CN101594723A - Backlight drive circuit - Google Patents
Backlight drive circuit Download PDFInfo
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- CN101594723A CN101594723A CN 200910145619 CN200910145619A CN101594723A CN 101594723 A CN101594723 A CN 101594723A CN 200910145619 CN200910145619 CN 200910145619 CN 200910145619 A CN200910145619 A CN 200910145619A CN 101594723 A CN101594723 A CN 101594723A
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Abstract
Backlight drive circuit, comprise a transformer, this transformer has first output, second output, the 3rd output and the 4th output, and these outputs are sampled respectively and produce first sample signal, second sample signal, the 3rd sample signal and the 4th sample signal; One circuit for detecting comprises: the first detecting node, the second detecting node, and the 3rd detecting node; And decision circuitry; be electrically connected to this circuit for detecting, when one abnormality took place these outputs, these detecting nodes produced at least one differential detecting signal; this decision circuitry is carried out a protection operation according to this at least one differential detecting signal, to protect this backlight drive circuit.The present invention has simple circuit configuration and low static power consumption.The circuit for detecting that it adopts circuit type to connect takes place when unusual simultaneously as more than one output, and these detecting nodes can produce at least one differential detecting signal and make backlight drive circuit execute protection operation according to this.
Description
Technical field
The invention relates to a kind of backlight drive circuit, and particularly relevant for a kind of backlight drive circuit with protective circuit.
Background technology
In recent years, along with the size of display panels constantly increases, the backlight drive circuit that comprises a plurality of fluorescent tubes is applied to provide display panels required high-quality light source more widely.
See also Fig. 1.Fig. 1 is the schematic diagram of backlight drive circuit 1 in the prior art.As shown in Figure 1, backlight drive circuit 1 comprises power module 10 and transformer 12, and backlight drive circuit 1 is in order to promote four groups of fluorescent tubes 14.Transformer 12 is driven with the required electric energy of supply fluorescent tube 14 by power module 10.This sentences one and pushes away four transformer 12 and four groups of fluorescent tubes 14 are example, and in the practical application, backlight drive circuit 1 can further comprise a plurality of transformers 12 with the more fluorescent tubes 14 of correspondence.
Because the lighting tube brightness of many fluorescent tubes backlight drive circuit is relevant with the lamp current of this fluorescent tube of flowing through; therefore; the difficult problem that many fluorescent tubes backlight drive circuit is faced how to comprise equiulbrium flow through each lamp tube current avoiding the phenomenon of each lighting tube brightness inequality, and problems such as circuit protection mechanism when the circuit of many fluorescent tubes back light system is short-circuited abnormalities such as fault, open fault or electric arc (arc) fault.So in traditional backlight drive circuit, need further couple the protection circuit for detecting at the output of transformer usually.
Please refer to Fig. 2, Fig. 2 is for having short-circuit protection in the prior art and feedbacking the schematic diagram of backlight drive circuit 2 of protection circuit for detecting 26 of compensation.As shown in Figure 2, in traditional backlight drive circuit that is installed in double-sided PCB 2, transformer 22 comprises two time coils (220a, 220b), and the two ends of inferior coil further couple with separately protection circuit for detecting 26 respectively.In protection circuit for detecting 26 among Fig. 2, whether the voltage of measuring point A can be measured less than a default value to judge whether short circuit.Measuring point B can be used to judge starting resistor (kick-off voltage) value of fluorescent tube 24; the magnitude of voltage of measuring point B can be used as the back coupling signal of power module 20, and the voltage that provides with adjustment power module 20 also can be in order to start the defencive function of backlight drive circuit 2.
In above-mentioned backlight drive circuit 2; must use quite a lot of capacitance component and resistor assembly to form protection circuit for detecting 26; and protection circuit for detecting 26 also needs further connection judgment module (not shown), the voltage of measuring point A, B is judged and then reached the effect of short-circuit protection and voltage back coupling compensation.Thus; each group one pushes away in four the backlight drive circuit; promptly need four groups of protection circuit for detecting 26 independent of each other and judge module, relative complex and bring bigger static power consumption (staticpower consumption) concerning hardware space design.
