CN101610630B - Drive circuit of fluorescent tube - Google Patents
Drive circuit of fluorescent tube Download PDFInfo
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- CN101610630B CN101610630B CN2008101266558A CN200810126655A CN101610630B CN 101610630 B CN101610630 B CN 101610630B CN 2008101266558 A CN2008101266558 A CN 2008101266558A CN 200810126655 A CN200810126655 A CN 200810126655A CN 101610630 B CN101610630 B CN 101610630B
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Abstract
The invention discloses a drive circuit of a fluorescent tube, which comprises a resonance module, a tube module, a detection device and a controller, wherein the resonance module comprises a primary side and a secondary side so as to convert the electric power of input voltage received by the primary side into an AC signal and output the AC signal from the secondary side; the resonance module also comprises a transformer, and a primary side of the transformer is provided with two connecting ends and a central tap end; the tube module comprises a plurality of tubes and is coupled to the secondary side of the resonance module so as to receive the AC signal; the detection device and the tube module are connected in series to the secondary side of the resonance module; one end of the detection device is connected with a reference potential end, and the detection device generates a current detection signal and a protection feedback signal according to current flowing through the tubes; the controller comprises two semiconductor switches which are mutually connected through one end of each semiconductor switch, and the other ends are respectively coupled to the two connecting ends of the primary side of the transformer; a base pin of the controller receives the current detection signal so as to achieve feedback control, while the other base pin receives the protection feedback signal so as to achieve protection control, thereby simplifying the circuit design.
Description
Technical field
The present invention is a kind of drive circuit of fluorescent tube, is meant the multiple lamp tube drive circuit of a kind of built-in MOSFET (mos field effect transistor) especially.
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 converter circuit of stream (DC/AC Inverter) reaches energy 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 through voltage and current detection circuit.One width modulation (PWM, Pulse Width Modulated) controller receives voltage detection signal and current detection signal, with as the usefulness of stablizing cold cathode ray lamp luminescence and circuit protection.
Because the development of the maximization of liquid crystal panel, the cold cathode ray fluorescent tube quantity of the required driving of back lighting device of using also increase thereupon.A PDM keyer in the past, a resonance modules drive the circuit of a fluorescent tube ... Deng, in design, all can cause the complicated circuit of back lighting device and with high costs.Drive the cost increase that causes circuit in order to reduce many fluorescent tubes, generally be applied to multiple lamp tube drive circuit and reduce the quantity of circuit unit and simplify circuit design with same PDM keyer.
Fig. 1 is the circuit diagram of traditional multiple lamp tube drive circuit.This multiple lamp tube drive circuit comprises a PDM keyer 100, a switch module SW, a resonance modules, a plurality of fluorescent tube module, current detection module 110,130 and voltage detection module 120,140; Wherein many fluorescent tube modules comprise fluorescent tube L1～L2, and resonance modules comprises a transformer T and resonant capacitance C1～C2.Switch module SW connects an input voltage vin, and according to the energy of control signal control transmission to the resonance modules of PDM keyer 100.The two primary side windings of transformer T connect fluorescent tube L1, L2 respectively.Current detection module 110,130 is connected with fluorescent tube L1, L2 respectively, to produce lamp tube status signal S3, the S6 that represents current detection signal S1, the S4 of fluorescent tube L1, L2 size of current and represent fluorescent tube L1, L2 state respectively.Voltage detection module 120,140 is parallelly connected with fluorescent tube L1, L2 respectively, represents fluorescent tube L1, the voltage detection signal S2 of L2 voltage swing, S5 to produce respectively.PDM keyer 100 receives above-mentioned signal S1～S6, and carries out soft start (soft start), FEEDBACK CONTROL in view of the above and carry out circuit protection when stablizing the luminous and circuit abnormality of fluorescent tube with the electric power size of CS module SW transmission.
Utilize above-mentioned circuit, can make same PDM keyer drive two fluorescent tubes simultaneously, to have reduced the quantity of PDM keyer.But the number of pin of PDM keyer and employed electronic package are still too much; So how to reduce the number of pin of PDM keyer and reduce electronic package quantity, be still the important directions of the research and development of present cold cathode ray lamp tube drive circuit with further simplification circuit design.
Summary of the invention
The technical matters that the present invention solves is, a kind of drive circuit of fluorescent tube is provided, and reduces the number of pin of multiple lamp tube drive circuit controller and reduces required electronic package, to reach the purpose that reduces circuit cost and simplify circuit layout.
