CN1149006C - Multi-load power supply system and multi-tube drive system - Google Patents
Multi-load power supply system and multi-tube drive system Download PDFInfo
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- CN1149006C CN1149006C CNB011037059A CN01103705A CN1149006C CN 1149006 C CN1149006 C CN 1149006C CN B011037059 A CNB011037059 A CN B011037059A CN 01103705 A CN01103705 A CN 01103705A CN 1149006 C CN1149006 C CN 1149006C
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Abstract
The present invention relates to a driving system with a plurality of strip lamps, which comprises a plurality of strip lamps, a transverter circuit and at least a current balance circuit, wherein the strip lamps comprise a main strip lamp and at least an auxiliary strip lamp; the transverter circuit is used for converting a direct current power supply into an alternating current power supply and supplying the alternating current power supply to the strip lamps; the current balance circuit is provided with an impedance component connected to at least an auxiliary strip lamp, the equivalent impedance value of the impedance component can be changed according to a current value flowing through the main strip lamp and at least an auxiliary strip lamp, and thus, current flowing through the main strip lamp and at least an auxiliary strip lamp can be balanced.
Description
The present invention relates to a kind of power system of multi-load, the particularly drive system of a plurality of discharge lamps of LCD panel back light system, but it has the current balance circuit of the electric current of each discharge lamp of balance.
The LCD panel is with discharge lamp, and (cold cathode fluorescentlamp CCFL), is used as back light system as cold-cathode fluorescence lamp.These discharge lamps are to be driven by converter circuit.In the large LCD panel, need to use a plurality of fluorescent tubes that enough brightness can be provided.In the application of fluorescent tube more than this kind, if drive the discharge lamp that is connected in parallel more than two with a transformer or power conversion stage, because the difference of impedance can have a strong impact on each lamp tube current in parallel of flowing through between each fluorescent tube, causes the inhomogeneous distribution of electric current.The unbalanced phenomenon of this kind lamp current not only makes some fluorescent tube cause luminance shortage because of electric current is too small, influences the uniformity of LCD panel, can make also that some lamp current is excessive and shortens the life-span that fluorescent tube itself reaches the entire backlight system.And this kind drives in the application of many fluorescent tubes with single power conversion stage and control loop, for the part error value of converter, and the fluorescent tube characteristic with situations such as variations service time, all can't in original design, do complete considering and controlling.In view of above-mentioned shortcoming, the converter of prior art all is to utilize one group of power conversion stage and control loop to drive a discharge lamp.Drive many tubes as desire, switching stage and control loop then need relatively increase electric power.Fig. 1 shows that promptly known technology drives the circuit structure diagram of two tubes with two groups of power conversion stage and control loop.Fluorescent tube Lpa and Lpb are driven by transformer 16a and 16b respectively, and are fed to other pulse-width modulation (pulse width modulation, PWM) a controller (not shown) by individual other sample resistance Ra and Rb negate.Yet this kind relatively increases many group power conversion stage and control loop to drive the mode of many tubes, though can reach the effect of the electric current between each fluorescent tube of balance, must increase the usage quantity of part, increases many costs and volume on foot.In addition, different electric power change inter-stage and have different frequency of operation, and this kind asynchronous operation causes mutual interference easily, then can influence the vision signal of LCD panel what is more, make picture the interference of water wave ripple etc. occur.Generally speaking, the known circuit structure of this kind has the cost height, volume is big and easily give birth to the shortcoming of disturbing.
The circuit structure that another kind of known technology is used to drive a plurality of discharge lamps is to be shown in Fig. 2, and it is that transformer 16a and 16b with the pair of series configuration drives two fluorescent tube Lpa and Lpb, and a common feedback loop is set.Though the circuit of Fig. 2 can improve the interference problem that is produced because of the frequency of operation difference, the current difference between its fluorescent tube is big than Fig. 1 person, can't reach good current balance type effect.
The object of the present invention is to provide a kind of power system of multi-load, its effectively equiulbrium flow through the electric current of each load.
