CN101834525A - Be applied to the electric pressure converter and the driving method thereof of backlight module - Google Patents
Be applied to the electric pressure converter and the driving method thereof of backlight module Download PDFInfo
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- CN101834525A CN101834525A CN 201010172727 CN201010172727A CN101834525A CN 101834525 A CN101834525 A CN 101834525A CN 201010172727 CN201010172727 CN 201010172727 CN 201010172727 A CN201010172727 A CN 201010172727A CN 101834525 A CN101834525 A CN 101834525A
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Abstract
The electric pressure converter that is applied to backlight module uses single inductance to store the energy of an input voltage, exports the plural groups output voltage more according to this.At first control the charge path of inductance, to allow first group of output voltage keep constant according to the value of first group of output voltage.Then control the discharge path of inductance according to the difference between other group output voltage and the first group of output voltage respectively, to allow other group output voltage all can keep constant to other group output voltage.
Description
Technical field
The present invention is relevant to a kind of electric pressure converter and driving method thereof, refers to a kind of electric pressure converter and driving method thereof that is applied to backlight module especially.
Background technology
Light-emitting diode (light-emitting diode, LED) have low power consumption, long service life, color saturation height, multiple advantages such as reaction speed is fast, shatter-proof, withstand voltage and volume is little, therefore often be used as LCD (liquid crystal display, LCD), scanner, advertising lamp box, or the back light in the electronic equipment such as mobile computer.According to the product actual demand, the backlight module of prior art can select to use the white light back light that comprises white light emitting diode, or uses the RGB back light that comprises redness, green and blueness (being called for short RGB) light-emitting diode.
Please refer to Fig. 1, the schematic diagram of a backlight module in Fig. 1 prior art has shown one a direct current-dc voltage changer 100 and a back light 130.Electric pressure converter 100 comprises a booster circuit 110 and a pulse width modulation, and (pulse width modulation, PWM) circuit 120, can be with an input voltage V
INBe converted to an output voltage V
OUTTo drive back light 130.Back light 130 uses white light-emitting diode D
W1～D
WnWhite light source is provided, utilizes filter to produce different colours again.Booster circuit 110 comprises an inductance L, a power switch QN, a diode D, resistance R 1 and R2, and an output capacitance Co.Power switch QN operates according to a control signal NG, its role is to control the path that discharges and recharges of inductance L: when power switch QN conducting, and input voltage V
INCan charge to inductance L; When power switch QN closed, inductance L can see through the diode D discharge of conducting, and its internal memory energy is sent to output capacitance Co, and then provided back light 130 runnings required output voltage V
OUTResistance R 1 and R2 form a feedback circuit, can be to output voltage V
OUTDividing potential drop is to provide a corresponding feedback voltage V
FBBoost control circuit 120 is again according to feedback voltage V
FBProduce control signal NG: work as output voltage V
OUTToo high, pwm circuit 120 can be adjusted the responsibility cycle (duty cycle) of control signal NG to reduce the opening time of power switch QN; Work as output voltage V
OUTToo low, boost control circuit 120 can be adjusted the responsibility cycle of control signal NG to increase the opening time of power switch QN.The electric pressure converter 100 of prior art can be according to output voltage V
OUTVariation adjust the rechargeable energy of inductance L, therefore can allow output voltage V
OUTKeep constant.The backlight module working voltage transducer 100 of prior art drives white backlight light source 130, and it is with low cost and power consumption is minimum, but the color saturation of image is quite low, and the high-quality image can't be provided.
Please refer to Fig. 2, the schematic diagram of a backlight module in Fig. 2 prior art has shown one a direct current-dc voltage changer 200 and a back light 230.DC-to-DC electric pressure converter 200 comprises a booster circuit 110 and a pwm circuit 120, can be with an input voltage V
INBe converted to an output voltage V
OUTTo drive back light 230.Back light 230 uses red light emitting diodes D
R1～D
Rn, green LED D
G1～D
GnWith blue LED D
B1～D
BnThe redgreenblue light source is provided respectively, does not therefore need to use filter, but the image of high color saturation directly is provided in the colour mixture mode.Because the characteristic difference (for example the pressure drop of red light emitting diodes is low than other two kinds of light-emitting diodes generally) of RGB light-emitting diode is at the output voltage V of a particular value
OUTCan't show two or more colors simultaneously, and need a period of time between two kinds of colors, to do conversion, therefore can influence the visual effect of picture.