For reaching above-mentioned purpose, the present invention provides a kind of drive circuit of fluorescent tube, comprises a resonance modules, a fluorescent tube module, a pick-up unit and a controller.This resonance modules has a primary side and a secondary side; Power conversions in order to a input voltage that this primary side is received becomes an AC signal in this secondary side output; Wherein this resonance modules comprises a transformer, and the primary side of this transformer has two links and a center tap end.This fluorescent tube module has a plurality of fluorescent tubes, and this secondary side that is coupled to this resonance modules is to receive this AC signal.This pick-up unit is connected a reference potential end with this secondary side and an end that this fluorescent tube module is series at this resonance modules, and produces a current detection signal and a protection feedback signal according to the electric current of the lamp tubes of flowing through.This controller comprises two semiconductor switchs, and an end of this two semiconductor switch interconnects, and the other end couples two links of the primary side of this transformer respectively.Wherein, This controller according to the switching of this two semiconductor switch of this current feedback signal control with the electric power that transmits this stable input voltage to this resonance modules; After this protection feedback signal is higher than one first predetermined value or is lower than one second predetermined value; Stop the switching of this two semiconductor switch, this first predetermined value is greater than this second predetermined value.
The present invention also provides another kind of drive circuit of fluorescent tube, comprises a resonance modules, a fluorescent tube module, a pick-up unit and a controller.This resonance modules has a primary side and a secondary side, becomes an AC signal in this secondary side output in order to the power conversions that this primary side is received.This fluorescent tube module has a plurality of fluorescent tubes, and this secondary side that is coupled to this resonance modules is to receive this AC signal.This pick-up unit is connected a reference potential end with this secondary side and an end that this fluorescent tube module is series at this resonance modules, and produces a current detection signal and a protection feedback signal according to the electric current of the lamp tubes of flowing through.This controller comprises two semiconductor switchs, and an end of this two semiconductor switch interconnects and be coupled to this primary side of this resonance modules, and the other end couples an input voltage and this reference potential end respectively.Wherein, This controller according to the switching of this two semiconductor switch of this current feedback signal control with the electric power that transmits this stable input voltage to this resonance modules; After this protection feedback signal is higher than one first predetermined value or is lower than one second predetermined value, stop the switching of this two semiconductor switch.
The present invention also provides a kind of drive circuit of fluorescent tube, comprises a resonance modules, a fluorescent tube module, a pick-up unit and a controller.This resonance modules has a primary side and a secondary side, becomes an AC signal in this secondary side output in order to the power conversions that this primary side is received.This secondary side that this fluorescent tube module has a plurality of fluorescent tubes and is coupled to this resonance modules is to receive this AC signal.This pick-up unit is connected a reference potential end with this secondary side and an end that this fluorescent tube module is series at this resonance modules, and produces a current detection signal and a protection feedback signal according to the electric current of the lamp tubes of flowing through.This controller comprises two semiconductor switchs, and an end of this two semiconductor switch interconnects and be coupled to this primary side of this resonance modules.Wherein, this controller according to the switching of this two semiconductor switch of this current feedback signal control with the electric power that transmits this stable input voltage to this resonance modules, after this protection feedback signal is lower than a predetermined value, stop the switching of this two semiconductor switch.
To sum up; Drive circuit of fluorescent tube provided by the invention; Drive at the same time under a plurality of light, its controller only needs a pin to come the received current detection signal can reach FEEDBACK CONTROL, can reach protection control and receive the protection feedback signal with another pin; The pin of event controller significantly reduces, and has also reduced feedback and corresponding required external electronic components and the simplification circuit design of protection simultaneously.
Above general introduction and ensuing detailed description are all demonstration, to further specify claim of the present invention.And about other purpose of the present invention and advantage, will set forth in follow-up explanation and accompanying drawing.
Description of drawings
Fig. 1 is the circuit diagram of the multiple lamp tube drive circuit of prior art;
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 is the circuit diagram of the multiple lamp tube drive circuit of a third embodiment in accordance with the invention;
Fig. 5 is the circuit diagram of the multiple lamp tube drive circuit of a fourth embodiment in accordance with the invention;
Fig. 6 is for can be applied to Fig. 3 and controller circuitry synoptic diagram embodiment illustrated in fig. 4;
Fig. 7 is for can be applied to Fig. 2 and controller circuitry synoptic diagram embodiment illustrated in fig. 5; And
Fig. 8 is the encapsulation synoptic diagram according to controller of the present invention.