Another object of the present invention is to provide a kind of drive system of many fluorescent tubes, particularly in the application of the cold-cathode fluorescence lamp (CCFL) of LCD panel back light system, its effectively equiulbrium flow through each lamp tube current, make that the brightness of each fluorescent tube is even, and the useful life that keeps fluorescent tube, can reduce production costs simultaneously, the reduction means volume, and improve the interference problem that is caused because of the frequency of operation difference.
Another purpose of the present invention is to provide a kind of drive system of many fluorescent tubes, can simplify power conversion stage and control circuit in the multi-lamp-tube driving system, and its whole efficiency is maintained near the optimum, and can not make efficient that tangible decay is arranged because of light, heavily loaded variation.
For reaching above-mentioned purpose, a kind of scheme of the drive system of many fluorescent tubes according to the present invention is to comprise: a plurality of fluorescent tubes comprise a king light pipe and at least one secondary fluorescent tube; One converter circuit is used for DC power supply is converted to AC power, and is supplied to this a plurality of fluorescent tubes; And at least one current balance circuit, it has a capacitances in series and is connected in respectively this at least one secondary fluorescent tube, can be according to this king light pipe and this at least one secondary lamp tube current value and change its equivalent capacitor value respectively of flowing through, but equiulbrium flow reaches respectively this at least one secondary lamp tube current through this king light pipe by this.
These a plurality of current balance circuits comprise again: a first transistor and a transistor seconds, and its collector electrode and emitter are coupled to the two ends of this electric capacity respectively, make when this first and second transistor is driven, and can discharge to this electric capacity; King light pipe and secondary lamp current sample circuit are in order to obtain king light pipe and secondary lamp tube current value; And comparison circuit, its input is coupled to this king light pipe and secondary lamp current sample circuit, output and is coupled to this first and second transistorized base stage, be used for the relatively size of this king light pipe and this pair lamp tube current value, and optionally export a voltage to drive this first and second transistor.
The another kind of scheme of the drive system of many fluorescent tubes according to the present invention is to comprise: one first fluorescent tube and one second fluorescent tube; One converter circuit is used for DC power supply is converted to AC power, and is supplied to this first and second fluorescent tube; And a current balance circuit, be used for equiulbrium flow through this first and second lamp tube current.
This current balance circuit comprises: one first electric capacity is connected in series with this first fluorescent tube; One second electric capacity is connected in series with this second fluorescent tube; One the first transistor and a transistor seconds, its collector electrode and emitter are coupled to the two ends of this first electric capacity respectively, and its base stage is coupled to this second electric capacity; And one the 3rd transistor AND gate 1 the 4th transistor, its collector electrode and emitter are coupled to the two ends of this second electric capacity respectively, and its base stage is coupled to this first electric capacity.
Fig. 1 is the circuit structure diagram that is used to drive a plurality of discharge lamps for known technology;
Fig. 2 is the circuit structure diagram that is used to drive a plurality of discharge lamps for another known technology;
Fig. 3 is the circuit diagram for first embodiment of the invention;
Fig. 4 (a) is the lamp current oscillogram when not using balancing circuitry for known technology, and Fig. 4 (b) is the lamp current oscillogram when using balancing circuitry for the present invention;
Fig. 5 (a)～5 (c) is the variation example for first embodiment of the invention, wherein Fig. 5 (a) and 5 (b) increase the negative half period waveform control circuit respectively in the application of single transformer and dual transformer, and Fig. 5 (c) then is to use in the shared circuit structure of fluorescent tube low-voltage line;
Fig. 6 is the circuit diagram for second embodiment of the invention; And
Fig. 7 is the circuit structure diagram when driving a plurality of fluorescent tube for the present invention with a plurality of power conversion stage.
Below reach and technology of the present invention is described in further detail with reference to accompanying drawing and preferred embodiment.
Fig. 3 shows the circuit diagram of first embodiment of the invention.As shown in the figure, the drive system of the many fluorescent tubes of the present invention comprises: a king light pipe Lpm and a secondary fluorescent tube Lps; One transformer 10, it is respectively via decoupling capacitance C and C and supply AC power to king light pipe Lpm and secondary fluorescent tube Lps; And a current balance circuit 20, be used for the electric current of equiulbrium flow through king light pipe Lpm and secondary fluorescent tube Lps.Such as hereinafter detailed description, the action of this current balance circuit will be as the pattern of same variable capacitance, change its equivalent capacitor value according to the current value of flow through king light pipe Lpm and secondary fluorescent tube Lps, control the waveform of lamp current linearly, and then reach the purpose of balanced balanced current.
