CN102661585A - LED (Light-Emitting Diode) device with function of simultaneously detecting open circuit and short circuit and method thereof - Google Patents
LED (Light-Emitting Diode) device with function of simultaneously detecting open circuit and short circuit and method thereof Download PDFInfo
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Abstract
The invention discloses a LED (Light-Emitting Diode) device with a function of simultaneously detecting an open circuit and a short circuit and a method thereof. The LED device comprises a plurality of LED serial devices, a voltage converter, a current driving unit, a loop control unit, an open circuit detector, a short circuit detector and a voltage detector. The open circuit detector and the short circuit detector are respectively used for carrying out open circuit detection and short circuit detection on a plurality of LED serial devices. The voltage detector is coupled to the loop control unit, the open circuit detector and the voltage converter and is used for generating a reset signal to the short circuit detector according to an output voltage of the voltage converter when the open circuit occurs to a plurality of LED serial devices so as to carry out short circuit detection on the a plurality of LED serial devices again.
Description
The application be that September 2, application number in 2009 are 200910171752.3 the applying date, denomination of invention divides an application for the application for a patent for invention of " having the light-emitting diode assembly and the method thereof that detect open circuit and short-circuit function simultaneously ".
Technical field
The present invention relates to a kind of light-emitting diode assembly and method thereof, particularly relate to a kind of light-emitting diode assembly and method thereof that detects open circuit and short-circuit function simultaneously that have.
Background technology
(LED) is more and more general as the application of light emitting source with light emitting diode.For example, the backlight module of traditional display panels is that (cold cathode fluorescent lamp is CCFL) as light source with cathode fluorescent tube.Nowadays, along with the luminous efficiency of light emitting diode constantly promotes and cost reduces day by day, light emitting diode has and replaces the trend that cathode fluorescent tube is used as the backlight module light source gradually.
In existing LED driving circuit; If the light emitting diode serial is opened a way (LED open); Because the corresponding delivery channel of drive circuit is suspension joint (floating) state; Therefore drive circuit has the situation generation of electric leakage, and influences the conversion efficiency of integrated circuit, or causes the upset operation in voltage transitions loop.In addition; If the light emitting diode serial is short-circuited (LED short); The cross-pressure that is some light emitting diode is zero; The head space voltage of current drives assembly (headroom voltage) can improve accordingly, and the power consumption that causes consuming at the current drives assembly becomes big and the conversion efficiency of integrated circuit is descended.Therefore, LED driving circuit needs the mechanism and the method for open circuit and short-circuit detecting.
Please refer to Fig. 1, Fig. 1 is the sketch map of an existing LED driving circuit 10.LED driving circuit 10 is used for driving a light-emitting diode (LED) module 11.As shown in Figure 1, light-emitting diode (LED) module 11 includes the light emitting diode serial C1～Cm of parallel connection, and each light emitting diode serial is made up of the light emitting diode of a plurality of serial connections.LED driving circuit 10 includes an electric pressure converter 12, a current drives unit 13 and a circuit controls unit 14.Electric pressure converter 12 is used for converting an input voltage V1 to an output voltage V 2, with driven for emitting lights diode (led) module 11 according to a Control of Voltage signal VCTRL.Current drives unit 13 is used for drawing the fixing drive current Id1～Idm of size of current from light-emitting diode (LED) module 11.14 of circuit controls unit are according to the cathode voltage VHR1～VHRm of light emitting diode serial and the difference between a preset reference voltage VREF, and the voltage transitions operation of control electric pressure converter 12 is with the level of regulated output voltage V2.
Wherein, circuit controls unit 14 also includes a voltage selector 142, an error amplifier 144 and a switching controller 146.Voltage selector 142 is coupled to light emitting diode serial C1～Cm, is used for from the cathode voltage VHR1～VHRm of light emitting diode serial, selects a minimum voltage as a feedback voltage VFB.Error amplifier 144 is coupled to voltage selector 142 and reference voltage VREF, is used for difference according to feedback voltage VFB and reference voltage VREF, produces an error voltage signal VERR.Switching controller 146 is coupled to error amplifier 144 and electric pressure converter 12, then is used for according to error voltage signal VERR, produces Control of Voltage signal VCTRL.