In prior art, also there is another kind of backlight drive circuit to adopt the differential signal mode to form protective circuit.See also Fig. 3, Fig. 3 is for having the schematic diagram of the backlight drive circuit 3 of the protection circuit for detecting that forms in differential mode in the prior art.For instance, as shown in Figure 3, inferior coil 320a can distinguish at two ends output drive signal to fluorescent tube 34a and fluorescent tube 34b, according to the interchange output characteristic of transformer 32, time coil 320a exports two drive signals of fluorescent tube 34a and fluorescent tube 34b to herein, and phase place is opposite each other for it.
Two drive signals based on inferior coil 320a output are the opposite characteristic of phase place, backlight drive circuit 3 is provided with simple sample circuit 36 (illustrating the capacitance partial pressure circuit among Fig. 3 is example) respectively to obtain two sample signal at two outputs of inferior coil 320a, further two sample signal is coupled to detecting node D1 subsequently.In normal operation, two sample signal can cancel each other out on the contrary because of phase place, so detecting node D1 can remain on low level (representative is normal).When one of them such as breaks down at abnormal case as fluorescent tube 34a or fluorescent tube 34b, one of them sample signal changes, two sample signal no longer by chance cancel each other out, the current potential of detecting node D1 is changed, and decision circuitry 38 can change by the current potential of detecting node D1 judges that abnormal case takes place for fluorescent tube 34a or fluorescent tube 34b.
On the other hand, also has corresponding circuit structure at the two ends of inferior coil 320b.Backlight drive circuit 3 can utilize the abnormal conditions of detecting node D2 corresponding detecting fluorescent tube 34c or fluorescent tube 34d.By the characteristic that anti-phase signal can be cancelled each other, only get final product the circuit practical application of corresponding four outputs with two groups of simple circuit for detecting.
But in backlight drive circuit 3, if fluorescent tube 34a and fluorescent tube 34b (or fluorescent tube 34c and fluorescent tube 34d) break down simultaneously (fault for example all is short-circuited).At this moment, will cause two sample signal to change simultaneously, and then can't bring into play the effect of differential detecting, detecting node D1 (or detecting node D2) still remains on low level (representative is normal) and causes erroneous judgement.
Summary of the invention
The present invention proposes a kind of backlight drive circuit, it has the differential protection circuit that forms the loop, to address the above problem.
Category of the present invention is to provide a kind of backlight drive circuit, and it is in order to drive a plurality of backlights, and backlight drive circuit comprises transformer, circuit for detecting and decision circuitry.Decision circuitry is electrically connected to circuit for detecting.
According to a specific embodiment, transformer has first output, second output, the 3rd output and the 4th output, these outputs are in order to each self-driven one of them these backlight, and these outputs are sampled respectively and produce first sample signal, second sample signal, the 3rd sample signal and the 4th sample signal, wherein between first and second sample signal phase place opposite, second with the 3rd sample signal between between opposite, the 3rd and the 4th sample signal of phase place phase place opposite.
In this embodiment, circuit for detecting comprises the first detecting node, the second detecting node and the 3rd detecting node.The first detecting node is coupled to first sample signal and second sample signal; The second detecting node is coupled to second sample signal and the 3rd sample signal; The 3rd detecting node is coupled to the 3rd sample signal and the 4th sample signal.
When these output generation abnormalities, these detecting nodes produce at least one differential detecting signal, and decision circuitry is according to this at least one differential detecting signal execute protection operation, to protect this backlight drive circuit.
Compared to prior art, the sample signal that backlight drive circuit of the present invention is opposite with phase place is coupled to each other, and to form the circuit for detecting of differential mode, it has simple circuit configuration and low static power consumption.The circuit for detecting that it adopts circuit type to connect takes place when unusual simultaneously as more than one output, and these detecting nodes can produce at least one differential detecting signal, make backlight drive circuit execute protection operation according to this.