Wherein, Reference numeral:
Current detection module 110,130 voltage detection module 120,140
Fluorescent tube L1, L2 transformer T
Resonant capacitance C1, C2 input voltage vin
Current detection signal S1, S4 lamp tube status signal S3, S6
Voltage detection signal S2, S5
Controller 210,310,410,510 resonance modules 220,320,420,520
Test section 232,332,432a, 432b, 532 current detecting feedback section 234,334,434
Voltage detecting feedback section 235
Protection detects feedback section 236,336,436,536 input voltage VCC
Activation pin EN processing unit 610,710
Error amplifying unit 620,720 protected locations 630,730
Frequency generator 640,740 pwm units 650,750
First semiconductor switch, 680,780 second semiconductor switchs 685,785
Fluorescent tube L1, L2, L3, L4 transformer T
Resonant capacitance C1, C2, C3 input voltage VCC
Pin D1, D2 resistance R 1, R2
Protection feedback signal PS protection pin PROT
Current detection signal FS feedback pin FB
Light modulation pin DIM dimming control signal DIMMING
Voltage division signal VS detection signal FB1, FB2, FB3, FB4
Voltage reference signal REF, REF_PRO, REF_H, REF_L, REF1, REF2/3
Soft-start signal SST protection comparer COMP
The first protection comparer COMP1, the second protection comparer COMP2
Activation/light modulation pin EN/DIM
Embodiment
Please refer to Fig. 2, be circuit diagram, comprise a controller 210, a resonance modules 220, a fluorescent tube module and a pick-up unit according to the multiple lamp tube drive circuit of the first embodiment of the present invention.Wherein, fluorescent tube module comprises fluorescent tube L1, L2, and pick-up unit comprises a test section 232, a current detecting feedback section 234, a voltage detecting feedback section 235 and a protection and detects feedback section 236.Resonance modules 220 has a primary side and a secondary side, has mainly comprised a transformer T and resonant capacitance C1～C3.The primary side of transformer T has two links and a center tap end, and its central tap terminals connects an input voltage VCC, and two links are connected to pin D1, the D2 of controller 210 respectively.So, the power conversions of the resonance modules 220 input voltage VCC that can primary side be received becomes an AC signal in its secondary side output, so that the usefulness of fluorescent tube module operation to be provided.Fluorescent tube module has a plurality of fluorescent tubes, and every fluorescent tube coupled in series in twos to receive this AC signal, is a secondary side that fluorescent tube L1, L2 be series at resonance modules 220 at present embodiment in the secondary side of resonance modules 220.The test section 232 and the fluorescent tube module of pick-up unit is series at the secondary side of resonance modules 220 and an end of test section 232 (for example: ground connection) is connected a reference potential end.The electric current that flows through fluorescent tube module produces through resistance R 1, R2 that a detection signal is sent to current detecting feedback section 234 respectively and protection detects feedback section 236.In the present embodiment, protection detects feedback section 236 and comprises two diodes and an electric capacity, receives detection signal and after diode rectification filtering, changes into the protection pin PROT that protection feedback signal PS exports controller 210 to; Current detecting feedback section 234 changes into the feedback pin FB that current detection signal FS exports controller 210 to detection signal after filtering.In addition, the output voltage of resonance modules 220 produces a voltage division signal VS after the dividing potential drop of resonant capacitance C1～C3, and input voltage detects feedback section 235, to reach the effect of high voltage protective.
Under normal operation, fluorescent tube module 220 steady current of can flowing through, the resistance R of flowing through 1, R2 and produce the stable detection signal, this moment, the level of detection signal can be within a safe range.When multiple lamp tube drive circuit is short-circuited; The resonance modules 220 bigger electric current of can flowing through; Or when open circuit takes place in multiple lamp tube drive circuit; Resonance modules 220 less current of can flowing through, the above-mentioned level that either way can cause detection signal exceed a safe range (that is, be higher than a high value or be lower than than low value).Therefore, whether controller 210 gets into the judgement of guard mode according to protection feedback signal PS.In addition; Secondary side electric voltage exception rising when resonance modules 220; Voltage division signal VS level will be higher than the level of detection signal, therefore draw high the level of current detection signal FS, make controller 210 reduce the electric power of importing resonance modules 220 and the voltage that reduces its secondary side.Controller 210 built-in two semiconductor switch (not shown), an end of this two semiconductor switch is interconnected to the reference potential end, and the other end couples two links of the primary side of transformer T respectively.Controller 210 comes into operation receive the enable signal of high level in activation pin EN after; According to the switching of this two semiconductor switch of current detection signal FS control, reach the effect of stable output with the electric power size of control input voltage VCC input resonance modules 220.And after protection feedback signal PS is higher than one first predetermined value or is lower than one second predetermined value (first predetermined value is greater than second predetermined value), the switching that controller 210 will stop this two semiconductor switch gets into guard mode to avoid the circuit damage.