Thus; LED driving circuit 10 can pass through circuit controls unit 14, and the cathode voltage VHR1～VHRm (being the head space voltage of current drives assembly) and the output voltage V 2 of electric pressure converter of light emitting diode serial is locked in a rational voltage range.
Under this situation, LED driving circuit 10 also includes an open circuit detector 15 and a short circuit detector 16, and being used for opens a way to light emitting diode serial C1～Cm respectively detects and short-circuit detecting.Because when open circuit takes place in the light emitting diode serial; The head space voltage of current drives assembly can be pulled to electronegative potential; Therefore whether open circuit detector 15 can be lower than a specific low critical voltage according to the cathode voltage VHR1～VHRm of light emitting diode serial, judges whether light emitting diode serial C1～Cm opens a way.Certainly, above-mentioned low critical voltage can not be higher than the head space voltage of the current drives assembly under the normal running, breaks in order to avoid under normal conditions, produce erroneous judgement.On the contrary; When the light emitting diode serial is short-circuited (cross-pressure that light emitting diode is arranged is zero); Because the head space voltage of current drives assembly can improve accordingly; Therefore short circuit detector 16 can judge whether light emitting diode serial C1～Cm is in short-circuit condition according to the cathode voltage VHR1～VHRm of light emitting diode serial whether greater than a specific high critical voltage.Likewise, above-mentioned high critical voltage can not be lower than the head space voltage of the current drives assembly under the normal running, breaks to avoid under normal conditions, producing erroneous judgement.
Yet, when simultaneously light emitting diode serial C1～Cm being opened a way and during short-circuit detecting, may the be short-circuited situation of erroneous judgement of LED driving circuit 10.For instance; When open circuit takes place in light emitting diode serial C1; Because the head space voltage of current drives assembly (for example: zero potential) can be pulled to electronegative potential; Therefore voltage selector 142 can select light emitting diode serial C1 cathode voltage VHR1 as feedback voltage VFB, and the output voltage V 2 of boosted voltage converter 12.Under this situation; Because the cross-pressure of light emitting diode size is fixing; Cathode voltage VHR2～the VHRm of other light emitting diode serial can raise along with output voltage V 2, and greater than above-mentioned specific high critical voltage, so will cause short circuit detector 16 that the situation of erroneous judgement takes place.
In other words, when simultaneously the light emitting diode string row is opened a way and to detect and during short-circuit detecting, prior art may have the situation generation of short circuit erroneous judgement immediately detecting after a certain light emitting diode serial opens a way.
Summary of the invention
Therefore, the object of the present invention is to provide a kind of light-emitting diode assembly and method thereof that detects open circuit and short-circuit function simultaneously that have.
The present invention also discloses a kind of light-emitting diode assembly that detects open circuit and short-circuit function simultaneously that has.This light-emitting diode assembly includes a plurality of light emitting diode serials, an electric pressure converter, a current drives unit, a circuit controls unit and an open circuit and a short circuit detector.Each light emitting diode serial of these a plurality of light emitting diode serials has an anodal and negative pole.This electric pressure converter is coupled to the positive pole of these a plurality of light emitting diode serials, is used for according to a Control of Voltage signal one first voltage transitions being become one second voltage.This current drives unit is coupled to the negative pole of these a plurality of light emitting diode serials, is used to provide a plurality of drive currents and gives these a plurality of light emitting diode serials.This circuit controls unit is coupled to this a plurality of light emitting diode serials and this electric pressure converter, is used for cathode voltage according to these a plurality of light emitting diode serials, produces this Control of Voltage signal.This open circuit and short circuit detector are coupled to these a plurality of light emitting diode serials, this circuit controls unit and this electric pressure converter; Be used for according to the cathode voltage of these a plurality of light emitting diode serials and the level variation tendency of this second voltage, these a plurality of light emitting diode string row opened a way detect and short-circuit detecting.
The present invention also discloses a kind of method that a light-emitting diode assembly detects open circuit and short circuit that is used for.This light-emitting diode assembly includes a plurality of light emitting diode serials and an electric pressure converter.Each light emitting diode serial of these a plurality of light emitting diode serials has an anodal and negative pole.This electric pressure converter is coupled to the positive pole of these a plurality of light emitting diode serials, is used for according to a Control of Voltage signal one first voltage transitions being become one second voltage.This method includes the cathode voltage according to these a plurality of light emitting diode serials, produces this Control of Voltage signal; And, these a plurality of light emitting diode string row are opened a way detect and short-circuit detecting according to the level variation tendency of cathode voltage and this second voltage of these a plurality of light emitting diode serials.
