CN101605416A - LED driving circuit and controller thereof - Google Patents
LED driving circuit and controller thereof Download PDFInfo
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- CN101605416A CN101605416A CNA2008101112827A CN200810111282A CN101605416A CN 101605416 A CN101605416 A CN 101605416A CN A2008101112827 A CNA2008101112827 A CN A2008101112827A CN 200810111282 A CN200810111282 A CN 200810111282A CN 101605416 A CN101605416 A CN 101605416A
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Abstract
The invention discloses a kind of LED driving circuit and controller thereof, traditional balanced balanced current LED driving circuit does not have functions such as light modulation, protection.LED driving circuit of the present invention is exported current potential detection signal into end according to the controlled end of semiconductor switch and first, second, judges whether the driving of light-emitting diode has unusually, whether starts protection mechanism with decision; And can accept the control of the dim signal of any pattern, use the brightness of adjusting light-emitting diode.
Description
Technical field
The present invention relates to a kind of LED driving circuit and controller thereof of being used for, particularly relate to the LED driving circuit and the controller thereof of a kind of tool light modulation and unusual feedback function.
Background technology
Light-emitting diode (Light Emitting Diode, LED) fluorescent tube that mainly throws light on compared to present conduct, advantages such as life-span length, power saving, low-voltage driving, safety, environmental protection are arranged, when especially being applied to the light source of panel of LCD (LCD panel) backlight module, its color saturation is far above cold cathode fluorescent lamp (the Cold Cathode Fluorescent Lamp of present main flow, CCFL), and have environmental protection (not mercurous) concurrently, conform with harmful substance fully and limit the use of (Restriction of Hazardous Substances, standard ROHS).Therefore, numerous manufacturers there's no one who doesn't or isn't endeavour to research and develop in the hope of replace other lighting source with light-emitting diode.
As shown in Figure 1, be the schematic circuit diagram of traditional current balance type (Current Balancing) LED driving circuit.One input power supply AC through one exchange change direct current transducer 30 and change into a direct current voltage VDD earlier after, change into required driving voltage Vin through the direct current transducer 40 that circulates always again, to offer LED driving circuit.Wherein, this interchange commentaries on classics direct current is changed 30 devices and is comprised a bridge rectifier (figure does not show), should import power supply AC and convert a direct current voltage VDD to, by the switching regulator change-over circuit in the DC-DC transducer 40 (figure does not show) this direct voltage VDD step-down be become driving voltage Vin again.This LED driving circuit has comprised a light-emitting diode (LED) module 10 and a current balancing device 20.Light-emitting diode (LED) module 10 by a plurality of light-emitting diodes parallel connection and being in series, and in order to make the brightness convergence unanimity of each string light-emitting diode, need by current balancing device 20, the current balance type that each string light-emitting diode is flow through is consistent and reach and be close to identical brightness.Current balancing device 20 reaches the current balance type effect with the framework of current mirror, and the adjustment by resistance R and control flows are through the size of current of each light-emitting diode (electric current I=(VDD-VG)/R, VG is the grid voltage of semiconductor switch).
Traditional current balance type LED driving circuit there is no protection mechanism; circuit is if having unusual; for example: but short circuit, open circuit, surpass opereating specification etc., and the current balance type LED driving circuit still can continue running and cause unnecessary power loss or circuit to damage.And traditional current balance type LED driving circuit also can't provide dimming function, can't cooperate demand to some application scenario (for example: backlight module), so also restriction to some extent on using.
Summary of the invention
In view of this, the invention provides the LED driving circuit of functions such as a kind of tool light modulation and unusual feedback signal, according to the detection signal of light-emitting diode, judge whether the driving of light-emitting diode has unusually, start protection mechanism and decommission or indicating device; And can accept the control of the dim signal of any pattern, adjust the brightness of light-emitting diode.
To achieve these goals, the invention provides a kind of LED driving circuit, comprise a change-over circuit, at least one current control unit, at least one current detecting unit and a driving control unit.Above-mentioned change-over circuit couples an input power supply to convert a direct current output signal to drive a light-emitting diode (LED) module.Each this current control unit has a controlled pin position, the pin position is gone in one first output and the pin position is gone in one second output, and this first output is gone into the pin position and coupled this light-emitting diode (LED) module.Each this current detecting unit correspondence couples this second output of each this current control unit and goes into the pin position, to produce at least one detection signal.Above-mentioned driving control unit couples this controlled pin position, this first output of this current control unit and goes into pin position and this current detecting unit, this driving control unit is adjusted the level of the controlled pin position of this corresponding current control unit based on this detection signal, and the current stabilization that makes this light-emitting diode (LED) module of flowing through is near a predetermined current value.Wherein, above-mentioned driving control unit ends this corresponding current control unit when arbitrary this first output is gone into the pin position and is higher than one first predetermined level.
