CN101730352A

CN101730352A - Backlight source for driving image display device and driving system for driving multi-tube lamp

Info

Publication number: CN101730352A
Application number: CN200810169400A
Authority: CN
Inventors: 江怡诏
Original assignee: HUANCI ELECTRONICS HOLDINGS CO Ltd
Current assignee: HUANCI ELECTRONICS HOLDINGS CO Ltd; Verticil Electronics Corp
Priority date: 2008-10-13
Filing date: 2008-10-13
Publication date: 2010-06-09

Abstract

The invention relates to a backlight source for driving an image display device and a driving system for driving a multi-tube lamp; the driving system comprises a plurality of transformers which are used for receiving, boosting or reducing a plurality of input alternating current signals, and the output of the transformers is used for driving a plurality of light sources or a plurality of loads; a plurality of uniform loading coils which are magnetically coupled in a magnetic path of the related transformer; and an impedance which is used for electrically coupling the uniform loading coils; the uniform loading coils is used for magnetic coupling of the transformers and the electrical coupling among the uniform loading coils, and the output voltage, current or power of the transformers are the same or the same in essence; in addition, the magnetic flux of the transformers are coupled, so as to lead the final magnetic flux in the transformer to be the same or the same in essence.

Description

The drive system that is used for driving the back light of image display or drives multi-tube lamp

Drive system

Technical field

The drive system of the relevant a kind of multi-load of the present invention.And relevant especially a kind of transducer (inverter or ballast), it is used for driving the back light of image display or is used to drive many fluorescent tubes light fixture, it utilizes the magnetic field coupling effect of all carrying coil and is electrically connected, and reaches current-sharing (balanced balanced current) or all carries (balanced load).

Background technology

Advantages such as that LCD TV (LCD TV) and LCD (LCD device) have is compact, power saving, low radiation are so become the main flow of display unit.In the used light source of LCD TV and LCD, cathode fluorescent tube (CCFL, Cold Cathode Fluorescent Lamp) is one of main flow, has advantages such as high brightness, high effect, high life, low-power consumption because of it.

Transducer (inverter) can drive cathode fluorescent tube.Transducer generally comprises drive circuit and transformer.Drive circuit is as full-bridge/half bridge rectifier etc., in order to direct voltage is converted to alternating current.Transformer boosts or step-down to the output of drive circuit, to drive cathode fluorescent tube.Introduce several frequently seen existing converter configurations below.

Figure 1A shows the configuration of first kind of existing transducer.Shown in Figure 1A, drive circuit 10 is converted to alternating current with direct current Vin, sending into transformer Y1 again boosts or step-down, boost or step-down after transformer output then be used for driving two groups shunt load, wherein one group load is made up of with fluorescent tube LP1 capacitor C 1, and another group load then is made up of with fluorescent tube LP2 capacitor C 2.The total lamp current I1+12 of these two groups of loads of flowing through can deliver to feedback control circuit 30 together.This feedback control circuit 30 judges whether the maximum lamp tube current between total lamp current or lamp current I1, I2 is enough, with the operating state of decision or control Driver Circuit 10.

In the configuration of Figure 1A, for balance lamp current I1 and I2, capacitor C 1 and C2 must be the very little high-voltage capacitance of capacitance, to overcome the lamp current imbalance that negative resistance character was caused of tube impedance tolerance (impedance tolerance) and fluorescent tube.But the part and the assembly cost of high-voltage capacitance are higher, and, transformer T1 must amount of exports outer high voltage (being approximately higher than more than a times of light tube electric voltage), cause the decline in transformer efficiency and life-span.And in product design, take high voltage and layout (layout) area into account, and then cause the misgivings on the Product Safety, and product is reached minimize.

In addition, the configuration of Figure 1A belongs to " passive compensation " control.Before product export, " adjust " balance of lamp current in advance with the lamp current testing result.But in use, inconsistent because of the degree of aging of each fluorescent tube or high-voltage capacitance, make the balance variation of lamp current, reduce the reliability of end product.

Figure 1B shows the configuration of second kind of existing transducer.In Figure 1B, the output of drive circuit 10 can send into transformer 1 and T2 boosts or step-down.The primary side of transformer T1 and T2 is connected in parallel to each other.Two groups of loads of the output of transformer T1 and T2 driving out of the ordinary, wherein one group of load is made up of with fluorescent tube LP1 capacitor C 1, and another group load is made up of with fluorescent tube LP2 capacitor C 2.Total lamp current I1+I2 of these two groups of loads delivers to pulse-width modulation pulse-width modulation (pulse-width modulation) control circuit 35 again, pulse width modulating control circuit 35 judges whether total lamp current or lamp current I1, I2 maximum lamp tube current between the two is enough thus, with the operating state of decision or control Driver Circuit 10.