It should be noted, though only show in the circuit structure of Fig. 3 and have a secondary fluorescent tube and a current balance circuit, but those skilled in the art can look the needs in the practical application according to the mode of Fig. 3, and suitably increase the quantity of secondary fluorescent tube and current balance circuit.In addition, the also visual desire of transformer 10 drives the quantity number of fluorescent tube, the rated power of institute's use transformer and the consideration on other designs and the cost, and adopts single transformer or most transformers.Above-mentioned variation can't have influence on the effect of current balance type of the present invention.
Current balance circuit 20 is arranged on the low-pressure end of fluorescent tube, and it comprises: a capacitor C x is connected in series in secondary fluorescent tube Lps; An one the first transistor Qp and a transistor seconds Qn, its collector electrode and emitter are coupled to the two ends of capacitor C x respectively; One first diode Dp and one second diode Dn are connected to collector electrode/emitter of the first transistor Qp and transistor seconds Qn; Sample resistance Rm and Rs are connected in series with king light pipe Lpm and secondary fluorescent tube Lps respectively; And a comparator 22, it has two inputs and is coupled to sample resistance Rm and Rs respectively, reaches the base stage that an output is coupled to the first transistor Qp and transistor seconds Qn.
Though showing first and second transistor Qp and Qn among Fig. 3 is the npn transistor, so also can use the pnp transistor as first and second transistor Qp and Qn, must be with two input end signal reversal connections of comparator 22.In addition, though the circuit of Fig. 3 and hereinafter described other change in the balancing circuitry among example and the embodiment and are to use the BJT transistor, those skilled in the art should understand, and also can use the transistor of other types to replace it, for example MOS transistor.
Next will describe the action of first embodiment of Fig. 3 in detail.Utilize sample resistance Rm and Rs, the positive half cycle current waveform of desirable fluorescent tube Lpm of winner and secondary fluorescent tube Lps, that is, the current value I m of flow through king light pipe Lpm and secondary fluorescent tube Lps is converted to magnitude of voltage Vm and the Vs that is directly proportional with Is.This two voltage signals Vm and Vs be the noninverting and inverting input of feed-in comparator 22 respectively, through comparator 22 relatively after will have following two kinds of situations.First kind of situation, if the comparative result of comparator 22 is that Vm is higher than Vs, that is, the electric current I m of king light pipe Lpm is greater than the electric current I s of secondary fluorescent tube Lps, and this moment, the voltage level of comparator 22 outputs rose, and then drove the first transistor Qp and transistor seconds Qn, it is discharged to capacitor C x, to reduce (perhaps also can be considered the voltage modulation of equivalent voltage source) this moment as the equivalent capacitive reactance of Cx, that is the equivalent capacitive reactance minimizing in secondary fluorescent tube Lps loop, and the electric current I s in this loop is increased.Second kind of situation, if the comparative result of comparator 22 is that Vs is higher than Vm, that is, the electric current I s of secondary fluorescent tube Lps is greater than the electric current I m of king light pipe Lpm, this moment, the voltage level of comparator 22 outputs descended, and can't drive the first transistor Qp and transistor seconds Qn and capacitor C x is discharged, so capacitor C x keeps the capacitor value (Xc=1/ ω C) of script, because the increase of secondary fluorescent tube Lps loop equivalence capacitive reactance will reduce the electric current I s in this loop.
Using the major and minor lamp current waveform of current balance circuit front and back and the output waveform of amplifier is to be shown in Fig. 4, wherein Fig. 4 (a) is a situation of not using current balance circuit for known technology, and Fig. 4 (b) is a situation of using current balance circuit for the present invention.It should be noted, in the situation of Fig. 4 (a), transistor Qp and Qn are not set in circuit, and only add a comparator so that make comparisons with the situation of Fig. 4 (b).In Fig. 4 (a), the current effective value of king light pipe Lpm is 6.58mA, and the current effective value of secondary fluorescent tube Lps is 5.36mA.In Fig. 4 (b), the current effective value of king light pipe Lpm is 6.56mA, and the current effective value of secondary fluorescent tube Lps is 6.56mA.By Fig. 4 (b), can clearly observe the action situation of amplifier 22, and the action drives transistor Qp and the Qn that can clearly observe because of amplifier 22 cause secondary fluorescent tube Lps current waveform to reach the effect of balance along with the change of king light pipe Lpm current waveform.