To achieve these goals, the present invention also provides another kind of LED driving circuit, comprises a change-over circuit, at least one current control unit, at least one current detecting unit and a driving control unit.Above-mentioned change-over circuit couples an input power supply to convert a direct current output signal to drive a light-emitting diode (LED) module.Each this current control unit has a controlled pin position, the pin position is gone in one first output and the pin position is gone in one second output, and this first output is gone into the pin position and coupled this light-emitting diode (LED) module.Each this current detecting unit correspondence couples this second output of each this current control unit and goes into the pin position, to produce at least one detection signal.Above-mentioned driving control unit couples this controlled pin position, this first output of this current control unit and goes into pin position and this current detecting unit, this driving control unit is adjusted the level of the controlled pin position of this corresponding current control unit based on this detection signal, and the current stabilization that makes this light-emitting diode (LED) module of flowing through is near a predetermined current value.Wherein, above-mentioned driving control unit is sent a rub-out signal when arbitrary this first output is gone into the pin position and is higher than one first predetermined level.
Described LED driving circuit, wherein, described rub-out signal is by this corresponding current control unit.
Described LED driving circuit, wherein, described change-over circuit comprises:
One transformer has a primary side and a primary side, and this primary side couples this input power supply, and this primary side produces this direct-flow output signal through a rectification unit;
One switches switches set, couples this primary side of this transformer, in order to according to a control signal switched conductive and a cut-off state;
One output capacitance couples this primary side of this transformer, with the noise of this direct-flow output signal of filtering;
One voltage detection unit couples this primary side of this transformer, produces a voltage detection signal according to this direct-flow output signal; And
One primary side control unit produces this control signal according to this voltage detection signal, and this direct-flow output signal is stable near the predeterminated voltage value.
Described LED driving circuit, wherein, described change-over circuit comprises:
One inductance couples this input power supply;
One switches switch, couples this inductance, in order to according to a control signal switched conductive and a cut-off state;
One rectification unit, an end couple coupling a little of this inductance and this diverter switch, and the other end couples this light-emitting diode (LED) module;
One output capacitance couples coupling a little of this rectification unit and this light-emitting diode (LED) module, so that this direct-flow output signal to be provided;
One voltage detection unit couples one of these light-emitting diode (LED) module two ends, and produces a voltage detection signal according to the level that couples this end; And
One TCU transfer control unit produces this control signal according to this voltage detection signal, makes this end level equalization that this voltage detection unit detects near a predeterminated voltage value.
Described LED driving circuit, wherein, each this current control unit comprises:
One current lens unit, comprise a plurality of semiconductor switchs, each semiconductor switch has a controlled end, end is gone in one first output and end is gone in one second output, these controlled ends are coupled to each other with as this controlled pin position, and these first outputs are gone into end and coupled this light-emitting diode (LED) module and these second output and go into end and all be coupled to this corresponding current detecting unit; And
One selected cell, end is gone in these first outputs that couple these semiconductor switchs, and a level signal of selecting these first outputs to go into end exports this driving control unit to.
Described LED driving circuit, wherein, described driving control unit receives a conducting pick-off signal, and ends this at least one current control unit according to this conducting pick-off signal.
Described LED driving circuit, wherein, described driving control unit detects this at least one controlled pin position in the time beyond this at least one current control unit, when this at least one controlled pin position arbitrary is lower than one second predetermined level, send this rub-out signal.
Described LED driving circuit, wherein, described driving control unit detects and should at least one second output go into the pin position, arbitraryly continues to be lower than one the 3rd predetermined level above after the scheduled time length time in what the pin position was gone in this at least one second output, sends this rub-out signal.
Described LED driving circuit, wherein, described driving control unit also receives a direct current dim signal, and exports a pulse-width signal in view of the above.
To achieve these goals, the present invention also provides a kind of LED driving circuit controller, to control a LED driving circuit driven for emitting lights diode (led) module, this LED driving circuit controller comprises an electric current regulation and control unit and a signal processing unit.Above-mentioned electric current regulation and control unit produces an electric current adjustment signal according to a current detection signal in order to the size of current of indicating a light-emitting diode (LED) module, to control a power switch that is series at this light-emitting diode (LED) module, make this current detection signal level equalization near a predeterminated voltage value.Above-mentioned signal processing unit detects one of this power switch and this light-emitting diode (LED) module and couples an electric potential signal, and receive this current detection signal, be lower than one first predetermined level in this current detection signal and continue a Preset Time length maybe this couples an electric potential signal when being higher than one second predetermined level, export a rub-out signal.
Described LED driving circuit controller, wherein, described signal processing unit also receives a conducting pick-off signal, in this conducting pick-off signal be positioned at the representative end level the time, control this first electric current adjustment signal this first power switch ended.
Described LED driving circuit controller, wherein, described signal processing unit receives a direct current dim signal, and exports a pulse-width signal in view of the above.
