TW201531150A - High power factor driving circuit for LED - Google Patents
High power factor driving circuit for LED Download PDFInfo
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- TW201531150A TW201531150A TW103102238A TW103102238A TW201531150A TW 201531150 A TW201531150 A TW 201531150A TW 103102238 A TW103102238 A TW 103102238A TW 103102238 A TW103102238 A TW 103102238A TW 201531150 A TW201531150 A TW 201531150A
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Abstract
Description
本發明係關於一種發光二極體之驅動電路，尤指一種發光二極體之高功率因數驅動電路。
The invention relates to a driving circuit of a light emitting diode, in particular to a high power factor driving circuit of a light emitting diode.
習用之發光二極體驅動電路係如第１圖所示，通常將電源101以橋式整流器103整流後，串接複數個發光二極體121、123及一限流元件125而形成燈具。
此一驅動電路之設計方式，雖可以最簡單的電路達到驅動燈具中發光二極體121、123之目的，但當電源101之電壓Vs低於發光二極體121、123之順向偏壓時，燈具即因無電流通過而熄滅，造成閃爍的現象。
部分廠商為解決燈具閃爍的問題，於發光二極體121、123與限流元件125之電路並接一電容器127，藉由電容器127於電源101之電壓Vs較低時放電提供電流，可令發光二極體121、123保持發光的狀態。
然而，此一類型之驅動電路，其電壓電流之曲線係如第２圖所示。其中，電源電壓21 (Vs)、電容器電壓23 (Vc)、發光二極體電流25 (I1)、電容器電流27 (Ic)及電源電流29 (Is)分別以對應於時間軸20 (t)的方式繪製。其中，假設電源電壓21為弦波的形式，則在第一時間201之前，通過發光二極體之電流25 (I1)由電容器提供。在第一時間201之後，由於電容器電壓23與電源電壓21相等，此時通過發光二極體之電流25開始轉由電源提供，同時電源也開始對電容器進行充電。因此，電容器電流27由負值轉為正值，並形成一充電波峰。
至第二時間203時，電源電壓21到達頂點並開始下降，此時電容器已充滿電並轉而開始放電。因此，電容器電流27由正值轉為負值，並取代通過發光二極體的電源電流。
由圖式可知，電源只在對電容器充電時才提供電流，由於提供電流的區間很小，導致電路的功率因數相當低落。
As shown in FIG. 1 , the conventional light-emitting diode drive circuit is generally rectified by the bridge rectifier 103, and a plurality of light-emitting diodes 121 and 123 and a current limiting element 125 are connected in series to form a lamp.
The design of the driving circuit can achieve the purpose of driving the LEDs 121, 123 in the simplest circuit, but when the voltage Vs of the power source 101 is lower than the forward bias of the LEDs 121, 123. The lamp is extinguished due to the absence of current, causing flicker.
In order to solve the problem of the flashing of the lamp, the circuit of the light-emitting diodes 121, 123 and the current limiting element 125 is connected to a capacitor 127, and the capacitor 127 discharges current when the voltage Vs of the power source 101 is low, so that the light can be emitted. The diodes 121 and 123 remain in a state of being illuminated.
However, the driving circuit of this type has a curve of voltage and current as shown in Fig. 2. Wherein, the power supply voltage 21 (Vs), the capacitor voltage 23 (Vc), the light-emitting diode current 25 (I1), the capacitor current 27 (Ic), and the power supply current 29 (Is) respectively correspond to the time axis 20 (t) Way to draw. Here, assuming that the power supply voltage 21 is in the form of a sine wave, the current 25 (I1) through the light-emitting diode is supplied from the capacitor before the first time 201. After the first time 201, since the capacitor voltage 23 is equal to the power supply voltage 21, the current 25 through the light-emitting diode begins to be supplied by the power supply, and the power supply also begins to charge the capacitor. Therefore, the capacitor current 27 changes from a negative value to a positive value and forms a charging peak.
By the second time 203, the supply voltage 21 reaches the apex and begins to fall, at which point the capacitor is fully charged and begins to discharge. Therefore, the capacitor current 27 is changed from a positive value to a negative value and replaces the power supply current through the light emitting diode.
As can be seen from the figure, the power supply only supplies current when the capacitor is charged, and the power factor of the circuit is rather low due to the small interval of current supply.
