CN1670590A - Feedback sampling control circuit for tube driving systems - Google Patents
Feedback sampling control circuit for tube driving systems Download PDFInfo
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- CN1670590A CN1670590A CN 200410030433 CN200410030433A CN1670590A CN 1670590 A CN1670590 A CN 1670590A CN 200410030433 CN200410030433 CN 200410030433 CN 200410030433 A CN200410030433 A CN 200410030433A CN 1670590 A CN1670590 A CN 1670590A
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Abstract
This invention relates to feedback sample control circuit used in one lamp driving system, which comprises one switch device and one current valid value-sampling controller. The switch device is coupled to the lamp driving system feedback route. The current valid value sample controller can control the switch through the voltage or current signals from one end of the lamp and also can control the real sampling valid value in the feedback controller of the lamp driving system to minimize the stray capacity current in the current valid value.
Description
Technical field
The present invention is relevant for a kind of lamp-tube driving system, and particularly about a kind of converter circuit that is used for driving the discharge lamp of display panels, it has backfeed loop in order to the adjusting lamp tube current of flowing through.
Background technology
Discharge lamp, particularly cold cathode fluorescent lamp pipe (cold cathode fluorescent lamp; CCFL), have high-level efficiency and advantage cheaply, therefore be used in widely in the display panels (LCD panel), as the light source of back light system.Converter circuit system is used to drive this kind cold cathode fluorescent lamp pipe, and it can supply a high exciting voltage when lamp tube starting, and will supply voltage be lowered into a less running voltage after lamp tube starting.
Fig. 1 is a kind of schematic circuit diagram of known technology lamp-tube driving system.One transverter 10 mainly comprises an one drive circuit 12 and a transformer 14.Driving circuit 12 can convert direct supply to AC signal, after boosting via transformer 14 again, produces an AC power and is supplied to a fluorescent tube 20.Herein, the output voltage of transverter 10 is V
OUT, and output current is I
OUT
In order accurately to control the brightness of fluorescent tube 20, and the brightness of fluorescent tube is directly proportional with the lamp tube current of flowing through haply, is equipped with the foundation that current feedback loop is regulated as lamp current in the lamp-tube driving system.Usually, backfeed loop utilizes a pulse-length modulation (pulse-width modulation; PWM) controller 16, according to the electric current I of taking a sample from transformer 14 secondary sides
OUT, produce a feedback control signal to driving circuit 12, use the duty cycle (duty cycle or duty cycle) of control Driver Circuit 12, reach the purpose of the average output current of adjusting transverter 10.
Yet, as shown in Figure 1, because fluorescent tube 20 itself promptly has potential stray capacitance (inherentparasitic capacitance) C
1, and fluorescent tube 20 also can have cloth electric capacity (distributed straycapacitance) C that dives between (panel housing) from any high-pressure side (fluorescent tube) to earth terminal when being assembled to the housing of LCD panel
21, C
22... C
2n, these stray capacitances can cause leakage current I respectively
1With I
2Hence one can see that, in the lamp-tube driving system of Fig. 1, and the electric current I that transverter 10 is exported
OUTBe not that actual flow is through lamp tube current I
L, and be lamp current I
LWith leakage current I
1, I
2Summation.
Stray capacitance system increases with the length of fluorescent tube, and stray capacitance is big more, and then leakage current is high more, wherein again with leakage current I
2Influence bigger.In addition, when fluorescent tube 20 was assembled to the housing of LCD panel, assembling tolerance slightly promptly can cause the cloth electric capacity difference of diving greatly.In the generalized case, leakage current I
2May be up to the output current I of transverter 10
OUT30% to 50% do not wait.
Please refer to Fig. 2, associated voltage in the lamp-tube driving system circuit of its displayed map 1 and current signal waveform figure.Because fluorescent tube is a resistive load, its electric current I
LBe voltage V with the fluorescent tube high-pressure side
OUTHomophase, and leakage current I
1, I
2Then with voltage V
OUTHave differing of 90 degree.Therefore, electric current I
OUTWith voltage V
OUTBetween differ between 0 to 90 the degree.