Among first embodiment of the invention described above,, can reach the purpose of balanced balanced current, and can not influence the waveform balanced ratio of positive and negative half cycle though only control at the positive half cycle current waveform of fluorescent tube.
As the control circuit of desire increase to electric current negative half period waveform, only need set up extra negative half-cycle current waveform sampling circuit and comparator and get final product, do not need to increase controlled capacitor C x, transistor Qp and Qn, reach diode Dp and Dn.Fig. 5 (a) and Fig. 5 (b) are the variation examples for first embodiment of the invention, and it is presented at the circuit structure that increases in the application of single transformer and dual transformer the control of electric current negative half period waveform respectively.
Fig. 5 (a) is for drive the circuit of two tubes with single transformer 12.King light pipe Lpm and secondary fluorescent tube Lps are connected to the secondary side of transformer 12 respectively via decoupling capacitance C and C.King light tube loop and secondary fluorescent tube loop are provided with positive half cycle current waveform sampling resistance R mp, Rsp and negative half-cycle current waveform sampling resistance R mn, Rsn respectively.Utilize these sample resistances, can obtain the positive and negative half cycle current waveform of king light pipe Lpm and secondary fluorescent tube Lps individually, convert magnitude of voltage Vmp, Vsp and Vmn, Vsn to.Then, voltage signal Vmp and the Vsp noninverting and inverting input of feed-in comparator 32a respectively compare, voltage signal Vmn and Vsn then respectively anti-phase the and non-inverting input of feed-in comparator 32b compare.The output of comparator 32a and 32b all is connected to the base stage of transistor Qp and Qn.By this, comparison circuit 30 can be according to positive half cycle current waveform or the negative half-cycle current different wave shape of king light pipe Lpm and secondary fluorescent tube Lps, and change the equivalent capacitor value of capacitor C x, control the waveform of lamp current and then the electric current of balance king light pipe Lpm and secondary fluorescent tube Lps linearly.
Fig. 5 (b) is for drive the circuit of two tubes with two transformer 12a and 12b.Negative half-cycle current waveform sampling resistance R mn, Rsn and negative half-cycle current comparator 32b have also been set up in this circuit.Though its circuit structure is slightly variant with the circuit structure of the single transformer of Fig. 5 (a), generally speaking, the circuit of its operating principle and Fig. 5 (a) is similar, and those skilled in the art should understand easily, is not therefore given unnecessary details at this.
Fig. 5 (c) is another variation example for first embodiment of the invention.In general the application, a tubes is to have high pressure and two lines of low pressure.Yet the product of some manufacturer is to be designed to the low-voltage line of a plurality of fluorescent tubes is interlinked.For the shared structure of this kind low-pressure end, then the circuit of first embodiment of this case can be changed slightly, reach the purpose of current balance type with the configuration mode of Fig. 5 (c).
Fig. 6 shows the circuit diagram of second embodiment of the invention.In this embodiment, current balance circuit has the structure that is different from first embodiment.As shown in the figure, the drive system of the many fluorescent tubes of the present invention comprises: one first fluorescent tube Lp1 and one second fluorescent tube Lp2; One transformer 14, it is respectively via decoupling capacitance C and C and supply AC power to the first fluorescent tube Lp1 and the second fluorescent tube Lp2; And a current balance circuit 40, be used for the electric current of equiulbrium flow through the first fluorescent tube Lp1 and the second fluorescent tube Lp2.