Described LED driving circuit controller, wherein, described signal processing unit is controlled this first electric current adjustment signal according to this pulse-width signal makes this first power switch periodically by reaching dimming function.
Described LED driving circuit controller, wherein, also comprise one second electric current regulation and control unit, one second current detection signal according to the size of current of indicating one second light-emitting diode (LED) module produces one second electric current adjustment signal to control one second power switch of this second light-emitting diode (LED) module of series connection, makes this second current detection signal level equalization near one second predeterminated voltage value.
Described LED driving circuit controller, wherein, described signal processing unit also detects one second of this second power switch and this second light-emitting diode (LED) module and couples an electric potential signal and receive this second current detection signal, be lower than this first predetermined level in this second current detection signal and continue this Preset Time length or this second and couple an electric potential signal when being higher than this second predetermined level, export this rub-out signal.
Described LED driving circuit controller, wherein, the described first predeterminated voltage value equals this second predeterminated voltage value.
Described LED driving circuit controller, wherein, described signal processing unit also receives a conducting pick-off signal, when this conducting pick-off signal is positioned at the level that representative ends, control this first electric current adjustment signal, the second electric current adjustment signal makes this first power switch, this second power switch end respectively.
Described LED driving circuit controller, wherein, described signal processing unit is this first electric current adjustment signal of time detecting beyond this conducting pick-off signal is positioned at the level that ends of representative and the level of this second electric current adjustment signal also, when this first electric current adjustment signal and the arbitrary level of this second electric current adjustment signal are lower than one the 3rd predetermined level, export this rub-out signal.
Described LED driving circuit controller, wherein, described signal processing unit is controlled this first electric current adjustment signal and this second electric current adjustment signal according to this pulse-width signal and is made this first power switch and this second power switch periodically by reaching dimming function.
Described LED driving circuit controller, wherein, it is poor to have a Preset Time between described first power switch and this second power switch end.
Describe the present invention below in conjunction with the drawings and specific embodiments, but not as a limitation of the invention.
Description of drawings
Fig. 1 is the schematic circuit diagram of traditional current balance type LED driving circuit;
Fig. 2 is the circuit diagram of LED driving circuit according to a preferred embodiment of the present invention;
Fig. 3 is the circuit diagram according to the driving control unit of one embodiment of the invention;
Fig. 4 is the circuit diagram of driving control unit according to another embodiment of the present invention;
Fig. 5 is according to the circuit diagram of the driving control unit of an embodiment more of the present invention; And
Fig. 6 is the circuit diagram of LED driving circuit according to still another embodiment of the invention.
The Reference numeral of prior art:
Light-emitting diode (LED) module 10
Exchanging changes direct current transducer 30
DC-DC transducer 40
Input power supply AC
Resistance R
Direct voltage VDD
Driving voltage Vin
Reference numeral among the present invention:
Light-emitting diode (LED) module 110,110a, 110b, 110c
Current detecting unit 122,122a, 122b, 122c
Driving control unit 130
Electric current regulation and control unit 134,134a, 134b, 134c
Divide facies unit 136
Or door 138
Change-over circuit 200,200 '
Converting unit 210 '
Auxiliary rectifier unit 214 '
Auxiliary output capacitance 216 '
Primary side control unit 220
TCU transfer control unit 220 '
Voltage detection unit 230,230 '
Comparator 302,304,306,308
With door 310
Or door 312
Time filtering unit 314,316,318
Input power supply AC
Bridge rectifier BD
Frequency signal Clock
Inhibit signal Delay
Rub-out signal FAULT, FAULTa, FAULTb, FAULTc
Conducting pick-off signal ONOFF
Direct current dim signal PWMDC
Pulse-width signal PWM, PWMa, PWMb, PWMc
Resistance R
Driving voltage VDD
Direct-current input power supplying Vdc
Direct-flow output signal Vout
The first predetermined level Vref1
The second predetermined level Vref2
The 3rd predetermined level Vref3
The 4th predetermined level Vref4
Current detection signal S1
Couple an electric potential signal S2
Controlled pin position electric potential signal S3
Diverter switch group SW
Transformer T
Embodiment
Below in conjunction with the drawings and specific embodiments technical scheme of the present invention is made further more detailed description.
LED driving circuit with a fixed voltage driven for emitting lights diode does not have light modulation and protection mechanism at present.LED driving circuit of the present invention also can be carried out light modulation according to a dim signal except that the circuit abnormality protection mechanism can be provided, and reaches the function of the synchronous light modulation of multi-group light-emitting diode drive circuit by output light modulation pulse-width signal.Below will technology of the present invention be described with a plurality of embodiment.