In the lamps known tube driving system of Fig. 1, a kind of feedback sample mode is shown in Fig. 2 (d), in electric current I
OLTOne section utmost point of peak point P1 take a sample in the short time, and another kind of feedback sample mode is shown in Fig. 2 (e), in electric current I
OUTWhole positive half cycle take a sample.No matter adopt which kind of mode, the electric current of being taken a sample all comprises the leakage current of significant proportion, can't obtain actual flow through lamp tube current I
LTherefore, this kind feedback controling mode can't be guaranteed the accurate control of brightness, produce tangible lighting tube brightness difference.
In order to improve above-mentioned shortcoming, can use the shown another kind of known technology lamp-tube driving system of Fig. 3.In the circuit of Fig. 3, be that the low pressure end with fluorescent tube 20 forms backfeed loop as feedback point, in this kind situation, the sampling current that PWM controller 16 is received is I
L+ I
1Though can eliminate leakage current I
2Influence, but this kind mode still can't be with the actual current I of accurate way sampling fluorescent tube
LAnd, in the design of many LCD panels, do not allow to use the mode of this kind by the low pressure end sampling feedback of fluorescent tube.Therefore, wait that still the feedback control technology that develops other solves this problem.
Summary of the invention
The object of the present invention is to provide a kind of feedback sample control circuit that is used for lamp-tube driving system, it can not be subjected to the influence of fluorescent tube stray capacitance, and the sampling lamp tube current of flowing through exactly, and feedback path need not be connected to the low pressure end of fluorescent tube.
Feedback sample control circuit of the present invention is used for a lamp-tube driving system with transverter and feedback controller.Feedback controller can export transverter to and produce a feedback control signal according to the sampling current from a feedback point in the lamp-tube driving system, is supplied to the AC power of a fluorescent tube with the adjusting transverter.
First kind of aspect of feedback sample control circuit of the present invention comprises: a switchgear is electrically coupled between feedback controller and the feedback point; One current effective value sampling controller, be electrically coupled to the high-pressure side and the switchgear of fluorescent tube, voltage according to the fluorescent tube high-pressure side produces a sampling control signal, with the switching of gauge tap device, make the stray capacitance electric current composition of feedback controller from the current effective value that sampling current receives reduce to minimum.
Second kind of aspect of feedback sample control circuit of the present invention comprises: a switchgear is electrically coupled between feedback controller and the feedback point; One capacity load is electrically coupled between the high-pressure side and ground connection of fluorescent tube; An and current effective value sampling controller, be electrically coupled to capacity load and switchgear, electric current according to the capacity load of flowing through produces a sampling control signal, with the switching of gauge tap device, make the stray capacitance electric current composition of feedback controller from the current effective value that sampling current receives reduce to minimum.
According to this kind structure, the stray capacitance electric current composition in the current effective value can be similar to zero or equal zero.In other words, the feedback controller current effective value of taking a sample can be similar to or equal lamp current.Therefore, can be under need not be with the situation of fluorescent tube low pressure end as feedback point, effectively reduce of the influence of the caused leakage current of fluorescent tube stray capacitance,, improve the problem of lighting tube brightness difference in the known technology circuit to guarantee the accurate control of lamp current to feedback controller.