Can be further understood by following execution mode and accompanying drawing about the advantages and spirit of the present invention.
Description of drawings
Fig. 1 is the schematic diagram of backlight drive circuit in the prior art.
Fig. 2 is for having short-circuit protection in the prior art and feedbacking the schematic diagram of backlight drive circuit of protection circuit for detecting of compensation.
Fig. 3 is for having the schematic diagram of the backlight drive circuit of the protection circuit for detecting that forms in differential mode in the prior art.
Fig. 4 is the schematic diagram of backlight drive circuit in the present invention's first specific embodiment.
Fig. 5 A is the detailed circuit schematic of backlight drive circuit in the present invention's second specific embodiment.
Fig. 5 B is the schematic diagram of backlight drive circuit in the present invention's the 3rd specific embodiment.
Fig. 6 is the schematic diagram of backlight drive circuit in the present invention's the 4th specific embodiment.
Embodiment
See also Fig. 4.Fig. 4 is the schematic diagram of backlight drive circuit 5 in the present invention's first specific embodiment.As shown in Figure 4, backlight drive circuit 5 comprises power module 50, transformer 52, circuit for detecting 54 and decision circuitry 58.In this embodiment, backlight drive circuit 5 is in order to promote four groups of backlights (6a, 6b, 6c, 6d), in the practical application, backlight drive circuit 5 pairing backlight numbers can be decided according to the hardware designs demand, not pushing away four with one exceeds, that is to say that backlight drive circuit 5 can be used for various one to be pushed away in many back lighting devices.
In this embodiment, power module 50 is in order to provide the alternating voltage input.Transformer 52 comprises main coil 520, for the first time coil 522 and coil 524 for the second time.Main coil 520 electrically connects with power module 50, and the alternating voltage input is by main coil 520.For the first time coil 522 and the corresponding respectively main coil 520 of coil 524 and respond to the alternating voltage input for the second time.
In this embodiment, transformer 52 has four outputs (first output 5220, second output 5222, the 3rd output 5240, the 4th output 5242).As shown in Figure 4, in the coiling of transformer 52 design, with the first time coil 522 anode be electrically connected to first output 5220 and negative terminal be electrically connected to second output 5222; On the other hand, with the second time coil 524 anode be electrically connected to the 3rd output 5240 and the 4th output 5242.Be noted that during above-mentioned four outputs were arranged, any two adjacent outputs had opposite phases to each other.
As shown in Figure 4, first output 5220, second output 5222, the 3rd output 5240 and the 4th output 5242 can be electrically connected to four backlights (6a, 6b, 6c, 6d) respectively and provide stable power to supply with, in order to drive corresponding separately backlight respectively.
In this simultaneously, first output 5220, second output 5222, the 3rd output 5240 and the 4th output 5242 in this backlight drive circuit 5 also are electrically connected to a sample circuit 56 respectively, for instance, the capacitance partial pressure circuit that the internal circuit configuration of sample circuit 56 can be among Fig. 4 to be illustrated in practical application.Four capacitance partial pressure circuit (sample circuit 56) produce first sample signal, second sample signal, the 3rd sample signal and the 4th sample signal in order to the output of corresponding transformer 52 respectively.
First sample signal herein, second sample signal, the 3rd sample signal and the 4th sample signal system produce first output 5220, second output 5222, the 3rd output 5240 and 5242 samplings of the 4th output respectively.Therefore, phase place is opposite between first sample signal and second sample signal; Phase place is opposite between second sample signal and the 3rd sample signal; Phase place is opposite between the 3rd sample signal and the 4th sample signal.In addition, also be that phase place is opposite between first sample signal and the 4th sample signal.
