CN101605422A - Drive circuit of fluorescent tube - Google Patents
Drive circuit of fluorescent tube Download PDFInfo
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- CN101605422A CN101605422A CNA2008101112831A CN200810111283A CN101605422A CN 101605422 A CN101605422 A CN 101605422A CN A2008101112831 A CNA2008101112831 A CN A2008101112831A CN 200810111283 A CN200810111283 A CN 200810111283A CN 101605422 A CN101605422 A CN 101605422A
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Abstract
Known multiple lamp tube drive circuit can increase feedback, the protection pin of controller, and the electronic component number of feedback circuit and protective circuit also increase thereupon along with the increase of fluorescent tube quantity.Drive circuit of fluorescent tube provided by the invention; carry out FEEDBACK CONTROL and protection by anti-phase current detection signal timesharing; can make the design simplification of the feedback circuit of many fluorescent tubes and protective circuit and reduce the quantity of required electronic component; simultaneously only need use same control unit to come control circuit; and the pin of control unit also reduces thereupon; not only can reduce the cost of circuit, also reach the advantage of simplifying circuit design.
Description
Technical field
The present invention is a kind of drive circuit of fluorescent tube, relates in particular to a kind of in order to drive the cold cathode ray lamp tube drive circuit of many fluorescent tubes.
Background technology
The liquid crystal panel backlight device uses high-frequency ac sine-wave power supply cold cathode ray fluorescent tube (CCFL, Cold Cathode Fluorescent Lamp) therefore luminous energy can use direct current to deliver the purpose that the inverter of stream (DC/AC Inverter) reaches power conversion.General cold cathode ray lamp tube drive circuit can use a resonance modules to become an alternating voltage driving a cold cathode ray lamp luminescence one direct current voltage transitions, and detects the driving voltage and the drive current of cold cathode ray fluorescent tube respectively by voltage and current detection circuit.One pulse-width modulation (PWM, Pulse Width Modulated) controller receives voltage detection signal and current detection signal, to stablize cold cathode ray lamp luminescence and protective circuit.
Because the large scale development of liquid crystal panel, the cold cathode ray fluorescent tube quantity of the required driving of back lighting device of using also increase thereupon.The circuit design that a PDM keyer in the past, a resonance modules drive a fluorescent tube can cause the circuit of back lighting device complicated and with high costs.Drive the cost that causes circuit and increase in order to reduce many fluorescent tubes, U.S. Patent number the 7291991st patent disclosure a kind of multiple lamp tube drive circuit, can reduce the quantity of circuit element and simplify circuit design.
Fig. 1 is the circuit diagram of the multiple lamp tube drive circuit of above-mentioned United States Patent (USP).This multiple lamp tube drive circuit comprises a PDM keyer 10, a resonance modules 20, many fluorescent tube modules and a switch module 40, and wherein many fluorescent tube modules comprise fluorescent tube L1～L4.Switch module 40 connects an input voltage vin, and according to the control signal control transmission of PDM keyer 10 energy to resonance modules 20.Resonance modules 20 comprises two transformer T1, T2 and open a plurality of transistor pass, and fluorescent tube L1, L2 are connected in the secondary side of transformer T1, fluorescent tube L3, L4 are connected in transformer T2 with series system secondary side with series system.Current detector 32,34 is connected with fluorescent tube L1, L2 respectively and is connected with fluorescent tube L3, L4, flows through the lamp current of fluorescent tube L1, L2 and flows through the lamp current of fluorescent tube L3, L4 and produce current detection signal I with detection
FB1And I
FB2Voltage detector 36,38 is in parallel with fluorescent tube L1, L2 respectively and in parallel with fluorescent tube L3, L4, produces voltage detection signal V with the light tube electric voltage of the light tube electric voltage of detection fluorescent tube L1, L2 and fluorescent tube L3, L4
FB1And V
FB2PDM keyer 10 received current detection signal I
FB1And I
FB2And voltage detection signal V
FB1And V
FB2, and carry out in view of the above FEEDBACK CONTROL with the electric power size of control switch module 40 transmission stablizing the luminous of fluorescent tube, and carry out circuit protection during circuit abnormality.
