CN104010408A - Drive circuit of high-voltage LED - Google Patents
Drive circuit of high-voltage LED Download PDFInfo
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- CN104010408A CN104010408A CN201310172576.1A CN201310172576A CN104010408A CN 104010408 A CN104010408 A CN 104010408A CN 201310172576 A CN201310172576 A CN 201310172576A CN 104010408 A CN104010408 A CN 104010408A
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Abstract
The invention provides a driving circuit of a high-voltage LED. The integrating circuit is used to filter the ripple of the input voltage with large variation and is not interfered by floating noise. Thus, the product of the input voltage and the output current can be controlled to obtain constant power output. The problem of output power drift of the high-voltage LED long string caused by the switch can be greatly improved.
Description
Technical field
The present invention utilizes integrating circuit (integration circuit), gets input voltage through computing, makes the power of LED string approach definite value.Can improve by this problem of input voltage drift, promote human eye comfort level.
Background technology
Long string high-voltage LED is because of cheap, and without electromagnetic interference (electromagnetic interference, EMI), widely popular institute adopts, but high voltage control still has many shortcomings to need to improve.
U.S. Patent number 6,989, in 807 and 7,081,722, drive current is constant current, or improves power factor (power factor, PF), make input current with input voltage linear increasing.But, in the time of input supply voltage unusual fluctuation, the drift that causes power output to increase.U.S. Patent number 7,439,944 propose restriction maximum output current or strangulation peak power output, to reach the method for electrical protection effect.This method is without constant power output characteristic, and in the time there is overvoltage protection, input voltage is higher, and output current will significantly reduce thereupon, affect PF; As shown in Figure 1.
In addition, the large Supertex of factory of american semiconductor, in June, 2012, delivers in the document of production code member CL800 and CL8801, uses Zener as dummy load, and in the time that input voltage increases, Zener is activated and converts electrical energy into heat energy, reduces electrical-optical conversion efficiency.For example, the Acrich series that South Korea Seoul semiconductor company delivered in October, 2012, wherein the input voltage of production code member SMJD-3V08W1P3 and SMJD-3V16W1P3 is in the time of 200V to 260V, and power output and lumen number are proportional to input voltage, and difference is greater than 30%.Therefore,, under input voltage unusual fluctuation or the excessive operational environment of interference noise, brightness easily produces optical flare and beats, and causes human eye discomfort.
In practical application, desirable control high-voltage LED framework, except maximum output current and maximum power, also should reduce the interference of input voltage noise.In addition, under broader input voltage condition, should possess the comfortableness of permanent brightness.Therefore, the present invention proposes a kind of device of controlling long string high-voltage LED, has constant power output and antimierophonic characteristic, can meet in LED light fixture safety standard the requirement of power output to input voltage vary stable degree.
Summary of the invention
The object of the present invention is to provide a kind of drive circuit of high-voltage LED, constant power output can be provided, there is the characteristics such as the system dependability of raising and anti-electric power networks noise jamming.
Drive circuit of the present invention can comprise the little string of one or more LED that are one another in series, one or more switch and a control circuit.
The little string of LED is made up of the LED of one or more serial or parallel connections, has a current input terminal and a current output terminal; Wherein current input terminal electrical couplings is to the voltage output end of power supply.Switch electrical couplings, to the corresponding little string of LED, can be controlled the startup of the little string of this LED or close.Control circuit electrical couplings, to the little string of LED, at least comprises an integrating circuit.Integrating circuit can obtain average voltage or the average mark voltage (ratio voltage) of the little Lu Shangyi of the getting lines crossed specified point of LED.This average voltage or average mark voltage in control circuit after computing, its result can be in order to revise the input current of power supply or the electric current of the little string of LED of flowing through.
If there is the little string of multiple LED in above-mentioned drive circuit, control circuit can electrical couplings to the little string of arbitrary LED, but be preferably the little string of LED that approaches power supply most.And the little specified point of getting lines crossed on road of LED is being preferably the current input terminal of the little string of LED, but not as limit.
After the electric current correction of the input current of above-mentioned power supply or the little string of this LED of flowing through, can make the power of the little string of LED approach a set point, or be the 90%-110% scope of this set point; Be more preferred from 95%-105%; The best is 98%-102%.
