltd. | Feedback circuit, control circuit, and power supply apparatus including the same |
| CN205726567U (en) * | 2016-06-08 | 2016-11-23 | 深圳市志和兴业电子有限公司 | A kind of multiple-channel output constant-current circuit |
| CN106304492A (en) * | 2016-08-30 | 2017-01-04 | 康佳集团股份有限公司 | A kind of two-way constant-current circuit and supply unit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109151351A (en) * | 2018-09-25 | 2019-01-04 | 深圳创维－Rgb电子有限公司 | A kind of power panel and TV |
| CN109151351B (en) * | 2018-09-25 | 2021-06-01 | 深圳创维－Rgb电子有限公司 | Power panel and television |
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| Publication number | Publication date |
|---|---|
| CN107592704B (en) | 2019-09-20 |
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