In the configuration of Figure 1B, balance lamp current I1 and I2 must control the tolerance (tolerance) of transformer T1 and T2.Just according to a plurality of little margins of tolerance, transformer T1 and T2 are done classification and pairing, the capacitance of capacitor C 1 and C2 then cooperates the classification of transformer to decide, or directly electric capacity is removed (short circuit) need not.Though the configuration of Figure 1B can use high-tension electricity perhaps only to use the higher electric capacity of capacitance, but because of doing special control to the transformer tolerance, degree of difficulty when increasing end product (for example multi-tube lamp or LCD TV) volume production except meeting, higher because of the cost of its transformer T1 and T2, also increased production cost.In addition, the configuration of Figure 1B still belongs to " passive compensation " control.

Fig. 1 C shows the configuration of the third existing

transducer.Drive circuit

10 and 20 is converted to alternating current with direct current Vin, distinctly sends into transformer T1 and T2 again and boosts or step-down.Boost or step-down after transformer output then distinctly be used for driving two groups of loads, wherein one group of load is made up of with fluorescent tube LP1 capacitor C 1, another group load is made up of capacitor C 2 and fluorescent tube LP2.The lamp current I1 of these two groups of loads and I2 distinctly deliver to two pulse width modulating control circuits 40 (comprising two PWM controller circuit) again.This pair pulse width modulating control circuit 40 judges respectively whether lamp current I1 and I2 be enough, with the operating state of decision or

control Driver Circuit

10 and 20.

In the configuration of Fig. 1 C, for balance lamp current I1 and I2, use two groups of complete circuit controls, wherein one group of circuit controls comprises a pulse width modulating control circuit in drive circuit 10 and the two pulse width modulating control circuits 40, and another group circuit controls comprises another pulse width modulating control circuit in drive circuit 20 and the two pulse width modulating control circuits 40.So it can effectively control the balance of lamp current, and need not use the transformer of high-voltage capacitance and special control.But the configuration of Fig. 1 C still belongs to " passive compensation " control for lamp current form-factor (crest factor).

With reference to figure 1D, it shows the configuration of the 4th kind of existing transducer.The transformer output of transformer T1 is delivered to high pressure balancing transformer (balance transformer) or high pressure balance coil (balance choke) 60 by capacitor C 1 (also making capacitor C 1 short circuit), and this high pressure balancing transformer 60 is made up of two winding (winding) W1 and W2.The output of high pressure balancing transformer 60 then distinctly is used for driving two groups of loads (fluorescent tube LP1 and LP2).The lamp current I1 of these two groups of loads and one of them of I2 (icon is I1) are delivered to feedback control circuit 30.Feedback control circuit 30 judges whether lamp current is enough, with the operating state of decision or control Driver Circuit 10.

In the configuration of Fig. 1 D,, additionally used high pressure balancing transformer 60 for balance lamp current I1 and I2.The operating principle of high pressure balancing transformer 60 as described later.When lamp current is flowed through each other winding, can produce self induction voltage (V1 and V2) at the two ends of winding, it can reduce the input voltage of fluorescent tube.The magnetic field coupling each other by iron core between winding W1 and W2.Therefore, the winding W1 though electric current I 2 is not flowed through, but still can induce mutual voltage V21 at winding W1 two ends, its polarity is in contrast to self induction voltage V1.Similarly, the winding W2 though electric current I 1 is not flowed through, but still can induce mutual voltage V12 at the two ends of winding W2, its polarity is in contrast to self induction voltage V2.

Mutual voltage V21 can increase the input voltage of fluorescent tube LP1, and mutual voltage V12 can increase the input voltage of fluorescent tube LP2.When I1=I2, V1=V21, so winding W1 two ends as short circuit, lamp current I1 can't be lowered or increase.But when I1＜I2, V1＜V21, the total voltage at winding W1 two ends can increase (because V21＞V1), increase lamp current I1 by this, until till the I1=I2.According to this, can make lamp current I1 and I2 reach poised state effectively.