Please refer to Fig. 3, the schematic diagram of a backlight module in Fig. 3 prior art has shown one a direct current-dc voltage changer 300 and a back light 330.DC-to-DC electric pressure converter 300 comprises three groups of booster circuits 111～113 and three groups of pwm circuits 121～123, can be with an input voltage V
INBe converted to three groups of output voltage V
OUT1～V
OUT3To drive the red light emitting diodes D in the back light 330 respectively
R1～D
Rn, green LED D
G1～D
GnWith blue LED D
B1～D
Bn, therefore do not need to use filter, but the image of high color saturation directly be provided in the colour mixture mode.At booster circuit shown in Figure 3 111～113 and boost control circuit 121～123, its structure is identical with boost control circuit 120 with booster circuit 110 shown in Figure 1 with running, does not add in addition at this and gives unnecessary details.At the property difference of RGB light-emitting diode, the DC-to-DC electric pressure converter 300 of prior art uses three groups of booster circuits 111～113 that three groups of output voltage V are provided
OUT1～V
OUT3, not only bulky and cost an arm and a leg because booster circuit 111～113 needs to use 3 groups of inductance L altogether, therefore can increase production cost, and be difficult to the requirement that reaches microminiaturized.
Summary of the invention
The invention provides a kind of electric pressure converter that is applied to backlight module, it comprises an inductance, is used for storing the energy of an input voltage; One power switch, it controls the charge path of this inductance according to a switch controlling signal; One first electric capacity is used for storing the energy of this inductance so that one first output voltage to be provided; One second electric capacity is used for storing the energy of this inductance so that one second output voltage to be provided; One first switch, its foundation one first control signal is controlled the signal transmission path between this inductance and this first electric capacity; One second switch, its foundation one second control signal is controlled the signal transmission path between this inductance and this second electric capacity; One first feedback circuit is used to provide one first feedback voltage corresponding to this first output voltage; One second feedback circuit is used to provide one second feedback voltage corresponding to this second output voltage; An and boost control circuit, its accurate position according to this first feedback voltage produces this switch controlling signal, accurate position according to this first feedback voltage and this switch controlling signal produces this first control signal, and produces this second control signal according to the accurate position of this first feedback voltage, this second feedback voltage and this first control signal.
According to the described electric pressure converter of preferred embodiment of the present invention, wherein this boost control circuit comprises:
One error amplifier is used for the relatively difference of this first feedback voltage and one first reference voltage, and produces corresponding first comparison signal according to this;
One first comparator, corresponding first digital controlled signal is exported in its accurate position according to this first comparison signal and one first ramp voltage:
One switch control unit, it produces this according to this first to the 3rd feedback voltage and first controls signal to the 3rd control signal; And
One first flip-flop, it produces this switch controlling signal according to this first digital controlled signal.
According to the described electric pressure converter of preferred embodiment of the present invention, wherein this switch control unit comprises:
One first current source to the 3rd current source is used to provide one first charging current to the 3rd charging current respectively;
One the 4th electric capacity to one the 6th electric capacity, be connected in series respectively to this first current source to the 3rd current source, be used for storing the energy of this first charging current respectively, and corresponding one second ramp voltage to the 4th ramp voltage be provided respectively to the 3rd charging current;
One the 4th switch to the 6th switch is parallel to the 4th electric capacity respectively to the 6th electric capacity, controls signal to one the 6th control signal according to one the 4th respectively and controls the charge path of the 4th electric capacity to the 6th electric capacity;
One second comparator, corresponding second digital controlled signal is exported in its accurate position according to this second ramp voltage and one second reference potential;
One the 3rd comparator, corresponding the 3rd digital controlled signal is exported in its accurate position according to the 3rd ramp voltage and one the 3rd reference potential;
One the 4th comparator, corresponding the 4th digital controlled signal is exported in its accurate position according to the 4th ramp voltage and one the 4th reference potential;
One second flip-flop, this first control signal is exported in its accurate position according to one the 7th control signal and this second digital controlled signal, and wherein the 4th control signal and the 7th control signal are inverting each other;
One the 3rd flip-flop, this second control signal is exported in its accurate position according to the 5th control signal and the 3rd digital controlled signal: and
One the 4th flip-flop, the 3rd control signal is exported in its accurate position according to the 6th control signal and the 4th digital controlled signal.
According to the described electric pressure converter of preferred embodiment of the present invention, wherein the 4th control signal is this switch controlling signal, and this first control signal and the 5th control signal are inverting each other, and this second control signal and the 6th control signal are inverting each other.
