CN100504527C - Circuit structure for LCD backlight - Google Patents
Circuit structure for LCD backlight Download PDFInfo
- Publication number
- CN100504527C CN100504527C CNB2007101546323A CN200710154632A CN100504527C CN 100504527 C CN100504527 C CN 100504527C CN B2007101546323 A CNB2007101546323 A CN B2007101546323A CN 200710154632 A CN200710154632 A CN 200710154632A CN 100504527 C CN100504527 C CN 100504527C
- Authority
- CN
- China
- Prior art keywords
- cold
- circuit
- cathode fluorescence
- input end
- fluorescence lamp
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Circuit Arrangements For Discharge Lamps (AREA)
- Inverter Devices (AREA)
Abstract
A circuit structure for LCD backlight is disclosed in the present invention. The circuit structure includes an inverter topology, a current balance circuit, and a plurality of loads. The current balance circuit is coupled to the plurality of loads and capable of balancing current of N loads by using N/2-1 balance chokes. The circuit structure may further include a protection circuit which is coupled to the low voltage sides of the plurality of loads. The protection circuit is capable of sensing lamp voltages and providing a feedback signal to a controller. Furthermore, the protection circuit is composed of count-reduced and cost-competitive electronic elements.
Description
Technical field
The present invention relates to a kind of backlight circuit, relate in particular to LCD (LCD) backlight circuit with a plurality of lamps.
Background technology
The LCD panel is used in the various application from mancarried electronic aid to the stationary positioned unit, video camera for example, automatic station-keeping system, PC on knee and industrial machine.But itself can not luminously be illuminated the LCD panel from the back side by light source.The most common backlight that is used is cold-cathode fluorescence lamp (CCFL).Usually, light and move CCFL and need high exchanging (AC) electric signal.In order to produce such one high AC signal, design a DC/AC inverter from for example direct current of a rechargeable battery (DC) power supply.
Yet in more nearest years, people have produced interest to large-sized LCD display, and as needed in LCD TV and graphoscope, they need a plurality of CCFL that necessary illumination is provided.Usually, the DC/AC inverter drives the CCFL of a plurality of parallel connections, and CCFL also can otherwise be configured.A kind of parallel organization is the direct parallel connection method of CCFL.This structure has well-known problem, exactly because the CCFL current unevenness that the constant voltage load characteristic of the variation of modulating voltage and CCFL causes weighing apparatus.The unbalanced life-span of CCFL minimizing and the unevenness of brightness of causing of CCFL electric current.
Another parallel organization is the parallel connection method at the primary end, as shown in Figure 1, wherein shows the illustrative diagram of the prior art circuits 100 that is used to drive a plurality of CCFL 140A to 140N.Circuit 100 is by DC power supply 110, inverter circuit 120, and a plurality of transformer 130A to 130N, holding circuit 150 and controller 160 are formed.Inverter circuit 120 is connected to the parallel connection method of the elementary winding of a plurality of transformer 130A to 130N.Inverter circuit 120 and a plurality of transformer 130A to 130N have formed inverter topology, and it is well known in the prior art.Inverter topology changes the DC input voltage VIN into a desirable AC output voltage VO UT from the DC power supply 110 of for example battery.Those skilled in the art admit that inverter topology can be a Royer, a full-bridge, a half-bridge, a push-pull type, and a D level.AC output voltage VO UT finally is transported on a plurality of CCFL 140A to 140N of the secondary rewinding winding that is connected respectively to a plurality of transformer 130A to 130N.
In addition, by detecting lamp current IS1 to ISN, holding circuit 150 can detect a short-circuit conditions and produce a current feedback signal ISEN then.By the high polygonal voltage HV1 to HVN of sensing CCFL, holding circuit 150 can detect one and disconnect or the situation of the lamp that opens circuit, and CCFL is not connected to inverter topology and causes and can not light or be damaged in this case, produces a voltage feedback signal VSEN then.Electric current and voltage feedback signal ISEN and VSEN are sent to these feedback signals of response then and take corresponding actions to prevent the controller 160 that damages.
Though can minimize the influence of lamp voltage change in the parallel connection method of primary winding shown in Fig. 1, the equilibrium that has improved electric current successively, some shortcomings have still influenced the performance/cost of the structure shown in Fig. 1.One of them shortcoming is exactly the great quantity owing to transformer 130A to 130N, and circuit 100 is compared the expense that increase is arranged with the structure of the direct parallel connection method of CCFL.In addition, the element that is used for sensing lamp voltages in holding circuit 150 is connected to high-pressure side HV1 to HVN, and it has usually and is higher than 1000 volts voltage.The element that can bear high like this voltage normally expensive and therefore increased whole cost.In addition, when element was connected to high-pressure side HV1 to HVN, the operator needed extra care to prevent any puncture or danger.The another one shortcoming is that the holding circuit 150 shown in Fig. 1 is complicated, and the complicacy of holding circuit 150 will become problem along with the increase of the quantity of lamp.