Utilize foregoing circuit, can make same resonance modules, current detector and voltage detector drive two fluorescent tubes simultaneously, and use same PDM keyer to control the operation of four fluorescent tubes, compared to known circuits, the pin of PDM keyer, the quantity and the simplification circuit design of electronic component have been reduced.But how further to reduce the number of pin and the use of employed electronic component of PDM keyer and simplify the important directions that circuit design is still the research and development of present cold cathode ray lamp tube drive circuit more.
Summary of the invention
In order to reduce the number of pin of multiple lamp tube drive circuit controller more and to reduce required electronic component; to reach the purpose that reduces circuit cost and simplify circuit layout; the invention provides a kind of drive circuit of fluorescent tube, comprise a switch module, a resonance modules, one first fluorescent tube module, one second fluorescent tube module, a detecting unit, a selected cell, a protected location and a control unit.The electric power size that this switch module connects a direct current input voltage and exports according to a plurality of control signal controls.This resonance modules couples this switch module, and in order to this power conversions is become one first AC signal and one second AC signal, wherein this first AC signal and this second AC signal are anti-phase.This first fluorescent tube module couples this resonance modules to receive this first AC signal; This second fluorescent tube module couples this resonance modules to receive this second AC signal.This detecting unit has one first test section and one second test section, and an end of this first test section and this second test section couples common ground mutually, wherein this first test section is connected with this first fluorescent tube module to produce one first detection signal, and this second test section is connected to produce one second detection signal with this second fluorescent tube module.This selected cell receives this first detection signal and this second detection signal, and exports one and select signal; This protected location receives this first detection signal and this second detection signal, and exports a protection feedback signal.This control unit couples this selected cell and this protected location, and produces these a plurality of control signals to control the switching of this switch module according to this selection signal, wherein after the current potential of this protection feedback signal is higher than a preset value, stops the switching of this switch module.
The present invention also provides another kind of drive circuit of fluorescent tube, comprises a switch module, a resonance modules, one first fluorescent tube module, one second fluorescent tube module, a detecting unit, a selected cell, a protected location and a control unit.This switch module connects a direct current input voltage, and controls the electric power size of output according to a plurality of control signals.This resonance modules couples this switch module, and in order to this power conversions is become one first AC signal and one second AC signal, wherein the phase difference of the phase place of this first AC signal and this second AC signal is positioned at upward next preset range of 180 degree.This first fluorescent tube module couples this resonance modules to receive this first AC signal; This second fluorescent tube module couples this resonance modules to receive this second AC signal.The end that this detecting unit has one first test section and one second test section and this first test section and this second test section couples common ground mutually, this first test section is connected with this first fluorescent tube module to produce one first detection signal, and this second test section is connected to produce one second detection signal with this second fluorescent tube module.This selected cell couples this detecting unit receiving this first detection signal and this second detection signal, and exports one and select signal.This protected location couples this selected cell and this detecting unit, and determines that according to this first detection signal and this second detection signal whether controlling this selection signal enters a guard mode.This control unit couples this selected cell, and produces these a plurality of control signals controlling the switching of this switch module according to this selection signal, and after detecting this selection signal and entering this guard mode, stops the switching of this switch module.