Next please refer to Fig. 3, be the circuit diagram of according to a second embodiment of the present invention multiple lamp tube drive circuit.Likewise, the multiple lamp tube drive circuit of this embodiment comprises a controller 310, a resonance modules 320, a fluorescent tube module and a pick-up unit.Wherein, fluorescent tube module comprises fluorescent tube L1, L2, and pick-up unit comprises a test section 332, a current detecting feedback section 334 and a protection and detects feedback section 336.Compare with the embodiment of Fig. 2, maximum difference is the arbitrary fluorescent tube damage of fluorescent tube L1, the L2 open circuit in the fluorescent tube module of present embodiment, with the secondary side that causes resonance modules 320 current return can't be provided, and causing lamp current is zero.Detection signal FB1, FB2 will detect the level of the protection pin PROT of feedback section 336 pull-down control devices 310 through protection at this moment, make controller 310 get into guard modes.And in the present embodiment, controller 310 also can receive the dim signal of a direct current level light modulation or pulse light modulation through light modulation pin DIM, with according to the switching of this two semiconductor switch of this dim signal control to reach dimming function.
Among above-mentioned two embodiment; Semiconductor switch in resonance modules and the controller forms the push-pull type converter, and ensuing embodiment will be that example describes with the semibridge system converter, and those skilled in the art can know; But mutual alternative between the circuit of these embodiment, and the claim of unrestricted this case.
Please refer to Fig. 4, be the circuit diagram of the multiple lamp tube drive circuit of a third embodiment in accordance with the invention.The multiple lamp tube drive circuit of present embodiment comprises a controller 410, a resonance modules 420, a fluorescent tube module and a pick-up unit.Wherein, fluorescent tube module comprises fluorescent tube L1～L4, and pick-up unit comprises two test section 432a, 432b, a current detecting feedback section 434 and a protection and detects feedback section 436.Resonance modules 420 has a primary side and a secondary side, has mainly comprised a transformer T and resonant capacitance C1～C3, becomes an AC signal to export in secondary side in order to the power conversions that primary side is received.Wherein the primary side of transformer T has two windings.Fluorescent tube module has a plurality of fluorescent tubes, a winding of the primary side of fluorescent tube L1, L2 coupled in series transformer T, another winding of the primary side of fluorescent tube L3, L4 coupled in series transformer T.The test section 432a of pick-up unit is connected a reference potential end (promptly with a secondary side and an end that fluorescent tube L1, L2 are series at resonance modules 420; Ground connection) to produce detection signal FB1, FB2; Test section 432b is connected a reference potential end (that is ground connection) to produce detection signal FB3, FB4 with a secondary side and an end that fluorescent tube L3, L4 are series at resonance modules 420.When resonance modules 420 output AC signals during in positive half-wave, electric current flow through in regular turn fluorescent tube L1, resistance R 1, with resistance R 2 diode connected in parallel and fluorescent tube L2, so the time output detection signal FB1; When resonance modules 420 output AC signals during in negative half-wave, electric current flow through in regular turn fluorescent tube L2, resistance R 2, with resistance R 1 diode connected in parallel and fluorescent tube L1, so the time output detection signal FB2.Therefore, pick-up unit of the present invention have timesharing output fluorescent tube detection signal to the function of protecting pin PROT.The detection signal that exports current detecting feedback section 434 to is then through rectification, and after the filtering of current detecting feedback section 434, transports to the feedback pin FB of controller 410, so do not influence the FEEDBACK CONTROL of controller 410.Controller 410 built-in two semiconductor switch (not shown), an end of two semiconductor switchs interconnects and is coupled to the primary side of resonance modules 420, and the other end couples an input voltage VCC and reference potential end respectively.Controller 410 comes into operation receive the enable signal of high level in activation pin EN after; According to the switching of this two semiconductor switch of current detection signal FS control, reach the effect of stable output with the electric power size of control input voltage VCC input resonance modules 420.And after protection feedback signal PS is higher than one first predetermined value or is lower than one second predetermined value (first predetermined value is greater than second predetermined value), the switching that controller 410 will stop this two semiconductor switch gets into guard mode to avoid the circuit damage.
In the present embodiment; Though the fluorescent tube number is many compared to previous embodiment; But pick-up unit utilizes each fluorescent tube detection signal of timesharing output; Protection detects feedback section 436 and receives those detection signals, reaches the function of protection with the protection pin PROT of detection signal to the controller 410 of selecting output abnormality.
Next please refer to Fig. 5, be the circuit diagram of the multiple lamp tube drive circuit of a fourth embodiment in accordance with the invention.Likewise, the multiple lamp tube drive circuit of this embodiment comprises a controller 510, a resonance modules 520, a fluorescent tube module and a pick-up unit.Wherein, fluorescent tube module comprises fluorescent tube L1～L4, and pick-up unit comprises a test section 532 and a protection detects feedback section 536.Compare the maximum different designs that are in of present embodiment in pick-up unit with the embodiment of Fig. 4.Because two winding polarities of the primary side of transformer T are opposite, so the roughly anti-phase of electric current of the electric current of the resistance R 1 of the test section 532 of flowing through and the resistance R 2 of flowing through.Therefore, under normal operation, the level of the protection feedback signal PS of protection detection feedback section 536 outputs is near zero potential.But if circuit abnormal, the difference in size of the detection signal that the detection signal that causes resistance R 1 to be produced and resistance R 2 are produced becomes big and/or phase differential departs from 180 degree more, and this all can cause the level of protection feedback signal PS to promote.Controller 510 is after the level of protection feedback signal PS is higher than a default value, and electric power to the resonance modules 520 that stops output-input voltage VCC is to reach the function of holding circuit.Can know that obviously the employed external electronic components of the embodiment of Fig. 5 is more simplified, circuit cost more reduces.