Current balance circuit 40 comprises: the D1 of one first capacitor C 1, a pair of reverse parallel connection diode and D2, and one first resistance R 1 are connected in series with this first fluorescent tube Lp1 in regular turn; The diode D3 of one second capacitor C 2, a pair of reverse parallel connection and D4, and one second resistance R 2 are connected in series with this second fluorescent tube Lp2 in regular turn; An one the first transistor Q1 and a transistor seconds Q2, its collector electrode and emitter are coupled to the two ends of this first capacitor C 1 respectively, and its base stage is coupled between this second capacitor C 2 and diode D3, the D4; And one the 3rd transistor Q3 and one the 4th transistor Q4, its collector electrode and emitter are coupled to the two ends of this second capacitor C 2 respectively, and its base stage is coupled between this first capacitor C 1 and diode D1, the D2.The first and the 3rd transistor Q1 and Q3 are the npn transistor herein, and the second and the 4th transistor Q2 and Q4 are the pnp transistor.
Next will describe the action of second embodiment of Fig. 6 in detail.When the electric current I 1 of the first fluorescent tube Lp1 that flows through during greater than the electric current I 2 of the second fluorescent tube Lp2 that flows through, voltage V1 can be higher than voltage V2, and therefore, the first transistor Q1 and transistor seconds Q2 enter cut-off region (Ic=0), and the 3rd transistor Q3 and the 4th transistor Q4 can move.During positive half cycle, the 3rd transistor Q3 enters active region or saturation region, and the 4th transistor Q4 then is in cut-off region; During negative half period, the 4th transistor Q4 enters active region or saturation region, and the 3rd transistor Q3 then is in cut-off region.The action that above-mentioned transistor Q1 and Q2 enter cut-off region be the equivalent capacitor value increase as the capacitor C 1 in the first fluorescent tube loop, and transistor Q3 and Q4 enters the action of active region or saturation region, are the equivalent capacitor value minimizings as the capacitor C 2 in the second fluorescent tube loop.Therefore, electric current I 1 can diminish and electric current I 2 meeting increases.Otherwise, as the second lamp tube current I2 during greater than the first lamp tube current I1, the action that the 3rd transistor Q3 and the 4th transistor Q4 enter cut-off region, it is equivalent capacitor value increase as the capacitor C 2 in the second fluorescent tube loop, and the action that the first transistor Q1 and transistor seconds Q2 enter active region or saturation region is the equivalent capacitor value minimizing as the capacitor C 1 in the first fluorescent tube loop.Therefore, electric current I 2 can diminish, and electric current I 1 can increase.So, can effectively reach the purpose of balanced balanced current.
In the circuit of second embodiment of the invention described above, the setting of diode D1～D4 is for the base stage of compensation transistor Q1～Q4 when the active region and emission voltage across poles VBE (being about 0.6V).
In addition, it should be noted each capacitor C x, C1 and C2 of being used in the balancing circuitry of the various embodiments described above of the present invention and variation example, needs in all visual side circuit design, and be transformed into other impedance components, as resistance or inductor part, can reach the effect of current balance type equally.
Current balance circuit of the present invention, be to be a kind of (real time) current waveform feedback control circuit in real time, in the application of many fluorescent tubes, it can make the waveform of each secondary lamp current accurately follow main controlled lamp tube current, and then reach and be close to identical current effective value, fully solve the negative effect that may cause, the electric current between active balance difference fluorescent tubes because of fluorescent tube property difference institute, keep lamp tube service life, and make the brightness of each fluorescent tube even.And, according to the drive system of many fluorescent tubes of the present invention, can only drive many tubes with single power conversion stage and control loop, therefore can use the part of lesser amt, not only reduce manufacturing cost, also dwindled the overall volume of converter, more be applicable in the frivolous day by day electronic product.Particularly in the application of fluorescent tube the more, can represent more that the present invention reduces cost and the excellent effect of reduced volume.In addition, because the unification of frequency of operation, the difference frequency that can eliminate in the known technology disturbs.
Because commutation circuit of the present invention and control circuit all are positioned at low-pressure end, thus do not need to control with high pressure part or technology, but the reliability of intensifier circuit and reduction manufacturing cost.
