CN100352068C - Method for driving LED by current mirror - Google Patents
Method for driving LED by current mirror Download PDFInfo
- Publication number
- CN100352068C CN100352068C CNB031548695A CN03154869A CN100352068C CN 100352068 C CN100352068 C CN 100352068C CN B031548695 A CNB031548695 A CN B031548695A CN 03154869 A CN03154869 A CN 03154869A CN 100352068 C CN100352068 C CN 100352068C
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- current mirror
- voltage
- light
- emitting diode
- input terminal
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Abstract
The present invention relates to a high efficient method of a boosted circuit using a current mirror for driving light emitting diodes (LED), which is used for driving a plurality of parallel LEDs coupled to an output end of the current mirror to obtain output with the highest efficiency. An operating mode comprises the following steps: the voltage of a control end of the current mirror serves as reference voltage; the voltage of an input end of the current mirror is enhanced, input ends of the LEDs are viewed as voltage feedback points to fix voltage differences between the input end and the output end of the current mirror to maintain constant; the LEDs are driven by the voltage of the output end of the current mirror.
Description
(1) technical field
The present invention is meant a kind of method with current mirror driven for emitting lights diode (LED), refers to a kind of method that drives white light emitting diode with current mirror especially.
(2) background technology
Desiring on the market now to drive the employed boosting mode of white light emitting diode (LED) with current mirror is common charge pump circuit (Charge Pump Circuit), as shown in Figure 1, it is to utilize the characteristic of diode element (diode-connected MOS) one-way transmission and electric capacity transmits and store charge and produce high-tension output; Traditional charge pump circuit is to be formed by several basic pump circuit 11 serial connections, and each basic pump circuit is to be coupled by first capacitor C 22, the first transistor N23, second capacitor C 25 and transistor seconds N26 to form.Wherein, the first transistor N23 and transistor seconds N26 are connected into common drain earlier, are connected with an end of first capacitor C 22 and second capacitor C 25 respectively, as shown in Figure 2 again.
Yet the mode that drives white light emitting diode with known charge pump circuit can produce two problems, and is as described below respectively:
(1) because charge pump circuit (seeing also Fig. 1) itself comes the framework of store charge to be limit with electric capacity, therefore as if the charge pump circuit with a secondary, its peak efficiency is to be V
OUT/ (2V
CC) or V
OUT/ (1.5V
CC), therefore, its boosting efficiency can be said and be transfused to voltage V
CCDetermine, can't be to improve application circuit or improve the efficient that peripheral element promotes charge pump circuit.
(2) see also Fig. 3, it is the circuit diagram that drives white light emitting diode in the known techniques with current mirror, and wherein, the input voltage of the current mirror that transistor N31, N32, N33 and N34 are constituted is the output voltage V of charge pump circuit among Fig. 1
OUTBecause charge pump circuit is with V for the control mode of current mirror
OUTBe fixed on 5V, and the input voltage V of white light emitting diode D35
FBe between 3.1 ~ 3.8V, therefore have excessive power loss on current mirror, promptly
P
LEDLOSS＝I
LED(V
OUT-V
F) (1)
(3) summary of the invention
Main purpose of the present invention is for proposing a kind of method with current mirror driven for emitting lights diode (LED), it is when lifting current mirror input terminal voltage is with the driven for emitting lights diode, also can fixed current mirror input and output between voltage drop, with improve known at the charge pump circuit that uses the capacitance boost kenel when driving white light emitting diode, low boosting efficiency that is caused and excessive power loss are in the situation of current mirror.
According to conception of the present invention, a kind of method with current mirror driven for emitting lights diode (LED) is proposed, be the light-emitting diode of a plurality of parallel connections that is coupled to the output of a current mirror in order to driving, comprise the following steps: that control end voltage with this current mirror is as reference voltage; Promote the input terminal voltage of this current mirror, and input that will these a plurality of light-emitting diodes is used as the Voltage Feedback point, remains unchanged with the input of fixing this current mirror and the voltage difference between the output; And drive these a plurality of light-emitting diodes with the output end voltage of this current mirror.
According to above-mentioned conception, wherein this current mirror is to be coupled by a plurality of identical metal oxide semiconductor transistors (MOS) to form.