And control circuit is by starting computing to obtaining the input current of power supply or the correction value required time of the electric current of the little string of LED of flowing through (or time of integration of integrating circuit) is preferably and is greater than the power input voltage cycle half; Be more preferred from and be greater than 2 times of the whole rear voltage cycle of bridge.This is because because the input current of power supply is less than 60 degree with input voltage phase is poor, and input current determines by the output current of switch, easily produces and shakes.In addition, for example, in the time that context has large-current electric device (large motor) running, input voltage easily dyes noise, and the input voltage amplitude of beating may be excessive, and input current also can present labile state.Therefore, in the time that reality measures, integrating circuit need to have sufficiently long sample time, could filter the noise of input voltage.Modal integrating circuit is digital integrating circuit, also can be analog circuit or low-pass filter circuit.
Control circuit still can comprise a waveform tracing device, and electrical couplings, to integrating circuit, makes the waveform of correcting current and the waveform similarity of power input voltage.
Above-mentioned switch has a current input terminal, a current output terminal conventionally, and a signal input part.Current input terminal electrical couplings is to the current output terminal of the corresponding little string of LED; Current output terminal electrical couplings is to the voltage output end of power supply.Accordingly, control circuit also has a voltage input end and a voltage output end.Voltage input end electrical couplings is between the current input terminal of the little string of LED and the voltage output end of power supply; Voltage output end electrical couplings is to the signal input part of switch.Typical switch is electrically to be composed in series by a high-pressure N-shaped assembly and a low pressure N-type assembly, but the present invention is not limited to this.
When control circuit obtains input voltage and after starting, integrating circuit just receives input voltage (dividing potential drop), constantly carry out computing work.Therefore,, in the time that input voltage changes, can revise input current by the result that continues computing, to reach the object of determining power.
Brief description of the drawings
Fig. 1 shows that known technology is in the time that overvoltage protection occurs, and input voltage is higher, and output current will significantly reduce thereupon.
Fig. 2 shows one the framework of control circuit embodiment of the present invention.
Fig. 3 shows the RC integrating circuit being made up of resistance and electric capacity.
When Fig. 4 demonstration reaches permanent power, average current input increases and diminishes with average input voltage.
Fig. 5 shows the framework of another embodiment, and its control circuit comprises a waveform tracing device.
Fig. 6 shows that the waveform of output current can be with the waviness of input voltage by waveform tracing device.
Fig. 7 shows the half-wave voltage signal that obtains input electric power net by half-bridge sample circuit.
Symbol description:
20 integrating circuit
30 multipliers
40 set points
51 master and servant's controllers
601-612 switch
The long string of 70 LED
The little string of 701-712 LED
80 waveform tracing devices
901 AC power
902 bridge rectifiers
C2 electric capacity
R2, R3, R4 resistance
Embodiment
Control circuit of the present invention is not limited to integrated circuit, can be whole circuit control framework or device.
Fig. 2 shows the framework of one of control circuit embodiment of the present invention.AC power 901 is connected to bridge rectifier 902.In the present embodiment, effective current or voltage are often referred to the root-mean-square value of this curtage within a period of time.The input voltage of AC power 901 has sinusoidal waveform, and its root-mean-square value is Va, and input current also has sinusoidal waveform, and its root-mean-square value is Ia.The output of bridge rectifier 902 does not connect electric capacity, so the high merit of tool is because of characteristic.The long string 70 of LED has 12 the little string of LED 701-712, is controlled by 12 switch 601-612 and master and servant's controller (master/slave controller) 51.Each switch can be electrically connected in series and form with a low pressure N-type assembly by a high-pressure N-shaped assembly (or N-MOS), as described in Chinese application number 201220356114.6 or 201210500840.5.The input voltage of the long string 70 of LED is the output voltage of bridge rectifier 902.The conducting voltage Vf=3.0V of each LED, a little string comprises the LED of 10 serial connections, the Vf of a little string is about 30V.The output of bridge rectifier 902 is connected to resistance R 2 and resistance R 3.