The present invention also provides another kind of drive circuit of fluorescent tube, comprises a switch module, a resonance modules, one first fluorescent tube module, one second fluorescent tube module, a detecting unit, a protected location and a control unit.This switch module connects a direct current input voltage, and controls the electric power size of output according to a plurality of control signals.This resonance modules has a primary side and a primary side, and this primary side couples this switch module, in order to export with this power conversions AC signal and in this primary side.This first fluorescent tube module couples this primary side of this resonance modules; This second fluorescent tube module couples this primary side of this resonance modules.This detecting unit has one first test section and one second test section, and an end of this first test section and this second test section couples common ground mutually, this first test section is connected to produce one first detection signal with this first fluorescent tube module, this second test section is connected with this second fluorescent tube module to produce one second detection signal, and wherein the phase difference of the phase place of the phase place of this first detection signal and this second detection signal is positioned at upward next preset range of 180 degree.This protected location receives this first detection signal and this second detection signal, and exports a protection feedback signal.This control unit couples this protected location, and when this protects feedback signal in one first state, exports a plurality of control signals, when this protects feedback signal in one second state, stops the switching of this switch module.
To sum up, drive circuit of fluorescent tube provided by the invention, control unit can be realized the FEEDBACK CONTROL and the defencive function of many fluorescent tubes by through selected detection signal of selected cell and protection feedback signal; Even adjust, control the detection signal current potential of selecting output according to the state of protection feedback signal, and reach the function that single feedback signal has FEEDBACK CONTROL and protection simultaneously.Simultaneously, the quantity of electronic component also can significantly be simplified and reduce to circuit design.
Above general introduction and ensuing detailed description are all exemplary in nature, are in order to further specify claim of the present invention.And relevant other objects and advantages of the present invention will be set forth in follow-up explanation and accompanying drawing.
Description of drawings
Fig. 1 is the circuit diagram of known multiple lamp tube drive circuit;
Fig. 2 is the circuit diagram according to the multiple lamp tube drive circuit of the first embodiment of the present invention;
Fig. 3 is the circuit diagram of multiple lamp tube drive circuit according to a second embodiment of the present invention;
Fig. 4 A is the circuit diagram of the multiple lamp tube drive circuit of a third embodiment in accordance with the invention;
Fig. 4 B is the multiple lamp tube drive circuit signal waveforms of Fig. 4 A;
Fig. 5 A is the circuit diagram of the multiple lamp tube drive circuit of a fourth embodiment in accordance with the invention; And
Fig. 5 B is the multiple lamp tube drive circuit signal waveforms of Fig. 5 A.
Wherein, Reference numeral:
PDM keyer 10
Switch module 40
Fluorescent tube L1～L4
Input voltage vin
Transformer T1, T2
Current detection signal I
FB1, I
FB2
Voltage detection signal V
FB1, V
FB2
Switch module SW
The first fluorescent tube module L1
The second fluorescent tube module L2
Fluorescent tube L11, L12, L21, L22
DC input voitage Vin
Transformer T
Resonant capacitance C1, C2
First detects resistance R 1 second detects resistance R 2
The first detection signal FB1, the second detection signal FB2
Selected cell SE
Select signal FB
Protection feedback signal PR
The FC of filtering portion
Compensating impedance element Z1, Z2
Compensating signal CP
Building-out capacitor C3, C4
Rectifier diode D1
Control part Q1
Threshold voltage Vth
Embodiment
Please refer to Fig. 2; circuit diagram for according to the multiple lamp tube drive circuit of first embodiment of the invention comprises a switch module SW, a resonance modules, one first fluorescent tube module L1, one second fluorescent tube module L2, a detecting unit, a protected location and a control unit 100.Switch module SW connects a direct current input voltage vin, and switch according to the control signal of control unit 100, electric power size with control output is full bridge structure at the switch module SW of present embodiment, yet in fact can also be half-bridge structure, push-pull configuration etc.Resonance modules has comprised transformer T and resonant capacitance C1, C2, and the primary side of transformer T couples switch module SW, primary side couples resonant capacitance C1, C2, and the electric power that is transmitted with receiving key module SW also converts AC signal to and exports in primary side.The first fluorescent tube module L1 couples an end of the primary side of resonance modules, and the second fluorescent tube module L2 also couples the other end of the primary side of resonance modules, and is luminous to receive AC signal that resonance modules exported in primary side.Detecting unit has one first test section and one second test section, and wherein first test section comprises one first and detects resistance R 1 and second test section comprises one second and detects resistance R 2.First test section and second test section respectively with the first fluorescent tube module L1 and the second fluorescent tube module L2 coupled in series in the primary side of resonance modules.One end of first test section and second test section couples common ground mutually, and the other end produces one first detection signal FB 1 and one second detection signal FB2 respectively, wherein because the sense of current of the flow through first fluorescent tube module L1 and the second fluorescent tube module L2 is opposite, so the phase place of the first detection signal FB1 can be roughly anti-phase with the phase place of the second detection signal FB2, in other words its phase difference is positioned at upward next scope of 180 degree.Certainly, because in fact the impedance of each fluorescent tube module is not to mate fully, so in fact the phase difference of the first detection signal FB1 and the second detection signal FB2 can just not equal 180 degree, but big more and be offset 180 degree more, but can drop in the 180 degree scope up and down with the difference of practical impedance.