Then, please refer to Fig. 6, for being applied to Fig. 3 and controller circuitry synoptic diagram embodiment illustrated in fig. 4.Controller mainly comprises a processing unit 610, an error amplifying unit 620, a protected location 630, a frequency generator 640, a pwm unit 650, one first semiconductor switch 680 and one second semiconductor switch 685, and wherein first semiconductor switch 680 and second semiconductor switch 685 can be MOS transistor, BJT transistor, SCR, TRAIC etc.Processing unit 610 comes into operation received the enable signal of high level by activation/light modulation pin EN/DIM after, and this moment, processing unit 610 can produce voltage reference signal REF, REF_PRO and soft-start signal SST.Two input ends of error amplifying unit 620 receive voltage reference signal REF respectively and reach the current detection signal of being imported by feedback pin FB and produce an error amplification signal.Protected location 630 comprises a protection comparer COMP and a holding circuit.The protection feedback signal that protection comparer COMP receives voltage reference signal REF_PRO and imported by protection pin PROT when the level of protection feedback signal is lower than voltage reference signal REF_PRO, produces a protection comparison signal.After protected location receives the protection comparison signal, in a schedule time, can produce a frequency change control signal, after the protection comparison signal continued to surpass this schedule time, protected location then produced a protection control signal.Frequency generator 640 operates in a normal running frequency and produces a ramp signal, and when receiving frequency change control signal, will transfer to operating in a higher startup frequency, to light fluorescent tube; Receiving the protection control signal after a period of time, frequency generator 640 is with shut-down operation.Pwm unit 650 receives soft-start signal SST, error amplification signal and ramp signal, and produces two drive signals in view of the above to control the switching of first semiconductor switch 680 and second semiconductor switch 685 respectively.
When multiple lamp tube drive circuit at the beginning of starting, fluorescent tube is not lighted as yet, the level of protection feedback signal is extremely low, makes protected location produce a frequency change control signal earlier.At this moment, frequency generator 640 operates in the startup frequency in protecting feedback signal to be lower than a predetermined value (that is the level of voltage reference signal REF_PRO).Soft-start signal SST gradually toward rising, becomes greatly the work period of the drive signal of pwm unit 650 generations by low level gradually, and the output voltage of resonance modules secondary side rises to light fluorescent tube gradually.When fluorescent tube is lighted smoothly, protect the level rising of feedback signal to surpass predetermined value, frequency generator 640 wherein starts frequency and is higher than the normal running frequency in the normal running frequency at this moment.In addition, when lamp tube starting failure or circuit abnormal, the protection feedback signal continues to be lower than predetermined value and surpasses the schedule time, and frequency generator 640 shut-down operations make pwm unit 650 stop to produce drive signal, and this moment, controller got into guard mode.
When the signal of activation/light modulation pin EN/DIM transfers dim signal to; When the frequency of the signal that processing unit 610 receives according to activation/light modulation pin EN/DIM or level judging are dim signal; To produce a dimming control signal DIMMING to frequency generator 640 according to dim signal, and make its shut-down operation and reach the purpose of light modulation.
Next, please refer to Fig. 7, for being applied to Fig. 2 and controller circuitry synoptic diagram embodiment illustrated in fig. 5.The controller of present embodiment mainly comprises a processing unit 710, an error amplifying unit 720, a protected location 730, a frequency generator 740, a pwm unit 750, a light modulation and hides from view unit 760, a frequency conversion hysteresis comparator 770, one first semiconductor switch 780 and one second semiconductor switch 785, and wherein first semiconductor switch 780 and second semiconductor switch 785 can be MOS transistor, BJT transistor, SCR, TRAIC etc.Processing unit 710 comes into operation received the enable signal of high level by activation/light modulation pin EN/DIM after, and this moment, processing unit 710 can produce voltage reference signal REF1, REF2/3, REF_H, REF_L, dimming control signal DIMMING and soft-start signal SST.Three input ends of error amplifying unit 720 receive voltage reference signal REF1 respectively, hide from view the dim signal that unit 760 is transmitted by the current detection signal and the light modulation of feedback pin FB input, and error amplifying unit 720 produces an error amplification signal in view of the above.Protected location 730 comprises one first protection comparer COMP1, one second protection comparer COMP2, a holding circuit and a current source.The non-inverting input of the first protection comparer COMP1 receives voltage reference signal REF_H; Its inverting input receives the protection feedback signal by protection pin PROT input; When the level of protection feedback signal is higher than voltage reference signal REF_H, produce one first protection comparison signal.The second protection comparer COMP2 non-inverting input receives voltage reference signal REF_L, and its inverting input receives the protection feedback signal, when the level of protection feedback signal is lower than voltage reference signal REF_L, produces one second protection comparison signal.Wherein, the level of voltage reference signal REF_H is higher than voltage reference signal REF_L.Holding circuit couples the output terminal of the first comparator C OMP1 and the second comparator C OMP2; Produce a protection control signal after receiving those protection comparison signals; Being preferably the arbitrary of those protection comparison signals continues above producing the protection control signal after the schedule time, to stop to switch through pwm unit 750 control first semiconductor switchs 780 and second semiconductor switch 785.
