CN202738221U - Light-emitting diode driving device - Google Patents
Light-emitting diode driving device Download PDFInfo
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- CN202738221U CN202738221U CN 201220455390 CN201220455390U CN202738221U CN 202738221 U CN202738221 U CN 202738221U CN 201220455390 CN201220455390 CN 201220455390 CN 201220455390 U CN201220455390 U CN 201220455390U CN 202738221 U CN202738221 U CN 202738221U
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Abstract
The utility model relates to a light-emitting diode driving device. The light-emitting diode driving device is suitable to drive a plurality of light-emitting diode units which are connected in parallel. The light-emitting diode driving device comprises a voltage converting unit, a plurality of current control units, a first detecting unit, a feedback unit, a second detecting unit and a control unit. The voltage converting unit converts working voltage to output voltage according to control signals and transmits the output voltage to anode terminals of the light-emitting diode units. The current control units are coupled with cathode terminals of the light-emitting diode units to receive a plurality of first reference signals and generate a plurality of current signals. The first detecting unit is coupled with the cathode terminals of the light-emitting diode units to generate a first detecting signal. The feedback unit receives the first detecting signal and generates a feedback signal. The second detecting unit receives output voltage and generates a second detecting signal. The control unit generates a control signal according to the feedback signal or the second detecting signal.
Description
Technical field
The utility model relates to a kind of drive unit, particularly a kind of light emitting diode drive device.
Background technology
That light-emitting diode (Light Emitting Diode, LED) has is long such as the life-span, volume is little, high shock resistance, low-heat produces and the advantage such as low power consumption, therefore has been widely used in indicating device or light source in family expenses and the various device.In recent years, light-emitting diode is towards multicolour and high brightness development, so its application has extended to large-scale billboards, traffic signal light and relevant lighting field.In future, light-emitting diode may become the main lighting source that has power saving and environment-friendly function concurrently.
For the type of drive of light-emitting diode, mostly be first alternating voltage to be converted to direct voltage or electric current, the recycling galvanic current is pressed or electric current, to drive light-emitting diode work and luminous.And the power supply that present most electrical equipment or electronic product provide is all from civil power, and these electrical equipment or electronic product mostly contain the electric conductors such as metal, to carry out power delivery.
Yet, LED driving circuit can be because some external factors, for example the thunderbolt, electromagnetic interference (Electromagnetic Interference, EMI), electromagnetic compatibility (Electromagnetic Compatibility, EMC), open-circuit condition etc. occurs in surge current or the two ends of light-emitting diode, and so that the drive current of light-emitting diode increase.In case drive current surpasses the rated value of light-emitting diode, will cause easily light-emitting diode to damage or the lost of life.Therefore, the space that LED driving circuit still is improved, the problem of damaging effectively to avoid the light-emitting diode product to suffer overcurrent, overvoltage and light-emitting diode two ends that the factor such as open-circuit condition occurs.
The utility model content
In view of above problem; the purpose of this utility model is to provide a kind of light emitting diode drive device; use and adjust suitable drive current; and the electric current between the balance light emitting diode, and reach the protective effect that open-circuit condition appears in overvoltage, overcurrent and light emitting diode.
For reaching above-mentioned purpose, the utility model provides a kind of light emitting diode drive device, is suitable for driving a plurality of light emitting diodes, and those light emitting diodes are connected in parallel, and wherein, this light emitting diode drive device comprises:
One voltage conversion unit, in order to receiving an operating voltage, and according to a control signal, and convert this operating voltage to an output voltage, and this output voltage exports the anode tap of those light emitting diodes to;
A plurality of current control units couple respectively the cathode terminal of those light emitting diodes, in order to receiving a plurality of the first reference signals, and produce a plurality of current signals;
One first detecting unit couples the cathode terminal of those light emitting diodes, in order to produce one first detection signal;
One feedback unit couples this first detecting unit, in order to receive this first detection signal, to produce a feedback signal;
One second detecting unit couples this voltage conversion unit, in order to receive this output voltage, to produce one second detection signal; And
One control unit couples this feedback unit and this second detecting unit, in order to receiving this feedback signal, this second detection signal and this output voltage, and according to this feedback signal or this second detection signal, to produce this control signal.
In one embodiment, above-mentioned light emitting diode drive device, wherein this voltage conversion unit comprises:
One first resistance has a first end and one second end, and this first end of this first resistance receives this operating voltage;
One first electric capacity has a first end and one second end, and this first end of this first electric capacity couples this first end of this first resistance, and this second end of this first electric capacity couples this second end of this first resistance;
One transformer has a primary side and a secondary side, and the first end of this primary side of this transformer couples this first end of this first resistance, and the second end of this secondary side of this transformer couples earth terminal;
One first diode has an anode tap and a cathode terminal, and this cathode terminal of this first diode couples this second end of this first resistance, and this anode tap of this first diode couples the second end of this primary side of this transformer;
One first switch element has a first end, one second end and one the 3rd end, and this first end of this first switch element couples this anode tap of this first diode, and this second termination of this first switch element is received this control signal;
One second resistance has a first end and one second end, and this first end of this second resistance couples the 3rd end of this first switch element;
One second diode has an anode tap and a cathode terminal, and this anode tap of this second diode couples the first end of this secondary side of this transformer;
One second electric capacity has a first end and one second end, and this first end of this second electric capacity couples this cathode terminal of this second diode, and this second end of this second electric capacity couples earth terminal;
One inductance has a first end and one second end, and this first end of this inductance couples this second end of this second electric capacity, and this of this inductance the second end produces this output voltage; And
One the 3rd electric capacity has a first end and one second end, and this first end of the 3rd electric capacity couples this second end of this inductance, and this second end of the 3rd electric capacity couples earth terminal.