Selected cell SE receives the first detection signal FB1 and the second detection signal FB2, and timesharing selects one output to select signal FB as one.At present embodiment, selected cell SE has two diodes, its anode couples first respectively and detects the resistance R 1 and the second detection resistance R 2, and negative terminal couples mutually, and so selected cell SE selects the first detection signal FB1 and second detection signal FB2 output with timesharing and becomes the selection signal FB of all-wave.Protected location couples detecting unit receiving the first detection signal FB1 and the second detection signal FB2, and exports a protection feedback signal PR.Protected location comprises a compensation section and a FC of filtering portion; wherein compensation section has compensating impedance element Z1, Z2; generally can use the element that has impedance as resistance, electric capacity etc.; it couples first of detecting unit respectively and detects the resistance R 1 and the second detection resistance R 2, so that the first detection signal FB1 and the second detection signal FB2 are compensated back generation one compensating signal CP mutually.Because under normal operation, the first detection signal FB1 and the second detection signal FB2 are roughly anti-phase and big or small also close, can quite approach zero potential through the compensating signal CP of compensation section output, and protect feedback signal PR to be in normal first state this moment.And any open circuit is arranged as the first fluorescent tube module L1 and the second fluorescent tube module L2; short circuit or circuit abnormality situation take place; the impedance that causes the first fluorescent tube module L1 and the second fluorescent tube module L2 is not matched situation than normally state is even more serious; make the difference in size of the first detection signal FB1 of generation and the second detection signal FB2 become big and/or phase difference departs from 180 degree more; thereby the amplitude that causes compensating signal CP becomes big; if export through rectifier diode D1 again; current potential by the protection feedback signal PR of the signal gained of the FC of filtering portion filtering HFS also can rise thereupon, and protect feedback signal PR to be in the second unusual state this moment.
Next please refer to Fig. 3, be circuit diagram according to the multiple lamp tube drive circuit of second embodiment of the invention.Compare with embodiment shown in Figure 2, transformer T in the resonance modules of present embodiment, its secondary side includes two coils, couple resonant capacitance C1, C2 respectively, power conversions is become one first AC signal and one second AC signal, wherein two coil polarity are opposite, so first AC signal that produces and the phase place of second AC signal also are anti-phase.The first fluorescent tube module L1 couples the secondary side coil of transformer T to receive first AC signal; The second fluorescent tube module L2 couples another secondary side coil of transformer T to receive second AC signal.Detecting unit has one first end that detects resistance R 1 and one second detection resistance R 2 and the first detection resistance R 1 and the second detection resistance R 2 and couples common ground mutually.First detects resistance R 1 connects with the first fluorescent tube module L1 to produce one first detection signal FB1, and second detects resistance R 2 connects to produce one second detection signal FB2 with the second fluorescent tube module L2.Because the phase place of first AC signal and second AC signal is anti-phase, under normal operation, feedback signal PR was protected in output one after protected location received the first detection signal FB1 and the second detection signal FB2, and its current potential is near zero potential.But if circuit abnormal; the impedance that causes the first fluorescent tube module L1 and the second fluorescent tube module L2 is not matched situation than normally state is even more serious; make the difference in size of the first detection signal FB1 of generation and the second detection signal FB2 become big and/or phase difference departs from 180 degree more, thereby cause the current potential of protection feedback signal PR to promote.So; control unit 100 is after the current potential of protection feedback signal PR is higher than a preset value; the switching of shutdown switch module SW: the current potential that is preferably protection feedback signal PR is higher than this preset value after also lasting one period scheduled time, and the switching of control unit 100 ability shutdown switch module SW is to avoid erroneous judgement.