Please refer to Fig. 2, be the circuit diagram of according to a preferred embodiment of the present invention LED driving circuit.This LED driving circuit comprises a change-over circuit 200, a current control unit 120, a current detecting unit 122, a driving control unit 130.This change-over circuit 200 couples an input power supply AC to convert a direct current output signal Vout to drive a light-emitting diode (LED) module 110.This current control unit 120 comprises the semiconductor switch, and have a controlled pin position, the pin position is gone in one first output and the pin position is gone in one second output.First output of this current control unit 120 is gone into that the pin position couples this light-emitting diode (LED) module 110 and is formed series connection.This current detecting unit 122 can be a resistance, and the pin position is gone in this second output that couples this current control unit 120, produces a current detection signal S1 with the size of current according to this light-emitting diode (LED) module 110 of flowing through.This driving control unit 130 couples this controlled pin position, this first output of this current control unit 120 and goes into pin position and this current detecting unit 122, and adjust the level of this controlled pin position of this current control unit 120 based on this detection signal S1, flow through the current stabilization of this light-emitting diode (LED) module 110 near a predetermined current value to adjust the equivalent resistance size of this current control unit 120, to make.
Above-mentioned change-over circuit 200 can be flyback power-switching circuit, forward type power-switching circuit, push-pull type power-switching circuit, semibridge system power-switching circuit, full-bridge type power-switching circuit or DC-to-DC switching circuit, is example explanation the present invention at this embodiment with the flyback power-switching circuit.This flyback power-switching circuit comprises a transformer T, and switches switches set SW (at the flyback change-over circuit, the diverter switch group comprises the semiconductor switch, and at other type conversion circuit, as: semibridge system, full-bridge type may comprise several semiconductor switchs), an output capacitance 216, a voltage detection unit 230 and a primary side control unit 220.This transformer T has a primary side and a primary side, and this primary side couples this input power supply AC by a bridge rectifier BD, and this primary side produces this direct-flow output signal Vout through a rectification unit 214.This diverter switch group SW couples this primary side of this transformer T, to switch to conducting and cut-off state according to a control signal.This output capacitance 216 couples this primary side of this transformer T, with the noise of this direct-flow output signal of filtering Vout, makes the voltage of direct-flow output signal Vout stable.Voltage detection unit 230 couples this primary side of this transformer T, and the level height that detects this direct-flow output signal Vout to be producing a voltage detection signal, and is sent to this primary side control unit 220 by an isolated location 232 again.By isolated location 232, can effectively isolate primary side and the primary side of this transformer T.This primary side control unit 220 confirms according to this voltage detection signal of feedback whether this direct-flow output signal Vout is too high or too low, to adjust the pulsewidth of this control signal that is produced, this direct-flow output signal Vout is stable near the predeterminated voltage value.
The primary side of above-mentioned transformer T can comprise an input capacitance 212, an initial driving circuit 222 and a primary side ancillary coil.Input capacitance 212 is in order to stablize the level through the direct current input voltage of bridge rectifier BD.This initial driving circuit 222 comprises a resistance, an electric capacity and a diode.After this input power supply AC connects this bridge rectifier BD, begin this electric capacity charging by this resistance.When the voltage of this electric capacity reached a triggering level, this primary side control unit 220 came into operation, and controlled the switching of this diverter switch group SW.The primary side ancillary coil will be stored in this electric capacity charging of diode pair by initial driving circuit 222 of the energy of transformer T, and compare for fixing because of the coil of this primary side ancillary coil with this primary side, when this direct-flow output signal Vout is stable near the predeterminated voltage value, this capacitance voltage of this initial driving circuit 222 also will be stable near the magnitude of voltage.In addition, the primary side of transformer T also can comprise a primary side ancillary coil.In like manner, have under the fixing coil ratio in this primary side ancillary coil and this secondary side coil, the voltage that charges to an auxiliary output capacitance 216 ' through an auxiliary rectifier unit 214 ' also is stable at a magnitude of voltage, drives this driving control unit 130 so that a driving voltage VDD to be provided.
Driving control unit 130 comprises a signal processing unit 132 and electric current regulation and control unit 134.The electric current of light-emitting diode (LED) module 110 of the flowing through current detecting unit 122 of can flowing through simultaneously, current detecting unit 122 thereby produce this current detection signal S1 in order to the size of current that indicates light-emitting diode (LED) module 110.Electric current regulation and control unit 134 can be a comparator, by comparing the electric current adjustment signal that current detection signal S1 and one first predetermined level Vref1 adjust its output, with the current potential of the controlled pin position of regulating and control semiconductor switch in this current control unit 120, just grid potential.So, can adjust the equivalent resistance of this semiconductor switch, and make this current detection signal S1 level equalization near this first predetermined level Vref1, the electric current of the light-emitting diode (LED) module 110 of promptly flowing through can be stable at a predetermined current value.The controlled pin position electric potential signal S3 and one that this signal processing unit 132 receives this current detection signal S1, this current control unit 120 couples an electric potential signal S2 (electric potential signal that the pin position is gone in second output of current control unit 120), one second predetermined level Vref2, one the 3rd predetermined level Vref3, one the 4th predetermined level Vref4, a conducting pick-off signal ONOFF, a direct current dim signal PWMDC and a frequency signal Clock.This signal processing unit 132 judges based on these above-mentioned signals whether LED driving circuit is unusual, unusually then send a rub-out signal FAULT if having, this rub-out signal is sent to primary side control unit 220 as can be as shown in Figure 2, whether is stopped the running of LED driving circuit by 220 decisions of primary side control unit.Perhaps, also may be output to the microprocessor of system, for example: the image microprocessor of liquid crystal screen display, by microprocessor decision processing mode; Or via user's interface module, for example: the mistake indicator light, notify the user, there is the user to determine whether to stop the running of LED driving circuit.The detailed operation of driving control unit 130 and internal circuit are with following explanation.