For the active balance lamp current, just, be the input voltage of control in time (increase or reduce) fluorescent tube, the proof voltage of high pressure balancing transformer 60 is very high.With the used cathode fluorescent tube of the LCD TV more than 32 o'clock is example, and the fluorescent tube input voltage that light cathode fluorescent tube must be more than 2000Vrms, and keep cathode fluorescent tube then is about 1000Vrms in the fluorescent tube input voltage of bright state.Therefore, the proof voltage of high pressure balancing transformer 60 also needs 100Vrms above (the reasonable tolerance scope of corresponding light tube electric voltage 10%), can the active balance lamp current.But when fluorescent tube is not lighted simultaneously, for example fluorescent tube LP1 lights earlier but fluorescent tube LP2 does not light (I1 ≠ 0 but I2=0) as yet, except that the two ends of winding W1 can occur the self induction voltage V1, still need and consider the voltage phase difference at winding W1 and W2 two ends, make the proof voltage of high pressure balancing transformer 60 must reach hundreds of volts and can bear this situation.But the cost of the high pressure balancing transformer of high withstand voltage is high.

What is more, if during the fluorescent tube opposed polarity, the proof voltage that must significantly promote high pressure balancing transformer 60 is to more than thousands of volts, and this will more raise the cost, and will face the technical bottleneck that promotes proof voltage.In addition, in end product (for example LCD TV), the fluorescent tube of identical polar generally can adjacently not arranged.So, when layout high pressure balancing transformer, must cooperate high pressure jumper wire device (HV Jumper) and bigger high-pressure area area can finish the layout of printed circuit board (PCB).This more causes its cost to improve, and it also has the misgivings of fail safe.

Fig. 1 E shows the configuration of the 5th kind of existing transducer, and wherein, high pressure balancing transformer 60 is connected on the low-pressure side of fluorescent tube.Though the configuration of Fig. 1 E need not used the high pressure jumper wire device, and reduce the area of high-pressure area.Yet the fluorescent tube low-pressure end no longer is real low-voltage.So in the design of end product, except that the fluorescent tube high-pressure side will have the insulating Design, the fluorescent tube low-pressure end also will have insulating Design, the design of this double ended insulation also easily causes the rising of cost.

Fig. 1 F shows the configuration of the 6th kind of existing transducer.AC power input 100 (being the output voltage of transformer) are through several high pressure balancing transformers 102 (1), 102 (2) ... the first side winding N11 of 102 (k), N12 ... N1k is to drive fluorescent tube 104 (1), 104 (2) respectively ... 104 (k).Each high pressure balancing transformer 102 (1), 102 (2) ... the secondary side winding N21 of 102 (k), N22 ... N2k can be serially connected, and makes the secondary side current of each high pressure balancing transformer identical, i.e. I21=I22=...=I2k.Because the first side winding of high pressure balancing transformer and secondary side winding can be coupled, primary side current I11, the I12 of each high pressure balancing transformer ... I1k is identical with its secondary side current or become fixed proportion, and this just causes the balance between each lamp current.

Though but the configuration balance multi-light tube current of Fig. 1 F, yet it need use the high pressure balancing transformer.So in the design of end product, still must use, and the area of required high-pressure area is also bigger with the collocation of high pressure jumper wire device.

So, needing a kind of transducer of back light, it is the control of Active Compensation formula, it can reach current-sharing or all carry, and it can avoid prior art problems.

Summary of the invention

The invention provides the back light in a kind of image display or the drive system of many fluorescent tubes light fixture, its utilize all carry coil to the magnetic field coupling of transformer with all carry coil electrical couplings to each other, reach current-sharing or all carry, wherein this all carries coil and can be: (1) is coupled to the absolute coil of transformer or the auxiliary winding in (2) transformer.

The invention provides the back light in a kind of image display or the drive system of many fluorescent tubes light fixture, wherein, distinctly all carry the magnetic circuit that coil is coupled to corresponding transformer, so, the power output that coil voltage is proportional to corresponding transformer all carried.In addition, these all carry coil each other by impedance network and electric property coupling, all carry the power output that electric current on the coil can influence each transformer, can make the power output of each transformer identical, the purpose that reaches the load current-sharing or all carry.This impedance network can be used for adjusting the balanced reaction degree of current-sharing/all carry.

The invention provides the back light in a kind of image display or the drive system of many fluorescent tubes light fixture; wherein; when unusual (imbalance) takes place in the transformer power output; protective device can detect the signal that impedance network is taken a sample, and this protective circuit controls according to this/ac input signal of blocking transformer.