In one embodiment, above-mentioned light emitting diode drive device, wherein those current control units comprise separately:
One first operational amplifier has a first input end, one second input and an output, and this first input end of this first operational amplifier receives this first reference signal;
One the 4th electric capacity has a first end and one second end, and this first end of the 4th electric capacity couples this second input of this first operational amplifier;
One the 3rd resistance has a first end and one second end, and this first end of the 3rd resistance couples this second end of the 4th electric capacity, and this second end of the 3rd resistance couples this output of this first operational amplifier;
One the 4th resistance has a first end and one second end, and this first end of the 4th resistance couples this second end of the 3rd resistance;
One second switch unit, have a first end, one second end and one the 3rd end, this first end of this second switch unit couples the cathode terminal of those light emitting diodes, and to produce this current signal, this second end of this second switch unit couples this second end of the 4th resistance;
One the 5th resistance has a first end and one second end, and this first end of the 5th resistance couples this first end of the 4th electric capacity, and this second end of the 5th resistance couples the 3rd end of this second switch unit; And
One the 6th resistance has a first end and one second end, and this first end of the 6th resistance couples this second end of the 5th resistance, and this second end of the 6th resistance couples earth terminal.
In one embodiment, above-mentioned light emitting diode drive device, wherein this first detecting unit comprises:
A plurality of the 3rd diodes, those the 3rd diodes have an anode tap and a cathode terminal separately, and those anode taps of those the 3rd diodes couple respectively the cathode terminal of those light emitting diodes;
One the 7th resistance has a first end and one second end, and this first end of the 7th resistance couples those cathode terminals of those the 3rd diodes, and this second end of the 7th resistance produces this first detection signal; And
One the 8th resistance has a first end and one second end, and this first end of the 8th resistance couples this second end of the 7th resistance, and this second end of the 8th resistance couples earth terminal.
In one embodiment, above-mentioned light emitting diode drive device, wherein this feedback unit comprises:
One second operational amplifier, have a first input end, one second input and an output, this first input end of this second operational amplifier receives one second reference signal, and this second input of this second operational amplifier couples this feedback unit, to receive this first detection signal;
One the 9th resistance has a first end and one second end, and this first end of the 9th resistance couples this second input of this second operational amplifier;
One the 5th electric capacity has a first end and one second end, and this first end of the 5th electric capacity couples this second end of the 9th resistance, and this second end of the 5th electric capacity couples this output of this second operational amplifier; And
One the 4th diode has an anode tap and a cathode terminal, and this anode tap of the 4th diode produces this feedback signal, and this cathode terminal of the 4th diode couples this output of this second operational amplifier.
In one embodiment, above-mentioned light emitting diode drive device, wherein this second detecting unit comprises:
1 the tenth resistance has a first end and one second end, and this first end of the tenth resistance receives this output voltage;
1 the 11 resistance has a first end and one second end, and this first end of the 11 resistance couples this second end of the tenth resistance, and this second end of the 11 resistance couples earth terminal;
One the 3rd operational amplifier, have a first input end, one second input and an output, this first input end of the 3rd operational amplifier receives one the 3rd reference signal, and this second input of the 3rd operational amplifier couples this first end of the 11 resistance;
1 the 12 resistance has a first end and one second end, and this first end of the 12 resistance couples this second input of the 3rd operational amplifier;
One the 6th electric capacity has a first end and one second end, and this first end of the 6th electric capacity couples this second end of the 12 resistance, and this second end of the 6th electric capacity couples this output of the 3rd operational amplifier; And
One the 5th diode has an anode tap and a cathode terminal, and this anode tap of the 5th diode produces this second detection signal, and this cathode terminal of the 5th diode couples this output of the 3rd operational amplifier.
In one embodiment, above-mentioned light emitting diode drive device, wherein this control unit comprises:
1 the 13 resistance has a first end and one second end, and this first end of the 13 resistance receives this output voltage;
One optical coupler, have a first end, one second end, one the 3rd end and one the 4th end, this first end of this optical coupler couples this second end of the 13 resistance, this of this optical coupler the second termination is received this feedback signal and this second detection signal, the 3rd end of this optical coupler produces a coupled signal, and the 4th end of this optical coupler couples earth terminal; And
One pulse-width modulation unit couples the 3rd end of this optical coupler, in order to receive this coupled signal, to produce this control signal.
In one embodiment, above-mentioned light emitting diode drive device wherein also comprises:
One filter unit receives a supply voltage, and this supply voltage is carried out filtering, to produce a filtering voltage; And
One rectification unit couples this filter unit, receives this filtering voltage, and this filtering voltage is carried out rectification, to produce this operating voltage.