In this embodiment, circuit for detecting 54 comprises the first detecting node D1, the second detecting node D2 and the 3rd detecting node D3.Each detecting node system sees through two capacitors and is coupled to wherein two sample signal of these sample signal respectively, and opposite this of phase place wherein two sample signal forms an addition current potential in this detecting node.For example in this embodiment, the first detecting node D1 sees through isolation capacitance respectively and is coupled to first sample signal and second sample signal.The second detecting node D2 sees through isolation capacitance respectively and is coupled to second sample signal and the 3rd sample signal.The 3rd detecting node D3 sees through isolation capacitance respectively and is coupled to the 3rd sample signal and the 4th sample signal.Wherein, two sample signal that phase place is opposite can form the addition current potential respectively on each detecting node.
When these output operate as normal, each output driven separately during backlight just, on each detecting node because of two opposite sample signal of phase place cancel each other out, so the addition current potential is stable at electronegative potential.
What need pay special attention to is, when these output generation abnormalities, wherein the addition current potential of at least one detecting node will thereby change and produces at least one differential detecting signal.In practical application, abnormality herein can be the pairing backlight of these outputs be short-circuited fault, open fault or arc fault.
In this embodiment, decision circuitry 58 electrically connects with circuit for detecting 54.After abnormality generation and circuit for detecting 54 generation differential detecting signals, the decision circuitry 58 in the backlight drive circuit 5 can be according to this at least one differential detecting signal execute protection operation.
In this embodiment, the protection operation that decision circuitry 58 is carried out can be alternating voltage input or the direct powered-down module 50 of adjusting power module 50, with protection backlight drive circuit 5.
In practical application; decision circuitry 58 can comprise comparator; comparator and these detecting nodes electrically connect; comparator receives the differential detecting signal that circuit for detecting 54 produces; and with the voltage quasi position and the accurate bit comparison of reference voltage of differential detecting signal; if the voltage quasi position of differential detecting signal is greater than the accurate position of reference voltage, then decision circuitry 58 execute protections operation.The circuit structure of comparator and actual be well known to those of ordinary skill in the art as flowing mode, do not give unnecessary details in addition at this.
Below the example that takes place for three abnormalities illustrates differential detecting effect of the present invention.In the example that first abnormality takes place, the fault if first output, 5220 pairing backlight 6a are short-circuited, this moment first sample signal thereby change.At this moment, on the first detecting node, first sample signal can't be cancelled out each other with second sample signal, and therefore the addition current potential of the first detecting node D1 no longer is stable at electronegative potential.At this moment, the variation of the addition current potential of the first detecting node D1 just can form a differential detecting signal.
In the example that second abnormality takes place, if abnormality takes place second output, 5222 pairing backlight 6b.At this moment, cause second sample signal changes and then can't cancel out each other with first sample signal, the 3rd sample signal, addition current potential thereby the change of win the detecting node D1 and the second detecting node D2 will be made, thereby, to form two differential detecting signals at the first detecting node D1 respectively altogether with the second detecting node D2, to react the abnormality of backlight 6b.
In the example that the 3rd abnormality takes place, if abnormality takes place all simultaneously for first output 5220 and second output, 5222 pairing backlights.At this moment, will form the differential detecting signal respectively with on the second detecting node D2 of second output 5222 and the 3rd output 5240.That is to say that even abnormality takes place adjacent a plurality of outputs simultaneously, backlight drive circuit 5 of the present invention also can be detected and the execute protection operation.
In this embodiment, the sample signal that backlight drive circuit is opposite with phase place is coupled to each other, and the circuit for detecting that loop (open loop) mode connects is opened in formation.It adopts circuit for detecting, takes place simultaneously when unusual as more than one output, and these detecting nodes can produce at least one differential detecting signal, makes backlight drive circuit execute protection operation according to this.
See also Fig. 5 A.Fig. 5 A for backlight drive circuit 5 in the present invention's second specific embodiment ' detailed circuit schematic.See also Fig. 4, be with the maximum difference of first specific embodiment, the backlight drive circuit 5 in second specific embodiment ' further comprise be arranged at circuit for detecting 54 ' and decision circuitry 58 ' between a plurality of diode filters 57 '.Each these detecting node and diode filter 57 ' electric connections, diode filter 57 ' can be in order to the negative potential part of filtering differential detecting signal, with the judgment processing of convenient follow-up differential detecting signal.