According to above-mentioned conception, wherein these a plurality of light-emitting diodes are to be white light emitting diode.
According to above-mentioned conception, wherein these a plurality of light-emitting diodes are to be blue light-emitting diode.
According to above-mentioned conception, be the input terminal voltage that promotes this current mirror with an inductance.
According to another conception of the present invention, a kind of method with current mirror driven for emitting lights diode (LED) is proposed, be the light-emitting diode of a plurality of parallel connections that is coupled to the output of a current mirror in order to driving, comprise the following steps: that input terminal voltage with this current mirror deducts offset voltage (Offset Voltage) as with reference to voltage; Promote the input terminal voltage of this current mirror, and input that will these a plurality of light-emitting diodes is used as the Voltage Feedback point, remains unchanged with the input of fixing this current mirror and the voltage difference between the output; And drive these a plurality of light-emitting diodes with the output end voltage of this current mirror.
According to above-mentioned conception, wherein this current mirror is to be coupled by a plurality of identical metal oxide semiconductor transistors (MOS) to form.
According to above-mentioned conception, wherein these a plurality of light-emitting diodes are to be white light emitting diode.
According to above-mentioned conception, wherein these a plurality of light-emitting diodes are to be blue light-emitting diode.
According to above-mentioned conception, be the input terminal voltage that promotes this current mirror with an inductance.
According to a conception more of the present invention, a kind of method with current mirror driven for emitting lights diode (LED) is proposed, it is the multi-group light-emitting diode that is coupled to the output of a current mirror in order to driving, be to be connected in parallel to each other between every group of light-emitting diode wherein, and each light-emitting diode in every group of light-emitting diode is to be one another in series, this method comprises the following steps: to promote input terminal voltage to a fixed voltage of this current mirror, to find out one group of maximum light-emitting diode of series connection number; With the control end voltage of this current mirror as reference voltage; The input of maximum this group light-emitting diode of series connection number is used as the Voltage Feedback point, and adjusts the input terminal voltage of this current mirror, remain unchanged with the input of fixing this current mirror and the voltage difference between the output; And drive this multi-group light-emitting diode with the output end voltage of this current mirror.
According to above-mentioned conception, wherein this current mirror is to be coupled by a plurality of identical metal oxide semiconductor transistors (MOS) to form.
According to above-mentioned conception, wherein these a plurality of light-emitting diodes are to be white light emitting diode.
According to above-mentioned conception, wherein these a plurality of light-emitting diodes are to be blue light-emitting diode.
According to above-mentioned conception, be the input terminal voltage that promotes this current mirror with an inductance.
According to a conception more of the present invention, a kind of method with current mirror driven for emitting lights diode (LED) is proposed, it is the multi-group light-emitting diode that is coupled to the output of a current mirror in order to driving, be to be connected in parallel to each other between every group of light-emitting diode wherein, and each light-emitting diode in every group of light-emitting diode is to be one another in series, this method comprises the following steps: to promote input terminal voltage to a fixed voltage of this current mirror, to find out one group of maximum light-emitting diode of series connection number; Deduct offset voltage (Offset Voltage) as with reference to voltage with the input terminal voltage of this current mirror; The input of maximum this group light-emitting diode of series connection number is used as the Voltage Feedback point, and adjusts the input terminal voltage of this current mirror, remain unchanged with the input of fixing this current mirror and the voltage difference between the output; And drive this multi-group light-emitting diode with the output end voltage of this current mirror.
According to above-mentioned conception, wherein this current mirror is to be coupled by a plurality of identical metal oxide semiconductor transistors (MOS) to form.
According to above-mentioned conception, wherein these a plurality of light-emitting diodes are to be white light emitting diode.
According to above-mentioned conception, wherein these a plurality of light-emitting diodes are to be blue light-emitting diode.
According to above-mentioned conception, be the input terminal voltage that promotes this current mirror with an inductance.