Description of drawings
Fig. 1 is the sketch map of an existing LED driving circuit.
Fig. 2 has the sketch map that detects a light-emitting diode assembly of open circuit and short-circuit function simultaneously for first embodiment of the invention.
Fig. 3 is used for the sketch map that a light-emitting diode assembly detects a flow process of open circuit and short circuit simultaneously for the embodiment of the invention.
Fig. 4 has explained that the embodiment of the invention after the light emitting diode serial is opened a way, restarts the situation of light emitting diode short-circuit detecting.
Fig. 5 has the sketch map that detects a light-emitting diode assembly of open circuit and short-circuit function simultaneously for second embodiment of the invention.
Fig. 6 is used for the sketch map that a light-emitting diode assembly detects a flow process of open circuit and short circuit simultaneously for the embodiment of the invention.
Fig. 7 has explained when open circuit or short circuit take place in the light emitting diode serial, the level variation tendency of the output voltage of its cathode voltage and electric pressure converter.
Wherein, description of reference numerals is following:
10 LED driving circuits
11 light-emitting diode (LED) modules
C1～Cm, the serial of Cx light emitting diode
12,21,51 electric pressure converters
13,22,52 current drives unit
14,23,53 circuit controls unit
VCTRL Control of Voltage signal
V1, V2 voltage
Id1～Idm drive current
VHR1～VHRm, VHRx cathode voltage
The VREF reference voltage
142,232,532 voltage selectors
144,234,534 error amplifiers
146,236,536 switching controllers
The VFB feedback voltage
VERR error voltage signal
15,24 open circuit detectors
16,25 short circuit detector
20,50 light-emitting diode assemblies
26 voltage detectors
RST replacement signal
30,60 flow processs
300～330,600～630 steps
54 open circuits and short circuit detector
The specific embodiment
Please refer to Fig. 2, Fig. 2 has the sketch map that detects a light-emitting diode assembly 20 of open circuit and short-circuit function simultaneously for first embodiment of the invention.Light-emitting diode assembly 20 includes light emitting diode serial C1～Cm, an electric pressure converter 21, a current drives unit 22, a circuit controls unit 23, an open circuit detector 24, a short circuit detector 25 and a voltage detector 26 of parallel connection.Electric pressure converter 21 is coupled to the positive pole of light emitting diode serial C1～Cm, is used for converting one first voltage V1 to one second voltage V2, with the stabilized driving voltage as light emitting diode serial C1～Cm according to a Control of Voltage signal VCTRL.Current drives unit 22 is coupled to the negative pole of light emitting diode serial C1～Cm, is used to provide the fixing drive current Id1～Idm of size of current and gives light emitting diode serial C1～Cm.Circuit controls unit 23 is coupled to light emitting diode serial C1～Cm and electric pressure converter 21, is used for cathode voltage VHR1～VHRm according to light emitting diode serial C1～Cm, produces Control of Voltage signal VCTRL.Open circuit detector 24 is coupled to light emitting diode serial C1～Cm and circuit controls unit 23, is used for cathode voltage VHR1～VHRm according to light emitting diode serial C1～Cm, to light emitting diode serial C1～Cm detection of opening a way.Short circuit detector 25 is coupled to light emitting diode serial C1～Cm and circuit controls unit 23, is used for cathode voltage VHR1～VHRm according to light emitting diode serial C1～Cm, and C1～Cm carries out short-circuit detecting to the light emitting diode serial.Voltage detector 26 is coupled to open circuit detector 24, short circuit detector 25 and electric pressure converter 26; Be used for when open circuit detector 24 detects light emitting diode serial C1～Cm open circuit takes place; Level according to the second voltage V2 changes; Produce a replacement signal RST to short circuit detector 25, to restart the short-circuit detecting of light emitting diode serial C1～Cm.