On the other hand, in second embodiment, decision circuitry 58 ' in further comprise logical circuit 580 ', rectification circuit 582 ' and comparator 584 '.Logical circuit 580 ' electrically connect with these detecting nodes wherein, this at least one differential detecting signal of logical circuit 580 ' reception is to produce total detection signal.Rectification circuit 582 ' carry out rectification with logical circuit 580 ' electric connection and to total detection signal.Comparator 584 ' with this rectification circuit 582 ' electric connection; comparator 584 ' reception is through total detection signal of rectification; and with the voltage quasi position and the accurate bit comparison of reference voltage of total detection signal; if the voltage quasi position of total detection signal is greater than the accurate position of reference voltage, then decision circuitry 58 ' execute protection operation.
See also Fig. 5 B.Fig. 5 B is backlight drive circuit 5 in the present invention's the 3rd specific embodiment " schematic diagram.See also Fig. 5 A, be with the maximum difference of second specific embodiment, backlight drive circuit 5 in the 3rd specific embodiment " in; backlight drive circuit 5 " comprises and be arranged at circuit for detecting 54 " and decision circuitry 58 " between a plurality of resistors 57 "; backlight drive circuit 5 " in each these detecting node see through resistor 57 " ground connection; resistor 57 " can be in order to promote the voltage quasi position of differential detecting signal, the differential detecting signal can be increased to the voltage quasi position of forward, with the judgment processing of convenient follow-up differential detecting signal.
Fig. 5 A and Fig. 5 B are that the thin circuit structure embodiment of portion at backlight drive circuit is described further, and the start principle of other assembly of backlight drive circuit is to the start method is roughly similar to previous first specific embodiment in detail, so do not give unnecessary details in addition at this.
See also Fig. 6.Fig. 6 is the schematic diagram of backlight drive circuit 7 in the present invention's the 4th specific embodiment.Backlight drive circuit 7 comprises power module 70, transformer 72, circuit for detecting 74 and decision circuitry 78.In this embodiment, backlight drive circuit 7 also can be with the maximum difference of previous embodiment in order to promote four groups of backlights (8a, 8b, 8c, 8d), further comprises the 4th detecting node D4 in the circuit for detecting 74 of backlight drive circuit 7.The 4th detecting node D4 is coupled to the 4th opposite sample signal of phase place and first sample signal.By this, four corresponding respectively being coupled between any two adjacent outputs of detecting node are to form the differential detecting circuit of loop circuit (close loop).Decision circuitry 78 can be judged according to the differential detecting signal that four detecting nodes (D1, D2, D3, D4) are produced, and then execute protection operation when abnormality takes place.The thin portion of other of backlight drive circuit 7 is provided with the previous described embodiment of the present invention roughly the same, sees also first to the 3rd specific embodiment, does not give unnecessary details in addition at this.
In the circuit for detecting of the loop circuit of this embodiment, if single output takes place unusually arbitrarily, then circuit for detecting 74 has two detecting nodes and produces the differential detecting signal.On the other hand, unusual if two or three adjacent outputs take place, circuit for detecting 74 has two detecting nodes and produces the differential detecting signal.That is to say; backlight drive circuit 7 in this embodiment is when abnormal conditions take place; the circuit for detecting 74 of backlight drive circuit 7 can produce plural differential detecting signal; decision circuitry 78 can be designed to according to two differential detecting signals and the execute protection operation, and the precision when judging the differential detecting signal is improved.
In the foregoing description, it is example that backlight drive circuit of the present invention pushes away four drive circuit structure with one, but the present invention is as limit, and backlight drive circuit of the present invention pushes away in many back lighting devices applicable to various one in practical application.
Compared to prior art, backlight drive circuit of the present invention is coupled to each other the sample signal of single spin-echo, To form the circuit for detecting of differential mode, it has simple circuit structure and low static power consumption. Its The circuit for detecting that adopts circuit type to connect, as more than one output simultaneously during abnormal, these The detecting node can produce at least one differential detecting signal, makes according to this execute protection operation of backlight drive circuit.