The present invention is used for driving the back light of image display or drives multi-tube lamp relevant for a kind of driving transducer.This drives transducer and comprises: first transformer, and receive and boost or step-down first input signal, the output voltage of first transformer is used for driving light source or load; Second transformer receives and boosts or step-down second input signal, and the output voltage of second transformer is used for driving light source or load; First all carries coil, and magnetic couplings is to the magnetic circuit one of at least of first and second transformer; Second all carries coil, and magnetic couplings is to the magnetic circuit one of at least of first and second transformer; And first impedance network, be used to make first all to carry coil and second and all carry coil electrical couplings each other.Wherein, all carry the magnetic couplings of coil and the electrical couplings of first impedance network by first magnetic couplings, second of all carrying coil, first transformer is identical with the output of second transformer or essence is identical.

The present invention is used for driving the back light of image display or drives multi-tube lamp relevant for a kind of driving transducer.This drives transducer and comprises: first transformer, and receive and boost or step-down first input signal, the output voltage of first transformer is used for driving light source or load; Second transformer receives and boosts or step-down second input signal, and the output voltage of second transformer is used for driving light source or load; First all carries coil, and magnetic couplings is to the magnetic circuit one of at least of first and second transformer; Second all carries coil, and magnetic couplings is to the magnetic circuit one of at least of first and second transformer; First impedance network is used to make first all to carry coil and second and all carry coil electrical couplings each other; And protective device, be coupled to first impedance network, when generation was unusual, protective device was controlled first input signal and second input signal according to the electric signal that first impedance network is sampled to.Wherein, all carry coil, second by first and all carry the coil and first impedance network, the magnetic flux in the magnetic flux in first transformer and second transformer is coupled to each other, so that the output of first transformer and second transformer much at one.

The present invention is used for driving the back light of image display or drives multi-tube lamp relevant for a kind of drive system.This drive system comprises: a plurality of transformers, and receive and boost or a plurality of input signals of step-down, the output voltage of these transformers is used for driving light source or load; A plurality of coils that all carry, magnetic couplings is to the magnetic circuit of related transformer; And impedance network, be used to make these all to carry coil electrical couplings each other.All carry coil by these magnetic couplings of these transformers and these are all carried coil electrical couplings to each other, the output of these transformers is mutually the same or essence is identical.And the magnetic flux in these transformers is coupled to each other.

Description of drawings

For foregoing of the present invention can be become apparent, below conjunction with figs. is elaborated to preferred embodiment of the present invention, wherein:

Figure 1A shows the configuration of first kind of existing transducer.

Figure 1B shows the configuration of second kind of existing transducer.

Fig. 1 C shows the configuration of the third existing transducer.

Fig. 1 D shows the configuration of the 4th kind of existing transducer.

Fig. 1 E shows the configuration of the 5th kind of existing transducer, and wherein, the high pressure balancing transformer is connected on the fluorescent tube low-pressure side.

Fig. 1 F shows the configuration of the 6th kind of existing transducer.

Fig. 2 A shows the transducer schematic diagram according to first embodiment of the invention.

Fig. 2 B shows may the actual disposition schematic diagram according to a kind of of first embodiment.

The equivalent electric circuit of Fig. 2 C displayed map 2B.

Fig. 2 D, Fig. 2 F, Fig. 2 H, Fig. 2 J are presented at the lamp current analogous diagram of the prior art under the different loads respectively.

Fig. 2 E, Fig. 2 G, Fig. 2 I, Fig. 2 K are presented at the lamp current analogous diagram of the first embodiment of the invention under the different loads respectively.

Fig. 3 shows the schematic diagram according to the transducer of second embodiment of the invention.

Fig. 4 shows the schematic diagram according to the transducer of third embodiment of the invention.

Fig. 5 shows the schematic diagram according to the transducer of fourth embodiment of the invention.

Fig. 6 shows the schematic diagram according to the transducer of fifth embodiment of the invention.

Fig. 7 shows the transducer schematic diagram according to sixth embodiment of the invention.

Fig. 8 A～Fig. 8 D shows that the several of impedance network Z may example.

Fig. 9 A shows that the low-pressure side of transformer T1 comprises a plurality of windings, and these windings are independent separately.

Fig. 9 B shows that the low-pressure side of transformer T1 comprises a plurality of windings, and these windings are coupled in together.

Fig. 9 C shows that the high-pressure side of transformer T1 comprises a plurality of windings, and these windings are independent separately.

Fig. 9 D shows that the high-pressure side of transformer T1 comprises a plurality of windings, and these windings are coupled in together.