Fig. 2 A shows the illustrative diagram of another prior art driving circuit 200A, and it has carried out open in U.S. Patent number US6781325B2 and compared with circuit 100 shown in Figure 1 having improved current balance type.By introducing the choking coil 250A to 250 (N-1) of a plurality of general modes, driving circuit 200A can obtain the lamp current balance effectively.Similarly, in order to stop potential destruction, comprised that holding circuit 260 is used for the sensing short circuit, fluorescent tube breaks or the situation of the lamp that opens circuit.In Fig. 2 A, the choking coil 250A to 250 (N-1) of general mode is connected respectively to the high-pressure side HV1 to HVN of CCFL, so the choking coil of these general modes has high cost and need extra attention in application.In order to reduce cost and to get rid of security consideration, the structure of circuit 200B has been shown among Fig. 2 B, wherein the choking coil 250A to 250 (N-1) of general mode is connected respectively to the low-pressure side LV1 to LVN of CCFL.
Though the circuit among Fig. 2 A and Fig. 2 B can provide the scheme of a solution lamp current balance, they can not overcome the shortcoming about circuit protection.In addition, those skilled in the art admit to have the structure of a plurality of transformers among Fig. 1, thereby the electric current of the CCFL that flows through will be sensed the brightness of regulating CCFL easily.Yet, have the structure of a transformer, need special design one current sensing circuit.In addition, if the quantity of the transformer in Fig. 2 and 3 can further reduce, can save very big cost.
Summary of the invention
Disclosed circuit structure comprises a transformer, a current balance circuit and electronic load.Transformer is designed to light and move electronic load.The low-pressure side of electronic load can be formed and be connected to current balance circuit by choking coil.Current balance circuit is designed to be can be by using the electric current of balanced N the electronic load of N/2-1 choking coil.Circuit structure further comprises the holding circuit of the low-pressure side that is connected to electronic load, is used to prevent that circuit structure from exempting from the situation or the short-circuit conditions of the lamp that disconnects or open circuit.
Description of drawings
Advantage of the present invention will be followed the detailed description of following embodiment and become distinct, and its description will be considered with accompanying drawing, wherein:
Fig. 1 is the synoptic diagram with prior art circuits of a plurality of CCFL.
Fig. 2 A is the synoptic diagram with another prior art circuits of a plurality of CCFL.
Fig. 2 B is the synoptic diagram with another prior art circuits of a plurality of CCFL.
Fig. 3 is the synoptic diagram according to the circuit of one embodiment of the invention.
Fig. 4 is the synoptic diagram of circuit according to another embodiment of the present invention.
Fig. 5 A is the experimental waveform figure that describes the lamp current among Fig. 3.
Fig. 5 B and Fig. 5 C have described the experimental waveform figure of lamp current among Fig. 4.
Fig. 6 is the synoptic diagram of circuit according to another embodiment of the present invention.
Fig. 7 is the form of lamp current among Fig. 6.
Fig. 8 A is the synoptic diagram of circuit according to another embodiment of the present invention.
Fig. 8 B is the synoptic diagram of circuit according to another embodiment of the present invention.
Fig. 9 is the synoptic diagram of circuit according to another embodiment of the present invention.
Figure 10 is the synoptic diagram of circuit according to another embodiment of the present invention.
Embodiment
Below will be in detail with reference to embodiments of the invention.When the present invention is described in conjunction with the embodiments, be to be understood that not to be to limit the present invention to these embodiment.On the contrary, the present invention attempts to cover alternative, revises and equivalent, and they all are included in the spirit and scope of appended claims definition of the present invention.