Fig. 4 A is the circuit diagram of the multiple lamp tube drive circuit of a third embodiment in accordance with the invention.In the present embodiment, the first fluorescent tube module L1 has comprised fluorescent tube L11, L12, and the second fluorescent tube module L2 has comprised fluorescent tube L21, L22.The secondary side of transformer T includes two coils, couples resonant capacitance C1, C2 respectively, power conversions is become one first AC signal and one second AC signal.First of detecting unit detects resistance R 1 and second end that detects resistance R 2 couples common ground mutually.First detects resistance R 1 connects to produce one first detection signal FB1 with the first fluorescent tube module L1, the second test section R2 connects to produce one second detection signal FB2 with the second fluorescent tube module L2, and because the mode that couples makes the electric current of the first detection resistance R 1 of flowing through opposite mutually with the value of the electric current of the second detection resistance R 2 of flowing through.Therefore; under normal operation; the current potential of the protection feedback signal PR of protected location output is near zero potential; but if circuit abnormal; become the difference in size that causes the first detection signal FB1 and the second detection signal FB2 big and/or phase difference departs from 180 degree more, thereby cause the current potential of protection feedback signal PR to promote.Similarly, control unit 100 after the current potential of protection feedback signal PR is higher than a preset value, the switching of shutdown switch module SW; And the current potential that is preferably protection feedback signal PR is higher than this preset value and after lasting one period scheduled time, the switching of control unit 100 ability shutdown switch module SW is to avoid erroneous judgement.
Fig. 4 B be in the multiple lamp tube drive circuit of Fig. 4 A the first detection signal FB1, the second detection signal FB2, compensating signal CP, select the signal waveforms of signal FB and protection feedback signal PR.Under normal operation, the impedance of the first fluorescent tube module L1 and the second fluorescent tube module L2 has slightly and does not match, and phase difference is also rough near 180 degree so the amplitude of vibration size of the first detection signal FB1 and the second detection signal FB2 has slightly difference.Therefore, in fact compensating signal CP can do concussion by a small margin up and down in zero potential.At time point t1; the second fluorescent tube module L2 unusually (for example: short circuit) takes place suddenly; the electric current of flowing through is risen suddenly; this moment, the amplitude of vibration gap of the first detection signal FB1 and the second detection signal FB2 strengthened; phase difference also departs from 180 degree, and protection feedback signal PR's amplitude of vibration of compensating signal CP progressively rises thereupon becoming big.At time point t3, the threshold voltage Vth of the high overprotection of protection feedback signal PR, control unit 100 also will enter guard mode and stop to supply power to resonance modules after a scheduled time.And in time point t2; unusual (for example: open a way) also takes place suddenly in the first fluorescent tube module L1; the electric current of flowing through is descended suddenly; this moment, the amplitude of vibration gap of the first detection signal FB1 and the second detection signal FB2 was very big, and the amplitude of vibration of compensating signal CP also significantly improves and feasible protection feedback signal PR fast rise.Protection feedback signal PR then continues to be higher than threshold voltage Vth, and control unit 100 also continued inverse and enter guard mode (not being shown among the figure) to the scheduled time.
By Fig. 4 B as can be known; no matter be the circuit abnormality that open circuit or short circuit take place; all can cause increasing of amplitude of vibration difference or the phase difference of the first detection signal FB1 and the second detection signal FB2 obviously to depart from 180 degree; make protection feedback signal PR exceed predetermined threshold voltage Vth and allow control unit 100 start defencive function, reach the protection purpose.