According to the described electric pressure converter of preferred embodiment of the present invention, wherein this switch control unit comprises in addition:
One the 5th comparator, corresponding the 5th digital controlled signal is exported in its accurate position according to this first feedback voltage and this second reference potential;
One the 6th comparator, corresponding the 6th digital controlled signal is exported in its accurate position according to this second feedback voltage and the 3rd reference potential;
One the 7th comparator, corresponding the 7th digital controlled signal is exported in its accurate position according to the 3rd feedback voltage and the 4th reference potential;
Wherein this second flip-flop is exported this first control signal according to the accurate position of the 5th digital controlled signal in addition, the 3rd flip-flop is exported this second control signal according to the accurate position of the 6th digital controlled signal in addition, and the 4th flip-flop is exported the 3rd control signal according to the accurate position of the 7th digital controlled signal in addition.
According to the described electric pressure converter of preferred embodiment of the present invention, wherein this switch control unit comprises in addition:
One first or door, it optionally triggers this second flip-flop according to this second digital controlled signal and the 5th digital controlled signal;
One second or door, it optionally triggers the 3rd flip-flop according to the 3rd digital controlled signal and the 6th digital controlled signal; And
One the 3rd or door, it optionally triggers the 4th flip-flop according to the 4th digital controlled signal and the 7th digital controlled signal.
According to the described electric pressure converter of preferred embodiment of the present invention, wherein the value of this second charging current is relevant to the difference of this first feedback voltage and this second feedback voltage, and the value of the 3rd charging current is relevant to the difference of this first feedback voltage and the 3rd feedback voltage.
According to the described electric pressure converter of preferred embodiment of the present invention, wherein this power switch, the 4th switch to the 6th switch are N type MOS (metal-oxide-semiconductor) transistor switch, and this first switch to the 3rd switch is a P type MOS (metal-oxide-semiconductor) transistor switch.
According to the described electric pressure converter of preferred embodiment of the present invention, wherein the 4th control signal is this switch controlling signal, and this first control signal and the 5th control signal are reverse each other, and this second control signal is reverse each other with the 6th control signal.
According to the described electric pressure converter of preferred embodiment of the present invention, above-mentioned this first feedback circuit to the 3rd feedback circuit respectively comprises a plurality of series resistors.
The present invention provide in addition a kind of backlight module driving method, it comprises that an energy storage component receives an input voltage to store corresponding energy; The energy that receives this energy storage component internal memory is to provide one first output voltage and one second output voltage; Foundation one first feedback voltage is controlled the signal transmission path between this input voltage and this energy storage component, and wherein this first feedback voltage is relevant to the value of this first output voltage; Control signal transmission path between this energy storage component and this first output voltage according to this first feedback voltage; And control signal transmission path between this energy storage component and this second output voltage according to this first feedback voltage and one second feedback voltage, wherein this second feedback voltage is relevant to the value of this second output voltage.
Description of drawings
Fig. 1～Fig. 3 is the schematic diagram of backlight module in the prior art;
Fig. 4 is the schematic diagram of a backlight module among the present invention;
Fig. 5 a is a backlight module of the present invention with the fixed frequently sequential chart when mode operates;
Fig. 5 b is a backlight module of the present invention with the non-fixed frequently sequential chart when mode operates;
Fig. 6 is the schematic diagram of a switch control unit in the embodiment of the invention;
Sequential chart when Fig. 7 operates for the non-fixed frequency backlight module of the present invention;
Fig. 8 is the present invention's sequential chart during backlight module running frequently surely.
Embodiment
Below in conjunction with accompanying drawing, specify the present invention.
Please refer to Fig. 4, Fig. 4 has shown one a direct current-dc voltage changer 400 and a back light 430 for the schematic diagram of a backlight module among the present invention.Electric pressure converter 400 comprises a booster circuit 410, and a boost control circuit 420, can be with an input voltage V
INBe converted to first to the 3rd output voltage V
OUT1～V
OUT3To drive the red light emitting diodes D in the back light 430 respectively
R1～D
Rn, green LED D
G1～D
GnWith blue LED D
B1～D
Bn, therefore do not need to use filter, but the image of high color saturation directly be provided in the colour mixture mode.Simultaneously, at the property difference of RGB light-emitting diode, electric pressure converter 400 of the present invention uses boost control circuit 420 to adjust output voltage V
OUT1～V
OUT3Value, therefore booster circuit 410 only need use one group of inductance L can light the light-emitting diode of the above different colours of two strings simultaneously, can save the space and reduces production costs.