The disclosed light emitting diode drive device of the utility model, it utilizes current control unit according to the first reference signal, to adjust suitable drive current.And, utilize and detect the electric current of light emitting diode of flowing through, and produce according to this first detection signal, produce feedback signal according to the first detection signal again.In addition, utilize the detection light emitting diode whether to produce open-circuit condition, to produce the second detection signal.Then, control unit is adjusted the voltage potential of control signal according to feedback signal or the second detection signal, and then whether the control voltage conversion unit produces output voltage.Thus; capable of regulating goes out suitable drive current; and the electric current between the balance light emitting diode, and reach the protective effect that open-circuit condition appears in overvoltage, overcurrent and light emitting diode, produce situation about damaging to avoid light emitting diode.
Below in conjunction with the drawings and specific embodiments the utility model is described in detail, but not as to restriction of the present utility model.
Description of drawings
Fig. 1 is the schematic diagram of LED driving circuit of the present utility model;
Fig. 2 is the detailed maps of LED driving circuit of the present utility model.
Wherein, Reference numeral
100,200 light emitting diode drive devices
110 voltage conversion units
120_1,120_2,120_3 current control unit
130 first detecting units
140 feedback units
150 second detecting units
160 control units
180_1,180_2,180_3 light emitting diode
210 filter units
220 rectification units
222 transformers
224 first switch elements
226 first operational amplifiers
228 second switch unit
230 second operational amplifiers
232 the 3rd operational amplifiers
234 optical couplers
236 pulse-width modulation unit
C1 the first electric capacity
C2 the second electric capacity
C3 the 3rd electric capacity
C4 the 4th electric capacity
C5 the 5th electric capacity
C6 the 6th electric capacity
D1 the first diode
D2 the second diode
D3_1, D3_2, D3_3 the 3rd diode
D4 the 4th diode
D5 the 5th diode
R1 the first resistance
R2 the second resistance
R3 the 3rd resistance
R4 the 4th resistance
R5 the 5th resistance
R6 the 6th resistance
R7 the 7th resistance
R8 the 8th resistance
R9 the 9th resistance
R10 the tenth resistance
R11 the 11 resistance
R12 the 12 resistance
R13 the 13 resistance
The L inductance
The CS control signal
The I current signal
VD1 the first detection signal
VD2 the second detection signal
The VFB feedback signal
The VIN operating voltage
The VO output voltage
VREF1 the first reference signal
VREF2 the second reference signal
VREF3 the 3rd reference signal
The VS supply voltage
The GND earth terminal
Embodiment
Below in conjunction with accompanying drawing structural principle of the present utility model and operation principle are done concrete description:
Please refer to shown in Figure 1ly, it is respectively the schematic diagram of light emitting diode drive device of the present utility model.The light emitting diode drive device 100 of present embodiment is suitable for driving light emitting diode 180_1,180_2 and 180_3.For convenience of description, in one embodiment, light emitting diode 180_1 comprises a light-emitting diode, and the anode tap of this light-emitting diode is as the anode tap of light emitting diode 180_1, and the cathode terminal of this light-emitting diode is as the cathode terminal of light emitting diode 180_1.
In another embodiment, light emitting diode 180_1 comprises a plurality of light-emitting diodes, and these light-emitting diodes are to be serially connected in a LED serial, the anode tap of this LED serial is as the anode tap of light emitting diode 180_1, and the cathode terminal of this LED serial is as the cathode terminal of light emitting diode 180_1.All the other light emitting diode 180_2 and 180_3 then analogize.In addition, present embodiment is driving 3 light emitting diodes as example, but the utility model is not limited to this, also can drive the light emitting diode more than 2 or 3.
Light emitting diode drive device 100 comprises voltage conversion unit 110, a plurality of current control unit 120_1,120_2,120_3, the first detecting unit 130, feedback unit 140, the second detecting unit 150 and control unit 160.Wherein, the quantity of the quantity respective leds unit of current control unit, the quantity that also is light emitting diode is 3, and then the quantity of current control unit is 3 also, and all the other are then analogized.
Current control unit 120_1,120_2 and 120_3 be respectively and coupling one to one the cathode terminal of light emitting diode 180_1,180_2 and 180_3, in order to receiving a plurality of the first reference signal VREF1, and produces a plurality of current signal I.In the present embodiment, the current signal I that provides of current control unit 120_1,120_2 and 120_3 is a constant current.
The first detecting unit 130 couples the cathode terminal of light emitting diode 180_1,180_2 and 180_3, in order to produce the first detection signal VD1.Feedback unit 140 couples the first detecting unit 130, in order to receive the first detection signal VD1, to produce feedback signal VFB.The second detecting unit 150 couples voltage conversion unit 110, in order to receive output voltage VO, to produce the second detection signal VD2.Control unit 160 couples feedback unit 140 and the second detecting unit 150, in order to receiving feedback signals VFB, the second detection signal VD2 and output voltage VO, and according to output voltage VO and feedback signal VFB or the second detection signal VD2, to produce control signal CS.