Fig. 3 shows the synoptic diagram according to the circuit 300 of one embodiment of the invention.Circuit 300 is used to drive CCFL 342,344, and 346 and 348.Except DC power supply 110, inverter circuit 120, transformer 130A and controller 160, circuit 300 further comprise the current balance circuit of being made up of balanced choking coil 350, wherein balanced choking coil is the choking coil of a general mode normally. CCFL 342 and 344 high-pressure side HV1 and HV2 are connected to transformer 130A respectively by ballast capacitor C1 and C2 high-pressure side HVA.CCFL 346 and 348 high-pressure side HV3 and HV4 are connected to transformer 130A respectively by ballast capacitor C3 and C4 high-pressure side HVB.Balanced choking coil 350 is connected to the low-pressure side LV1 to LV4 of CCFL.The terminal 1 and 2 of first winding 352 that CCFL 344 and 346 low-pressure side LV2 and LV3 are connected respectively to balanced choking coil 350.The terminal 3 and 4 of second winding 354 that CCFL 342 and 348 low-pressure side LV1 and LV4 are connected respectively to balanced choking coil 350.In theory, series connection CCFL 342 and 348 electric current equate, and series connection CCFL 344 is identical with 346 electric current.Therefore, I1 is defined as the electric current of CCFL 342 or 348, and I2 is defined as the electric current of CCFL 344 or 346.When first and second windings 352 have identical circle and reversed polarity with 354, electric current I 1 will equal electric current I 2, thereby obtain the current balance type of CCFL 342 to 348.
Compare with traditional circuit, the quantity of the balanced choking coil among Fig. 4 has been reduced greatly.In addition because balanced choking coil is connected to the low-pressure side of CCFL, can bear high pressure costliness transformer not necessarily, therefore whole cost is further reduced.In addition, when balanced choking coil is connected to low-pressure side, the operator does not need potential destruction is paid extra concern, for example punctures, dangerous or the like.
Those skilled in the art recognize that the ballast capacitor among Fig. 3 and Fig. 4 can help to light CCFL, but these ballast capacitor are not necessary in these embodiments.In application, CCFL can be directly connected to high-pressure side HVA and the HVB of transformer 130A.And, those skilled in the art will know that a plurality of balanced choking coil 410-1 to 410-(N/2-1) can be by molybdenum permalloy powder (MPP) material magnetic core, little metal powder iron core, ferrite EE core (Ferrite EE-core), the transformer that pot core and toroidal core constitute.
Fig. 5 A shows the experimental waveform of the lamp current of the CCFL shown in Fig. 3 that flows through.Curve (A) to (D) is represented the lamp current of CCFL 342 to 348 respectively.In experiment, the inductance of balanced choking coil 350 is set to 300 milihenries (mH), and the iron core of balanced choking coil 350 is made into the EE10 core.The test lamp current that can notice CCFL 342 to 348 equals 5.40mA, 5.45mA, 5.49mA, 5.44mA respectively.Thereby current deviation remains on the current balance type that 0.1mA can obtain.
Suppose that the Integer N among Fig. 4 equals 6, the experimental waveform of the lamp current of the CCFL 420-1 to 420-6 that flows through is shown in Fig. 5 B and the 5C.Curve (A) is represented the lamp current of CCFL 420-1 to 420-6 respectively to (F).In experiment, the inductance of balancing transformer 410-1 and 410-2 is set to 250 milihenries (mH), and the iron core of balancing transformer 410-1 and 410-2 is made by the EE8.3 core.The test lamp current that can see CCFL 420-1 to 420-6 equals 4.79mA respectively, 4.85mA, and 4.95mA, 5.21mA obtains good current balance type thereby 4.95mA and 4.95mA. current deviation remain on 0.3mA.
Fig. 6 shows the synoptic diagram of the circuit structure with a plurality of CCFL 620-1 to 620-N 600 according to another embodiment of the present invention.For the sake of clarity, the components identical that occurs among Fig. 5 is omitted at this, only emphasizes difference.With reference to figure 6, the CCFL 620-1 of odd number, 620-3,620-5, to the high-pressure side HV1 of 620-(N-1), HV3, HV5 to HV (N-1) is connected to the high-pressure side HVB of the transformer 130A shown in Fig. 5.The CCFL 620-2 of even number, 620-4,620-6, to the high-pressure side HV2 of 620-N, HV4, HV6 to HVN are connected to the high-pressure side HVA of the transformer 130A shown in Fig. 5.The low-pressure side of adjacent C CFL, low-pressure side LV1 for example, LV2, LV3 and LV4 to LV (N-1) and LVN, are connected to the balanced choking coil in the current balance circuit.In order to realize the current balance type of CCFL 620-1 to 620-N, circuit 600 needs N/2 balanced choking coil 610-1 to 610-N/2 altogether in current balance circuit, and wherein N is no less than 6.