Claims (16)
1. backlight drive circuit is characterized in that comprising:
One transformer, this transformer has first output, second output, the 3rd output and the 4th output, these outputs are in order to each self-driven backlight, these outputs are sampled respectively and produce first sample signal, second sample signal, the 3rd sample signal and the 4th sample signal, wherein between this first sample signal and this second sample signal between opposite, this second sample signal of phase place and the 3rd sample signal between opposite, the 3rd sample signal of phase place and the 4th sample signal phase place opposite;
One circuit for detecting comprises:
The first detecting node, this first detecting node is coupled to this first sample signal and this second sample signal;
The second detecting node, this second detecting node is coupled to this second sample signal and the 3rd sample signal; And
The 3rd detecting node, the 3rd detecting node is coupled to the 3rd sample signal and the 4th sample signal; And
Decision circuitry; be electrically connected to this circuit for detecting, when one abnormality took place these outputs, these detecting nodes produced at least one differential detecting signal; this decision circuitry is carried out a protection operation according to this at least one differential detecting signal, to protect this backlight drive circuit.
2. backlight drive circuit as claimed in claim 1 is characterized in that this backlight drive circuit further comprises a power module, and in order to alternating voltage input to be provided, wherein this transformer further comprises:
Main coil electrically connects with this power module, and this alternating voltage input is by this main coil;
Coil for the first time, corresponding to this main coil and respond to this alternating voltage input, this, two ends of coil were electrically connected to this first output and this second output respectively first time; And
Coil for the second time, corresponding to this main coil and respond to this alternating voltage input, this, two ends of coil were electrically connected to the 3rd output and the 4th output respectively second time.
3. backlight drive circuit as claimed in claim 2 is characterized in that this protection is operating as this alternating voltage input of adjustment or closes this power module.
4. backlight drive circuit as claimed in claim 1, it is characterized in that this first output, this second output, the 3rd output and the 4th output are electrically connected to a capacitance partial pressure circuit respectively, these capacitance partial pressure circuit are respectively in order to produce this first sample signal, this second sample signal, the 3rd sample signal and the 4th sample signal.
5. backlight drive circuit as claimed in claim 1, it is characterized in that each these detecting nodes see through two capacitors and are coupled to wherein two sample signal of these sample signal respectively, opposite this of phase place wherein two sample signal forms an addition current potential in this detecting node.
6. backlight drive circuit as claimed in claim 5, it is characterized in that when these output operate as normal, these addition current potentials all are stable at an electronegative potential, when one abnormality took place these outputs, these detecting nodes wherein this addition current potential of at least one detecting node changed and this at least one differential detecting signal of generation.
7. backlight drive circuit as claimed in claim 5 is characterized in that each these detecting node further electrically connects with a diode filter, and this diode filter is in order to the negative potential part of this differential detecting signal of filtering;
Perhaps, each these detecting node further sees through a resistance-grounded system, and this resistor is in order to promote the voltage quasi position of this differential detecting signal.
8. backlight drive circuit as claimed in claim 1 is characterized in that this decision circuitry comprises:
Comparator; electrically connect with these detecting nodes; this comparator receives this at least one differential detecting signal; and voltage quasi position and the accurate bit comparison of a reference voltage that will this at least one differential detecting signal; if the voltage quasi position of this at least one differential detecting signal is greater than the accurate position of this reference voltage, then this decision circuitry is carried out this protection operation.
9. backlight drive circuit as claimed in claim 1 is characterized in that this decision circuitry comprises:
Logical circuit electrically connects with these detecting nodes, and this logical circuit receives this at least one differential detecting signal, to produce a total detection signal;
Rectification circuit electrically connects with this logical circuit, and this rectification circuit carries out rectification to this total detection signal; And
Comparator; electrically connect with this rectification circuit, this comparator receives this total detection signal through rectification, and voltage quasi position and the accurate bit comparison of a reference voltage that will this total detection signal; if the voltage quasi position of this total detection signal is greater than the accurate position of this reference voltage, then this decision circuitry is carried out this protection operation.