When light emitting diode drive device 100 comes into operation, voltage conversion unit 110 can be according to the voltage potential of control signal CS, and according to this operating voltage VIN is converted to output voltage VO, and export output voltage VO the anode tap of light emitting diode 180_1,180_2 and 180_3 to, to drive light emitting diode 180_1,180_2 and 180_3.
For instance, when the voltage potential of control signal CS was high voltage potential, then voltage conversion unit 110 can not carry out the conversion of operating voltage VIN, was the operation that voltage conversion unit 110 carries out energy storage yet.When the voltage potential of control signal CS is low voltage potential, voltage conversion unit 110 can convert operating voltage VIN to output voltage VO, and also being voltage conversion unit 110 becomes output voltage VO and output with the voltage transitions of energy storage.
Then, current control unit 120_1,120_2 and 120_3 produce corresponding current signal I respectively according to the first reference signal VREF1, with the control electric current of light emitting diode 180_1,180_2 and 180_3 of flowing through, and then reach the control of constant current.In addition, the first detecting unit 130 can detect the electric current of light emitting diode 180_1,180_2 and 180_3 of flowing through, and aforesaid current conversion is become the first detection signal VD1.Afterwards, feedback unit 140 can receive aforesaid the first detection signal VD1, and the voltage potential of foundation the first detection signal VD1, and produces corresponding feedback signal VP.
For instance, when the voltage potential of the first detection signal VD1 was higher than a preset value, it for example was the feedback signal VFB of low voltage potential that feedback unit 140 can correspondingly produce.When the voltage potential of the first detection signal VD1 is not higher than aforesaid preset value, feedback unit 140 can corresponding produce for example feedback signal VFB of high voltage potential.
On the other hand, the second detecting unit 150 can receive output voltage VO, and according to the voltage potential of output voltage VO, and produce the second corresponding detection signal VD2.For instance, when the voltage potential of output voltage VO was higher than a preset value, the second detecting unit 150 can corresponding produce for example the second detection signal VD2 of low voltage potential.When the voltage potential of output voltage VO was not higher than aforesaid preset value, the second detecting unit can corresponding produce for example the second detection signal VD2 of high voltage potential.
Then, control unit 160 receives output voltage VO, feedback signal VFB and the second detection signal VD2, and according to the voltage potential of feedback signal VFB or the second detection signal VD2, and produce according to this control signal CS, also namely adjust the voltage potential of control signal CS, whether convert operating voltage VIN to output voltage VO with control voltage conversion unit 110.
For instance, when one of them voltage potential of feedback signal VFB and the second detection signal VD2 for example is low voltage potential, or the voltage potential of feedback signal VFB and the second detection signal VD2 is when for example all being low voltage potential, control unit 160 for example produces the control signal CS of low voltage potential, can not convert operating voltage VIN to output voltage VO to cause voltage conversion unit 110.When the voltage potential of feedback signal VFB and the second detection signal VD2 for example all is high voltage potential, control unit 160 for example produces the control signal CS of high voltage potential, to cause voltage conversion unit 110 to convert operating voltage VIN to output voltage VO, and export the anode tap of light emitting diode 180_1,180_2 and 180_3 to, to drive light emitting diode 180_1,180_2 and 180_3.
Utilize monitoring flow through the electric current of light emitting diode 180_1,180_2 and 180_3, and the first corresponding detection signal VD1 is provided and produces according to this feedback signal VFB, and the monitoring output voltage VO is to produce the second corresponding detection signal VD2, to adjust the voltage potential of control signal CS, whether produce the foundation of output voltage VO as control voltage conversion unit 110.And, utilize according to the first reference signal VREF1, with the flow through current signal I of light emitting diode 180_1,180_2 and 180_3 of control.Thus; capable of regulating goes out suitable drive current; and the electric current between balance light emitting diode 180_1,180_2 and the 180_3; and reach the protective effect that open-circuit condition appears in overvoltage, overcurrent and light emitting diode 180_1,180_2 and 180_3, produce situation about damaging to avoid light emitting diode.
Please refer to shown in Figure 2ly, it is the detailed maps of light emitting diode drive device of the present utility model.The light emitting diode drive device 200 of present embodiment is suitable for driving light emitting diode 180_1,180_2 and 180_3.Light emitting diode drive device 200 comprises filter unit 210, rectification unit 220, voltage conversion unit 110, current control unit 120_1,120_2,120_3, the first detecting unit 130, feedback unit 140, the second detecting unit 150 and control unit 160.
The first resistance R 1 has first end and the second end, and the first end of the first resistance R 1 receives operating voltage VIN.The first capacitor C 1 has first end and the second end, and the first end of the first capacitor C 1 couples the first end of the first resistance R 1, and the second end of the first capacitor C 1 couples the second end of the first resistance R 1.Transformer 222 has primary side and secondary side, and the first end of the primary side of transformer couples the first end of the first resistance R 1, and the second end of the secondary side of transformer 222 couples earth terminal GND.
The first diode D1 has anode tap and cathode terminal, and the cathode terminal of the first diode D1 couples the second end of the first resistance R 1, and the anode tap of the first diode D1 couples the second end of the primary side of transformer 222.The first switch element 224 has first end, the second end and the 3rd end, and the first end of the first switch element 224 couples the anode tap of the first diode D1, and the second termination of the first switch element 224 is received control signal CS.