Embodiment

In several embodiment of the present invention, utilize and all to carry coil and reach current-sharing or all carry.This all carries coil and can be (1) two or more absolute coil; Or (2) have the two or more separated transformer of auxiliary winding.In situation (1), plural absolute coil is separately around plural transformer, again these absolute coils are done the connection on electric, magnetic flux in the iron core of these transformers is coupled by these absolute coils, will reaches active balance current-sharing or effect of load balancing mechanism by the absolute coil electric current that magnetic flux difference is caused.In situation (2), the auxiliary winding of a plurality of separated transformers is coupled in together, the auxiliary winding current that magnetic flux difference is caused these transformer fe magnetic flux in the heart is coupled, because of will be reached active balance current-sharing or effect of load balancing mechanism because of these auxiliary windings.

First embodiment

Fig. 2 A shows the transducer schematic diagram according to first embodiment of the invention.V _AC1With V _AC2For same-phase or be close to synchronous ac input signal.Ac input signal V _AC1With V _AC2Distinctly deliver to the first side winding of transformer T1 and T2, the output voltage of the secondary side winding of transformer T1 and T2 can drive fluorescent tube (or load) LP1 and LP2.Transformer T1 is with the first side winding of T2 independence or be coupled in separately; And transformer T1 is with the secondary side winding of T2 independence or be coupled in separately.

All carry the magnetic circuit that coil BC1 and BC2 distinctly are coupled to transformer T1 and T2, so all carry the flux change rate that the induced voltage at coil BC1 and BC2 two ends is proportional to the iron core of transformer T1 and T2 respectively, that is it is proportional to the power output of first side winding or the input power of secondary side winding respectively.

It is coupled to each other via impedance network Z all to carry coil BC1 and BC2.This impedance network Z can be two-port network, and its intraware can be parallel connection, series connection or connection in series-parallel each other to be mixed.Perhaps, this impedance network Z can be short circuit.That is to say that the coupled relation that all carries between coil BC1 and BC2 can be parallel connection, series connection or connection in series-parallel mixing, perhaps all carries directly coupling (short circuit) between coil BC1 and BC2.

Fig. 2 B shows a kind of possibility actual disposition schematic diagram according to first embodiment, the equivalent electric circuit of Fig. 2 C displayed map 2B.The pressure-sensitive voltage V3 and the V4 that all carry coil BC1 and BC2 two ends are proportional to magnetic flux ψ m1 and ψ m2.

When the power output identical (that is all carrying) of transformer T1 and T2, the pressure-sensitive voltage that all carries coil BC1 and BC2 two ends equates (V3=V4), do not have electric current to produce (that is I=0) in the formed loop of coil BC1 and BC2 so all carry, any influence can not arranged the power output of T1 and T2.

When the power output of transformer T1 was bigger than transformer T2, the pressure-sensitive voltage that all carries coil BC1 two ends can be bigger than the pressure-sensitive voltage that all carries coil BC2 two ends, and (V3＞V4) all carried have electric current in coil BC1 and the formed loop of BC2 and produce (I＞0) this moment.This electric current can reduce the input power of secondary side winding of magnetic flux, transformer T1 of transformer T1 and the pressure-sensitive voltage V3 that all carries coil BC1 two ends; And this electric current can increase transformer T2 magnetic flux, transformer T2 secondary side winding input power and all carry the pressure-sensitive voltage V4 at coil BC2 two ends.So, the pressure-sensitive voltage differences at the two ends of all carrying coil BC1 and BC2 is dwindled, last, the magnetic flux that the output of transformer T1 and T2 is close in identical (also can reach all and carry) and transformer T1 and the T2 is close to identical.

Otherwise, when the power output of transformer T1 is also littler than transformer T2, the pressure-sensitive voltage that all carries coil BC1 two ends can littler (V3＜V4), all carry this moment and have electric current generation (I＜0) in coil BC1 and the formed loop of BC2 than the pressure-sensitive voltage that all carries coil BC2 two ends.This electric current can force the input power of secondary side winding of magnetic flux, transformer T1 of transformer T1 and the pressure-sensitive voltage V3 that all carries coil BC1 two ends to increase; And this electric current can make the input power of secondary side winding of magnetic flux, transformer T2 of transformer T2 and the pressure-sensitive voltage V4 that all carries coil BC2 two ends reduce.So, the pressure-sensitive voltage differences of all carrying coil BC1 and BC2 two ends is dwindled, and the magnetic flux that makes the output of transformer T1 and T2 be close to identical and transformer T1 and T2 (also can be reached all and carry) much at one.

In the present embodiment, impedance network Z can be used for adjusting and all carries effect.Such as, when the resistance value of resistance R big (that is equiva lent impedance of impedance network Z), effect of load balancing mechanism is relatively poor but waveform lamp current is comparatively level and smooth; Vice versa.