Next please refer to Fig. 5 A, be the circuit diagram of the multiple lamp tube drive circuit of a fourth embodiment in accordance with the invention.Compare with the embodiment of Fig. 4 A, the compensation section of the embodiment of Fig. 5 A is used two building-out capacitor C3, C4, and the one end couples first of detecting unit respectively and detects the resistance R 1 and the second detection resistance R 2, and the other end couples mutually.Use electric capacity portion by way of compensation can compensate not matching of the first fluorescent tube module L1 and the second fluorescent tube module L2 itself, makes the electric current of flowing through almost equal.In addition, protected location more comprises a control part Q1, and it is coupled to selected cell SE.Control part Q1 can force the current potential of selecting signal FB to be pulled to about zero potential when protection feedback signal PR is higher than a protection potential, makes and selects signal FB to enter a guard mode.Control unit 100 only need use single pin to receive and select signal FB, and carries out FEEDBACK CONTROL or protection control according to the current potential judgement of selecting signal FB.Please also refer to Fig. 5 B, be the signal waveforms of the first detection signal FB1 in the multiple lamp tube drive circuit of Fig. 5 A, the second detection signal FB2, compensating signal CP, selection signal FB and protection feedback signal PR.Similarly; at time point t1; the second fluorescent tube module L2 is short-circuited suddenly; and because building-out capacitor C3, C4; the size of electric current of the first test section R1 and the second test section R2 of flowing through does not change too big, makes the amplitude of vibration size of the first detection signal FB1 and the second detection signal FB2 still quite approaching, yet but obviously departs from 180 degree at phase difference; the amplitude of vibration of compensating signal CP thereby change are big, and protection feedback signal PR also progressively rises.At time point t3, the threshold voltage Vth of the high overprotection of protection feedback signal PR selects signal FB to be forced to drag down, and control unit 100 also will enter guard mode and stop to supply power to resonance modules after a scheduled time.And at time point t2; it is unusual that open circuit also takes place suddenly the first fluorescent tube module L1; similarly; this moment the first detection signal FB1 and the second detection signal FB2 the amplitude of vibration size obviously variant but phase difference depart from 180 degree more, the amplitude of vibration that makes compensating signal CP also significantly improves and makes protection feedback signal PR fast rise.Protection feedback signal PR then continues to be higher than threshold voltage Vth, and control unit 100 also continued inverse and enter guard mode (not being shown among the figure) to the scheduled time.
According to the above embodiments, drive circuit of fluorescent tube provided by the invention, control unit can be realized the FEEDBACK CONTROL and the defencive function of many fluorescent tubes by through selected detection signal of selected cell and protection feedback signal; Even adjust, control the detection signal current potential of selecting output according to the state of protection feedback signal.Therefore, control unit of the present invention does not need the increase with fluorescent tube quantity to increase feedback and protection pin, and only will be with two pins, even a pin and realize the feedback and the defencive function of many fluorescent tubes.So, corresponding circuit design also can significantly be simplified, and required number of electronic components also significantly reduces.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.
Claims (19)
1. drive circuit of fluorescent tube is characterized in that comprising:
One switch module connects a direct current input voltage, and controls the electric power size of output according to a plurality of control signals;
One resonance modules couples this switch module, and in order to power conversions is become one first AC signal and one second AC signal, wherein the phase difference of this first AC signal and this second AC signal is positioned at upward next preset range of 180 degree;
One first fluorescent tube module couples this resonance modules to receive this first AC signal;
One second fluorescent tube module couples this resonance modules to receive this second AC signal;
One detecting unit, end with one first test section and one second test section and this first test section and this second test section couples common ground mutually, this first test section is connected with this first fluorescent tube module to produce one first detection signal, and this second test section is connected to produce one second detection signal with this second fluorescent tube module;
One selected cell receives this first detection signal and this second detection signal, and exports one and select signal;
One protected location receives this first detection signal and this second detection signal, and exports a protection feedback signal; And
One control unit couples this selected cell and this protected location, and produces described control signal to control the switching of this switch module according to this selection signal, wherein after the current potential of this protection feedback signal is higher than a preset value, stops the switching of this switch module.