Each balanced choking coil has first winding that terminal 1 and 2 are arranged and second winding with terminal 3 and 4.The terminal 2 and 3 of each balanced choking coil is connected respectively to the low-pressure side that is connected CCFL.For example, the terminal 2 of balanced choking coil 610-1 and 3 is connected low-pressure side LV1 and the LV2 of CCFL 620-1 and 620-2 respectively, and the terminal 2 of balanced choking coil 610-N/2 and 3 is connected low-pressure side LV (N-1) and the LVN of CCFL 620-(N-1) and 620-N respectively.The terminal 4 of each balanced choking coil is connected to the terminal 1 of next adjacent balanced choking coil.For example, the terminal 4 of balanced choking coil 610-1 is connected to the terminal 1 of balanced choking coil 610-2, and the terminal 4 of balanced choking coil 610-2 further is connected to the terminal 1 of balanced choking coil 610-3.Similarly, the terminal 4 of transformer 610-(N/2-1) finally is connected to the terminal 1 of balanced choking coil 610-N/2, and the terminal 4 of transformer 610-N/2 is connected to the terminal 1 of transformer 610-1 backward.In addition, capacitor 630 can be connected between the terminal 1 of the terminal 4 of balanced choking coil 610-N/2 and transformer 610-1.
Fig. 7 shows the form according to the test lamp current of Fig. 6 Experiment of Electrical Circuits.Experimental circuit is used to drive 12 CCFL, CCFL1 to CCFL12, and they provide backlight to 30 inches LCD panels.The operating frequency of hookup is 55KHZ.Can see that the root-mean-square value (RMS) when lamp current is set to the first value 4mArms, the deviation range of the electric current of the CCFL1 to CCFL12 that flows through+/-0.25mA in.When the RMS value is set as the second value 6mArms, the deviation of the electric current of the CCFL1 to CCFL12 that flows through+/-0.25mA in, when the RMS value is set as one the 3rd value 8mArms, the deviation of the electric current of the CCFL1 to CCFL12 that flows through+/-0.17mA in.Therefore, can reach a conclusion when the time by the drives among Fig. 6, the current balance type that a plurality of CCFL can realize, thus can be obtained uniform brightness by the LCD panel that these CCFL illuminate from the back side.
Fig. 8 A shows the synoptic diagram of circuit 800 according to another embodiment of the present invention.Compare with the circuit among Fig. 3, circuit 800 further comprises a holding circuit 810A, and it can the sensing abnormal conditions, for example, and lamp situation disconnection or that open circuit and short-circuit conditions.Thereby holding circuit 810A provides voltage feedback signal VSEN to controller 160 by the low side voltage sensing abnormal conditions that detect CCFL.In order to respond the voltage feedback signal VSEN of acquisition, controller 160 can be discerned abnormal conditions, takes corresponding operation to prevent to destroy then.
With reference to figure 8A, holding circuit 810A is by voltage sensing circuit 862,864,866 and 868 and RC circuit 870 form.Voltage sensing circuit 862 to 868 is connected respectively to the low-pressure side LV1 to LV4 of CCFL.Simultaneously, all voltage sensing circuit 862 to 868 further is connected to RC circuit 870 at node 873.RC circuit 870 comprises a resistance 875 and a capacitor 877, their parallel being connected between node 873 and the ground.Each voltage sensing circuit further is made up of resistance in series and diode.For example, current sensing circuit 862 comprises one first resistance, 861, one second resistance 863 and a diode 865.First and second resistance 861 and 863 are connected in series between low terminal voltage LV1 and the ground.The anode of diode 865 is connected on the connected node of first and second resistance 861 and 863.The negative electrode of diode 865 connects RC circuit 870 on node 873.Voltage sensing circuit 862 is the voltage of sensing low-pressure side LV1 in time.With similar method, voltage sensing circuit 864,866 and 868 is configured to be respectively applied for the voltage of sensing low-pressure side LV2 to LV4.Based on sensing voltage, on node 873, produce voltage feedback signal VSEN, present then to controller 160.
If there are abnormal conditions, controller 160 can response voltage sensing signal VSEN identification as disconnection or various abnormal conditions such as lamp situation that opens circuit or short circuit.By following analysis, the person skilled in the art will easily understand these features.In normal operation, 0 volt no better than of the low terminal voltage of each lamp, for example V
LV1Equal 0V, wherein V
LV1Be defined as the voltage of low-pressure side LV1.If the situation of the lamp that exist to disconnect or open circuit, for example CCFL 342 is removed, and opens circuit or can not light, and the normal electric current 11 of flow through originally CCFL342 and 348 will reduce to electric current 11
, and low terminal voltage V
LV1To increase greatly.Low terminal voltage V
LV1Can provide by equation (1).