In addition, all carry the detection that the formed loop of coil BC1 and BC2 can be used for abnormality (when load is extremely uneven).Shown in Fig. 2 C, in this first embodiment, protective device 210 can detect the signal that impedance network Z is sampled to.Such as, when fluorescent tube wherein disconnects difference value between (open circuit) or lamp current when too big, according to the signal that impedance network Z is sampled to, protective device 210 may command/the close AC-input voltage that inputs to transformer.In addition, this protective device 210 can be the electrical circuit, but its detectable voltage signals, current signal, power signal, frequency signal or its mixing.

In sum, in the present embodiment, " all carrying " is meant that the power output of transformer, curtage are identical, according to the actual product design, its for constant power output, etc. electric current output or etc. voltage export.

In the prior art, in order to reach current-sharing/all carry, must will control the alternating voltage that is input to transformer or the equiva lent impedance or the equivalent voltage of load end, could control lamp current.But in the present embodiment, by all carrying coil, make that the magnetic flux of transformer can be coupled to each other, use the output of control transformer, to reach the effect of current-sharing/all carry, so do not need to control the alternating voltage (unless situation is unusual) that is input to transformer, do not need the equiva lent impedance or the equivalent voltage of control load end yet.

For more highlighting the effect of present embodiment, Fig. 2 D～Fig. 2 K is presented at the lamp current experimental waveform figure under the different loads.Fig. 2 D, Fig. 2 F, Fig. 2 H, Fig. 2 J are presented at the lamp current analogous diagram of the prior art under the different loads respectively.Can find out that by Fig. 2 D, Fig. 2 F, Fig. 2 H, Fig. 2 J in the prior art, the difference between two lamp current I1 and I2 is quite big.Fig. 2 E, Fig. 2 G, Fig. 2 I, Fig. 2 K are presented at the lamp current experimental waveform figure of the first embodiment of the invention under the different loads respectively.Can be found out that by Fig. 2 E, Fig. 2 G, Fig. 2 I, Fig. 2 K in first embodiment of the invention, the difference between two lamp currents (or load current) I1 and I2 is very little, much at one, that is first embodiment of the invention can be reached good current-sharing/effect of load balancing mechanism.

Second embodiment

Fig. 3 shows the schematic diagram according to the transducer of second embodiment of the invention.The operating principle of first embodiment and second embodiment much at one.Yet, in Fig. 3, ac input signal V _AC1With V _AC2Phase place be antiphase or be close to antiphase.So, adjust the connected mode of all carrying coil BC1 and BC2 accordingly, with the output of balancing transformer, reach the purpose of current-sharing/all carry.

The 3rd embodiment

Fig. 4 shows the transducer schematic diagram according to third embodiment of the invention, and its principle is same as the foregoing description.But, a plurality of (more than two) transformer T1, T2 used in the configuration of Fig. 4 ... Tk.According to the mode of Fig. 4, with these transformers T1, T2 ... Tk is coupled in together, can make the output of all transformers identical, reaches the purpose of each fluorescent tube or load current-sharing by this.V _AC1～V _AC2Be ac input signal, LP1～LPk is a fluorescent tube, and Z1～Zk is an impedance network.

The 4th embodiment

Fig. 5 shows the transducer schematic diagram according to fourth embodiment of the invention, and its principle is same as the foregoing description.But, in Fig. 5, transformer T1 and T2 are dual output kenel (secondary side winding of transformer T1 and T2 separately independent, be connected in parallel to each other or connect).Each transformer can promote two above fluorescent tubes, can promote fluorescent tube LP1 and LP2 as transformer T1, and transformer T2 then promotes fluorescent tube LP3 and LP4.In Fig. 5, ac input signal V _AC1With V _AC2Be same-phase or same-phase almost.The circuit connecting mode that all carries coil BC1 and BC2 with the output of balancing transformer, is reached the purpose of current-sharing/all carry as shown in the figure.

The 5th embodiment

Fig. 6 shows the transducer schematic diagram according to fifth embodiment of the invention, and its principle is same as the 4th embodiment.But, in Fig. 6, ac input signal V _AC1With V _AC2Be antiphase or antiphase almost,,, reach the purpose of current-sharing/all carry with the output of balancing transformer so the circuit connecting mode that all carries coil BC1 and BC2 as shown in Figure 6.

The 6th embodiment

Fig. 7 shows the transducer schematic diagram according to sixth embodiment of the invention, and its principle is same as first embodiment.But, in Fig. 7, all carry coil BC1 and BC2 and be arranged at secondary side,, reach the purpose of current-sharing/all carry with the output of balancing transformer.