On the other hand,, utilize the characteristic of balancing circuitry scalable lamp current, still can other power conversion stage beyond the main controlled power conversion stage be simplified its circuit structure, even remove its control circuit according to the present invention.In more detail, as shown in Figure 7, when the fluorescent tube One's name is legion, and the power rating deficiency of transformer, can't drive all fluorescent tubes with single transformer, and must adopt multiple transformers the time, except main controlled transformer, remaining teaser transformer can fixed pulse width (pulse width) type of drive, the operation of complex equilibrium circuit reaches the purpose of Current Control.This fixed pulse width can be designed to the pulsewidth near full load, so, this drive circuit is maintained near the working point of optimum efficiency.Thereby can improve whole efficiency, it is unlikely because of light, heavily loaded variation tangible efficient relaxation phenomenon.
Though, above-mentioned explanation all is the drive circuits about fluorescent tube, particularly at the discharge lamp of LCD panel back light system, but those skilled in the art should understand, current balance circuit of the present invention also can be applicable in the multi-load drive system of other kinds load, to reach the purpose of equiulbrium flow through the electric current of each load.Above-mentioned explanation only is for character for example but not limitation, and any variation and modification of being made according to claim scope spirit of the present invention all should belong to scope of the present invention.
Claims (20)
1. the drive system of fluorescent tube more than a kind comprises:
A plurality of fluorescent tubes comprise a king light pipe and at least one secondary fluorescent tube;
One converter circuit is used for DC power supply is converted to AC power, and is supplied to this a plurality of fluorescent tubes;
At least one current balance circuit, it has an impedance component and is connected in respectively this at least one secondary fluorescent tube, can be according to this king light pipe and this at least one secondary lamp tube current value and change its equivalent impedance respectively of flowing through, but equiulbrium flow reaches respectively this at least one secondary lamp tube current through this king light pipe by this;
One the first transistor and a transistor seconds, its collector electrode and emitter are coupled to this impedor two ends respectively, make when this first and second transistor is driven, and can change this impedor equivalent impedance;
King light pipe and secondary lamp current sample circuit are in order to obtain flow through this king light pipe and secondary lamp tube current value; And
Comparison circuit, its input is coupled to this king light pipe and secondary lamp current sample circuit, output and is coupled to this first and second transistorized base stage, be used for the size of this king light pipe and this pair lamp tube current value of relatively flowing through, and optionally export a voltage with drive this one and transistor seconds.
2. the drive system of many fluorescent tubes as claimed in claim 1, wherein this impedance component is to be electric capacity.
3. the drive system of many fluorescent tubes as claimed in claim 1, wherein this impedance component is to be resistance.
4. the drive system of many fluorescent tubes as claimed in claim 1, wherein this impedance component is to be inductance.
5. the drive system of many fluorescent tubes as claimed in claim 1, wherein this king light pipe and the secondary fluorescent tube sample circuit positive half cycle current waveform that is desirable winner fluorescent tube and secondary fluorescent tube; And this comparison circuit only comprises a comparator, is used for the relatively positive half cycle current waveform of this king light pipe and secondary fluorescent tube.
6. the drive system of many fluorescent tubes as claimed in claim 1, wherein this king light pipe and secondary fluorescent tube sample circuit be desirable winner fluorescent tube and secondary fluorescent tube positive half cycle current waveform and negative half-cycle current waveform; And this comparison circuit comprises two comparators, is respectively applied for relatively the positive half cycle current waveform and the negative half-cycle current waveform of this king light pipe and secondary fluorescent tube.
7. the drive system of many fluorescent tubes as claimed in claim 1, wherein this converter circuit comprises single transformer.
8. the drive system of many fluorescent tubes as claimed in claim 1, wherein this converter circuit comprises a plurality of transformers.
9. the drive system of fluorescent tube more than a kind comprises:
One first fluorescent tube and one second fluorescent tube;
One converter circuit is used for DC power supply is converted to AC power, and is supplied to this first and second fluorescent tube; And
One current balance circuit is used for equiulbrium flow through this first and second lamp tube current, and this current balance circuit comprises:
One first impedance component is connected with this first fluorescent tube;
One second impedance component is connected with this second fluorescent tube;
One the first transistor and a transistor seconds, its collector electrode and emitter are coupled to this first impedor two ends respectively, and its base stage is coupled to this second impedance component; And
One the 3rd transistor AND gate 1 the 4th transistor, its collector electrode and emitter are coupled to this second impedor two ends respectively, and its base stage is coupled to this first impedance component.