The present invention's foundation is corresponding to output voltage V
OUT1Feedback voltage V
FB1Come closing of power controlling switch QN.Error amplifier EA can compare feedback voltage V
FB1With one first reference voltage V
REF1Difference, export a corresponding comparative voltage V again
CThe first comparator C MP1 can be with comparative voltage V
CCompare with the ramp voltage SAW1 of a fixed slope, when the value of ramp voltage SAW1 reaches comparative voltage V
CThe time, the first comparator C MP1 can export the digital controlled signal V of a high potential (logical one)
D1The first flip-flop FF1 can be a RS flip-flop, when its R holds by the signal triggering of logical one, can hold the switch controlling signal NG of output device decapacitation current potential to close power switch QN in its Q; When its S holds by the signal triggering of logical one, can hold the switch controlling signal NG of output device activation current potential to open power switch QN (if power switch QN is a nmos transistor switch, its activation current potential is a logical one, and its decapacitation current potential is a logical zero) in its Q.That is the switch controlling signal NG of power controlling switch QN is from switch control unit 600.
Please refer to 5a and 5b figure, 5a and 5b figure are the sequential chart of electric pressure converter of the present invention 400 when operating.5a and 5b figure have illustrated the method for the opening and closing of power controlling switch QN0, have shown comparative voltage V
C, ramp voltage SAW1, switch controlling signal NG, first to the 3rd control signal PG1～PG3, and the waveform of a pulse signal NMOS_ON.In one-period T, the ON time of switch QN0, QP1, QP2 and QP3 is respectively by T
N, T
P1, T
P2And T
P3Represent.The unlatching that driving method shown in Fig. 5 a adopts fixed mode frequently to come power controlling switch QN0, utilize switch control unit 600 that the pulse signal NMOS_ON of fixed frequency is provided, when the S of first flip-flop FF1 end is triggered by the pulse signal NMOS_ON of logical one, the switch controlling signal NG of its Q end output switches to the activation current potential by the decapacitation current potential, this moment, power switch QN0 can be switched on, and inductance L begins charging.In period T, T extra time after opening switch QN0, QP1, QP2 and QP3 in regular turn
0In, all switches are all closes, and this moment, the dump energy of inductance L can be discharged through the parasitic diode of switch QP1～QP3.The unlatching that driving method shown in Fig. 5 b adopts non-fixed mode frequently to come power controlling switch QN0 open power switch QN0 immediately behind off switch QP3, so period T is the shortest circulation timei.When fixed frequently control, pulse signal NMOS_ON can not triggered by a fixed oscillator (illustrating); When non-fixed frequency was controlled, pulse signal NMOS_ON triggered (for example PG3) by last control signal of organizing switch.
Driving method shown in Fig. 5 a and Fig. 5 b all adopts same way as to come closing of power controlling switch QN: when the ramp voltage SAW1 of fixed slope reaches comparative voltage V
CAccurate position the time, the R end of the first flip-flop FF1 can be by the signal triggering of first comparator C MP1 output, the switch controlling signal NG of its Q end output switches to the decapacitation current potential by the activation current potential, this moment, power switch QN can be closed, and inductance L stops charging.As previously mentioned, comparative voltage V
CValue can react output voltage V
OUT1Accurate position: if output voltage V
OUT1Be lower than predetermined value, corresponding feedback voltage V
FB1Can diminish, this moment, error amplifier EA can heighten comparative voltage V
C, so ramp voltage SAW1 needs the long period just can reach comparative voltage V
CAccurate position, so the ON time T of switch QN0
NAlso can be elongated, and then the charging interval that see through to increase inductance L allows output voltage V
OUT1Rise to desirable accurate position; If output voltage V
OUT1Be higher than predetermined value, corresponding feedback voltage V
FB1Can become big, this moment, error amplifier EA can downgrade comparative voltage V
C, so ramp voltage SAW1 only needs the short period just can reach comparative voltage V
CAccurate position, so the ON time T of switch QN0
NAlso can shorten, and then the charging interval that see through to reduce inductance L allows output voltage V
OUT1Drop to desirable accurate position.
Please refer to Fig. 6 and Fig. 7, Fig. 6 is the schematic diagram of switch control unit 600 in the embodiment of the invention, Fig. 7 comes the sequential chart of the unlatching of control switch QP1～QP3 for the present invention in non-fixed mode frequently, and Fig. 8 comes the sequential chart of the unlatching of control switch QP1～QP3 for the present invention in fixed mode frequently.In the embodiment shown in fig. 6, switch control unit 600 comprises first to the 6th comparison circuit the 601～606, second to the 4th flip-flop FF2～FF4, first to the 3rd or door (OR gate) OR1～OR3, an and oscillator (not illustrating).First or the digital controlled signal V that transmits according to first comparison circuit 601 of door OR1
D2The digital controlled signal V that transmits with the 4th comparison circuit 604
D5Optionally trigger the R end of the second flip-flop FF2; Second or the digital controlled signal V that transmits according to second comparison circuit 602 of door OR2
D3The digital controlled signal V that transmits with the 5th comparison circuit 605
D6Optionally trigger the R end of the 3rd flip-flop FF3; The 3rd or the digital controlled signal V that transmits according to the 3rd comparison circuit 603 of door OR3
D4The digital controlled signal V that transmits with the 6th comparison circuit 606
D7Optionally trigger the R end of the 4th flip-flop FF4.