Please refer to Fig. 3, be circuit diagram according to the driving control unit of one embodiment of the invention.Driving control unit 130 comprises a signal processing unit 132 and electric current regulation and control unit 134.Signal processing unit 132 comprises comparator 302,304,306 and 308, one and door 310, one or door 312, time filtering unit 314,316 and 318, an and ramp signal generator 320.Electric current regulation and control unit 134 can be comparator, relatively the current detection signal S1 and the first predetermined level Vref1.When current detection signal S1 is lower than this first predetermined level Vref1, heighten the level of the electric current adjustment signal of being exported, it is the grid potential of the semiconductor switch in the current control unit 120, the equiva lent impedance of semiconductor switch is descended, improve the size of current of light-emitting diode (LED) module 110 and the level of current detection signal S1; When current detection signal S1 is higher than this first predetermined level Vref1, turn down the level of the electric current adjustment signal of being exported, the equiva lent impedance of semiconductor switch is risen, reduce the size of current of light-emitting diode (LED) module 110 and the level of current detection signal S1.By above-mentioned feedback control mechanism, the current stabilization that makes light-emitting diode (LED) module 110 is near the predetermined current value.
Comparator 302 in the signal processing unit 132 compares an electric potential signal S2 that couples of the 3rd predetermined level Vref3 and this current control unit 120 and this light-emitting diode (LED) module 110, i.e. the electric potential signal that the pin position is gone in second of this current control unit 120 output.Under normal condition, this couples an electric potential signal S2 and can drop in the safety operation zone (SOA, safe operating area), and in other words, this couples an electric potential signal S2 can be lower than the 3rd predetermined level Vref3.The setting of the 3rd predetermined level Vref3 considers to be that this couples an electric potential signal S2 and whether surpasses voltage that this current control unit 120 can bear or too high and cause conversion efficiency not high, and it can be produced or provided by the outside by driving control unit 130 is inner.For example: this current control unit 120 is by 30 volts of withstand voltage manufacture method mades, the 3rd predetermined level Vref3 can be set in 25 volts, perhaps direct-flow output signal Vout is 30 volts, and under conversion efficiency was consideration more than 80%, the 3rd predetermined level Vref3 can be set in 6 volts.The situation that has light-emitting diode to damage short circuit or other short circuit in light-emitting diode (LED) module 110 takes place and causes the cross-pressure on the light-emitting diode (LED) module 110 to reduce, this current potential that couples an electric potential signal S2 raise and surpass the 3rd predetermined level Vref3, the unusual high level signal of these comparator 302 output representatives to or door 312.It is noted that what this coupled an electric potential signal S2 more also can set two or more comparative levels simultaneously, in for example above-mentioned example 6 volts and 25 volts, and different suitable processing can be provided under different conditions.
Under normal condition, the semiconductor switch of this current control unit 120 can operate in linear zone, to reach the effect of the equiva lent impedance of adjusting this current control unit 120 by the current potential of adjusting controlled pin position.So, when conducting pick-off signal ONOFF be representative end low level signal the time, the electric current adjustment signal will be in low level and make this current control unit 120 for ending, detect this controlled pin position electric potential signal S3 this moment will misjudgment.So comparator 306 decommissions when this conducting pick-off signal ONOFF is positioned at the level that representative ends, and the level of this electric current adjustment signal of time detecting beyond this conducting pick-off signal is positioned at the level that ends of representative.When this current control unit 120 is damaged and during short circuit, in any case controlled pin position electric potential signal S3 turns down the size of current that can't reduce light-emitting diode (LED) module 110, this moment, the controlled pin position electric potential signal S3 of this current control unit 120 can be lower than the 4th predetermined level Vref4, and comparator 306 will be exported the unusual high level signal of representative.For avoiding this conducting pick-off signal ONOFF to cause the possible erroneous judgement of comparator 306 at conversion process, but by the possible erroneous judgement of time filtering unit 318 filterings.
When or door 312 when receiving in the comparators 302,304 and 306 the arbitrary abnormal signal that transmits, promptly represent the unusual and output error signal FAULT of circuit operation.In addition, when circuit operation unusual and when sending rub-out signal FAULT, can be as shown in Figure 3 as, by closing the operation of driving control unit 130 with door 310, other microprocessor or user of reporting system only perhaps as above-mentioned.Certainly, in the practical application, can according to the reason of circuit abnormality handle and be not limited to the present invention for the application mode of embodiment.