In the present embodiment, the first switch element 224 is for example implemented with the N-type transistor.The first end of the first switch element 224 for example is the transistorized drain electrode end of N-type (Drain), the second end of the first switch element 224 for example is the transistorized gate terminal of N-type (Gate), and the 3rd end of the first switch element 224 for example is the transistorized source terminal of N-type (Source).Yet the utility model is not limited to this, the first switch element 224 also can the P transistor npn npn or other switch elements implement.
The second resistance R 2 has first end and the second end, and the first end of the second resistance R 2 couples the 3rd end of the first switch element 224.The second diode D2 has anode tap and cathode terminal, and the anode tap of the second diode D2 couples the first end of the secondary side of transformer 222.The second capacitor C 2 has first end and the second end, and the first end of the second capacitor C 2 couples the cathode terminal of the second diode D2, and the second end of the second capacitor C 2 couples earth terminal GND.Inductance L has first end and the second end, and the first end of inductance L couples the second end of the second capacitor C 2, and the second end of inductance L produces output voltage VO.The 3rd capacitor C 3 has first end and the second end, and the first end of the 3rd capacitor C 3 couples the second end of inductance L, and the second end of the 3rd capacitor C 3 couples earth terminal GND.
Current control unit 120_1,120_2 and 120_3 comprise the first operational amplifier 226, the 4th capacitor C 4, the 3rd resistance R 3, the 4th resistance R 4, second switch unit 228, the 5th resistance R 5 and the 6th resistance R 6 separately.The first operational amplifier 226 has first input end (for example positive input terminal), the second input (for example negative input end) and output, and the first input end of the first operational amplifier 226 receives the first reference signal VREF1.The 4th capacitor C 4 has first end and the second end, and the first end of the 4th capacitor C 4 couples the second input of the first operational amplifier 226.
The 3rd resistance R 3 has first end and the second end, and the first end of the 3rd resistance R 3 couples the second end of the 4th capacitor C 4, and the second end of the 3rd resistance R 3 couples the output of the first operational amplifier 226.The 4th resistance R 4 has first end and the second end, and the first end of the 4th resistance R 4 couples the second end of the 3rd resistance R 3.Second switch unit 228 has first end, the second end and the 3rd end, and the first end of second switch unit 228 couples the cathode terminal of light emitting diode, and with generation current signal I, the second end of second switch unit 228 couples the second end of the 4th resistance R 4.
In the present embodiment, second switch unit 228 is for example implemented with the N-type transistor.The first end of second switch unit 228 for example is the transistorized drain electrode end of N-type, and the second end of second switch unit 228 for example is the transistorized gate terminal of N-type, and the 3rd end of second switch unit 228 for example is the transistorized source terminal of N-type.Yet the utility model is not limited to this, second switch unit 228 also can the P transistor npn npn or other switch elements implement.
The 5th resistance R 5 has first end and the second end, and the first end of the 5th resistance R 5 couples the first end of the 4th capacitor C 4, and the second end of the 5th resistance R 5 couples the 3rd end of second switch unit 226.The 6th resistance R 6 has first end and the second end, and the first end of the 6th resistance R 6 couples the second end of the 5th resistance R 5, and the second end of the 6th resistance R 6 couples earth terminal GND.
The first detecting unit 130 comprises the 3rd diode D3_1, D3_2, D3_3, the 7th resistance R 7 and the 8th resistance R 8.Wherein, the quantity of the quantity respective leds unit of the 3rd diode, the quantity that also is light-emitting diode is 3, and the quantity of the 3rd diode is 3 also, and all the other are then analogized.
The 3rd diode D3_1, D3_2, D3_3 have respectively anode tap and cathode terminal, and the anode tap of the 3rd diode D3_1, D3_2, D3_3 couples respectively the cathode terminal of light emitting diode 180_1,180_2,180_3.The 7th resistance R 7 has first end and the second end, and the first end of the 7th resistance R 7 couples the 3rd diode D3_1, D3_2, D3_3 cathode terminal, and the second end of the 7th resistance R 7 produces the first detection signal VD1.The 8th resistance R 8 has first end and the second end, and the first end of the 8th resistance R 8 couples the second end of the 7th resistance R 7, and the second end of the 8th resistance R 8 couples earth terminal GND.
The 9th resistance R 9 has first end and the second end, and the first end of the 9th resistance R 9 couples the second input of the second operational amplifier 230.The 5th capacitor C 5 has first end and the second end, and the first end of the 5th capacitor C 5 couples the second end of the 9th resistance R 9, and the second end of the 5th capacitor C 5 couples the output of the second operational amplifier 230.The 4th diode D4 has anode tap and cathode terminal, and the anode tap of the 4th diode D4 produces feedback signal VFB, and the cathode terminal of the 4th diode D4 couples the output of the second operational amplifier 230.
The second detecting unit 150 comprises the tenth resistance R 10, the 11 resistance R 11, the 3rd operational amplifier 232, the 12 resistance R 12, the 6th capacitor C 6 and the 5th diode D5.The tenth resistance R 10 has first end and the second end, and the first end of the tenth resistance R 10 receives output voltage VO.