Description of drawings
Fig. 1 is a kind of schematic circuit diagram of known technology lamp-tube driving system;
Fig. 2 has shown associated voltage and the current signal waveform figure in the lamp-tube driving system circuit of Fig. 1;
Fig. 3 is the schematic circuit diagram of another kind of known technology lamp-tube driving system;
Fig. 4 is the schematic circuit diagram of the lamp-tube driving system of the feedback sample control circuit of use the present invention first concrete example;
Fig. 5 has shown first kind of example circuit of the current effective value sampling controller of Fig. 4;
Associated voltage and current signal waveform figure when Fig. 6 has shown the current effective value sampling controller that uses Fig. 5 in the lamp-tube driving system of Fig. 4;
Fig. 7 has shown second kind of example circuit of the current effective value sampling controller of Fig. 4;
Associated voltage and current signal waveform figure when Fig. 8 has shown the current effective value sampling controller that uses Fig. 7 in the lamp-tube driving system of Fig. 4;
Fig. 9 is the schematic circuit diagram of the lamp-tube driving system of the feedback sample control circuit of use the present invention second concrete example;
Figure 10 has shown first kind of example circuit of the current effective value sampling controller of Fig. 9;
Associated voltage and current signal waveform figure when Figure 11 has shown the current effective value sampling controller that uses Figure 10 in the lamp-tube driving system of Fig. 9;
Figure 12 has shown second kind of example circuit of the current effective value sampling controller of Fig. 9;
Associated voltage and current signal waveform figure when Figure 13 has shown the current effective value sampling controller that uses Figure 12 in the lamp-tube driving system of Fig. 9;
Figure 14 has shown the third example circuit of the current effective value sampling controller of Fig. 9;
Associated voltage and current signal waveform figure when Figure 15 has shown the current effective value sampling controller that uses Figure 14 in the lamp-tube driving system of Fig. 9;
Figure 16 is the schematic circuit diagram of the lamp-tube driving system of the feedback sample control circuit that uses the present invention's first concrete example, and it is that low pressure end with fluorescent tube is as feedback point; And
Figure 17 is the schematic circuit diagram of the lamp-tube driving system of the feedback sample control circuit that uses the present invention's second concrete example, and it is that low pressure end with fluorescent tube is as feedback point.
Embodiment
For more understanding technology contents of the present invention, be described as follows especially exemplified by several preferred embodiment.
Fig. 4 is the schematic circuit diagram of the lamp-tube driving system of the feedback sample control circuit of use the present invention first concrete example.
In the lamp-tube driving system of Fig. 4, a transverter 100 mainly comprises an one drive circuit 120 and a transformer 140.Driving circuit 120 can convert direct supply to AC signal, after boosting via transformer 140 again, produces an AC power and is supplied to a fluorescent tube 200.Herein, the output voltage of transverter 100 is V
OUT, and output current is I
OUTOne PWM controller 160 can be according to the sampling current I from transformer 140 secondary sides
OUTAnd produce a feedback control signal to driving circuit 120, use the output of regulating transverter 100.As described in the previously known technology, because fluorescent tube has stray capacitance C
1And C
21, C
22... C
2n, so electric current I
OUTTo comprise a lamp current composition I
LAn and stray capacitance electric current composition I
1+ I
2Feedback sample control circuit of the present invention is to make PWM controller 160 only at sampling current I
OUTIn a current effective value take a sample the stray capacitance electric current composition I in this current effective value
1+ I
2Reduce to minimum, even can eliminate fully, only stay lamp current composition I
L
According to first concrete example of the present invention, the feedback sample control circuit comprises a switch 170 and a current effective value sampling controller 180.Switch 170 is arranged in the feedback path of lamp-tube driving system, that is, be coupled between the secondary side and PWM controller 160 of transformer 140.According to this kind structure, the sampling current I that when switch 170 is opened, is flow through only
OUTThe side is a current effective value.The input end of current effective value sampling controller 180 is coupled to the high-pressure side of fluorescent tube 200, and output terminal then is coupled to switch 170, and it can be according to the voltage V of fluorescent tube 200 high-pressure sides
OUT, and produce a sampling control signal to switch 170, the switching of gauge tap 170.
On real the work, for example can use a MOS transistor as switch 170.
First kind of example circuit of current effective value sampling controller 180 is shown among Fig. 5, comprises a voltage divider 182 and a voltage peak detection circuit 184, and its function mode will cooperate the associated voltage of Fig. 6 and current signal waveform figure to be described as follows.