The structure and the running of first to the 3rd comparison circuit 601～603 at first are described.First comparison circuit 601 comprises one second comparator C MP2, one the 4th capacitor C 4, one the 4th switch QN4, and one first current source I1.Second comparison circuit 602 comprises one the 3rd comparator C MP3, one the 5th capacitor C 5, one the 5th switch QN5, and one second current source I2.The 3rd comparison circuit 603 comprises one the 4th comparator C MP4, one the 6th capacitor C 6, one the 6th switch QN6, and one the 3rd current source I3.Switch QN4～QN6 can be nmos transistor switch, can operate according to the 4th to the 6th control signal respectively, its role is to the charge path of control capacitance C4～C6.In this embodiment, the 4th control signal adopts switch controlling signal NG, and the 5th control signal adopts the inversion signal of the first control signal PG1
And the 6th control signal adopts the inversion signal of the second control signal PG2
Current source I1 is a constant current source, and the value of current source I2 is relevant to feedback voltage V
FB1And V
FB2Between difference, and the value of current source I3 is relevant to feedback voltage V
FB1And V
FB3Between difference, its relation is as follows:
I2＝I1+K(V
FB2-V
FB1)
I3=I1+K (V
FB3-V
FB2), wherein K is an intended conversion multiple.
After switch controlling signal NG switched to the decapacitation current potential, the S of flip-flop FF2 end can (be adopted the inversion signal of switch controlling signal NG by one the 7th control signal
) trigger, so the control signal PG1 of its Q end output can switch to the activation current potential to open switch QP1.This moment, switch QN4 can be closed, and current source I1 can be to capacitor C 4 chargings to provide the second ramp voltage SAW2 of a fixed slope.When the accurate position of the second ramp voltage SAW2 is higher than one second reference voltage V
REF2The time, the signal of comparator C MP2 meeting output device activation current potential is held with the R that triggers flip-flop FF2, and flip-flop FF2 can switch to the decapacitation current potential with off switch QP1 in the control signal PG1 of Q end output.Change, the charging interval of capacitor C 4 is exactly the ON time TP1 of switch QP1, and the second ramp voltage SAW2 can react feedback voltage V
FB1Accurate position.
The present invention is then according to feedback voltage V
FB1And V
FB2Value determine whether opening switch QP2 and opening time length.Behind off switch QP1, switch QN5 can be by the 5th control signal
Close, and current source I2 begins capacitor C 5 chargings so that the 3rd ramp voltage SAW3 of a tool certain slope to be provided.Suppose to close the back output voltage V at switch QP1
OUT2Do not reach predetermined value, that is (V
FB2-V
FB1) value less, and current source I2 can die down to the charging current of capacitor C 5, allows the 3rd ramp voltage SAW3 more just can reach the 3rd reference voltage V
REF3Accurate position, therefore can increase the ON time TP2 of switch QP2, so inductance L can be supplied more energy through switch QP2, to allow output voltage V
OUT2Rise to predetermined value.
In like manner, the present invention is then according to feedback voltage V
FB1And V
FB3Value determine whether opening switch QP3 and opening time length.Behind off switch QP2, switch QN3 can be by the 6th control signal
Close, and current source I3 begins capacitor C 6 chargings so that the 4th ramp voltage SAW4 of a tool certain slope to be provided.Suppose to close the back output voltage V at switch QP2
OUT3Surpass predetermined value, that is (V
FB3-V
FB1) value bigger, and current source I3 can grow to the charging current of capacitor C 6, allows the 4th ramp voltage SAW4 reach the 4th reference voltage V quickly
REF4Accurate position, therefore can reduce the ON time TP3 of switch QP3, so inductance L can be supplied less energy through switch QP3, to allow output voltage V
OUT3Drop to predetermined value.