Therefore; When light-emitting diode assembly 20 is opened a way detection and short-circuit detecting to light emitting diode serial C1～Cm simultaneously; If light emitting diode serial C1～Cm opens a way; The embodiment of the invention can change according to the level of the second voltage V2, produces replacement signal RST to short circuit detector 25, to restart the short-circuit detecting of light emitting diode serial C1～Cm.Thus, the embodiment of the invention situation of erroneous judgement of can avoiding after light-emitting diode open-circuit, being short-circuited immediately.
Preferably, circuit controls unit 23 also includes a voltage selector 232, an error amplifier 234 and a switching controller 236.Voltage selector 232 is coupled to light emitting diode serial C1～Cm, is used for from cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm, selects a minimum voltage as a feedback voltage VFB.Error amplifier 234 is coupled to a voltage selector 232 and a reference voltage VREF, is used for difference according to feedback voltage VFB and reference voltage VREF, produces an error voltage signal VERR.Switching controller 236 is coupled to error amplifier 234 and electric pressure converter 21, is used for according to error voltage signal VERR, produces Control of Voltage signal VCTRL, with the voltage transitions operation of control electric pressure converter 21.About the detail operations of light-emitting diode assembly 20, please continue with reference to following explanation.
Please refer to Fig. 3, Fig. 3 is used for the sketch map that light-emitting diode assembly 20 detects a flow process 30 of open circuit and short circuit simultaneously for the embodiment of the invention.Flow process 30 is used for realizing an operating process of above-mentioned light-emitting diode assembly 20, and it includes the following step:
Step 300: beginning.
Step 310:, light emitting diode serial C1～Cm opened a way detect and short-circuit detecting according to cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm.
Step 320: when detecting light emitting diode serial C1～Cm open circuit takes place,, restart the short-circuit detecting of light emitting diode serial C1～Cm according to the level of the second voltage V2.
Step 330: finish.
According to flow process 30, the embodiment of the invention is at first according to cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm, light emitting diode serial C1～Cm opened a way detect and short-circuit detecting.When detecting light emitting diode serial C1～Cm open circuit take place; The embodiment of the invention further changes according to the level of the second voltage V2; Restart the short-circuit detecting of light emitting diode serial C1～Cm, with the situation of avoiding being short-circuited immediately and judging by accident after the light-emitting diode open-circuit.
Of prior art; Because when open circuit takes place in the light emitting diode serial; The cathode voltage of light emitting diode serial (being the head space voltage of current drives assembly) (for example: zero potential) can be pulled to electronegative potential; Therefore whether open circuit detector 24 can be lower than one first critical voltage according to cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm, judges whether light emitting diode serial C1～Cm opens a way.On the contrary; Because when the light emitting diode serial is short-circuited; The cathode voltage of light emitting diode serial can improve accordingly; Therefore short circuit detector 25 can judge whether light emitting diode serial C1～Cm the light-emitting diodes tube short circuit takes place according to cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm whether greater than one second critical voltage.Certainly, above-mentioned first critical voltage can not be higher than the head space voltage of the current drives assembly under the normal running, and second critical voltage can not be lower than the head space voltage of the current drives assembly under the normal running, breaks to avoid under normal conditions, producing erroneous judgement.
In addition, because voltage selector 232 can select to take place the cathode voltage of light emitting diode serial of open circuit as feedback voltage VFB, and the output voltage V 2 of boosted voltage converter 21.Therefore, whether the level that embodiment of the invention voltage detector 26 capable of using detects the second voltage V2 produces replacement signal RST, and restarts the short-circuit detecting of light emitting diode serial greater than one the 3rd critical value.
For instance, please refer to Fig. 4, Fig. 4 has explained that the embodiment of the invention after light emitting diode serial C1 opens a way, restarts the situation of light emitting diode short-circuit detecting.As shown in Figure 4; When open circuit takes place in light emitting diode serial C1; (for example: zero potential), so voltage selector 232 can select its cathode voltage VHR1 as feedback voltage VFB, and the output voltage V 2 of boosted voltage converter 21 because its cathode voltage VHR1 can be pulled to electronegative potential.When output voltage V 2 was higher than the 3rd critical value, voltage detector 26 produced replacement signal RST immediately, to restart the short-circuit detecting of light emitting diode.Simultaneously, circuit controls unit 23 also can carry out overvoltage protection to output voltage, output voltage V 2 is remained on a rational voltage range.