Current source is coupled to protection pin PROT; Can make the level of protecting pin PROT to top offset through a resistance; So when the circuit normal running; The level of protection pin PROT falls between voltage reference signal REF_H and the voltage reference signal REF_L, and makes protected location 730 be unlikely to malfunction.
The current detection signal that frequency conversion hysteresis comparator 770 receives voltage reference signal REF2/3 and imported by feedback pin FB, when fluorescent tube was not lighted, current detection signal was lower than voltage reference signal REF2/3, and frequency conversion hysteresis comparator 770 produces a frequency change control signal.Light modulation is hidden from view unit 760 and is comprised a light modulation and hide from view a device and a hysteresis comparator, and hysteresis comparator receives voltage reference signal REF2/3 and by the current detection signal of feedback pin FB input.Light modulation is hidden from view device and is received dimming control signal DIMMING; In when fluorescent tube is not lighted; Current detection signal is lower than voltage reference signal REF2/3, and the output that device stops dimming control signal DIMMING is hidden from view in light modulation this moment, makes controller not influence lighting of fluorescent tube because of light modulation; In when lamp tube starting the time, current detection signal is higher than voltage reference signal REF2/3, and device output dim signal is hidden from view in light modulation this moment, makes controller begin to carry out dimming function.Frequency generator 740 operates in a normal running frequency and produces a ramp signal; And when receiving the frequency change control signal that frequency conversion hysteresis comparator 770 produced, will transfer to and operate in a higher startup frequency, to light fluorescent tube.Pwm unit 750 receives soft-start signal SST, error amplification signal, protection control signal and ramp signal, and produces two drive signals in view of the above to control the switching of first semiconductor switch 780 and second semiconductor switch 785 respectively.
Embodiment at Fig. 7; Also can be as as Fig. 6 embodiment; Replace frequency conversion hysteresis comparator 770 by protected location 730; With the operating frequency of controlled frequency generator 740, make frequency generator 740 when the protection feedback signal is between voltage reference signal REF_H, voltage reference signal REF_L, operate in the normal running frequency; When being higher than voltage reference signal REF_H or being lower than voltage reference signal REF_L, operate in one and start frequency, to reach the function of fluorescent tube variable frequency starting.
Fig. 8 is the encapsulation synoptic diagram according to controller of the present invention; Wherein feed back pin FB and separate one more than the pin, have influence on feedback pin FB and the signal level of protecting pin PROT to be received because of coupling with the pin of avoiding two semiconductor switchs with protecting the special pins of pin PROT with two semiconductor switchs.Because semiconductor switch and pulse width modulator are encapsulated in the same packaging body; And only need a pin to come the received current detection signal can reach FEEDBACK CONTROL; Can reach protection control and receive the protection feedback signal with another pin; The pin of controller significantly reduces, and can effectively reduce the required cost of encapsulation.Also reduce simultaneously the corresponding required external electronic components of feedback and protection and simplified circuit design.
The said best specific embodiment of the present invention that is merely, characteristic of the present invention is not limited thereto, any those skilled in the art in the field of the invention, can think easily and variation or modification, all can be encompassed in the claim of following this case.
Claims (19)
1. drive circuit of fluorescent tube is characterized in that comprising:
One resonance modules; Have a primary side and a secondary side; Power conversions in order to a input voltage that this primary side is received becomes an AC signal in this secondary side output, and this resonance modules comprises a transformer, and the primary side of this transformer has two links and a center tap end;
One fluorescent tube module, this secondary side that has a plurality of fluorescent tubes and be coupled to this resonance modules is to receive this AC signal;
One pick-up unit, this secondary side and the end that are series at this resonance modules with this fluorescent tube module are connected a reference potential end, and produce a current detection signal and a protection feedback signal according to the electric current of the lamp tubes of flowing through; And
One controller comprises two semiconductor switchs, and an end of this two semiconductor switch interconnects, and the other end couples two links of the primary side of this transformer respectively;
Wherein, This controller according to the switching of this two semiconductor switch of this current feedback signal control with the electric power that transmits this stable input voltage to this resonance modules; After this protection feedback signal is higher than one first predetermined value or is lower than one second predetermined value; Stop the switching of this two semiconductor switch, this first predetermined value is greater than this second predetermined value.