In figure, dotted line frame represents control circuit, and by the electric current of suitable computing and the long string of correction input LED, the power that can maintain LED is a set point, or in the particular range of this set point.Control circuit mainly comprises integrating circuit 20, multiplier 30 and set point 40.Integrating circuit 20 is connected to the contact between resistance R 2 and resistance R 3, can in certain hour, obtain the component voltage (ratio voltage) of the input voltage of the long string 70 of LED, calculates and tries to achieve mean value Vr, then this mean value is delivered to multiplier 30 through integrating circuit.As shown in the figure, the input of multiplier 30 is connected to integrating circuit 20 and set point 40, carries out computing.In the time that control circuit starts, if the root-mean-square value Ia of power supply input current is Iao, the mean value Vr of component voltage is Vro; , in the time that the mean value Vr of component voltage is Vr1 with power input voltage variation, the root-mean-square value Ia of power supply input current should be modified to Ia1(=Iao × Vro/Vr1), make LED power keep definite value.That is, be using component voltage mean value as the reference value of revising power supply input current, form and determine power framework.Iao × the Vro of the desirable power form of set point 40 or the Iao of current forms.In this embodiment, the electric current of power supply input current, the LED that flows through or the electric current of the switch of flowing through should be identical, therefore revise wherein arbitrary current value.
In the present embodiment, the about 50Hz of frequency or the 60Hz of input 220V alternating current, after bridge rectifier, doubled frequency is to 100Hz or 120Hz; This frequency still belongs to low frequency.In high merit because of under condition, minimum voltage=0V, ceiling voltage=310V, voltage fluctuation is very large.If value centered by input voltage vin (220V), front 10 groups of current switches can be lighted in turn according to input voltage, but rear two groups of current switches can not start because of brownout.If power output is set as 10W, input current Iin is about 45.4mA(=10W/220V).In the time that input voltage step-down is 180V, only have front 8 groups switch activated, rear 4 groups of switch no currents pass through.By computing and the correction of control circuit, can make input current be increased to 55.5mA(=10W/180V).If input voltage is increased to 260V, 12 groups of current switches start totally.By computing and the correction of control circuit, can make input current be reduced to 38mA(=10W/260V).In other words, though input voltage in the dynamic change of 180V～260V scope, or input voltage rate of change by-20% increasing to+20%, its power output still keeps definite value.Result shows the permanent brightness output of integral LED, irrelevant with input voltage.
The invention is not restricted to use switch and master and servant's controller as shown in the Examples, also can use other switching device, as long as can reach the object of firm power of the present invention.For example, can be used as and determine current switch in conjunction with a high potential assembly and an operational amplifier.
Fig. 3 shows a kind of typical integrating circuit, the RC(resister-capacitor being made up of resistance R 4 and capacitor C 2).In general, the time constant of integrating circuit (time constant) should be greater than 1/100 second or 1/120 second, can will input ripple filtering by plug-in capacitor.If the time constant of integrating circuit is shorter, electric capacity is less, and the reaction time is faster, more easily shakes.But electric capacity increase may cause the reaction time long, is also not suitable for.
In the time that input voltage increases or diminishes, after a period of time sampling and calculating, can obtain the root-mean-square value of component voltage, carry out computing with set point, can revise the root-mean-square value of input current, input current is diminished or increase.Fig. 4 demonstration, in the time of input voltage convergence zero, actual input current is convergence zero also, but actual input current can be definite value At All Other Times.Compared to the known technology of Fig. 1, electric current of the present invention can not produce depression in the time of voltage peak or generation surging, makes power keep definite value.The cycle of input voltage is generally 1/60,1/120,1/50 or 1/100 second.
Fig. 5 shows the framework of another embodiment.Be with Fig. 2 difference, between the output of integrating circuit 20, multiplier 30 and set point 40 and master and servant's controller, be connected a waveform tracing device 80.By waveform tracing device, the waveform of input current, can be with the waviness of input voltage, as shown in Figure 6 through integration and after computing time.Similarly, electric current can not produce depression in the time of voltage peak, makes power keep definite value.