At first, the voltage V of fluorescent tube 200 high-pressure sides
OUTSuitably carry out dividing potential drop via voltage divider 182.Then, detect its positive peak point by voltage peak detection circuit 184, that is, voltage V detected
OUTPositive peak point P2.When voltage peak detection circuit 184 detected positive peak, it exported a logic high voltage signal as sampling control signal, makes switch open; Otherwise, then export a logic low voltage signals as sampling control signal, switch cuts out.In view of the above, at voltage V
OUTOne section utmost point short time Δ T of positive peak point P2 in, switch 170 is opened, and PWM controller 160 can be taken a sample.That is, the electric current I of this moment
OUTBe current effective value.
With reference to the waveform of Fig. 6, because the leakage current I of the stray capacitance of flowing through
1+ I
2Phase-lead voltage V
OUTPhase place 90 degree, so voltage V
OUTPositive peak point P2 just corresponding to leakage current I
1+ I
2Zero point.Hence one can see that, in the utmost point short time at positive peak point P2 place Δ T, and leakage current I
1+ I
2Approach zero, therefore can make the stray capacitance electric current composition in the current effective value reduce to minimum.In other words, PWM controller 160 current effective value of being taken a sample is similar to lamp current I
L
Second kind of example circuit of current effective value sampling controller 180 is shown among Fig. 7, comprises the accurate testing circuit 186 of a voltage divider 182 and a voltage direct current position, and its function mode will cooperate the associated voltage of Fig. 8 and current signal waveform figure to be described as follows.
At first, the voltage V of fluorescent tube 200 high-pressure sides
OUTSuitably carry out dividing potential drop via voltage divider 182.Then, the accurate testing circuit 186 in signal feed voltage direct current position after the dividing potential drop compares with a reference voltage level.If the voltage signal of feed-in is higher than reference voltage level, then accurate testing circuit 186 outputs in voltage direct current position one logic high voltage signal makes switch open as sampling control signal; Otherwise, then export a logic low voltage signals as sampling control signal, switch cuts out.
According to this kind mode, with reference to the waveform of Fig. 8, at voltage V
OUTBe higher than a predetermined voltage V
TThe time, that is, the time T between a P3 and P4
1+ T
2In, switch 170 is opened, and makes the PWM controller 160 can be at the leakage current I of stray capacitance
1+ I
2Identical time (the T of point two end
1=T
2) in take a sample.Therefore, in time T
1+ T
2In, the stray capacitance electric current composition I in the current effective value
1+ I
2Equal zero.In other words, PWM controller 160 current effective value of being taken a sample just equals lamp current I
L
Fig. 9 is the schematic circuit diagram of the lamp-tube driving system of the feedback sample control circuit of use the present invention second concrete example.In the lamp-tube driving system of Fig. 9, transverter 100 is identical with structure and Fig. 4 of PWM controller 160, so repeat no more.
According to second concrete example of the present invention, the feedback sample control circuit comprises a switch 170, a capacitor C
3An and current effective value sampling controller 190.Switch 170 is arranged in the feedback path of lamp-tube driving system, that is, be coupled between the secondary side and PWM controller 160 of transformer 140.Be same as the circuit of Fig. 4, only the sampling current I that when switch 170 is opened, is flow through
OUTThe side is a current effective value.Capacitor C
3Be coupled between the high-pressure side and ground connection of fluorescent tube 200, so that from electric current I
OUTDerive an electric current I
3, its phase place is same as the phase place of stray capacitance electric current.The input end of current effective value sampling controller 190 is coupled to capacitor C
3, output terminal then is coupled to switch 170, and it can be according to the capacitor C that flows through
3Electric current I
3, and produce a sampling control signal to switch 170, the switching of gauge tap 170.
Be different from first concrete example, in second concrete example, the electric current I that transverter 100 is exported
OUTBe lamp current I
L, condenser current I
3And stray capacitance electric current I
1, I
2Summation.
First kind of example circuit of current effective value sampling controller 190 is shown among Figure 10, comprises a current zero testing circuit 194, and its function mode will cooperate the associated voltage of Figure 11 and current signal waveform figure to be described as follows.