10. backlight drive circuit as claimed in claim 1 is characterized in that this circuit for detecting further comprises one the 4th detecting node, and the 4th detecting node is coupled to the 4th sample signal and this first sample signal.
11. backlight drive circuit as claimed in claim 10, it is characterized in that each these detecting nodes see through two capacitors and are coupled to wherein two sample signal of these sample signal respectively, opposite this of phase place wherein two sample signal forms an addition current potential in this detecting node.
12. backlight drive circuit as claimed in claim 11, it is characterized in that when these output operate as normal, these addition current potentials all are stable at an electronegative potential, when one abnormality took place these outputs, these detecting nodes wherein this addition current potential of at least one detecting node changed and this at least one differential detecting signal of generation.
13. backlight drive circuit as claimed in claim 11 is characterized in that each these detecting node further electrically connects with a diode filter, this diode filter is in order to the negative potential part of this differential detecting signal of filtering;
Perhaps, each these detecting node further sees through a resistance-grounded system, and this resistor is in order to promote the voltage quasi position of this differential detecting signal.
14. backlight drive circuit as claimed in claim 10 is characterized in that this decision circuitry comprises:
Comparator; electrically connect with these detecting nodes; this comparator receives this at least one differential detecting signal; and voltage quasi position and the accurate bit comparison of a reference voltage that will this at least one differential detecting signal; if the voltage quasi position of this at least one differential detecting signal is greater than the accurate position of this reference voltage, then this decision circuitry is carried out this protection operation.
15. backlight drive circuit as claimed in claim 10 is characterized in that this decision circuitry comprises:
Logical circuit electrically connects with these detecting nodes, and this logical circuit receives this at least one differential detecting signal, to produce a total detection signal;
Rectification circuit electrically connects with this logical circuit, and this rectification circuit carries out rectification to this total detection signal; And
Comparator; electrically connect with this rectification circuit, this comparator receives this total detection signal through rectification, and voltage quasi position and the accurate bit comparison of a reference voltage that will this total detection signal; if the voltage quasi position of this total detection signal is greater than the accurate position of this reference voltage, then this decision circuitry is carried out this protection operation.
16. backlight drive circuit as claimed in claim 1 is characterized in that a short trouble, an open fault or the arc fault of this abnormality for pairing these backlights of these outputs.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 200910145619 CN101594723B (en) | 2009-05-15 | 2009-05-15 | Backlight driving circuit |
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|---|---|---|---|
| CN 200910145619 CN101594723B (en) | 2009-05-15 | 2009-05-15 | Backlight driving circuit |
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| CN101594723A true CN101594723A (en) | 2009-12-02 |
| CN101594723B CN101594723B (en) | 2013-01-09 |
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| CN 200910145619 Expired - Fee Related CN101594723B (en) | 2009-05-15 | 2009-05-15 | Backlight driving circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111477182A (en) * | 2019-01-23 | 2020-07-31 | 纬联电子科技(中山)有限公司 | Display device and power-off control method thereof |
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| JPH09129382A (en) * | 1995-10-17 | 1997-05-16 | Internatl Business Mach Corp <Ibm> | Detector and information processing system for anomaly in discharge tube circuit |
| CN101340767B (en) * | 2007-07-04 | 2012-01-04 | 青岛海信电器股份有限公司 | Protection circuit and liquid crystal screen having the protection circuit |
| CN101360379B (en) * | 2007-08-03 | 2013-05-08 | 奇美电子股份有限公司 | Light source protection circuit and application thereof in backlight module unit and LCD |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111477182A (en) * | 2019-01-23 | 2020-07-31 | 纬联电子科技(中山)有限公司 | Display device and power-off control method thereof |
| CN111477182B (en) * | 2019-01-23 | 2022-03-04 | 纬联电子科技(中山)有限公司 | Display device and power-off control method thereof |
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