The component voltage that control circuit of the present invention is got is not limited to full-wave type, also can be half-wave type.As shown in Figure 7, can obtain by half-bridge sample circuit the half-wave voltage signal of input electric power net.And for different voltage input modes, can utilize current potential translation (level shift) circuit, eliminate and compensate the input signal of variant type, all can obtain permanent power identical characteristics.
Combine it, effect of the present invention and derivative advantage comprise:
1. constant power output that can linear multistage control LED, tool anti-noise jamming characteristic, and simple in structure, be difficult for producing because of the unsteady color break-up of input voltage, with low cost.
2. under broader input voltage changing environment, work, still the high merit of tool is because of characteristic, and lower total harmonic distortion value (Total Harmonic Distortion, THD).
3. due to constant power output, make LED light fixture unlikely overheated, simplify radiating module design, more can extend light fixture useful life.
Should be noted, no matter there are how many switches to switch, comprise that N-type high potential assembly is connected in series control with N-type low pressure assembly in LED heap, no matter and whether have LED ground connection or earth-free, the present invention is suitable for.
Although the present invention discloses as above with embodiment; so it is not in order to limit the present invention; under any, in technical field, have and conventionally know the knowledgeable; without departing from the spirit and scope of the present invention; when doing a little change and retouching, therefore protection scope of the present invention is as the criterion with the content being defined in claim.
Claims (19)
1. a drive circuit for high-voltage LED, is characterized in that, comprising:
The little string of one LED, is made up of the LED of one or more serial or parallel connections, has the voltage output end of current input terminal electrical couplings to power supply, and a current output terminal;
One switch, electrical couplings is to the little string of this LED, to control the startup of the little string of this LED or to close; And
One control circuit, electrical couplings is to the little string of this LED, at least comprise that an integrating circuit can obtain average voltage or the average mark voltage of the little Lu Shangyi of the getting lines crossed specified point of this LED, in this control circuit, carry out computing, then according to the electric current of the input current of this power supply of operation result correction or the little string of this LED of flowing through.
2. drive circuit as claimed in claim 1, is characterized in that, after the electric current correction of the input current of this power supply or the little string of this LED of flowing through, can make the power of the little string of this LED approach a set point.
3. drive circuit as claimed in claim 2, is characterized in that, the 90%-110% that the scope after the power correction of the little string of this LED is this set point.
4. drive circuit as claimed in claim 1, is characterized in that, the little specified point of getting lines crossed on road of this LED is referring to the current input terminal of the little string of this LED.
5. drive circuit as claimed in claim 1, is characterized in that, this control circuit is by starting computing to obtaining the input current of this power supply or the correction value required time of the electric current of the little string of this LED of flowing through is greater than the power input voltage cycle half.
6. drive circuit as claimed in claim 1, is characterized in that, this control circuit still comprises a waveform tracing device.
7. drive circuit as claimed in claim 1, is characterized in that, this switch has the current output terminal of a current input terminal electrical couplings to the little string of this LED, and a current output terminal electrical couplings is to the voltage output end of this power supply, and a signal input part.
8. drive circuit as claimed in claim 7, it is characterized in that, this control circuit has a voltage input end electrical couplings between the current input terminal and the voltage output end of this power supply of the little string of this LED, and a voltage output end electrical couplings is to the signal input part of this switch.
9. drive circuit as claimed in claim 1, is characterized in that, this switch is electrically to be composed in series by a high-pressure N-shaped assembly and a low pressure N-type assembly.
10. a drive circuit for high-voltage LED, is characterized in that, comprising:
The little string of LED of multiple series connection, the little string of each LED is made up of the LED of one or more serial or parallel connections, and has the voltage output end of current input terminal electrical couplings to power supply, and a current output terminal;
Multiple switches, each switch electrical couplings is to the corresponding little string of LED, to control the startup of the little string of this LED or to close; And
One control circuit, the little string of the specific LED of electrical couplings to one and corresponding switch, at least comprise that an integrating circuit can obtain average voltage or the average mark voltage of the little Lu Shangyi of the getting lines crossed specified point of this specific LED, in this control circuit, carry out computing, then according to the electric current of the input current of this power supply of operation result correction or the little string of this specific LED of flowing through.