The 11 resistance R 11 has first end and the second end, and the first end of the 11 resistance R 11 couples the second end of the tenth resistance R 10, and the second end of the 11 resistance R 11 couples earth terminal GND.The 3rd operational amplifier 232 has first input end (for example positive input terminal), the second input (for example negative input end) and output, the first input end of the 3rd operational amplifier 232 receives the 3rd reference signal VREF3, and the second input of the 3rd operational amplifier 232 couples the first end of 11 resistance R 11.
The 12 resistance R 12 has first end and the second end, and the first end of the 12 resistance R 12 couples the second input of the 3rd operational amplifier 232.The 6th capacitor C 6 has first end and the second end, and the first end of the 6th capacitor C 6 couples the second end of the 12 resistance R 12, and the second end of the 6th capacitor C 6 couples the output of the 3rd operational amplifier 232.The 5th diode D5 has anode tap and cathode terminal, and the anode tap of the 5th diode D5 produces the second detection signal VD2, and the cathode terminal of the 5th diode D5 couples the output of the 3rd operational amplifier 232.
After light emitting diode drive device 200 runnings, and voltage conversion unit 110 produces output voltage VO to drive light emitting diode 180_1, behind 180_2 and the 180_3, current control unit 120_1, the first operational amplifier 226 meetings of 120_2 and 120_3 are according to the voltage potential of the signal of its first input end and the second input, it also is the pressure drop on the first reference signal VREF1 and the 6th resistance R 6, whether control the conducting of the first switch element 228, so that the first switch element 228 works in linear condition, and then the generation of control current signal I, to adjust suitable light-emitting diode driver element 180_1, the drive current of 180_2 and 180_3.
In addition, the first detecting unit 130 can detect the electric current of flow through light emitting diode 180_1,180_2 and 180_3, to produce the first detection signal VD1.And the first detection signal VD1 exports the second input of the second operational amplifier 230 to.Then, the signal that the second operational amplifier 230 meeting comparison first input ends and the second input receive also namely compares the voltage potential of the first detection signal VD1 and the second reference signal VREF2, and adjusts according to this voltage potential of feedback signal VFB.
When the electric current of flow through light emitting diode 180_1,180_2 and 180_3 is normal, the voltage potential of the first detection signal VD1 can't surpass the voltage potential of the second reference voltage VREF2, so signal of the second operational amplifier 230 meeting output HIGH voltage current potentials of feedback unit 140, then the 4th not conducting of diode D4, and so that the feedback signal VFB that feedback unit 140 produces is high voltage potential.
Yet, when the electric current of flow through light emitting diode 180_1,180_2 and 180_3 increases suddenly, also be that overcurrent, superpotential situation occur, the voltage potential of the first detection signal VD1 also can continue to rise.And the second operational amplifier 230 of feedback unit 140 can continue relatively the first detection signal VD1 and the second reference signal VREF2.Then, the voltage potential that compares the first detection signal VD1 when the second operational amplifier 230 is during greater than the second reference signal VREF2, the corresponding signal that produces low voltage potential of meeting, then the 4th diode D4 conducting, and so that the feedback signal VFB that feedback unit 140 produces is low voltage potential.
On the other hand, the second detecting unit 150 can utilize the tenth resistance R 10 and the 11 resistance R 11, and output voltage VO is carried out dividing potential drop, and producing a voltage division signal, and voltage division signal can export the second input of the 3rd operational amplifier 232 to.Then, the signal that the 3rd operational amplifier 232 meeting comparison first input ends and the second input receive also namely compares the voltage potential of voltage division signal and the 3rd reference signal VREF3, and adjusts according to this voltage potential of the second detection signal VD2.
When open-circuit condition does not appear in light emitting diode 180_1,180_2 and 180_3, the voltage division signal that the voltage potential of output voltage VO produces via dividing potential drop, the voltage potential that can't surpass the 3rd reference voltage VREF3, so signal of the 3rd operational amplifier 232 meeting output HIGH voltage current potentials of the second detecting unit 150, then the 5th not conducting of diode D5, and so that the second detection signal VD2 that the second detecting unit 150 produces is high voltage potential.
Yet when open-circuit condition appearred in light emitting diode 180_1,180_2 and 180_3, the voltage potential of output voltage VO can continue to rise, and the voltage potential of voltage division signal also with rising.And the 3rd operational amplifier 232 of the second detecting unit 150 can continue relatively voltage division signal and the 3rd reference signal VREF3.Then, the voltage potential that compares voltage division signal when the 3rd operational amplifier 232 is during greater than the 3rd reference signal VREF3, the corresponding signal that produces low voltage potential of meeting, then the 5th diode D5 conducting, and so that the second detection signal VD2 that the second detecting unit 150 produces is low voltage potential.
Then, control unit 160 can receive output voltage VO, and output voltage VO can be sent to via the 13 resistance R 13 first end of optical coupler 234.Afterwards, the feedback signal VFB that optical coupler 234 can receive according to its second end or the voltage potential of the second detection signal VD2, and determine the whether conducting of light transmitting terminal of optical coupler 234.