V wherein
HVABe defined in the voltage of high-pressure side HVA, C is defined as the electric capacity of ballast capacitor C1, and L is defined as the inductance of balanced choking coil 350, R
L4Be defined as the resistance of CCFL 348.Because electric current I 1 ' be lower than normal current I1, V as a result greatly
LV1To increase greatly.Therefore, holding circuit 810A can sense owing to disconnect or the increase of the voltage that the situation of the lamp that opens circuit causes at low-pressure side LV1, and controller 160 can take action to prevent to destroy immediately.In a similar fashion, holding circuit 810A can detect the situation of disconnection that occurs in other CCFL or the lamp that opens circuit.
If one of them among the high terminal voltage HV1 to HV4 is shorted to ground, for example, high terminal voltage HV1 is shorted to ground, so normal current I1 will reduce to significantly electric current I 1 ', and low terminal voltage V
LV1To change accordingly.Low terminal voltage V
LV1Provide by equation (2).
V wherein
HVBBe defined in the voltage of high-pressure side HVB.The voltage that holding circuit 810A sends sensing changes controller 160, and it is taked immediately successively to move and prevents the destruction that caused by short-circuit conditions.If one of them among the high terminal voltage HV1 to HV4 is shorted to corresponding low terminal voltage, for example, HV1 is shorted to LV1, and normal current I1 will be increased to electric current I 1 significantly " ', low terminal voltage V
LV1To correspondingly change.Low terminal voltage VLV1 provides by equation (3).
Again, holding circuit 810A sends sensing voltage and changes to controller 160, and it is taked immediately successively to move and prevents the destruction that caused by short-circuit conditions.In a similar fashion, holding circuit 810A can detect the short-circuit conditions that other CCFL takes place.
Those skilled in the art will recognize that holding circuit 810A can be extended to the circuit 810B shown in Fig. 8 B, it is used to protect as shown in Figure 4 circuit structure 400 to exempt from the lamp or the short-circuit conditions of disconnection.The low-pressure side VL1 to LVN of CCFL among Fig. 4 is connected respectively to voltage sensing circuit 810-1 to 810-N.Based on low terminal voltage by voltage sensing circuit 810-1 to 810-N sensing, on node 873, produce voltage feedback signal VSEN, be fed to the controller 160 among Fig. 4 then.
Those skilled in the art recognize that with traditional holding circuit and compare that wherein the holding circuit of Miao Shuing is made up of the competitive element of cost, number of elements is reduced greatly simultaneously.Therefore, cost that can obtain to save and size.In addition, wherein the holding circuit of Miao Shuing is connected to the low-pressure side of CCFL, thereby can pay extra attention in puncture or other potential harm.In addition, realize that holding circuit is not limited to the circuit in Fig. 4 and 6.In fact, those skilled in the art will admit that the holding circuit of wherein describing can be applied to various backlight circuit structure, and wherein at least one balanced choking coil is connected to the low-pressure side of backlight.
Fig. 9 shows the synoptic diagram of the circuit structure 900 that has a plurality of CCFL according to another embodiment of the present invention.Compare with the circuit among Fig. 8 A, circuit 900 further comprises the current sensing circuit of being made up of current sensing resistor 901 910.As shown in Figure 9, current sensing resistor 901 is connected between second winding 354 of CCFL 348 and balanced choking coil 350.The connected node of the current sensing resistor 901 and second winding 354 further is connected to ground.On the connected node between current sensing resistor 901 and the CCFL 348, obtain current feedback signal ISEN and be fed to controller 160.For response current feedback signal ISEN, controller 160 can be regulated lamp current, therefore regulates the brightness of lamp.Therefore, can obtain tight control to the brightness of lamp.In addition, should be noted that low terminal voltage LV4 pulled down to low pressure and for example situation of lamp that disconnect or that open circuit or abnormal conditions of short circuit of indication never again because the voltage sensing circuit 868 that influences among Fig. 8 A of current sensing resistor 901 is left out.
In fact, indicate the current sense signal of the electric current of flow through CCFLs 342 and 348 to stride across current sensing resistor 901 formation, and be imported into controller 160 as current feedback signal ISEN.For response current feedback signal ISEN, thereby controller 160 is regulated the brightness that the electric current of the CCFL that flows through is regulated CCFL.
Those skilled in the art will recognize that current sensing circuit 910 there is no need to be placed between the CCFL 348 and second winding 354.Other possible structure is arranged, and for example, current sensing circuit 910 places between the CCFL 342 and second winding 354.In addition, current sensing circuit 910 can be applied in the circuit structure that has a plurality of CCFL among Fig. 4 with identical method.