2. drive circuit of fluorescent tube according to claim 1 is characterized in that this protected location comprises a compensation section, in order to this first detection signal and this second detection signal are compensated back generation one compensating signal mutually.
3. drive circuit of fluorescent tube according to claim 2 is characterized in that this protected location more comprises a filtering portion, in order to this compensating signal filtering to produce this protection feedback signal.
4. drive circuit of fluorescent tube according to claim 2 is characterized in that this compensation section comprises at least two electric capacity, to compensate the electric current of this first fluorescent tube module and the second fluorescent tube module.
5. drive circuit of fluorescent tube is characterized in that comprising:
One switch module connects a direct current input voltage, and controls the electric power size of output according to a plurality of control signals;
One resonance modules couples this switch module, and in order to power conversions is become one first AC signal and one second AC signal, wherein the phase difference of this first AC signal and this second AC signal is positioned at upward next preset range of 180 degree;
One first fluorescent tube module couples this resonance modules to receive this first AC signal;
One second fluorescent tube module couples this resonance modules to receive this second AC signal;
One detecting unit, have one first test section and one second test section, and an end of this first test section and this second test section couples common ground mutually, this first test section is connected with this first fluorescent tube module to produce one first detection signal, and this second test section is connected to produce one second detection signal with this second fluorescent tube module;
One selected cell couples this detecting unit receiving this first detection signal and this second detection signal, and exports one and select signal;
One protected location couples this selected cell and this detecting unit, and determines that according to this first detection signal and this second detection signal whether controlling this selection signal enters a guard mode; And
One control unit couples this selected cell, and produces described control signal controlling the switching of this switch module according to this selection signal, and after detecting this selection signal and entering this guard mode, stops the switching of this switch module.
6. drive circuit of fluorescent tube according to claim 5 is characterized in that this control unit stops the switching of this switch module after this selection signal enters this guard mode and continues one period scheduled time.
7. drive circuit of fluorescent tube according to claim 6 is characterized in that this protected location comprises a compensation section, in order to this first detection signal and this second detection signal are compensated back generation one compensating signal mutually.
8. drive circuit of fluorescent tube according to claim 7 is characterized in that this protected location more comprises a filtering portion, in order to this compensating signal filtering to produce this protection feedback signal.
9. drive circuit of fluorescent tube according to claim 7 is characterized in that this compensation section comprises at least two electric capacity, to compensate the electric current of this first fluorescent tube module and the second fluorescent tube module.
10. drive circuit of fluorescent tube according to claim 7; it is characterized in that this protected location more comprises a control part and is coupled to this selected cell; when this control part was higher than a protection potential in this protection feedback signal, this control part was controlled this selection signal and is entered this guard mode.
11. a drive circuit of fluorescent tube is characterized in that comprising:
One switch module connects a direct current input voltage, and controls the electric power size of output according to a plurality of control signals;
One resonance modules has a primary side and a primary side, and this primary side couples this switch module, in order to power conversions become AC signal and to export in this primary side;
One first fluorescent tube module couples this primary side of this resonance modules;
One second fluorescent tube module couples this primary side of this resonance modules;
One detecting unit, end with one first test section and one second test section and this first test section and this second test section couples common ground mutually, this first test section is connected to produce one first detection signal with this first fluorescent tube module, this second test section is connected with this second fluorescent tube module to produce one second detection signal, and wherein the phase difference of this first detection signal and this second detection signal is positioned at upward next preset range of 180 degree;
One protected location receives this first detection signal and this second detection signal, and exports a protection feedback signal; And
One control unit couples this protected location, and when this protects feedback signal in one first state, exports described control signal, when this protects feedback signal in one second state, stops the switching of this switch module.