Current zero testing circuit 194 detects the capacitor C of flowing through
3Electric current I
3By on the occasion of the zero point that transfers negative value to, when detecting zero point, it exports a logic high voltage signal as sampling control signal, makes switch open; Otherwise, then export a logic low voltage signals as sampling control signal, switch cuts out.In view of the above, in electric current I
3Zero point P5 one section utmost point short time Δ T in, switch 170 is opened, and PWM controller 160 can be taken a sample.That is, the electric current I of this moment
OUTBe current effective value.
With reference to the waveform of Figure 11, because the capacitor C of flowing through
3Electric current I
3Phase-lead voltage V
OUTPhase place 90 degree, that is, with the leakage current I of the stray capacitance of flowing through
1, I
2So homophase is electric current I
3P5 at zero point be leakage current I
1, I
2Zero point.Hence one can see that, in one section utmost point short time Δ T at P5 place at zero point, and electric current I
1, I
2With I
3Approach zero, therefore the current effective value that PWM controller 160 is taken a sample is similar to lamp current I
L
Second kind of example circuit of current effective value sampling controller 190 is shown among Figure 12, comprises the accurate testing circuit 196 in an electric current absolute value position, and its function mode will cooperate the associated voltage of Figure 13 and current signal waveform figure to be described as follows.
The accurate testing circuit 196 in electric current absolute value position detects the capacitor C of flowing through
3Electric current I
3Electric current position standard, work as electric current I
3The electric current position accurate descend and absolute value less than a predetermined value I
TThe time, it exports a logic high voltage signal as sampling control signal, makes switch open; Otherwise, then export a logic low voltage signals as sampling control signal, switch cuts out.
According to this kind mode, with reference to the waveform of Figure 13, in electric current I
3From I
TDrop to-I
TDuring, that is, the time T between a P6 and P7
1+ T
2In, switch 170 is opened, and makes the PWM controller 160 can be at the leakage current I of stray capacitance
1+ I
2Identical time (the T of point two end
1=T
2) in take a sample.Therefore, in time T
1+ T
2In, electric current I
1, I
2With I
3Equal zero.In other words, PWM controller 160 current effective value of being taken a sample just equals lamp current I
L
The third example circuit of current effective value sampling controller 190 is shown in Figure 14, comprises an electric current slope detection circuit 198, and its function mode will cooperate the associated voltage of Figure 15 and current signal waveform figure to be described as follows.
Electric current slope detection circuit 198 detects the capacitor C of flowing through
3Electric current I
3The slope of waveform is worked as electric current I
3Slope greater than a predetermined value S
TThe time, it exports a logic high voltage signal as sampling control signal, makes switch open; Otherwise, then export a logic low voltage signals as sampling control signal, switch cuts out.
According to this kind mode, with reference to the waveform of Figure 154, the time T between a P8 and P9
1+ T
2In, switch 170 is opened, and makes the PWM controller 160 can be at the leakage current I of stray capacitance
1+ I
2Identical time (the T of point two end
1=T
2) in take a sample.Therefore, in time T
1+ T
2In, electric current I
1, I
2With I
3Equal zero.In other words, PWM controller 160 current effective value of being taken a sample just equals lamp current I
L
In the lamp-tube driving system of above-mentioned Fig. 4 and Fig. 9, though be that a node (being an end of transformer 140 second siding rings) with the output terminal of transverter 100 is as feedback point, right feedback sample control circuit of the present invention also can be applicable to in the lamp-tube driving system of fluorescent tube 200 low pressure ends as feedback point, and reaches effect as hereinbefore.。
With reference to Figure 16 and 17, it in the lamp-tube driving system of fluorescent tube 200 low pressure ends as feedback point, uses the feedback sample control circuit of the present invention's first concrete example and second concrete example respectively.In the circuit of Figure 16 and 17, switch 170 is coupled between the low pressure end and PWM controller 160 of fluorescent tube 200, utilizes it to switch the current effective value of controlling sampling.Because its operating principle and Fig. 4 and Fig. 9 are similar, so do not repeat them here.