Certainly, embodiment of the invention flow process 30 also includes the following step: when detecting light emitting diode serial C1～Cm open circuit takes place, cut off the light emitting diode serial of open circuit and being electrically connected of circuit controls unit 23; And when detecting light emitting diode serial C1～Cm and be short-circuited, the light emitting diode serial of the cutting-off of short-circuit and being electrically connected of current drives unit 22.Aforesaid operations is a technology well-known to those skilled in the art, does not add to give unnecessary details in this.
In brief; When simultaneously the light emitting diode string row being opened a way detection and short-circuit detecting; Open a way if detect the light emitting diode serial; The embodiment of the invention can change according to the level of the second voltage V2, restarts the short-circuit detecting of light emitting diode serial C1～Cm, with the situation of avoiding being short-circuited and judging by accident.Thus, the embodiment of the invention can be improved prior art and can't be simultaneously the light emitting diode string row be opened a way and detect and the shortcoming of short-circuit detecting.
Please refer to Fig. 5, Fig. 5 has the sketch map that detects a light-emitting diode assembly 50 of open circuit and short-circuit function simultaneously for second embodiment of the invention.Light-emitting diode assembly 50 includes light emitting diode serial C1～Cm, an electric pressure converter 51, a current drives unit 52, a circuit controls unit 53 and an open circuit and short circuit detector 54 of parallel connection.Electric pressure converter 51, current drives unit 52 and circuit controls unit 53 are similar to electric pressure converter 21, current drives unit 22 and the circuit controls unit 23 among Fig. 2, do not add to give unnecessary details in this.Open circuit is coupled to light emitting diode serial C1～Cm, circuit controls unit 53 and electric pressure converter 51 with short circuit detector 54; Be used for level variation tendency according to the cathode voltage VHR1～VHRm and the second voltage V2 of light emitting diode serial C1～Cm, light emitting diode serial C1～Cm opened a way detect and short-circuit detecting.
Because the cross-pressure size of light emitting diode is constant; Therefore (any light-emitting diode open-circuit or short circuit promptly do not take place) under normal operation, cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm can have identical level variation tendency with the output voltage V 2 of electric pressure converter 51.Under this situation, when the level variation tendency of the cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm and the second voltage V2 not simultaneously, the open circuit that the embodiment of the invention can be carried out the light emitting diode serial according to this detects and short-circuit detecting.Thus, the embodiment of the invention also can be improved prior art and can't be simultaneously the light emitting diode string row be opened a way and detect and the shortcoming of short-circuit detecting.About the detail operations of light-emitting diode assembly 50, please continue with reference to following explanation.
Please refer to Fig. 6, Fig. 6 is used for the sketch map that light-emitting diode assembly 50 detects a flow process 60 of open circuit and short circuit simultaneously for the embodiment of the invention.Flow process 60 is used for realizing an operating process of light-emitting diode assembly 50, and it includes the following step:
Step 600: beginning.
Step 610:, produce Control of Voltage signal VCTRL according to cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm.
Step 620:, light emitting diode serial C1～Cm opened a way detect and short-circuit detecting according to the level variation tendency of the cathode voltage VHR1～VHRm and the second voltage V2 of light emitting diode serial C1～Cm.
Step 630: finish.
According to flow process 60, the embodiment of the invention produces Control of Voltage signal VCTRL at first according to cathode voltage VHR1～VHRm of light emitting diode serial C1～Cm.Then, the embodiment of the invention can be according to the level variation tendency of the cathode voltage VHR1～VHRm and the second voltage V2 of light emitting diode serial C1～Cm, light emitting diode serial C1～Cm is opened a way detect and short-circuit detecting.