2. drive circuit of fluorescent tube as claimed in claim 1; It is characterized in that this controller also comprises one first comparer, one second comparer; The non-inverting input of this first comparer receives one first reference voltage signal of representing this first predetermined value; The inverting input of this second comparer receives one second reference voltage signal of representing this second predetermined value, and the non-inverting input of the inverting input of this first comparer and this second comparer receives should the protection feedback signal.
3. drive circuit of fluorescent tube as claimed in claim 2; It is characterized in that this controller also comprises a holding circuit; This holding circuit couples the output terminal of this first comparer and the output terminal of this second comparer; With according to the comparative result of those comparers output one protection control signal, whether with the switching of controlling this two semiconductor switch.
4. drive circuit of fluorescent tube as claimed in claim 1, it is characterized in that this two semiconductor switch switch on this protection feedback signal be higher than this first predetermined value or be lower than this second predetermined value and continue a schedule time after stop.
5. drive circuit of fluorescent tube as claimed in claim 1 is characterized in that this controller also comprises a frequency generator, and this frequency generator operates in a first frequency when this protection feedback signal is between this first predetermined value and this second predetermined value; When this protection feedback signal is higher than this first predetermined value or is lower than this second predetermined value, operate in a second frequency, wherein this second frequency is higher than this first frequency.
6. drive circuit of fluorescent tube as claimed in claim 5 is characterized in that this controller receives a dim signal, when this frequency generator operates in this first frequency, carries out light modulation according to the switching of this this two semiconductor switch of dim signal control.
7. drive circuit of fluorescent tube as claimed in claim 1 is characterized in that this pick-up unit comprises;
One test section, in order to the electric current that detects lamp tubes to produce a detection signal;
One current detecting feedback section couples this test section and this detection signal is produced this current detection signal after rectification; And
One protection detects feedback section, couples this test section and this detection signal is produced this protection feedback signal after rectification.
8. drive circuit of fluorescent tube is characterized in that comprising:
One resonance modules has a primary side and a secondary side, becomes an AC signal in this secondary side output in order to the power conversions that this primary side is received;
One fluorescent tube module, this secondary side that has a plurality of fluorescent tubes and be coupled to this resonance modules is to receive this AC signal;
One pick-up unit, this secondary side and the end that are series at this resonance modules with this fluorescent tube module are connected a reference potential end, and produce a current detection signal and a protection feedback signal according to the electric current of the lamp tubes of flowing through; And
One controller comprises two semiconductor switchs, and an end of this two semiconductor switch interconnects and be coupled to this primary side of this resonance modules, and the other end couples an input voltage and this reference potential end respectively;
Wherein, This controller according to the switching of this two semiconductor switch of this current feedback signal control with the electric power that transmits this stable input voltage to this resonance modules; After this protection feedback signal is higher than one first predetermined value or is lower than one second predetermined value, stop the switching of this two semiconductor switch.
9. drive circuit of fluorescent tube as claimed in claim 8; It is characterized in that this controller also comprises one first comparer, one second comparer; The non-inverting input of this first comparer receives one first reference voltage signal of representing this first predetermined value; The inverting input of this second comparer receives one second reference voltage signal of representing this second predetermined value, and the non-inverting input of the inverting input of this first comparer and this second comparer receives should the protection feedback signal.
10. drive circuit of fluorescent tube as claimed in claim 9; It is characterized in that this controller also comprises a holding circuit; This holding circuit couples the output terminal of this first comparer and the output terminal of this second comparer; With according to the comparative result of those comparers output one protection control signal, whether with the switching of controlling this two semiconductor switch.
11. drive circuit of fluorescent tube as claimed in claim 8, it is characterized in that this two semiconductor switch switch on this protection feedback signal be higher than this first predetermined value or be lower than this second predetermined value and continue a schedule time after stop.
12. drive circuit of fluorescent tube as claimed in claim 8 is characterized in that this controller also comprises a frequency generator, this frequency generator operates in a first frequency when this protection feedback signal is between this first predetermined value and this second predetermined value; When this protection feedback signal is higher than this first predetermined value or is lower than this second predetermined value, operate in a second frequency, wherein this second frequency is higher than this first frequency.