Figure 10 shows the synoptic diagram of the circuit with a plurality of CCFL 1000 according to another embodiment of the present invention.Compare with the circuit among Fig. 4, current sensing circuit 1110 is connected between first winding 405 of second winding 403 of balanced choking coil 410-1 and balanced choking coil 410-2.Current sensing circuit 1110 is by the first diode D1, the second diode D2, and a current sensing resistor Rs and capacitor Cs form.The anode of the first diode D1 is connected on the terminal 3 of second winding 403, and the negative electrode of the first diode D1 is connected to the terminal 2 of first winding 405.Thereby the terminal 2 second diode D2 that the anode of the second diode D2 is connected to first winding 405 with respect to the first diode D1 by reverse bias.The negative electrode of the second diode D2 is connected to the terminal 3 of second winding 403 by current sensing resistor Rs.Current sensing resistor Rs is further in parallel with capacitor Cs.In addition, the terminal 3 of second winding 403 is connected to ground.At the connected node 1101 of the second diode D2 and current sensing resistor Rs, produced current feedback signal ISEN and be fed to controller 160.
In fact, indication is flowed through, and the current sense signal of electric current of CCFL 420-3 and 420-4 strides across current sensing resistor Rs and capacitor Cs generates, and is used as current feedback signal ISEN and is imported into controller 160.For response current feedback signal ISEN, thereby controller 160 is regulated the brightness that the electric current of the CCFL that flows through is regulated CCFL.
Those skilled in the art will recognize that and necessarily current sensing circuit 1110 to be connected between balanced choking coil 410-1 and the 410-2.On the contrary, current sensing circuit 1110 can be positioned between two between the 410-1 to 410-(N/2-1) any adjacent balanced choking coils.In addition, thus can comprise that the holding circuit 810B holding circuit 1000 among Fig. 8 B exempts from the situation of lamp disconnection or that open circuit or the situation of short circuit.
In operation, circuit structure can comprise an inverter topology, a plurality of loads, for example CCFL, be connected to the illumination that inverter topology is used to provide the LCD panel, be connected to the current balance circuit of at least one the balanced choking coil that is used for the balance lamp current of a plurality of loads.At least two loads in a plurality of loads are by at least one balanced choking coil series connection.At least four loads in a plurality of loads be connected at least one load one of them be used to realize the current balance of at least four loads.What at least one balanced choking coil was continuous is connected to each other in order to realize the current balance type of a plurality of loads.
In addition, circuit structure can comprise the holding circuit of the low-pressure side that is connected to a plurality of loads.Holding circuit can the holding circuit structure exempts from the situation or the short-circuit conditions of lamp disconnection or that open circuit.And circuit structure can comprise the current sensing circuit that is used for tight Control current brightness.
Those skilled in the art will know that wherein disclosed circuit structure can be applied to comprises Royer, full-bridge, and half-bridge, push-pull type, and in the various inverter topology of D level.In addition, controller can be taked different deepening control methods, comprises simulation control, pulsed modulation (PWM) control and mixing control.Those skilled in the art will recognize that all these change all within the scope of claim.
Use therein term and expression are employed as description but are unrestricted, use this term and express to be not intended to get rid of feature (perhaps part wherein) that illustrate and equivalence description, will be appreciated that various change is in the possible scope of claim.Other changes, and it also all is possible changing and substituting, and therefore, claim attempts to cover all such equivalences.
Claims (19)
1, a kind of circuit structure is characterized in that, comprising:
One transformer;
A plurality of loads comprise first to N load, and N is even number and N 〉=4, and wherein said a plurality of loads have high-pressure side and low-pressure side, and wherein said transformer is connected to the described high-pressure side of described a plurality of loads; And
A plurality of choking coils, comprise first to M choking coil, the quantity M=N/2-1 of wherein said a plurality of choking coils, wherein said a plurality of choking coil is connected to the described low-pressure side of described load, wherein first choking coil has a first input end, one second input end, one the 3rd input end, and a four-input terminal, wherein said first load, second load, the 3rd load and the 4th load connect the first input end of described first choking coil respectively, second input end of described first choking coil, the 3rd input end of described first choking coil, the four-input terminal of described first choking coil, wherein the M choking coil has a first input end, one second input end, the 3rd input end and a four-input terminal, wherein (N-3) load, (N-2) load, (N-1) load and described N load are connected respectively to the first input end of described M choking coil, second input end of described M choking coil, the 3rd input end of described M choking coil, the four-input terminal of described M choking coil.
2, circuit structure according to claim 1 is characterized in that, at least one load of described a plurality of loads is a cold-cathode fluorescence lamp.
3, circuit structure according to claim 1 is characterized in that, further comprises:
One is connected to the inverter circuit of described transformer.
4, circuit structure according to claim 1 is characterized in that, further comprises:
One is connected to the holding circuit of described a plurality of loads.