The present invention is by following accompanying drawing and detailed description and can obtain a more deep understanding:
(4) description of drawings
Fig. 1 is existing charge pump circuit;
Fig. 2 is the element circuit of existing charge pump circuit;
Fig. 3 is the circuit diagram that drives white light emitting diode in the known techniques with current mirror;
Fig. 4 is the circuit diagram of the present invention with the method one preferable enforcement sample attitude of current mirror driven for emitting lights diode; And
Fig. 5 is the circuit diagram of the present invention with another preferable enforcement sample attitude of method of current mirror driven for emitting lights diode.
(5) embodiment
See also Fig. 4, it is the circuit diagram of the present invention with the method one preferable enforcement sample attitude of current mirror driven for emitting lights diode, it is the input terminal voltage that promotes current mirror 41 with an inductance type booster circuit 40, be coupled to a plurality of light-emitting diodes (LED) of the output of current mirror 41 with driving, light source colour as for light-emitting diode then is not defined as white light, and the light-emitting diode of blue light even other color of light is all applicable to method of the present invention; And the convenience in order to explain orally and to draw, present embodiment only is that the current mirror 41 that constitutes with four identical metal oxide semiconductor transistors (MOS) and the white light emitting diode of three parallel connections explain, and right person skilled in the art scholar all should know the circuit arrangement method that expands to more and the light-emitting diode that connects.
In Fig. 4, inductance type booster circuit 40 is to be coupled jointly by inductance 401, metal oxide semiconductor transistor 402, diode 403 and electric capacity 404 to form, because the inductance type booster circuit still has other multiple circuit connectings, hereat only lift a kind of explaining commonly used herein.When utilizing inductance type booster circuit 40 to promote the input terminal voltage of current mirror 41, be with the charge pump circuit difference of known techniques based on capacitance boost, the output end voltage (input terminal voltage of current mirror 41 just) of inductance type booster circuit 40 need not be fixed in a high voltage (for example 5V) more at this moment, but utilize inductance type booster circuit 40, with input terminal voltage V with current mirror 41
OUTAnd the mode that the voltage difference between the output end voltage VA42 is fixing utilizes current mirror 41 to drive white light emitting diode D42, D43 and D44; That is to say, earlier with the control end voltage VA41 of current mirror 41 as reference voltage, utilize inductance type booster circuit 40 to promote the input terminal voltage V of current mirrors 41 again
OUT, and white light emitting diode D42, D43 and D44 input node A42, A43 and A44 separately be used as the Voltage Feedback point, with fixing V
OUTAnd the voltage difference between VA42, VA43 and the VA44 remains unchanged it, and drives white light emitting diode D42, D43 and D44 by this.
In addition, aspect the decision of reference voltage, also can be with the input terminal voltage V of current mirror 41
OUTDeduct offset voltage (Offset Voltage) with as reference voltage, remaining step is then same as described above.
Above-described dual mode all is a plurality of white light emitting diodes that drive the output that is coupled to current mirror with the booster circuit of inductance type; Owing to be the framework that boosts based on inductance, therefore no longer be subjected to the restriction in the sky of charge pump circuit elder generation, therefore can promote the efficient of pressure with the mode of synchronous rectification or to hang down the synchro switch of conducting (turn on) resistance.
In addition, since this moment current mirror 41 input terminal voltage V
OUTNeed not be fixed in a high voltage again, but with the input terminal voltage V of current mirror 41
OUTAnd the voltage difference V between the output end voltage VA42
XFixing, thus the power of loss on current mirror 41 just reduce many, promptly
P
LEDLOSS=I
LEDV
XV wherein
X=V
OUT-V
A42(2)
In addition, because the booster circuit of inductance type can be promoted to the input voltage of current mirror higher current potential, so the output of current mirror can also not must be confined to couple the white light emitting diode of a plurality of parallel connections.As shown in Figure 5, it is the circuit diagram of the present invention with another preferable enforcement sample attitude of method of current mirror driven for emitting lights diode.In the figure, node A52, A53 and A54 connect the white light emitting diode that the serial connection number does not wait respectively, if boosted with above-mentioned circuit How It Works this moment without leave, then have the situation that partly white light emitting diode can't conducting and take place, therefore the preceding of the circuit How It Works of stating in the use must be earlier through a feedback point define program; That is to say, utilize the input terminal voltage V of inductance type booster circuit 50 earlier current mirror 51
OUTBe promoted to a higher fixed voltage V
H, and utilize this fixed voltage V
HFind out the maximum one group of white light emitting diode (being the white light emitting diode that is connected in series for node A53) of series connection number herein, then regard the Voltage Feedback point with the input of this group white light emitting diode again, and with a plurality of same type of drive of white light emitting diode in parallel of above-mentioned driving, keeping V
HWith V
A53Between the changeless situation of voltage difference under drive node A52, A53 and A54 the white light emitting diode of serial connection respectively.