本發明之一目的，在於提供一種發光二極體之驅動電路，尤指一種發光二極體之高功率因數驅動電路。
本發明之又一目的，在於提供一種發光二極體之高功率因數驅動電路，利用發光二極體、電容器及開關單元之特殊配置，可根據電壓之變化改變電流之路徑，藉以提高電路之功率因數。
本發明提供一種發光二極體之高功率因數驅動電路，包含：一輸入端，用以連接一電源；一輸出端，用以接地；一第一發光二極體、一第一開關單元及一第二發光二極體，依序串接於輸入端與輸出端之間，其中第一發光二極體之正極連接輸入端，負極連接第一開關單元，第二發光二極體之正極連接第一開關單元，負極連接輸出端；一第一二極體及一電容器，依序串接於第一發光二極體之負極與輸出端之間，其中第一二極體之正極連接第一發光二極體之負極，負極連接電容器；及一第二二極體，連接於輸入端與電容器之間，其正極連接電容器，負極連接輸入端。
上述高功率因數驅動電路之一實施例，其中電源電壓之最大值大於第一發光二極體順向偏壓之兩倍加上第二發光二極體之順向偏壓。
上述高功率因數驅動電路之一實施例，其中該第一開關單元可為一限流元件。
上述高功率因數驅動電路之一實施例，尚包含有：一第二開關單元，連接於輸入端與第二發光二極體正極之間；及一控制電路，連接第一開關單元與第二開關單元，用以控制各開關單元為導通或斷路。
上述高功率因數驅動電路之一實施例，其中各開關單元之初始狀態皆為導通，當第一開關單元有電流通過時，控制電路控制第二開關單元為斷路；當第一開關單元無電流通過時，控制電路控制第二開關單元為導通。
上述高功率因數驅動電路之一實施例，其中各開關單元係可分別以一電晶體實施。
上述高功率因數驅動電路之一實施例，其中各發光二極體係可分別以一燈串取代，其中各燈串分別包含有複數個串接的發光二極體。
本發明尚提供一種發光二極體之高功率因數驅動電路，包含：一輸入端，用以連接一電源之正端；一輸出端，用以連接該電源之負端；一第一發光二極體、一第一開關單元及一第二發光二極體，依序串接於輸入端與輸出端之間，其中第一發光二極體之正極連接輸入端，負極連接第一開關單元，第二發光二極體之正極連接第一開關單元，負極連接輸出端；一電容器，串接於第一發光二極體負極與輸出端之間；一第二開關單元，連接於輸入端與第二發光二極體正極之間；及一控制電路，連接各開關單元，用以控制各開關單元為導通或斷路。
上述高功率因數驅動電路之一實施例，其中令電源之電壓為Vs，第一發光二極體之順向偏壓為Vf1，第二發光二極體之順向偏壓為Vf2，則：當Vs＜Vf2時，控制電路控制第一開關單元為導通；當Vf2＜Vs＜Vf1＋Vf2時，控制電路控制第一開關單元為斷路，第二開關單元為導通；及當Vf1＋Vf2＜Vs時，控制電路控制控制第一開關單元為導通，第二開關單元為斷路。
上述高功率因數驅動電路之一實施例，尚包含：一二極體，其正極連接第一發光二極體之負極，負極連接電容器；及一第三開關單元，連接於二極體負極與第二發光二極體正極之間；其中控制電路連接第三開關單元，用以控制第三開關單元為導通或斷路。
上述高功率因數驅動電路之一實施例，其中當第一開關單元或第二開關單元有電流通過時，控制電路控制第三開關單元為斷路；當第一開關單元有電流通過時，控制電路控制第二開關單元為斷路；當第一開關單元無電流通過時，控制電路控制第二開關單元為導通；當第二開關單元為導通且無電流通過時，控制電路控制第三開關單元為導通。
上述高功率因數驅動電路之一實施例，其中各開關單元係可分別以一電晶體實施。
上述高功率因數驅動電路之一實施例，其中各發光二極體係可分別由一燈串取代，其中各燈串分別包含有複數個串接的發光二極體。
An object of the present invention is to provide a driving circuit for a light emitting diode, and more particularly to a high power factor driving circuit for a light emitting diode.
Another object of the present invention is to provide a high power factor driving circuit for a light emitting diode. The special configuration of the light emitting diode, the capacitor and the switching unit can change the path of the current according to the change of the voltage, thereby improving the power of the circuit. Factor.
The invention provides a high power factor driving circuit for a light emitting diode, comprising: an input terminal for connecting a power source; an output terminal for grounding; a first light emitting diode, a first switching unit and a The second light-emitting diode is serially connected between the input end and the output end, wherein the positive electrode of the first light-emitting diode is connected to the input end, the negative electrode is connected to the first switch unit, and the positive electrode of the second light-emitting diode is connected. a switching unit, the negative electrode is connected to the output end; a first diode and a capacitor are sequentially connected in series between the negative electrode and the output end of the first light emitting diode, wherein the positive electrode of the first diode is connected to the first light emitting The negative pole of the diode, the negative pole is connected to the capacitor; and a second diode is connected between the input end and the capacitor, the positive pole is connected to the capacitor, and the negative pole is connected to the input end.
An embodiment of the above high power factor driving circuit, wherein the maximum value of the power supply voltage is greater than twice the forward bias of the first light emitting diode plus the forward bias of the second light emitting diode.