Dim signal also may be the direct current dim signal except that being the pulse signal as above-mentioned.As shown in Figure 3, the ramp signal that comparator 308 reception direct current dim signal PWMDC and ramp signal generator 320 are produced, and export a pulse-width signal PWMOUT in view of the above.By this, the driving control unit of other group LED driving circuit reaches this pulse-width signal PWMOUT the function of synchronous light modulation as conducting pick-off signal ONOFF input.Periodicity reaches dimming function by this current control unit 120 if no above-mentioned synchronisation requirement can be failed back former driving control unit 130 as conducting pick-off signal ONOFF with this pulse-width signal PWMOUT.On the practice output of this pulse-width signal PWMOUT of driving control unit 130 and the input of conducting pick-off signal ONOFF are packaged into two different pins respectively, when dim signal is direct current light modulation and when not having synchronisation requirement, above-mentioned two pins are connected get final product.
Please refer to Fig. 4, be the circuit diagram of according to another embodiment of the present invention driving control unit.The embodiment of Fig. 4 and the embodiment of Fig. 3 compare, and main difference is in current control unit 120.Current control unit 120 shown in Figure 4 comprises a current lens unit 124 and a selected cell 126.This current lens unit 124 comprises a plurality of semiconductor switchs, each semiconductor switch has a controlled end, end is gone in one first output and end is gone in one second output, these controlled ends are coupled to each other with the controlled pin position as this current control unit 120, and these first outputs go into to hold to couple this light-emitting diode (LED) module 110 and these second output goes into to hold this current detecting unit 122 that all is coupled to correspondence to go into the pin position with second output as this current control unit 120.This selected cell 126 couples first output of these semiconductor switchs of this current lens unit 124 and goes into end, selects these first outputs of output to go into an end level signal wherein and exports this driving control unit 130 to as coupling an electric potential signal S2.This selected cell 126 can comprise a plurality of diodes, the anode of these diodes is that end is gone in corresponding respectively first output that is coupled to the semiconductor switch in this current lens unit 124, and the negative terminal of these diodes then is coupled to each other and goes into the pin position as first output of this current control unit 120.So, this selected cell 126 can be exported first output of these semiconductor switchs and go in the end to have maximum potential person, promptly cause first of a certain semiconductor switch to export when going into to hold undesired rising as unusual generation, driving control unit 130 can be declared and know and output error signal FAULT.By this, driving control unit of the present invention can be driven and have more the application many and light-emitting diode (LED) modules of going here and there more.
Please refer to Fig. 5, be the circuit diagram of the driving control unit of an embodiment more according to the present invention.Compared to embodiment shown in Figure 4, the driving control unit 130 of Fig. 5 is judged and the execute exception protection mechanism individually with the signal processing unit 132 that a plurality of signal processor 132a, 132b, 132c are constituted.In Fig. 5, the assembly that has an identical function with the assembly of embodiment shown in Figure 3 will give the same components numbering and add a, b according to pairing control group, c is distinguished.Because the operation of the inter-module of each control group only illustrates the signal relation of respectively controlling between group as the explanation of Fig. 3 at this.In the present embodiment, switch when avoiding semiconductor switch 120a, 120b, 120c and cause bigger mains ripple (volatgeripple), by one fen facies unit 136, it produces pulse-width signal PWMa, PWMb, PWMc Control current regulation and control unit 134a, 134b, 134c respectively according to inhibit signal Delay, makes the conducting of these semiconductor switchs 120a, 120b, 120c and end to have the time difference.This inhibit signal Delay can be by external signal or by driving control unit 130 inner generations.When judging corresponding LED driving circuit, any signal processor 132a, 132b, 132c have unusually, for example: the controlled pin position of semiconductor switch 120a, 120b, 120c is arbitrary Vref4 when being lower than the 4th predetermined level; Second output is gone into the arbitrary of pin position and is continued to be lower than one second predetermined level Vref2 above a scheduled time length; First output is gone into appointing of pin position and is higher than one the 3rd predetermined level Vref3, driving control unit 130 only can be selected semiconductor switch 120a, 120b in this corresponding current control unit or 120c and close the running of unusual LED driving circuit, or semiconductor switch 120a, 120b and 120c in this whole current control units, and then by or door 138 send rub-out signal FAULT.Divide pulse light modulation signal that facies unit 136 received except that can being the above-mentioned conducting pick-off signal ONOFF, can also be a direct current dim signal PWMDC, and by arbitrary signal processor 132a, 132b, 132c, the pulse light modulation signal that signal processor 132c as shown in Figure 5 converts to.Divide facies unit 136 and will export a pulse-width signal PWMOUT as the synchronous usefulness of other circuit.In addition, light-emitting diode (LED) module 110a, 110b, 110c can be identical light-emitting diode or different light-emitting diodes, for example are respectively red light emitting diodes module, green LED module, blue LED module.When being identical light-emitting diode (LED) module, the first predetermined level Vref1 that each electric current regulation and control unit 134a, 134b, 134c are received can be for identical; And when being different light-emitting diode (LED) module, these first predetermined level Vref1 can be difference.