Claims (10)
1. method with current mirror driven for emitting lights diode is coupled to the light-emitting diode of a plurality of parallel connections of the output of a current mirror in order to driving, comprise the following steps:
With the control end voltage of this current mirror as reference voltage;
Promote the input terminal voltage of this current mirror, and input that will these a plurality of light-emitting diodes is used as the Voltage Feedback point, remains unchanged with the input of fixing this current mirror and the voltage difference between the output; And
Output end voltage with this current mirror drives these a plurality of light-emitting diodes.
2. the method for claim 1 is characterized in that, this current mirror is to be coupled by a plurality of identical metal oxide semiconductor transistors to form.
3. the method for claim 1 is characterized in that, these a plurality of light-emitting diodes are to be white light emitting diode.
4. the method for claim 1 is characterized in that, these a plurality of light-emitting diodes are to be blue light-emitting diode.
5. the method for claim 1 is the input terminal voltage that promotes this current mirror with an inductance.
6. method with current mirror driven for emitting lights diode is the light-emitting diode of a plurality of parallel connections that is coupled to the output of a current mirror in order to driving, comprises the following steps:
Input terminal voltage with this current mirror deducts offset voltage as reference voltage;
Promote the input terminal voltage of this current mirror, and input that will these a plurality of light-emitting diodes is used as the Voltage Feedback point, remains unchanged with the input of fixing this current mirror and the voltage difference between the output; And
Output end voltage with this current mirror drives these a plurality of light-emitting diodes.
7. method with current mirror driven for emitting lights diode, be coupled to the multi-group light-emitting diode of the output of a current mirror in order to driving, be to be connected in parallel to each other between every group of light-emitting diode wherein, and each light-emitting diode in every group of light-emitting diode is to be one another in series, this method comprises the following steps:
Promote input terminal voltage to a fixed voltage of this current mirror, to find out one group of maximum light-emitting diode of series connection number;
With the control end voltage of this current mirror as reference voltage;
The input of maximum this group light-emitting diode of series connection number is used as the Voltage Feedback point, and adjusts the input terminal voltage of this current mirror, remain unchanged with the input of fixing this current mirror and the voltage difference between the output; And
Output end voltage with this current mirror drives this multi-group light-emitting diode.
8. method as claimed in claim 7 is characterized in that, is the input terminal voltage that promotes this current mirror with an inductance.
9. method with current mirror driven for emitting lights diode, be coupled to the multi-group light-emitting diode of the output of a current mirror in order to driving, be to be connected in parallel to each other between every group of light-emitting diode wherein, and each light-emitting diode in every group of light-emitting diode is to be one another in series, this method comprises the following steps:
Promote input terminal voltage to a fixed voltage of this current mirror, to find out one group of maximum light-emitting diode of series connection number;
Input terminal voltage with this current mirror deducts offset voltage as reference voltage;
The input of maximum this group light-emitting diode of series connection number is used as the Voltage Feedback point, and adjusts the input terminal voltage of this current mirror, remain unchanged with the input of fixing this current mirror and the voltage difference between the output; And
Output end voltage with this current mirror drives this multi-group light-emitting diode.