Above-mentioned concrete example only is illustrative principle of the present invention and effect thereof, but not is used to limit the scope of the invention.Any be familiar with present technique field person all can be under know-why of the present invention and spirit, concrete example is made an amendment and changes.The scope of the present invention claim as described later is described.
Claims (31)
1. feedback sample control circuit that is used for lamp-tube driving system, this lamp-tube driving system comprises a converter circuit, being used for a direct current power source conversion is an AC power, and be supplied to a fluorescent tube, and comprise a feedback controller, be used for according to regulating this converter circuit from the sampling current of a feedback point, this sampling current comprises a lamp current composition and a stray capacitance electric current composition, and this feedback sample control circuit comprises:
One switchgear is electrically coupled between this feedback controller and this feedback point; And
One current effective value sampling controller, be used for a voltage or the current signal of basis from the high-pressure side of this fluorescent tube, and control the switching of this switchgear, use this feedback controller of control from the current effective value that this sampling current receives, make that the stray capacitance electric current composition in this current effective value reduces to minimum.
2. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 1 is characterized in that this current effective value sampling controller is the voltage according to the high-pressure side of this fluorescent tube, and controls the switching of this switchgear.
3. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 1, it is characterized in that, this feedback sample control circuit comprises a capacitor again, it is electrically coupled between the high-pressure side and a ground connection of this fluorescent tube, and this current effective value sampling controller, be according to the electric current of this capacitor of flowing through, and control the switching of this switchgear.
4. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 1 is characterized in that, this stray capacitance comprises the potential stray capacitance of this fluorescent tube itself.
5. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 1 is characterized in that, this stray capacitance comprise fluorescent tube and arround latent cloth electric capacity between the object.
6. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 1 is characterized in that this feedback controller is a Pwm controller.
7. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 1 is characterized in that this feedback point is one of the output terminal of this a transverter node.
8. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 1 is characterized in that this feedback point is the low pressure end of this fluorescent tube.
9. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 1 is characterized in that this transverter comprises an one drive circuit and a transformer.
10. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 9 is characterized in that, this feedback point is an end of this transformer secondary lateral coil.
11. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 2 is characterized in that this current effective value sampling controller comprises a voltage peak detection circuit.
12. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 2 is characterized in that, this current effective value sampling controller comprises the accurate testing circuit in a voltage direct current position.
13. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 3 is characterized in that this current effective value sampling controller comprises a current zero testing circuit.
14. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 3 is characterized in that, this current effective value sampling controller comprises the accurate testing circuit in an electric current absolute value position.
15. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 3 is characterized in that, the current effective value sampling controller comprises an electric current slope detection circuit.
16. feedback sample control circuit that is used for lamp-tube driving system, this lamp-tube driving system comprises a converter circuit, being used for a direct current power source conversion is an AC power, and be supplied to a fluorescent tube, and comprise a feedback controller, be used for producing a feedback control signal and export this transverter to according to sampling current from a feedback point, to regulate the AC power that this transverter is supplied, this sampling current comprises a lamp current composition and a stray capacitance electric current composition, and this feedback sample control circuit comprises:
One switchgear is electrically coupled between this feedback controller and this feedback point, and it is subjected to the control of a sampling control signal and switches;
One current effective value sampling controller, be electrically coupled to high-pressure side and this switchgear of this fluorescent tube, voltage signal according to this fluorescent tube high-pressure side, and produce this sampling control signal, by the switching of this switchgear of control, and make the stray capacitance electric current composition of this feedback controller from the current effective value that this sampling current receives reduce to minimum.
17. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 16 is characterized in that, this feedback point is a node of the output terminal of this transverter.
18. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 16 is characterized in that this feedback point is the low pressure end of this fluorescent tube.
19. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 16 is characterized in that this current effective value sampling controller comprises a voltage peak detection circuit.
20. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 19, it is characterized in that, utmost point when the peak value of the voltage signal that detects this fluorescent tube high-pressure side is in the short time, and this current effective value sampling controller produces this sampling control signal, and this switchgear is opened.
21. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 16 is characterized in that, this current effective value sampling controller comprises the accurate testing circuit in a voltage direct current position.
22. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 21, it is characterized in that, when the voltage signal that detects this fluorescent tube high-pressure side was higher than a predetermined level, this current effective value sampling controller produced this sampling control signal, and this switchgear is opened.
23. feedback sample control circuit that is used for lamp-tube driving system, this lamp-tube driving system comprises a converter circuit, being used for a direct current power source conversion is an AC power, and be supplied to a fluorescent tube, and comprise a feedback controller, be used for producing a feedback control signal and export this transverter to according to sampling current from a feedback point, to regulate the AC power that this transverter is supplied, this sampling current comprises a lamp current composition and a stray capacitance electric current composition, and this feedback sample control circuit comprises:
One switchgear is electrically coupled between this feedback controller and this feedback point, and it is to be subjected to the control of a sampling control signal and to switch;
One capacity load is electrically coupled between the high-pressure side and a ground connection of this fluorescent tube; And
One current effective value sampling controller, be electrically coupled to this capacity load and this switchgear, current signal according to this capacity load of flowing through, and produce this sampling control signal, by the switching of this switchgear of control, and make the stray capacitance electric current composition of this feedback controller from the current effective value that this sampling current receives reduce to minimum.
24. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 23 is characterized in that this feedback point is one of the output terminal of this a transverter node.
25. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 23 is characterized in that this feedback point is the low pressure end of this fluorescent tube.
26. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 23 is characterized in that this current effective value sampling controller comprises a current zero testing circuit.
27. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 26, it is characterized in that, utmost point when the zero point of the current signal that detects this capacity load of flowing through is in the short time, this current effective value sampling controller produces this sampling control signal, and this switchgear is opened.
28. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 23 is characterized in that, this current effective value sampling controller comprises the accurate testing circuit in an electric current absolute value position.
29. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 28, it is characterized in that, when the absolute value of the current signal that detects this capacity load of flowing through is lower than a predetermined level, this current effective value sampling controller produces this sampling control signal, and this switchgear is opened.
30. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 23 is characterized in that, the current effective value sampling controller comprises an electric current slope detection circuit.
31. the feedback sample control circuit that is used for lamp-tube driving system as claimed in claim 30, it is characterized in that, when the slope of the current signal that detects this capacity load of flowing through is higher than a predetermined slope, this current effective value sampling controller produces this sampling control signal, and this switchgear is opened.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200410030433A CN100585465C (en) | 2004-03-19 | 2004-03-19 | The feedback sample control circuit that is used for lamp-tube driving system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200410030433A CN100585465C (en) | 2004-03-19 | 2004-03-19 | The feedback sample control circuit that is used for lamp-tube driving system |
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| Publication Number | Publication Date |
|---|---|
| CN1670590A true CN1670590A (en) | 2005-09-21 |
| CN100585465C CN100585465C (en) | 2010-01-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200410030433A Expired - Fee Related CN100585465C (en) | 2004-03-19 | 2004-03-19 | The feedback sample control circuit that is used for lamp-tube driving system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101467491B (en) * | 2006-06-09 | 2011-02-16 | 奥斯兰姆有限公司 | Circuit unit |
| CN113973411A (en) * | 2020-07-22 | 2022-01-25 | 斯坦雷电气株式会社 | Lighting control device and lighting device |
-
2004
- 2004-03-19 CN CN200410030433A patent/CN100585465C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101467491B (en) * | 2006-06-09 | 2011-02-16 | 奥斯兰姆有限公司 | Circuit unit |
| CN113973411A (en) * | 2020-07-22 | 2022-01-25 | 斯坦雷电气株式会社 | Lighting control device and lighting device |
| CN113973411B (en) * | 2020-07-22 | 2024-03-08 | 斯坦雷电气株式会社 | Lighting control device and lighting device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100585465C (en) | 2010-01-27 |
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