Similar in appearance to first embodiment, in the above embodiment of the present invention and other possibility embodiment, can utilize protective device to detect the signal that impedance network is sampled to.

Fig. 8 A～Fig. 8 C shows that the several of impedance network Z may example.In Fig. 8 A, all carry between coil BC1 and BC2 to connecting.In Fig. 8 B, all carry between coil BC1 and BC2 and directly be connected (short circuit).In Fig. 8 C, all carry between coil BC1 and BC2 connection in series-parallel and mix and be connected.In Fig. 8 D, all carry between coil BC1, BC2 and BC3 in parallel.

The rest may be inferred, and the transformer of dual output kenel that the present invention can be applicable to a plurality of (more than two), or be applied in the transformer of multi-output type attitude (plural output) of a plurality of (more than two) is reached the purpose of current-sharing/all carry.

In the above embodiment of the present invention, the low-pressure side of the low-pressure side of transformer T1 and transformer T2 can be independent separately, or be coupled to each other (being similar to Figure 1B).The high-pressure side of the high-pressure side of transformer T1 and transformer T2 can be independent separately, or be coupled to each other (being similar to Figure 1B).

In addition, the low-pressure side of transformer T1/T2 can comprise single winding, or a plurality of winding, and wherein, these windings are independence or be coupled in together separately.Fig. 9 A shows that the low-pressure side of transformer T1 comprises a plurality of windings, and these windings can be independent separately.Fig. 9 B shows that the low-pressure side of transformer T1 comprises a plurality of windings, and these windings are coupled in together.

The high-pressure side of transformer T1/T2 can comprise single winding, or a plurality of winding, and wherein, these windings are independence or be coupled in together separately.Fig. 9 C shows that the high-pressure side of transformer T1 comprises a plurality of windings, and these windings can be independent separately.Fig. 9 D shows that the high-pressure side of transformer T1 comprises a plurality of windings, and these windings are coupled in together.

The present invention can be applicable in the image display (as the LCD device), as the drive system of backlight (cathode fluorescent tube), makes the output of transformer identical or much at one, to stablize the output of backlight.In addition, the present invention also can treat as electric stabilizer, is applied in the light fixture/lighting apparatus of many fluorescent tubes of tool, so that the luminosity of stable/balanced these fluorescent tubes.

In the present invention, use (1) be coupled to transformer all carry coil or (2) have the transformer that all carries coil, but the electric current of active balance fluorescent tube or load.The present invention has more following advantage compared to other located by prior art:

One, need not use extra high-voltage capacitance, cost and life-span are good.

Two, step-up ratio is low, and efficient is good.

Three, need not do the transformer classification, be convenient to volume production, reduce cost.

Four, need not to use extra high pressure balance coil or high pressure balancing transformer, effectively reduce cost.

Five, need not adjust to all carrying coil or having the transformer that all carries coil, just applicable to the configuration of various load polarity.

Six, the design of active compensation/balance can be guaranteed the reliability and the life-span of end product.

Seven, in the time of can detecting load abnormal, with the protection transducer.

Eight, can be arranged at step down side owing to all carry coil, the high-pressure area area can minimize, and need not use high pressure jumper wire device or other high potential assembly, has solved the layout bottleneck and the cost of printed circuit board (PCB), significantly promotes the fail safe of end product simultaneously.In addition, all carry the high-pressure side that coil also can be arranged at transformer.

In sum, though the present invention with several embodiment exposure as above, yet it is not in order to limit the present invention.The persond having ordinary knowledge in the technical field of the present invention, without departing from the spirit and scope of the present invention, when doing various changes that are equal to or replacement.Therefore, protection scope of the present invention is when looking accompanying being as the criterion that the application's claim scope defined.

Claims

1. one kind drives transducer, a back light that is used for driving a multi-load light fixture or drives an image display, and this driving transducer comprises:

One first transformer receives and boosts or step-down one first input signal, and an output voltage of this first transformer is used to drive this light source or these loads;

One second transformer receives and boosts or step-down one second input signal, and an output voltage of this second transformer is used to drive this light source or these loads;

One first all carries coil, magnetic couplings to this first with at least one a magnetic circuit of this second transformer;

One second all carries coil, magnetic couplings to this first with at least one a magnetic circuit of this second transformer; And

One first impedance network is used to make this first all to carry coil and this second and all carry coil electrical couplings each other;

Wherein, by this first magnetic couplings of all carrying coil, this second all carries the magnetic couplings of coil and the electrical couplings of this first impedance network, this first transformer is identical with the output of this second transformer or essence is identical.