5, circuit structure according to claim 4 is characterized in that, described holding circuit further comprises:
A plurality of voltage sensing circuits comprise first to the N voltage sensing circuit, and wherein said a plurality of voltage sensing circuits are connected to the described low-pressure side of described load; And
Be connected to the rescap circuit of described a plurality of voltage sensing circuits.
6, circuit structure according to claim 4 is characterized in that, described holding circuit configuration is used for short-circuit protection.
7, circuit structure according to claim 4 is characterized in that, the load protection that described holding circuit configuration is used to disconnect.
8, circuit structure according to claim 1 is characterized in that, each of described a plurality of choking coils all is connected at least four loads.
9, circuit structure according to claim 1 is characterized in that, further comprises:
A plurality of capacitors, each of wherein said a plurality of capacitors all have one first end and one second end, and wherein said first end is connected to described transformer, and described second end is connected to one of them load of described a plurality of loads.
10, circuit structure according to claim 1 is characterized in that, at least one of described a plurality of choking coils is the choking coil of general mode.
11, circuit structure according to claim 1 is characterized in that, at least one of described a plurality of choking coils is transformer.
12, circuit structure according to claim 1 is characterized in that, at least one of described a plurality of choking coils be by molybdenum permalloy powder core, little metal powder iron core, and ferrite EE core, pot core and toroidal core constitute.
13, circuit structure according to claim 1 is characterized in that, (N-3) load in described a plurality of loads and (N-2) load series connection, and (N-1) load and N load series connection.
14, a kind of circuit structure is characterized in that, comprising:
One inverter circuit;
One is connected to the transformer of described inverter circuit;
A plurality of cold-cathode fluorescence lamps comprise first to the N cold-cathode fluorescence lamp, and N is even number and N 〉=4, and wherein each cold-cathode fluorescence lamp has a high-pressure side and a low-pressure side; And
A plurality of choking coils, comprise first to (N/2-1) individual choking coil, wherein each choking coil has at least one first input end, one second input end, one the 3rd input end, an and four-input terminal, wherein said first cold-cathode fluorescence lamp is connected to described transformer by the high-pressure side of described first cold-cathode fluorescence lamp, wherein said N cold-cathode fluorescence lamp is received described transformer by the high-pressure side of described N cold-cathode fluorescence lamp, wherein said first cold-cathode fluorescence lamp, second cold-cathode fluorescence lamp, the 3rd cold-cathode fluorescence lamp, and the 4th cold-cathode fluorescence lamp be connected to the first input end of described first choking coil, second input end, the 3rd input end, four-input terminal, (N-3) cold-cathode fluorescence lamp wherein, (N-2) cold-cathode fluorescence lamp, (N-1) cold-cathode fluorescence lamp, and the N cold-cathode fluorescence lamp is connected to the first input end of described (N/2-1) choking coil, second input end, the 3rd input end, four-input terminal.
15, circuit structure according to claim 14, it is characterized in that, (N-3) cold-cathode fluorescence lamp in described a plurality of cold-cathode fluorescence lamp and the series connection of (N-2) cold-cathode fluorescence lamp, and (N-1) cold-cathode fluorescence lamp and the series connection of N cold-cathode fluorescence lamp.
16, circuit structure according to claim 14 is characterized in that, at least one of described a plurality of choking coils is the general mode choking coil.
17, circuit structure according to claim 14 is characterized in that, described a plurality of choking coil ground connection.
18, circuit structure according to claim 14 is characterized in that, further comprises:
The holding circuit of short-circuit protection and open end circuit protection is provided.