13. drive circuit of fluorescent tube as claimed in claim 12 is characterized in that this controller receives a dim signal, when this frequency generator operates in this first frequency, carries out light modulation according to the switching of this this two semiconductor switch of dim signal control.
14. drive circuit of fluorescent tube as claimed in claim 8 is characterized in that this pick-up unit comprises;
One test section, in order to the electric current that detects lamp tubes to produce a detection signal;
One current detecting feedback section couples this test section and this detection signal is produced this current detection signal after rectification; And
One protection detects feedback section, couples this test section and this detection signal is produced this protection feedback signal after rectification.
15. a drive circuit of fluorescent tube is characterized in that comprising:
One resonance modules has a primary side and a secondary side, becomes an AC signal in this secondary side output in order to the power conversions that this primary side is received;
One fluorescent tube module, this secondary side that has a plurality of fluorescent tubes and be coupled to this resonance modules is to receive this AC signal;
One pick-up unit, this secondary side and the end that are series at this resonance modules with this fluorescent tube module are connected a reference potential end, and produce a current detection signal and a protection feedback signal according to the electric current of the lamp tubes of flowing through; And
One controller comprises two semiconductor switchs, and an end of this two semiconductor switch interconnects and be coupled to this primary side of this resonance modules;
Wherein, this controller according to the switching of this two semiconductor switch of this current feedback signal control with the electric power that transmits this stable input voltage to this resonance modules, after this protection feedback signal is lower than a predetermined value, stop the switching of this two semiconductor switch.
16. drive circuit of fluorescent tube as claimed in claim 15 is characterized in that this pick-up unit comprises;
One test section, in order to the electric current that detects lamp tubes to produce a detection signal;
One current detecting feedback section couples this test section and this detection signal is produced this current detection signal after rectification; And
One protection detects feedback section, couples this test section and this detection signal is produced this protection feedback signal after rectification.
17. drive circuit of fluorescent tube as claimed in claim 16 is characterized in that switching on of this two semiconductor switch stops after this protection feedback signal is lower than this predetermined value and continues a schedule time.
18. drive circuit of fluorescent tube as claimed in claim 17 is characterized in that this controller also comprises a frequency generator, when this frequency generator is higher than this predetermined value in this protection feedback signal, operates in a first frequency; When this protection feedback signal is lower than this predetermined value, operate in a second frequency, wherein this second frequency is higher than this first frequency.
19. drive circuit of fluorescent tube as claimed in claim 18 is characterized in that this controller receives a dim signal, when this frequency generator operates in this first frequency, carries out light modulation according to the switching of this this two semiconductor switch of dim signal control.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101266558A CN101610630B (en) | 2008-06-17 | 2008-06-17 | Drive circuit of fluorescent tube |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101266558A CN101610630B (en) | 2008-06-17 | 2008-06-17 | Drive circuit of fluorescent tube |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101610630A CN101610630A (en) | 2009-12-23 |
| CN101610630B true CN101610630B (en) | 2012-08-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008101266558A Expired - Fee Related CN101610630B (en) | 2008-06-17 | 2008-06-17 | Drive circuit of fluorescent tube |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6827753B2 (en) * | 2016-09-28 | 2021-02-10 | ラピスセミコンダクタ株式会社 | Interface circuit |
| CN108966394B (en) * | 2017-05-22 | 2021-03-19 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system, IGBT drive control circuit and fault detection method thereof |
| CN108966396B (en) * | 2017-05-22 | 2021-03-19 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system, IGBT drive control circuit and fault detection method thereof |
| CN108966395B (en) * | 2017-05-22 | 2021-03-19 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system, IGBT drive control circuit and fault detection method thereof |
| CN108934095B (en) * | 2017-05-22 | 2021-07-13 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system, IGBT drive control circuit and fault detection method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2175510Y (en) * | 1993-09-03 | 1994-08-24 | 马继波 | Electronic ballast for fluorescent lamp |
| CN1242136A (en) * | 1996-10-24 | 2000-01-19 | 恩康股份有限公司 | A power control apparatus for lighting system |
| WO2001098853A1 (en) * | 2000-06-19 | 2001-12-27 | International Rectifier Corporation | Ballast control ic with minimal internal and external components |
-
2008
- 2008-06-17 CN CN2008101266558A patent/CN101610630B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2175510Y (en) * | 1993-09-03 | 1994-08-24 | 马继波 | Electronic ballast for fluorescent lamp |
| CN1242136A (en) * | 1996-10-24 | 2000-01-19 | 恩康股份有限公司 | A power control apparatus for lighting system |
| WO2001098853A1 (en) * | 2000-06-19 | 2001-12-27 | International Rectifier Corporation | Ballast control ic with minimal internal and external components |
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|---|---|
| CN101610630A (en) | 2009-12-23 |
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