2. driving transducer according to claim 1 is characterized in that also comprising:

One the 3rd transformer receives and boosts or step-down 1 the 3rd input signal, and an output voltage of the 3rd transformer is used to drive this light source or these loads;

One the 3rd all carries coil, and magnetic couplings is to a magnetic circuit of the 3rd transformer; And

One second impedance network, be used to make the 3rd all carry the coil electrical couplings to this first all carry coil and this second all carry coil one of at least;

Wherein, all carry the magnetic couplings of coil, the electrical couplings of this first impedance network and the electrical couplings of this second impedance network by this first magnetic couplings, this second magnetic couplings, the 3rd of all carrying coil of all carrying coil, this first transformer, this second transformer is identical with the output of the 3rd transformer or essence is identical.

3. driving transducer according to claim 1 is characterized in that, this first all carries a low-pressure side or the high-pressure side that coil is arranged at this first transformer; This second all carries a low-pressure side or the high-pressure side that coil is arranged at this second transformer.

4. driving transducer according to claim 1 is characterized in that,

One low-pressure side of this first transformer and a low-pressure side of this second transformer be independence or be coupled to each other separately, and;

One high-pressure side of this first transformer and a high-pressure side of this second transformer be independence or be coupled to each other separately.

5. driving transducer according to claim 1 is characterized in that,

One low-pressure side of this first transformer comprises: single winding, and perhaps independently a plurality of separately windings perhaps are coupled in a plurality of windings together;

One high-pressure side of this first transformer comprises: single winding, and perhaps independently a plurality of separately windings perhaps are coupled in a plurality of windings together;

One low-pressure side of this second transformer comprises: single winding, and perhaps independently a plurality of separately windings perhaps are coupled in a plurality of windings together; And

One high-pressure side of this second transformer comprises: single winding, perhaps independently a plurality of separately windings perhaps are coupled in a plurality of windings together.

6. driving transducer according to claim 1 is characterized in that, by this first impedance network, this first all carries coil and this second and all carry between coil to being connected in series, or is connected in parallel, or and series hybrid connect or directly connection.

7. one kind drives transducer, a back light that is used for driving a multi-load light fixture or drives an image display, and this driving transducer comprises:

One first all carries coil, magnetic couplings to this first with the magnetic circuit one of at least of this second transformer;

One second all carries coil, magnetic couplings to this first with the magnetic circuit one of at least of this second transformer;

One first impedance network is used to make this first all to carry coil and this second and all carry coil electrical couplings each other; And

One protective device is coupled to this first impedance network, and when generation was unusual, this protective device was controlled this first input signal and this second input signal according to the electric signal that this first impedance network is sampled to;

Wherein, by this first all carry coil, this second all carries coil and this first impedance network, the magnetic flux in this first transformer is coupled to each other so that the output of this first transformer and this second transformer is identical with the magnetic flux in this second transformer.

8. driving transducer according to claim 7 is characterized in that also comprising:

9. driving transducer according to claim 7 is characterized in that this first all carries a low-pressure side or the high-pressure side that coil is arranged at this first transformer; This second all carries a low-pressure side or the high-pressure side that coil is arranged at this second transformer.

10. driving transducer according to claim 7, a low-pressure side that it is characterized in that a low-pressure side of this first transformer and this second transformer be independence or be coupled to each other separately, and;

11. driving transducer according to claim 7 is characterized in that a low-pressure side of this first transformer comprises: single winding, perhaps independently a plurality of separately windings perhaps are coupled in a plurality of windings together;

12. driving transducer according to claim 7 is characterized in that, by this impedance network, this first all carries coil and this second and all carries between coil to being connected in series, or is connected in parallel, or and series hybrid connect or directly connection.

13. driving transducer according to claim 7 is characterized in that, this protective device detects a voltage signal, a current signal, the power signal that this impedance network is sampled to, or a frequency signal.

14. a drive system is used for driving a back light of a multi-load fluorescent tube or an image display, this drive system comprises:

A plurality of transformers distinctly receive and boost or a plurality of input signals of step-down, and the output voltage of these transformers is used to drive this light source or these loads;

A plurality of coils that all carry, magnetic couplings is to the magnetic circuit of related transformer; And

At least one impedance network is used to make these all to carry coil electrical couplings each other,

Wherein, all carry coil by these magnetic couplings of these transformers and these are all carried coil electrical couplings to each other, the output of these transformers is mutually the same or essence is identical, and, magnetic flux in these transformers is coupled to each other, and this coupling makes that the final magnetic flux in these transformers is mutually the same or essence is identical.