On the other hand, if comparison circuit 601～603 is former thereby do not match because of processing procedure, cause output voltage V
OUT1～V
OUT3In wherein one group always too high, this moment the present invention can utilize comparison circuit 604～606 to be compensated.The 4th comparison circuit 604 comprises one the 5th comparator C MP5, and its two input receives the first feedback voltage V respectively
FB1With the second reference voltage V
REF2, and its output be coupled to first or the door OR1.The 5th comparison circuit 605 comprises one the 6th comparator C MP6, and its two input receives the second feedback voltage V respectively
FB2With the 3rd reference voltage V
REF3, and its output be coupled to second or the door OR2.The 6th comparison circuit 606 comprises one the 7th comparator C MP7, and its two input receives the 3rd feedback voltage V respectively
FB3With the 4th reference voltage V
REF4, and its output be coupled to the 3rd or the door OR3.
For instance, power switch QN0 close the back and ramp voltage SAW2 does not reach reference voltage V as yet
REF2Accurate position before, if feedback voltage V
FB1Be higher than reference voltage V
REF2, this moment the 4th, comparison circuit 604 can trigger the R end of the second flip-flop FF2, and then the premature closure first switch QP1, therefore can reduce being supplied to output voltage V
OUT1Energy; Power switch QN0 close the back and ramp voltage SAW3 does not reach reference voltage V as yet
REF3Accurate position before, if feedback voltage V
FB2Be higher than reference voltage V
REF3, this moment second, comparison circuit 602 can trigger the R end of the 3rd flip-flop FF3, and then premature closure second switch QP2, therefore can reduce being supplied to output voltage V
OUT2Energy; Power switch QN0 close the back and ramp voltage SAW4 does not reach reference voltage V as yet
REF4Accurate position before, if feedback voltage V
FB3Be higher than reference voltage V
REF4, this moment the 3rd, comparison circuit 603 can trigger the R end of the 4th flip-flop FF4, and then premature closure the 3rd switch QP3, therefore can reduce being supplied to output voltage V
OUT3Energy.
In other words, after power switch QN0 closes, if ramp voltage SAW2 has reached reference voltage V
REF2Accurate position or as feedback voltage V
FB1Be higher than reference voltage V
REF2The time, represent output voltage V
OUT1Reached predetermined value, the present invention's this moment can't open switch QP1; If ramp voltage SAW3 has reached reference voltage V
REF3Accurate position or as feedback voltage V
FB2Be higher than reference voltage V
REF3The time, represent output voltage V
OUT2Reached predetermined value, the present invention's this moment can't open switch QP2; If ramp voltage SAW4 has reached reference voltage V
REF4Accurate position or as feedback voltage V
FB3Be higher than reference voltage V
REF4The time, represent output voltage V
OUT3Reached predetermined value, the present invention's this moment can't open switch QP3.
The present invention is according to the first feedback voltage V
FB1Control major loop, no matter be that to decide frequency also be non-fixed control frequently, all can be according to first output voltage V
OUT1Adjust switch controlling signal NG, to allow output voltage V
OUT1Maintain predetermined value.At output voltage V
OUT1～V
OUT3Indivedual outgoing routes, the present invention is according to feedback voltage V
FB1～V
FB3Difference opening time of coming control switch QP1～QP3, to allow output voltage V
OUT1～V
OUT3Maintain predetermined value.Owing to only need use one group of inductance, the present invention not only can reduce the volume of backlight module and reduce production costs, and also can come simultaneously and drive apace the RGB back light of different colours according to the property difference at the RGB light-emitting diode.
The above only is preferred embodiment of the present invention, and all equalizations of being done according to the present patent application claim change and modify, and all should belong to covering scope of the present invention.
Claims (12)
1. an electric pressure converter that is applied to backlight module is characterized in that, comprising:
One inductance is used for storing the energy of an input voltage;
One power switch, it controls the charge path of this inductance according to a switch controlling signal;
One first electric capacity is used for storing the energy of this inductance so that one first output voltage to be provided;
One second electric capacity is used for storing the energy of this inductance so that one second output voltage to be provided;
One the 3rd electric capacity is used for storing the energy of this inductance so that one the 3rd output voltage to be provided;
One first switch, its foundation one first control signal is controlled the signal transmission path between this inductance and this first electric capacity;
One second switch, its foundation one second control signal is controlled the signal transmission path between this inductance and this second electric capacity;
One the 3rd switch, its foundation one the 3rd control signal is controlled the signal transmission path between this inductance and the 3rd electric capacity;
One first feedback circuit is used to provide one first feedback voltage corresponding to this first output voltage;
One second feedback circuit is used to provide one second feedback voltage corresponding to this second output voltage;
One the 3rd feedback circuit is used to provide one the 3rd feedback voltage corresponding to the 3rd output voltage; And,
One boost control circuit, its accurate position according to this first feedback voltage produces this switch controlling signal, accurate position according to this first feedback voltage and this switch controlling signal produces this first control signal, accurate position according to this first feedback voltage, this second feedback voltage and this first control signal produces this second control signal, and produces the 3rd control signal according to the accurate position of this first feedback voltage, the 3rd feedback voltage and this second control signal.