10. method as claimed in claim 9 is characterized in that it being the input terminal voltage that promotes this current mirror with an inductance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031548695A CN100352068C (en) | 2003-08-20 | 2003-08-20 | Method for driving LED by current mirror |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031548695A CN100352068C (en) | 2003-08-20 | 2003-08-20 | Method for driving LED by current mirror |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1585572A CN1585572A (en) | 2005-02-23 |
| CN100352068C true CN100352068C (en) | 2007-11-28 |
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ID=34598020
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031548695A Expired - Fee Related CN100352068C (en) | 2003-08-20 | 2003-08-20 | Method for driving LED by current mirror |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100352068C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371800C (en) * | 2005-06-15 | 2008-02-27 | 友达光电股份有限公司 | Backlight module structure |
| CN106941751A (en) * | 2017-04-27 | 2017-07-11 | 宁波迪明斯电子科技有限公司 | A kind of drive circuit of variable voltage |
| CN108601144A (en) * | 2017-10-09 | 2018-09-28 | 东莞市翔实信息科技有限公司 | Unmanned electric light drive integrated circult |
| TWI707325B (en) * | 2019-07-01 | 2020-10-11 | 友達光電股份有限公司 | Light emitting diode driving circuit |
Citations (10)
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|---|---|---|---|---|
| JPH06196746A (en) * | 1992-12-25 | 1994-07-15 | Canon Inc | Photoelectric converter, driving circuit, semiconductor light emitting device driving circuit, storage device and sequential access memory |
| US5608339A (en) * | 1994-08-30 | 1997-03-04 | Rohm, Co. Ltd. | Device for driving a LED display |
| US5701133A (en) * | 1994-10-13 | 1997-12-23 | Lucent Technologies Inc. | Cascaded multiplying current mirror driver for LED's |
| JPH10242522A (en) * | 1997-02-24 | 1998-09-11 | Sharp Corp | Light emitting diode driving circuit |
| US6255868B1 (en) * | 2000-02-28 | 2001-07-03 | Mitsubishi Denki Kabushiki Kaisha | Buffer circuit and hold circuit |
| JP2002043684A (en) * | 2000-07-21 | 2002-02-08 | Nippon Precision Circuits Inc | Control circuit for light emitting device |
| JP2002064433A (en) * | 2000-06-08 | 2002-02-28 | Matsushita Electric Ind Co Ltd | Driving circuit for light emitting element, and optical transmission system using the same |
| JP2002237745A (en) * | 2001-02-08 | 2002-08-23 | Glory Ltd | Load driving circuit |
| US6486726B1 (en) * | 2001-05-18 | 2002-11-26 | Eugene Robert Worley, Sr. | LED driver circuit with a boosted voltage output |
| JP2003100472A (en) * | 2001-07-19 | 2003-04-04 | Denso Corp | Driving equipment for light emitting diode |
-
2003
- 2003-08-20 CN CNB031548695A patent/CN100352068C/en not_active Expired - Fee Related
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06196746A (en) * | 1992-12-25 | 1994-07-15 | Canon Inc | Photoelectric converter, driving circuit, semiconductor light emitting device driving circuit, storage device and sequential access memory |
| US5608339A (en) * | 1994-08-30 | 1997-03-04 | Rohm, Co. Ltd. | Device for driving a LED display |
| US5701133A (en) * | 1994-10-13 | 1997-12-23 | Lucent Technologies Inc. | Cascaded multiplying current mirror driver for LED's |
| JPH10242522A (en) * | 1997-02-24 | 1998-09-11 | Sharp Corp | Light emitting diode driving circuit |
| US6255868B1 (en) * | 2000-02-28 | 2001-07-03 | Mitsubishi Denki Kabushiki Kaisha | Buffer circuit and hold circuit |
| JP2002064433A (en) * | 2000-06-08 | 2002-02-28 | Matsushita Electric Ind Co Ltd | Driving circuit for light emitting element, and optical transmission system using the same |
| JP2002043684A (en) * | 2000-07-21 | 2002-02-08 | Nippon Precision Circuits Inc | Control circuit for light emitting device |
| JP2002237745A (en) * | 2001-02-08 | 2002-08-23 | Glory Ltd | Load driving circuit |
| US6486726B1 (en) * | 2001-05-18 | 2002-11-26 | Eugene Robert Worley, Sr. | LED driver circuit with a boosted voltage output |
| JP2003100472A (en) * | 2001-07-19 | 2003-04-04 | Denso Corp | Driving equipment for light emitting diode |
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| Publication number | Publication date |
|---|---|
| CN1585572A (en) | 2005-02-23 |
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Granted publication date: 20071128 Termination date: 20130820 |