Please refer to Fig. 6, be the circuit diagram of according to still another embodiment of the invention LED driving circuit.Compared to the above embodiments, change-over circuit 200 ' in the LED driving circuit of Fig. 6 is the DC-DC voltage up converting circuit, its ratio of boosting (output voltage/input voltage) is determined by the duty ratio of the control signal of PDM keyer, but not is determined to be compared by coil as transformer.Change-over circuit 200 ' shown in Figure 6 comprises a converting unit 210 ', a TCU transfer control unit 220 ' (being PDM keyer) and a voltage detection unit 230 '.This converting unit 210 ' comprises an inductance, a rectification unit, an electric capacity and a switching switch.This inductance couples a direct-current input power supplying Vdc, and this diverter switch couples this inductance, in order to switch between conducting and cut-off state according to the control signal that TCU transfer control unit 220 ' produced.One end of this rectification unit couples coupling a little of this inductance and this diverter switch, and the other end couples a light-emitting diode (LED) module 110.This electric capacity couples coupling a little of this rectification unit and this light-emitting diode (LED) module 110, so that this direct-flow output signal Vout to be provided.This voltage detection unit 230 ' couples one of these light-emitting diode (LED) module 110 two ends, and produces a voltage detection signal according to the level that couples this end.TCU transfer control unit 220 ' produces this control signal according to this voltage detection signal, makes this end level equalization that this voltage detection unit 230 ' detects near a predeterminated voltage value.As shown in Figure 6, this voltage detection unit 230 ' couples the negative terminal of this light-emitting diode (LED) module 110, the pin position is gone in first output that is current control unit 120, and the voltage that can make this first output go into the pin position by this is stable on the predetermined magnitude of voltage and guarantees the conversion efficiency of LED driving circuit.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.
Claims (20)
1, a kind of LED driving circuit is characterized in that, comprises:
One change-over circuit couples an input power supply to convert a direct current output signal to drive a light-emitting diode (LED) module;
At least one current control unit, each current control unit have a controlled pin position, the pin position is gone in one first output and the pin position is gone in one second output, and this first output is gone into the pin position and coupled this light-emitting diode (LED) module;
At least one current detecting unit, correspondence couple this second output of this at least one current control unit and go into the pin position, to produce at least one detection signal; And
One driving control unit, pin position and this current detecting unit are gone in this controlled pin position, this first output of coupling this current control unit, this driving control unit is based on the level of this controlled pin position of this corresponding current control unit of this at least one detection signal adjustment, and the current stabilization that makes this light-emitting diode (LED) module of flowing through is near a predetermined current value;
Wherein, this driving control unit in this at least one first output go into the pin position arbitrary when being higher than one first predetermined level, send a rub-out signal.
2, LED driving circuit according to claim 1 is characterized in that, described rub-out signal is by this corresponding current control unit.
3, LED driving circuit according to claim 1 and 2 is characterized in that, described change-over circuit comprises:
One transformer has a primary side and a primary side, and this primary side couples this input power supply, and this primary side produces this direct-flow output signal through a rectification unit;
One switches switches set, couples this primary side of this transformer, in order to according to a control signal switched conductive and a cut-off state;
One output capacitance couples this primary side of this transformer, with the noise of this direct-flow output signal of filtering;
One voltage detection unit couples this primary side of this transformer, produces a voltage detection signal according to this direct-flow output signal; And
One primary side control unit produces this control signal according to this voltage detection signal, and this direct-flow output signal is stable near the predeterminated voltage value.
4, LED driving circuit according to claim 1 and 2 is characterized in that, described change-over circuit comprises:
One inductance couples this input power supply;
One switches switch, couples this inductance, in order to according to a control signal switched conductive and a cut-off state;
One rectification unit, an end couple coupling a little of this inductance and this diverter switch, and the other end couples this light-emitting diode (LED) module;
One output capacitance couples coupling a little of this rectification unit and this light-emitting diode (LED) module, so that this direct-flow output signal to be provided;
One voltage detection unit couples one of these light-emitting diode (LED) module two ends, and produces a voltage detection signal according to the level that couples this end; And
One TCU transfer control unit produces this control signal according to this voltage detection signal, makes this end level equalization that this voltage detection unit detects near a predeterminated voltage value.