10. the drive system of many fluorescent tubes as claimed in claim 9, wherein this impedance component is to be electric capacity.
11. the drive system of many fluorescent tubes as claimed in claim 9, wherein this impedance component is to be resistance.
12. the drive system of many fluorescent tubes as claimed in claim 9, wherein this impedance component is to be inductance.
13. the drive system of many fluorescent tubes as claimed in claim 9, wherein this first and the 3rd transistor is to be the npn transistor, and this second and the 4th transistor is to be the pnp transistor.
14. the drive system of many fluorescent tubes as claimed in claim 9, it comprises one first pair of diode and one second pair of diode again, is used to compensate the voltage between this first and second transistor and the 3rd and the 4th transistorized base stage and the emitter.
15. the drive system of many fluorescent tubes as claimed in claim 9, wherein this converter circuit comprises single transformer.
16. the drive system of many fluorescent tubes as claimed in claim 9, wherein this converter circuit comprises a plurality of transformers.
17. the power system of a multi-load, it comprises:
A plurality of loads comprise a main load and at least one secondary load;
One drive circuit is used for power supply to these a plurality of loads; And
At least one current balance circuit is used for equiulbrium flow and reaches the respectively electric current of this at least one secondary load through this main load, and respectively these a plurality of current balance circuits comprise:
One impedance component is connected in respectively this at least one secondary load,
One the first transistor and a transistor seconds, its collector electrode and emitter are coupled to this impedor two ends respectively, make when this first and second transistor is driven, and can change this impedor equivalent impedance;
Current sampling circuit is in order to obtain the current value of flow through this main load and secondary load; And
Comparison circuit, its input is coupled to this current sampling circuit, output and is coupled to this first and second transistorized base stage, the size of current value of this main load and this pair load that is used for relatively flowing through, and optionally export a voltage to drive this first and second transistor.
18. as the power system of the multi-load of claim 17, wherein this impedance component is to be electric capacity.
19. as the power system of the multi-load of claim 17, wherein this impedance component is to be resistance.
20. as the power system of the multi-load of claim 17, wherein this impedance component is to be inductance.
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| CNB011037059A CN1149006C (en) | 2001-02-09 | 2001-02-09 | Multi-load power supply system and multi-tube drive system |
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| CNB011037059A CN1149006C (en) | 2001-02-09 | 2001-02-09 | Multi-load power supply system and multi-tube drive system |
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| CN100529893C (en) * | 2005-11-18 | 2009-08-19 | 鸿富锦精密工业（深圳）有限公司 | Multi-lamp driven system and its anomaly detection circuit |
| CN101009962B (en) * | 2006-01-26 | 2010-05-12 | 尼克森微电子股份有限公司 | Backlight power device of the LCD panel |
| CN1921727B (en) * | 2006-09-15 | 2011-06-01 | 友达光电股份有限公司 | Current transducing unit and current transducer |
| CN102842287A (en) * | 2011-06-20 | 2012-12-26 | 国琏电子（上海）有限公司 | Light emitting diode drive system and display device using same |
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Owner name: FOXCONN PRECISE INDUSTRY STOCK CO., LTD. Free format text: FORMER NAME OR ADDRESS: AMBIT MICROSYSTEMS CORPORATION |
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Address after: Taipei County of Taiwan Province Patentee after: Hon Hai Precision Industry Co., Ltd. Address before: Taipei County of Taiwan Province Patentee before: Guoqi Electric Co., Ltd. |
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Assignee: Guolian Electronics (Shanghai) Co., Ltd. Assignor: Hon Hai Precision Industry Co., Ltd. Contract fulfillment period: 2008.1.1 to 2021.2.9 contract change Contract record no.: 2009990000257 Denomination of invention: Multi-load power supply system and multi-tube drive system Granted publication date: 20040505 License type: Exclusive license Record date: 2009.4.2 |
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Free format text: EXCLUSIVE LICENSE; TIME LIMIT OF IMPLEMENTING CONTACT: 2008.1.1 TO 2021.2.9; CHANGE OF CONTRACT Name of requester: GUO LIAN ELECTRONICS (SHANGHAI) CO., LTD. Effective date: 20090402 |
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