When the voltage potential of feedback signal VFB and the second detection signal VD2 all is high voltage potential, the light transmitting terminal of optical coupler 234 does not produce light source, the then not conducting of optical receiving end of optical coupler 234 is so that the 3rd end of optical coupler 234 produces the coupled signal of high voltage potential to pulse-width modulation unit 236.Then, the signal of the high voltage potential that pulse-width modulation unit 236 produces according to optical coupler, and the corresponding control signal CS that produces high voltage potential is to voltage conversion unit 110, so that voltage conversion unit 110 produces output voltage VO.
On the other hand, when the voltage potential of feedback signal VFB or the second detection signal VD2 all during low voltage potential, the light transmitting terminal of optical coupler 234 produces light source, the then optical receiving end conducting of optical coupler is so that the 3rd end of optical coupler 234 produces the coupled signal of low voltage potential to pulse-width modulation unit 236.Then, the signal of the low voltage potential that pulse-width modulation unit 236 produces according to optical coupler 234, and the corresponding control signal CS that produces low voltage potential is to voltage conversion unit 110, so that voltage conversion unit 110 produces output voltage VO.
Thus; light emitting diode drive device 200 capable of regulatings of present embodiment go out suitable drive current; and the electric current between balance light emitting diode 180_1,180_2 and the 180_3; and reach the protective effect that open-circuit condition appears in overvoltage, overcurrent and light emitting diode 180_1,180_2 and 180_3, produce situation about damaging to avoid light emitting diode 180_1,180_2 and 180_3.
Light emitting diode drive device of the present utility model, it utilizes current control unit according to the first reference signal, to adjust suitable drive current.And, utilize and detect the electric current of light emitting diode of flowing through, and produce according to this first detection signal, produce feedback signal according to the first detection signal again.In addition, utilize the detection light emitting diode whether to produce open-circuit condition, to produce the second detection signal.Then, control unit is adjusted the voltage potential of control signal according to feedback signal or the second detection signal, and then whether the control voltage conversion unit produces output voltage.Thus; capable of regulating goes out suitable drive current; and the electric current between the balance light emitting diode, and reach the protective effect that open-circuit condition appears in overvoltage, overcurrent and light emitting diode, produce situation about damaging to avoid light emitting diode.
Certainly; the utility model also can have other various embodiments; in the situation that does not deviate from the utility model spirit and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the utility model, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the utility model.
Claims (8)
1. a light emitting diode drive device is suitable for driving a plurality of light emitting diodes, and those light emitting diodes are connected in parallel, and it is characterized in that, this light emitting diode drive device comprises:
One voltage conversion unit, in order to receiving an operating voltage, and according to a control signal, and convert this operating voltage to an output voltage, and this output voltage exports the anode tap of those light emitting diodes to;
A plurality of current control units couple respectively the cathode terminal of those light emitting diodes, in order to receiving a plurality of the first reference signals, and produce a plurality of current signals;
One first detecting unit couples the cathode terminal of those light emitting diodes, in order to produce one first detection signal;
One feedback unit couples this first detecting unit, in order to receive this first detection signal, to produce a feedback signal;
One second detecting unit couples this voltage conversion unit, in order to receive this output voltage, to produce one second detection signal; And
One control unit couples this feedback unit and this second detecting unit, in order to receiving this feedback signal, this second detection signal and this output voltage, and according to this feedback signal or this second detection signal, to produce this control signal.
2. light emitting diode drive device according to claim 1 is characterized in that, this voltage conversion unit comprises:
One first resistance has a first end and one second end, and this first end of this first resistance receives this operating voltage;
One first electric capacity has a first end and one second end, and this first end of this first electric capacity couples this first end of this first resistance, and this second end of this first electric capacity couples this second end of this first resistance;
One transformer has a primary side and a secondary side, and the first end of this primary side of this transformer couples this first end of this first resistance, and the second end of this secondary side of this transformer couples earth terminal;
One first diode has an anode tap and a cathode terminal, and this cathode terminal of this first diode couples this second end of this first resistance, and this anode tap of this first diode couples the second end of this primary side of this transformer;
One first switch element has a first end, one second end and one the 3rd end, and this first end of this first switch element couples this anode tap of this first diode, and this second termination of this first switch element is received this control signal;
One second resistance has a first end and one second end, and this first end of this second resistance couples the 3rd end of this first switch element;
One second diode has an anode tap and a cathode terminal, and this anode tap of this second diode couples the first end of this secondary side of this transformer;
One second electric capacity has a first end and one second end, and this first end of this second electric capacity couples this cathode terminal of this second diode, and this second end of this second electric capacity couples earth terminal;
One inductance has a first end and one second end, and this first end of this inductance couples this second end of this second electric capacity, and this of this inductance the second end produces this output voltage; And
One the 3rd electric capacity has a first end and one second end, and this first end of the 3rd electric capacity couples this second end of this inductance, and this second end of the 3rd electric capacity couples earth terminal.