2. electric pressure converter as claimed in claim 1 is characterized in that, this boost control circuit comprises:
One error amplifier is used for the relatively difference of this first feedback voltage and one first reference voltage, and produces corresponding first comparison signal according to this;
One first comparator, corresponding first digital controlled signal is exported in its accurate position according to this first comparison signal and one first ramp voltage:
One switch control unit, it produces this according to this first to the 3rd feedback voltage and first controls signal to the 3rd control signal; And
One first flip-flop, it produces this switch controlling signal according to this first digital controlled signal.
3. electric pressure converter as claimed in claim 2 is characterized in that, this switch control unit comprises:
One first current source to the 3rd current source is used to provide one first charging current to the 3rd charging current respectively;
One the 4th electric capacity to one the 6th electric capacity, be connected in series respectively to this first current source to the 3rd current source, be used for storing the energy of this first charging current respectively, and corresponding one second ramp voltage to the 4th ramp voltage be provided respectively to the 3rd charging current;
One the 4th switch to the 6th switch is parallel to the 4th electric capacity respectively to the 6th electric capacity, controls signal to one the 6th control signal according to one the 4th respectively and controls the charge path of the 4th electric capacity to the 6th electric capacity;
One second comparator, corresponding second digital controlled signal is exported in its accurate position according to this second ramp voltage and one second reference potential;
One the 3rd comparator, corresponding the 3rd digital controlled signal is exported in its accurate position according to the 3rd ramp voltage and one the 3rd reference potential;
One the 4th comparator, corresponding the 4th digital controlled signal is exported in its accurate position according to the 4th ramp voltage and one the 4th reference potential;
One second flip-flop, this first control signal is exported in its accurate position according to one the 7th control signal and this second digital controlled signal, and wherein the 4th control signal and the 7th control signal are inverting each other;
One the 3rd flip-flop, this second control signal is exported in its accurate position according to the 5th control signal and the 3rd digital controlled signal: and
One the 4th flip-flop, the 3rd control signal is exported in its accurate position according to the 6th control signal and the 4th digital controlled signal.
4. electric pressure converter as claimed in claim 3 is characterized in that, the 4th control signal is this switch controlling signal, and this first control signal and the 5th control signal are inverting each other, and this second control signal and the 6th control signal are inverting each other.
5. electric pressure converter as claimed in claim 3 is characterized in that, this switch control unit comprises in addition:
One the 5th comparator, corresponding the 5th digital controlled signal is exported in its accurate position according to this first feedback voltage and this second reference potential;
One the 6th comparator, corresponding the 6th digital controlled signal is exported in its accurate position according to this second feedback voltage and the 3rd reference potential;
One the 7th comparator, corresponding the 7th digital controlled signal is exported in its accurate position according to the 3rd feedback voltage and the 4th reference potential;
Wherein this second flip-flop is exported this first control signal according to the accurate position of the 5th digital controlled signal in addition, the 3rd flip-flop is exported this second control signal according to the accurate position of the 6th digital controlled signal in addition, and the 4th flip-flop is exported the 3rd control signal according to the accurate position of the 7th digital controlled signal in addition.
6. electric pressure converter as claimed in claim 5 is characterized in that, this switch control unit comprises in addition:
One first or door, it optionally triggers this second flip-flop according to this second digital controlled signal and the 5th digital controlled signal;
One second or door, it optionally triggers the 3rd flip-flop according to the 3rd digital controlled signal and the 6th digital controlled signal; And
One the 3rd or door, it optionally triggers the 4th flip-flop according to the 4th digital controlled signal and the 7th digital controlled signal.
7. electric pressure converter as claimed in claim 3, it is characterized in that, the value of this second charging current is relevant to the difference of this first feedback voltage and this second feedback voltage, and the value of the 3rd charging current is relevant to the difference of this first feedback voltage and the 3rd feedback voltage.
8. electric pressure converter as claimed in claim 3 is characterized in that, this power switch, the 4th switch to the 6th switch are N type MOS (metal-oxide-semiconductor) transistor switch, and this first switch to the 3rd switch is a P type MOS (metal-oxide-semiconductor) transistor switch.