12. drive circuit of fluorescent tube according to claim 11, it is characterized in that this resonance modules comprises a transformer, this transformer has one first secondary coil and a second subprime coil, couples this first fluorescent tube module and this second fluorescent tube module respectively.
13. drive circuit of fluorescent tube according to claim 11 is characterized in that this resonance modules comprises a transformer, this transformer has the level coil one time, and this first fluorescent tube module and this second fluorescent tube module coupled in parallel are in this secondary coil.
14., it is characterized in that this control unit stops the switching of this switch module after this protection feedback signal is positioned at this second state and continues one period scheduled time according to claim 12 or 13 described drive circuit of fluorescent tube.
15. according to claim 12 or 13 described drive circuit of fluorescent tube, it is characterized in that this protected location comprises a compensation section, in order to this first detection signal and this second detection signal are compensated back generation one compensating signal mutually.
16. drive circuit of fluorescent tube according to claim 15 is characterized in that this protected location more comprises a filtering portion, in order to this compensating signal filtering to produce this protection feedback signal.
17. drive circuit of fluorescent tube according to claim 15 is characterized in that this compensation section comprises at least two electric capacity, to compensate the electric current of this first fluorescent tube module and the second fluorescent tube module.
18. drive circuit of fluorescent tube according to claim 13 is characterized in that more comprising a selected cell, couples this detecting unit receiving this first detection signal and this second detection signal, and exports one and select signal.
19. drive circuit of fluorescent tube according to claim 18; it is characterized in that this protected location couples this selected cell; when this protects feedback signal in this second state; control this selection signal and enter a guard mode; after this control unit detects this selection signal and enters this guard mode, stop the switching of this switch module.
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|---|---|---|---|
| CN2008101112831A CN101605422B (en) | 2008-06-13 | 2008-06-13 | Fluorescent lighting tube driving circuit |
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|---|---|---|---|
| CN2008101112831A CN101605422B (en) | 2008-06-13 | 2008-06-13 | Fluorescent lighting tube driving circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103219705A (en) * | 2013-03-12 | 2013-07-24 | 中兴通讯股份有限公司 | Method and device for short circuit protection of half-bridge resonant converter |
| EP2590288A3 (en) * | 2011-11-07 | 2018-01-24 | S-Printing Solution Co., Ltd. | Switching mode power supply including surge protection circuit and image forming apparatus including the same |
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|---|---|---|---|---|
| CN2636585Y (en) * | 2003-06-13 | 2004-08-25 | 龙裕斌 | High performance fully digital controlled dimming electron ballast |
| CN2710247Y (en) * | 2004-01-02 | 2005-07-13 | 英属开曼群岛凹凸微系国际有限公司 | High-efficient switch circuit for non-linear load |
-
2008
- 2008-06-13 CN CN2008101112831A patent/CN101605422B/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2590288A3 (en) * | 2011-11-07 | 2018-01-24 | S-Printing Solution Co., Ltd. | Switching mode power supply including surge protection circuit and image forming apparatus including the same |
| US9941689B2 (en) | 2011-11-07 | 2018-04-10 | S-Printing Solution Co., Ltd. | Switching mode power supply including surge protection circuit and image forming apparatus including the same |
| CN103219705A (en) * | 2013-03-12 | 2013-07-24 | 中兴通讯股份有限公司 | Method and device for short circuit protection of half-bridge resonant converter |
| CN103219705B (en) * | 2013-03-12 | 2016-02-24 | 中兴通讯股份有限公司 | The short-circuit protection method of half bridge resonant transformer and device |
| US9812857B2 (en) | 2013-03-12 | 2017-11-07 | Xi'an Zhongxing New Software Co. Ltd. | Short-circuit protection method and device for a half-bridge resonant converter |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101605422B (en) | 2012-11-07 |
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