In other words; After the voltage transitions loop is set up; Whether the embodiment of the invention can identical with the level variation tendency of the second voltage V2 by the cathode voltage VHR1～VHRm that detects light emitting diode serial C1～Cm, comes open a way detection and short-circuit detecting to light emitting diode serial C1～Cm.For instance, please refer to Fig. 7, Fig. 7 has explained when open circuit or short circuit take place light emitting diode serial Cx, the level variation tendency of the cathode voltage VHRx of light emitting diode serial Cx and the output voltage V 2 of electric pressure converter.As previously mentioned; When open circuit takes place in light emitting diode serial Cx; Its cathode voltage VHRx can be pulled to electronegative potential, and (for example: zero potential), and voltage selector 532 can select its cathode voltage VHRx as feedback voltage VFB, and the output voltage V 2 of boosted voltage converter 51.On the contrary, when light emitting diode serial Cx is short-circuited, i.e. the cross-pressure of some light emitting diode is zero among the light emitting diode serial Cx, and causes its cathode voltage VHRx therefore to be enhanced.
Therefore, descend, and during the level rising of the second voltage V2, open circuit can judge that with short circuit detector 54 light emitting diode serial Cx opens a way when detecting corresponding to the cathode voltage VHRx of light emitting diode serial Cx.On the contrary, rise when detecting corresponding to the cathode voltage VHRx of light emitting diode serial Cx, and the level of the second voltage V2 is when constant, then open circuit can judge that with short circuit detector 54 light emitting diode serial Cx is short-circuited.Thus, by this kind detection mode, the embodiment of the invention also can be improved prior art and can't be simultaneously the light emitting diode string row be opened a way and detect and the shortcoming of short-circuit detecting.
Certainly, embodiment of the invention flow process 60 also includes the following step: when detecting light emitting diode serial C1～Cm open circuit takes place, cut off the light emitting diode serial of open circuit and being electrically connected of circuit controls unit 53; And when detecting light emitting diode serial C1～Cm and be short-circuited, the light emitting diode serial of the cutting-off of short-circuit and being electrically connected of current drives unit 52 etc., it is the technology that this area tool is known the knowledgeable usually and known, and does not add to give unnecessary details in this.
Generally speaking, the method that the present invention provides light-emitting diode assembly to open a way detection and short-circuit detecting simultaneously produces the situation of short circuit erroneous judgement to avoid prior art after light-emitting diode open-circuit.
The above is merely preferred embodiment of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to covering scope of the present invention.
Claims (11)
1. one kind has the light-emitting diode assembly that detects open circuit and short-circuit function simultaneously, and this light-emitting diode assembly includes;
A plurality of light emitting diode serials, each light emitting diode serial have an anodal and negative pole;
One electric pressure converter is coupled to the positive pole of these a plurality of light emitting diode serials, is used for according to a Control of Voltage signal one first voltage transitions being become one second voltage;
One current drives unit is coupled to the negative pole of these a plurality of light emitting diode serials, is used to provide a plurality of drive currents and gives these a plurality of light emitting diode serials;
One circuit controls unit is coupled to this a plurality of light emitting diode serials and this electric pressure converter, is used for cathode voltage according to these a plurality of light emitting diode serials, produces this Control of Voltage signal; And
One open circuit and short circuit detector; Be coupled to these a plurality of light emitting diode serials, this circuit controls unit and this electric pressure converter; Be used for according to the cathode voltage of these a plurality of light emitting diode serials and the level variation tendency of this second voltage, these a plurality of light emitting diode string row opened a way detect and short-circuit detecting.
2. light-emitting diode assembly as claimed in claim 1; Wherein this open circuit and the short circuit detector cathode voltage corresponding to one first light emitting diode serial in detecting these a plurality of light emitting diode serials descends; And during the level rising of this second voltage, judge that this first light emitting diode serial opens a way.
3. light-emitting diode assembly as claimed in claim 2, wherein this open circuit and short circuit detector also are used for when open circuit takes place for this first light emitting diode serial, cut off being electrically connected of this first light emitting diode serial and this circuit controls unit.
4. light-emitting diode assembly as claimed in claim 1; Wherein this open circuit and the short circuit detector cathode voltage corresponding to one second light emitting diode serial in detecting these a plurality of light emitting diode serials rises; And the level of this second voltage judges that this second light emitting diode serial is short-circuited when constant.
5. light-emitting diode assembly as claimed in claim 4, wherein this open circuit and short circuit detector also are used for when this second light emitting diode serial is short-circuited, and cut off being electrically connected of this second light emitting diode serial and this current drives unit.