19, a kind of circuit structure that is used to drive a plurality of cold-cathode fluorescence lamps is characterized in that, comprising:
One inverter circuit;
Be connected to the transformer and the controller of described inverter circuit;
A plurality of capacitors comprise first to the N capacitor, and N is even number and N 〉=4, and wherein said a plurality of capacitors are connected to described transformer;
A plurality of cold-cathode fluorescence lamps, comprise first to the N cold-cathode fluorescence lamp, first cold-cathode fluorescence lamp of wherein said a plurality of cold-cathode fluorescence lamps is connected to described first capacitor of described a plurality of capacitors, and wherein said N cold-cathode fluorescence lamp is connected to described N capacitor;
A plurality of choking coils, comprise first to (N/2-1) choking coil, wherein each choking coil has at least one first input end, one second input end, one the 3rd input end, and a four-input terminal, wherein said first cold-cathode fluorescence lamp, second cold-cathode fluorescence lamp, the 3rd cold-cathode fluorescence lamp, the 4th cold-cathode fluorescence lamp is connected to the first input end of described first choking coil, second input end, the 3rd input end, four-input terminal, (N-3) cold-cathode fluorescence lamp wherein, (N-2) cold-cathode fluorescence lamp, (N-1) cold-cathode fluorescence lamp, and the N cold-cathode fluorescence lamp is connected to the first input end of described (N/2-1) choking coil, second input end, the 3rd input end, four-input terminal; And
Be connected to the holding circuit of described controller.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US84578306P | 2006-09-18 | 2006-09-18 | |
| US60/845,783 | 2006-09-18 | ||
| US11/600,615 | 2006-11-15 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101149501A CN101149501A (en) | 2008-03-26 |
| CN100504527C true CN100504527C (en) | 2009-06-24 |
Family
ID=39250099
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2007101546323A Expired - Fee Related CN100504527C (en) | 2006-09-18 | 2007-09-17 | Circuit structure for LCD backlight |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100504527C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101058684B1 (en) * | 2009-04-02 | 2011-08-22 | 삼성전기주식회사 | Lamp driving circuit |
| CN102186296A (en) * | 2011-05-20 | 2011-09-14 | 台达能源技术（上海）有限公司 | Current balancing circuit |
| CN103037554B (en) * | 2012-12-24 | 2015-12-09 | 泓芯泰业科技(北京)有限公司 | A kind of efficient cold light disc driving device |
| CN113194569A (en) * | 2021-04-09 | 2021-07-30 | 深圳市立创普电源技术有限公司 | Multi-path constant-current driving circuit and driving power supply |
-
2007
- 2007-09-17 CN CNB2007101546323A patent/CN100504527C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN101149501A (en) | 2008-03-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8054001B2 (en) | Circuit structure for LCD backlight | |
| US7242147B2 (en) | Current sharing scheme for multiple CCF lamp operation | |
| US7166969B2 (en) | Drive circuit for illumination unit | |
| US7285921B2 (en) | Electric current balancing device | |
| US7218063B2 (en) | Two light level ballast | |
| CN100591186C (en) | Method and protection apparatus for driving discharge lamps in large panel applications | |
| CN1770227B (en) | Display device and driving device of light source therefor | |
| JP2007018997A (en) | Equalizing of discharge lamp current in circuit | |
| US8120262B2 (en) | Driving circuit for multi-lamps | |
| WO2005101920A2 (en) | A primary side current balancing scheme for multiple ccf lamp operation | |
| JP2009064789A (en) | Equalizing discharge lamp currents in circuits | |
| CN100504527C (en) | Circuit structure for LCD backlight | |
| US7977888B2 (en) | Direct coupled balancer drive for floating lamp structure | |
| US7205726B2 (en) | Discharge lamp drive apparatus and liquid crystal display apparatus | |
| US7777425B2 (en) | Backlight circuit for LCD panel | |
| US8247982B2 (en) | Method of driving a light source, light source assembly for performing the method, and liquid crystal display apparatus having the same | |
| US7365502B2 (en) | Device for driving light sources | |
| CN1711807B (en) | Power supply apparatus, backlight assembly and liquid crystal display apparatus having the same | |
| US20070132400A1 (en) | Apparatus for driving backlight of liquid crystal display | |
| US20060108947A1 (en) | Discharge lamp drive apparatus and liquid crystal display apparatus | |
| CN101115340B (en) | Inverter circuit | |
| CN201369867Y (en) | Multi lamp-tube driving system | |
| CN101258782B (en) | Discharge lamp drive control circuit | |
| US20070001622A1 (en) | Balance transformer | |
| CN100529893C (en) | Multi-lamp driven system and its anomaly detection circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| REG | Reference to a national code |
Ref country code: HK Ref legal event code: DE Ref document number: 1115643 Country of ref document: HK |
|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| REG | Reference to a national code |
Ref country code: HK Ref legal event code: GR Ref document number: 1115643 Country of ref document: HK |
|
| ASS | Succession or assignment of patent right |
Owner name: O2 TECH. INTERNATIONAL LTD. Free format text: FORMER OWNER: O2 MICRO INC Effective date: 20101122 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| COR | Change of bibliographic data |
Free format text: CORRECT: ADDRESS; FROM: CALIFORNIA, AMERICA TO: ENGLISH CAYMAN ISLANDS, ENGLAND |
|
| TR01 | Transfer of patent right |
Effective date of registration: 20101122 Address after: British Cayman Islands Patentee after: O2 Tech. International Ltd. Address before: American California Patentee before: O2 Micro Inc |
|
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090624 Termination date: 20140917 |
|
| EXPY | Termination of patent right or utility model |