3. light emitting diode drive device according to claim 1 is characterized in that, those current control units comprise separately:
One first operational amplifier has a first input end, one second input and an output, and this first input end of this first operational amplifier receives this first reference signal;
One the 4th electric capacity has a first end and one second end, and this first end of the 4th electric capacity couples this second input of this first operational amplifier;
One the 3rd resistance has a first end and one second end, and this first end of the 3rd resistance couples this second end of the 4th electric capacity, and this second end of the 3rd resistance couples this output of this first operational amplifier;
One the 4th resistance has a first end and one second end, and this first end of the 4th resistance couples this second end of the 3rd resistance;
One second switch unit, have a first end, one second end and one the 3rd end, this first end of this second switch unit couples the cathode terminal of those light emitting diodes, and to produce this current signal, this second end of this second switch unit couples this second end of the 4th resistance;
One the 5th resistance has a first end and one second end, and this first end of the 5th resistance couples this first end of the 4th electric capacity, and this second end of the 5th resistance couples the 3rd end of this second switch unit; And
One the 6th resistance has a first end and one second end, and this first end of the 6th resistance couples this second end of the 5th resistance, and this second end of the 6th resistance couples earth terminal.
4. light emitting diode drive device according to claim 1 is characterized in that, this first detecting unit comprises:
A plurality of the 3rd diodes, those the 3rd diodes have an anode tap and a cathode terminal separately, and those anode taps of those the 3rd diodes couple respectively the cathode terminal of those light emitting diodes;
One the 7th resistance has a first end and one second end, and this first end of the 7th resistance couples those cathode terminals of those the 3rd diodes, and this second end of the 7th resistance produces this first detection signal; And
One the 8th resistance has a first end and one second end, and this first end of the 8th resistance couples this second end of the 7th resistance, and this second end of the 8th resistance couples earth terminal.
5. light emitting diode drive device according to claim 1 is characterized in that, this feedback unit comprises:
One second operational amplifier, have a first input end, one second input and an output, this first input end of this second operational amplifier receives one second reference signal, and this second input of this second operational amplifier couples this feedback unit, to receive this first detection signal;
One the 9th resistance has a first end and one second end, and this first end of the 9th resistance couples this second input of this second operational amplifier;
One the 5th electric capacity has a first end and one second end, and this first end of the 5th electric capacity couples this second end of the 9th resistance, and this second end of the 5th electric capacity couples this output of this second operational amplifier; And
One the 4th diode has an anode tap and a cathode terminal, and this anode tap of the 4th diode produces this feedback signal, and this cathode terminal of the 4th diode couples this output of this second operational amplifier.
6. light emitting diode drive device according to claim 1 is characterized in that, this second detecting unit comprises:
1 the tenth resistance has a first end and one second end, and this first end of the tenth resistance receives this output voltage;
1 the 11 resistance has a first end and one second end, and this first end of the 11 resistance couples this second end of the tenth resistance, and this second end of the 11 resistance couples earth terminal;
One the 3rd operational amplifier, have a first input end, one second input and an output, this first input end of the 3rd operational amplifier receives one the 3rd reference signal, and this second input of the 3rd operational amplifier couples this first end of the 11 resistance;
1 the 12 resistance has a first end and one second end, and this first end of the 12 resistance couples this second input of the 3rd operational amplifier;
One the 6th electric capacity has a first end and one second end, and this first end of the 6th electric capacity couples this second end of the 12 resistance, and this second end of the 6th electric capacity couples this output of the 3rd operational amplifier; And
One the 5th diode has an anode tap and a cathode terminal, and this anode tap of the 5th diode produces this second detection signal, and this cathode terminal of the 5th diode couples this output of the 3rd operational amplifier.
7. light emitting diode drive device according to claim 1 is characterized in that, this control unit comprises:
1 the 13 resistance has a first end and one second end, and this first end of the 13 resistance receives this output voltage;
One optical coupler, have a first end, one second end, one the 3rd end and one the 4th end, this first end of this optical coupler couples this second end of the 13 resistance, this of this optical coupler the second termination is received this feedback signal and this second detection signal, the 3rd end of this optical coupler produces a coupled signal, and the 4th end of this optical coupler couples earth terminal; And
One pulse-width modulation unit couples the 3rd end of this optical coupler, in order to receive this coupled signal, to produce this control signal.
8. light emitting diode drive device according to claim 1 is characterized in that, also comprises:
One filter unit receives a supply voltage, and this supply voltage is carried out filtering, to produce a filtering voltage; And
One rectification unit couples this filter unit, receives this filtering voltage, and this filtering voltage is carried out rectification, to produce this operating voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220455390 CN202738221U (en) | 2012-09-07 | 2012-09-07 | Light-emitting diode driving device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220455390 CN202738221U (en) | 2012-09-07 | 2012-09-07 | Light-emitting diode driving device |
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| Publication Number | Publication Date |
|---|---|
| CN202738221U true CN202738221U (en) | 2013-02-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 201220455390 Expired - Fee Related CN202738221U (en) | 2012-09-07 | 2012-09-07 | Light-emitting diode driving device |
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| CN (1) | CN202738221U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112312617A (en) * | 2020-09-24 | 2021-02-02 | 昂宝电子（上海）有限公司 | LED backlight control system and method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112312617A (en) * | 2020-09-24 | 2021-02-02 | 昂宝电子（上海）有限公司 | LED backlight control system and method |
| CN112312617B (en) * | 2020-09-24 | 2023-05-12 | 昂宝电子（上海）有限公司 | LED backlight control system and method |
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