6. light-emitting diode assembly as claimed in claim 1, wherein this circuit controls unit includes:
One voltage selector is coupled to this light-emitting diode (LED) module, is used for from the cathode voltage of these a plurality of light emitting diode serials, selects a minimum voltage as a feedback voltage;
One error amplifier is coupled to this voltage selector and a reference voltage, is used for difference according to this feedback voltage and this reference voltage, produces an error voltage signal; And
One switching controller is coupled to this error amplifier and this electric pressure converter, is used for producing this Control of Voltage signal according to this error voltage signal.
7. one kind is used for the method that a light-emitting diode assembly detects open circuit and short circuit; This light-emitting diode assembly includes a plurality of light emitting diode serials and an electric pressure converter; Each light emitting diode serial of these a plurality of light emitting diode serials has an anodal and negative pole, and this electric pressure converter is coupled to the positive pole of these a plurality of light emitting diode serials, is used for according to a Control of Voltage signal; One first voltage transitions is become one second voltage, and this method includes:
According to the cathode voltage of these a plurality of light emitting diode serials, produce this Control of Voltage signal; And
According to the level variation tendency of cathode voltage and this second voltage of these a plurality of light emitting diode serials, these a plurality of light emitting diode string row are opened a way detect and short-circuit detecting.
8. method as claimed in claim 7 wherein according to the cathode voltage of this a plurality of light emitting diode serials and the level variation tendency of this second voltage, to the open a way step of detection and short-circuit detecting of these a plurality of light emitting diode string row, includes:
In detecting these a plurality of light emitting diode serials, descend, and during the level rising of this second voltage, judge that this first light emitting diode serial opens a way corresponding to the cathode voltage of one first light emitting diode serial.
9. method as claimed in claim 8; Wherein this light-emitting diode assembly also includes a circuit controls unit; Be coupled to this a plurality of light emitting diode serials and this electric pressure converter; Be used for cathode voltage according to these a plurality of light emitting diode serials, produce this Control of Voltage signal, this method also comprises:
When open circuit takes place for this first light emitting diode serial, cut off being electrically connected of this first light emitting diode serial and this circuit controls unit.
10. method as claimed in claim 7 wherein according to the cathode voltage of this a plurality of light emitting diode serials and the level variation tendency of this second voltage, to the open a way step of detection and short-circuit detecting of these a plurality of light emitting diode string row, includes:
In detecting these a plurality of light emitting diode serials, rise, and the level of this second voltage judges that this second light emitting diode serial is short-circuited when constant corresponding to the cathode voltage of one second light emitting diode serial.
11. method as claimed in claim 10; Wherein this light-emitting diode assembly also includes a current drives unit; Be coupled to the negative pole of these a plurality of light emitting diode serials, be used to provide a plurality of drive currents and give these a plurality of light emitting diode serials, this method also includes:
When this second light emitting diode serial is short-circuited, cut off being electrically connected of this second light emitting diode serial and this current drives unit.
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| CN2012101360113A CN102661585A (en) | 2009-09-02 | 2009-09-02 | LED (Light-Emitting Diode) device with function of simultaneously detecting open circuit and short circuit and method thereof |
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| CN2012101360113A CN102661585A (en) | 2009-09-02 | 2009-09-02 | LED (Light-Emitting Diode) device with function of simultaneously detecting open circuit and short circuit and method thereof |
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| CN2009101717523A Division CN102003689B (en) | 2009-09-02 | 2009-09-02 | Light-emitting diode device with function of simultaneously detecting open circuit and short circuit and method thereof |
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| CN104125694A (en) * | 2013-04-28 | 2014-10-29 | 深圳市海洋王照明工程有限公司 | Method and device for testing LED driving power supply output short-circuit protection defects |
| CN106604458A (en) * | 2016-12-07 | 2017-04-26 | 武汉精立电子技术有限公司 | Constant current source driving device and method capable of detecting open and short circuit of LED lamp string |
| CN108983453A (en) * | 2018-07-26 | 2018-12-11 | 武汉天马微电子有限公司 | Detection device, detection jig and the display module of backlight module |
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| CN111712018A (en) * | 2020-06-30 | 2020-09-25 | 深圳市创新微源半导体有限公司 | Multichannel LED drive circuit with open-circuit fault detection function |
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Application publication date: 20120912 |