5, LED driving circuit according to claim 1 and 2 is characterized in that, each this current control unit comprises:
One current lens unit, comprise a plurality of semiconductor switchs, each semiconductor switch has a controlled end, end is gone in one first output and end is gone in one second output, these controlled ends are coupled to each other with as this controlled pin position, and these first outputs are gone into end and coupled this light-emitting diode (LED) module and these second output and go into end and all be coupled to this corresponding current detecting unit; And
One selected cell, end is gone in these first outputs that couple these semiconductor switchs, and a level signal of selecting these first outputs to go into end exports this driving control unit to.
6, LED driving circuit according to claim 1 and 2 is characterized in that, described driving control unit receives a conducting pick-off signal, and ends this at least one current control unit according to this conducting pick-off signal.
7, LED driving circuit according to claim 6, it is characterized in that, described driving control unit is in the time beyond this at least one current control unit, detect this at least one controlled pin position, when this at least one controlled pin position arbitrary is lower than one second predetermined level, send this rub-out signal.
8, LED driving circuit according to claim 6, it is characterized in that, described driving control unit detects this at least one second output and goes into the pin position, in this at least one second output go into the pin position arbitrary continue to be lower than one the 3rd predetermined level to surpass a scheduled time length after the time, send this rub-out signal.
9, LED driving circuit according to claim 1 and 2 is characterized in that, described driving control unit also receives a direct current dim signal, and exports a pulse-width signal in view of the above.
10, a kind of LED driving circuit controller is characterized in that, controls this LED driving circuit and drives a light-emitting diode (LED) module, comprises:
One first electric current regulation and control unit, one first current detection signal according to the size of current of indicating one first light-emitting diode (LED) module produces one first electric current adjustment signal to control one first power switch of this first light-emitting diode (LED) module of series connection, makes this first current detection signal level equalization near one first predeterminated voltage value; And
One signal processing unit, detecting one first of this first power switch and this first light-emitting diode (LED) module couples an electric potential signal and receives this first current detection signal, be lower than one first predetermined level in this first current detection signal and continue a Preset Time length or this first and couple an electric potential signal when being higher than one second predetermined level, export a rub-out signal.
11, LED driving circuit controller according to claim 10, it is characterized in that, described signal processing unit also receives a conducting pick-off signal, in this conducting pick-off signal be positioned at the representative end level the time, control this first electric current adjustment signal this first power switch ended.
12, LED driving circuit controller according to claim 10 is characterized in that, described signal processing unit receives a direct current dim signal, and exports a pulse-width signal in view of the above.
13, LED driving circuit controller according to claim 12 is characterized in that, described signal processing unit is controlled this first electric current adjustment signal according to this pulse-width signal makes this first power switch periodically by reaching dimming function.
14, LED driving circuit controller according to claim 10, it is characterized in that, also comprise one second electric current regulation and control unit, one second current detection signal according to the size of current of indicating one second light-emitting diode (LED) module produces one second electric current adjustment signal to control one second power switch of this second light-emitting diode (LED) module of series connection, makes this second current detection signal level equalization near one second predeterminated voltage value.
15, LED driving circuit controller according to claim 14, it is characterized in that, described signal processing unit also detects one second of this second power switch and this second light-emitting diode (LED) module and couples an electric potential signal and receive this second current detection signal, be lower than this first predetermined level in this second current detection signal and continue this Preset Time length or this second and couple an electric potential signal when being higher than this second predetermined level, export this rub-out signal.
16, LED driving circuit controller according to claim 14 is characterized in that, the described first predeterminated voltage value equals this second predeterminated voltage value.
17, LED driving circuit controller according to claim 14, it is characterized in that, described signal processing unit also receives a conducting pick-off signal, when this conducting pick-off signal is positioned at the level that representative ends, control this first electric current adjustment signal, the second electric current adjustment signal makes this first power switch, this second power switch end respectively.
18, according to claim 11 or 17 described LED driving circuit controllers, it is characterized in that, described signal processing unit is this first electric current adjustment signal of time detecting beyond this conducting pick-off signal is positioned at the level that ends of representative and the level of this second electric current adjustment signal also, when this first electric current adjustment signal and the arbitrary level of this second electric current adjustment signal are lower than one the 3rd predetermined level, export this rub-out signal.
19, LED driving circuit controller according to claim 13, it is characterized in that described signal processing unit controls this first electric current adjustment signal according to this pulse-width signal and this second electric current adjustment signal makes this first power switch and this second power switch periodically by reaching dimming function.
According to claim 17 or 19 described LED driving circuit controllers, it is characterized in that 20, it is poor to have a Preset Time between described first power switch and this second power switch end.
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| CN 200810111282 CN101605416B (en) | 2008-06-13 | 2008-06-13 | LED driving circuit and controller thereof |
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| CN 200810111282 CN101605416B (en) | 2008-06-13 | 2008-06-13 | LED driving circuit and controller thereof |
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| CN 200810111282 Expired - Fee Related CN101605416B (en) | 2008-06-13 | 2008-06-13 | LED driving circuit and controller thereof |
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