9. electric pressure converter as claimed in claim 8 is characterized in that, the 4th control signal is this switch controlling signal, and this first control signal and the 5th control signal are reverse each other, and this second control signal is reverse each other with the 6th control signal.
10. electric pressure converter as claimed in claim 3 is characterized in that, this first feedback circuit to the 3rd feedback circuit respectively comprises a plurality of series resistors.
11. electric pressure converter as claimed in claim 1 is characterized in that, this first feedback circuit to the 3rd feedback circuit respectively comprises a plurality of series resistors.
12. a method that drives a backlight module is characterized in that, comprising:
One energy storage component receives an input voltage to store corresponding energy;
The energy that receives this energy storage component internal memory is to provide one first output voltage, one second output voltage and one the 3rd output voltage;
Foundation one first feedback voltage is controlled the signal transmission path between this input voltage and this energy storage component, and wherein this first feedback voltage is relevant to the value of this first output voltage;
Control signal transmission path between this energy storage component and this first output voltage according to this first feedback voltage;
Control signal transmission path between this energy storage component and this second output voltage according to this first feedback voltage and one second feedback voltage, wherein this second feedback voltage is relevant to the value of this second output voltage; And
Control signal transmission path between this energy storage component and the 3rd output voltage according to this first feedback voltage and one the 3rd feedback voltage, wherein the 3rd feedback voltage is relevant to the value of the 3rd output voltage.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201010172727XA CN101834525B (en) | 2010-05-05 | 2010-05-05 | Voltage converter applied to backlight module and driving method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201010172727XA CN101834525B (en) | 2010-05-05 | 2010-05-05 | Voltage converter applied to backlight module and driving method thereof |
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| CN101834525A true CN101834525A (en) | 2010-09-15 |
| CN101834525B CN101834525B (en) | 2012-09-05 |
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| CN102740541A (en) * | 2011-04-15 | 2012-10-17 | 登丰微电子股份有限公司 | Switching controller |
| CN103354083A (en) * | 2013-07-11 | 2013-10-16 | 京东方科技集团股份有限公司 | Backlight drive circuit and display device |
| WO2013152603A1 (en) * | 2012-04-09 | 2013-10-17 | 京东方科技集团股份有限公司 | Drive circuit, drive power supply, and display device |
| CN105991029A (en) * | 2015-02-05 | 2016-10-05 | 通嘉科技股份有限公司 | Single-inductor multiple-output power supply converter using adaptive gate biasing technology |
| CN107683630A (en) * | 2015-04-23 | 2018-02-09 | 港大科桥有限公司 | The multiple output LED drivers of AC DC single inductors |
| CN109410848A (en) * | 2018-11-22 | 2019-03-01 | 昂宝电子（上海）有限公司 | LED backlight drives the cascade system and method for dual controller |
| CN114495807A (en) * | 2020-10-26 | 2022-05-13 | 华为技术有限公司 | Driving system, electronic board, display screen and electronic equipment |
| WO2023024454A1 (en) * | 2022-02-18 | 2023-03-02 | 京东方数字科技有限公司 | Drive circuit, drive method, and electronic price tag system |
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| CN102740541B (en) * | 2011-04-15 | 2016-05-11 | 登丰微电子股份有限公司 | Switching controller |
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| CN105991029A (en) * | 2015-02-05 | 2016-10-05 | 通嘉科技股份有限公司 | Single-inductor multiple-output power supply converter using adaptive gate biasing technology |
| CN105991029B (en) * | 2015-02-05 | 2018-11-30 | 通嘉科技股份有限公司 | Using the single inductor multi-output power converter of adaptability grid bias technology |
| CN107683630A (en) * | 2015-04-23 | 2018-02-09 | 港大科桥有限公司 | The multiple output LED drivers of AC DC single inductors |
| CN107683630B (en) * | 2015-04-23 | 2020-11-10 | 港大科桥有限公司 | AC-DC single inductor multiple output LED driver |
| CN109410848A (en) * | 2018-11-22 | 2019-03-01 | 昂宝电子（上海）有限公司 | LED backlight drives the cascade system and method for dual controller |
| CN109410848B (en) * | 2018-11-22 | 2020-09-29 | 昂宝电子（上海）有限公司 | System and method for LED backlight driving double-controller cascade |
| CN114495807A (en) * | 2020-10-26 | 2022-05-13 | 华为技术有限公司 | Driving system, electronic board, display screen and electronic equipment |
| WO2023024454A1 (en) * | 2022-02-18 | 2023-03-02 | 京东方数字科技有限公司 | Drive circuit, drive method, and electronic price tag system |
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