11. drive circuits as claimed in claim 10, is characterized in that, after the electric current correction of the input current of this power supply or the little string of this specific LED, can make the power of the little string of this specific LED approach a set point.
12. drive circuits as claimed in claim 11, is characterized in that, the 90%-110% that the scope after the power correction of the little string of this specific LED is this set point.
13. drive circuits as claimed in claim 10, is characterized in that, this control circuit is by starting computing to obtaining the input current of this power supply or the correction value required time of the electric current of the little string of this specific LED of flowing through is greater than the power input voltage cycle half.
14. drive circuits as claimed in claim 10, is characterized in that, this control circuit still comprises a waveform tracing device.
15. drive circuits as claimed in claim 10, is characterized in that, each switch has the current output terminal of a current input terminal electrical couplings to the little string of corresponding LED, and a current output terminal electrical couplings is to the voltage output end of this power supply, and a signal input part.
16. drive circuits as claimed in claim 15, it is characterized in that, this control circuit has a voltage input end electrical couplings between the current input terminal and the voltage output end of this power supply of the little string of this specific LED, and a voltage output end electrical couplings is to the signal input part of each switch.
17. drive circuits as claimed in claim 10, is characterized in that, the little string of this specific LED refers to the little string of LED that approaches power supply most.
18. drive circuits as claimed in claim 10, is characterized in that, the little specified point of getting lines crossed on road of this specific LED is referring to the current input terminal of the little string of this specific LED.
19. drive circuits as claimed in claim 10, is characterized in that, this switch is electrically to be composed in series by a high-pressure N-shaped assembly and a low pressure N-type assembly.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW102106842A TW201434347A (en) | 2013-02-27 | 2013-02-27 | Driving circuit of high-voltage LED string |
| TW102106842 | 2013-02-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104010408A true CN104010408A (en) | 2014-08-27 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310172576.1A Pending CN104010408A (en) | 2013-02-27 | 2013-05-10 | Drive circuit of high-voltage LED |
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| Country | Link |
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| CN (1) | CN104010408A (en) |
| TW (1) | TW201434347A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107708246A (en) * | 2016-08-09 | 2018-02-16 | 东林科技股份有限公司 | LED drive and its driving method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201758472U (en) * | 2010-03-19 | 2011-03-09 | 技领半导体(上海)有限公司 | LED lighting string circuit containing long strings connected by a plurality of short strings |
| US20120126713A1 (en) * | 2010-11-24 | 2012-05-24 | Mamoru Horino | Led driving apparatus |
| CN102523663A (en) * | 2012-01-06 | 2012-06-27 | 广州市隆都电子有限公司 | Constant-power LED drive circuit |
| CN102791055A (en) * | 2011-05-18 | 2012-11-21 | 西安阿普莱特光电科技有限公司 | Constant light of switch power supply maintaining lamp and with power feedback |
| CN202587465U (en) * | 2012-01-17 | 2012-12-05 | 主一科技股份有限公司 | A long LED string device and a current-limiting integrated circuit |
-
2013
- 2013-02-27 TW TW102106842A patent/TW201434347A/en unknown
- 2013-05-10 CN CN201310172576.1A patent/CN104010408A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201758472U (en) * | 2010-03-19 | 2011-03-09 | 技领半导体(上海)有限公司 | LED lighting string circuit containing long strings connected by a plurality of short strings |
| US20120126713A1 (en) * | 2010-11-24 | 2012-05-24 | Mamoru Horino | Led driving apparatus |
| CN102791055A (en) * | 2011-05-18 | 2012-11-21 | 西安阿普莱特光电科技有限公司 | Constant light of switch power supply maintaining lamp and with power feedback |
| CN102523663A (en) * | 2012-01-06 | 2012-06-27 | 广州市隆都电子有限公司 | Constant-power LED drive circuit |
| CN202587465U (en) * | 2012-01-17 | 2012-12-05 | 主一科技股份有限公司 | A long LED string device and a current-limiting integrated circuit |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107708246A (en) * | 2016-08-09 | 2018-02-16 | 东林科技股份有限公司 | LED drive and its driving method |
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| Publication number | Publication date |
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| TW201434347A (en) | 2014-09-01 |
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Application publication date: 20140827 |