An embodiment of the above high power factor driving circuit, wherein the first switching unit is a current limiting component.
An embodiment of the high power factor driving circuit further includes: a second switching unit connected between the input end and the positive electrode of the second LED; and a control circuit connecting the first switch unit and the second switch The unit is used to control each switch unit to be turned on or off.
An embodiment of the high power factor driving circuit, wherein an initial state of each of the switching units is conductive, and when the first switching unit has a current, the control circuit controls the second switching unit to be open; when the first switching unit has no current The control circuit controls the second switching unit to be turned on.
An embodiment of the above high power factor driving circuit, wherein each of the switching units can be implemented by a transistor.
An embodiment of the above-mentioned high power factor driving circuit, wherein each of the light emitting diode systems can be replaced by a light string, wherein each light string comprises a plurality of serially connected light emitting diodes.
The invention further provides a high power factor driving circuit for a light emitting diode, comprising: an input end for connecting a positive end of a power source; an output end for connecting a negative end of the power source; and a first light emitting diode The body, a first switch unit and a second light-emitting diode are serially connected between the input end and the output end, wherein the anode of the first light-emitting diode is connected to the input end, and the negative electrode is connected to the first switch unit, The positive pole of the two light emitting diodes is connected to the first switching unit, and the negative pole is connected to the output end; a capacitor is connected in series between the negative pole of the first light emitting diode and the output end; and a second switching unit is connected to the input end and the second end Between the positive electrodes of the light-emitting diodes; and a control circuit connecting the switch units for controlling the switch units to be turned on or off.
An embodiment of the high power factor driving circuit, wherein the voltage of the power source is Vs, the forward bias voltage of the first light emitting diode is Vf1, and the forward bias voltage of the second light emitting diode is Vf2, then: When Vs<Vf2, the control circuit controls the first switching unit to be turned on; when Vf2<Vs<Vf1+Vf2, the control circuit controls the first switching unit to be open, the second switching unit is turned on; and when Vf1+Vf2<Vs, the control circuit controls The first switching unit is controlled to be turned on, and the second switching unit is turned off.
An embodiment of the high power factor driving circuit further includes: a diode having a positive electrode connected to a negative electrode of the first light emitting diode and a negative electrode connected to the capacitor; and a third switching unit connected to the diode negative electrode and the first Between the positive electrodes of the two light emitting diodes; wherein the control circuit is connected to the third switching unit for controlling the third switching unit to be turned on or off.
An embodiment of the above high power factor driving circuit, wherein when the first switching unit or the second switching unit has a current, the control circuit controls the third switching unit to be open; when the first switching unit has a current, the control circuit controls The second switching unit is open; when the first switching unit has no current, the control circuit controls the second switching unit to be turned on; when the second switching unit is turned on and no current flows, the control circuit controls the third switching unit to be turned on.
An embodiment of the above high power factor driving circuit, wherein each of the switching units can be implemented by a transistor.
An embodiment of the above-mentioned high power factor driving circuit, wherein each of the light emitting diode systems can be replaced by a light string, wherein each light string comprises a plurality of serially connected light emitting diodes.
101‧‧‧電源
103‧‧‧整流器
121‧‧‧第一發光二極體
123‧‧‧第二發光二極體
125‧‧‧限流元件
127‧‧‧電容器
20‧‧‧時間軸
201‧‧‧第一時間
203‧‧‧第二時間
21‧‧‧電源電壓
23‧‧‧電容器電壓
25‧‧‧發光二極體電流
27‧‧‧電容器電流
29‧‧‧電源電流
30‧‧‧發光二極體驅動電路
301‧‧‧電源
303‧‧‧整流器
305‧‧‧輸入端
307‧‧‧輸出端
321‧‧‧第一發光二極體
323‧‧‧第二發光二極體
341‧‧‧第一開關單元
361‧‧‧第一二極體
363‧‧‧第二二極體
38‧‧‧電容器
40‧‧‧時間軸
401‧‧‧第一時間
402‧‧‧第二時間
403‧‧‧第三時間
404‧‧‧第四時間
41‧‧‧電源電壓
43‧‧‧電容器電壓
471‧‧‧第一二極體電流
473‧‧‧第二二極體電流
49‧‧‧電源電流
50‧‧‧驅動電路
509‧‧‧控制電路
543‧‧‧第二開關單元
60‧‧‧時間軸
601‧‧‧第一時間
602‧‧‧第二時間
603‧‧‧第三時間
604‧‧‧第四時間
605‧‧‧第五時間
606‧‧‧第六時間
61‧‧‧電源電壓
63‧‧‧電容器電壓
65‧‧‧第二發光二極體電流
66‧‧‧第一二極體電流
67‧‧‧第二二極體電流
69‧‧‧電源電流
70‧‧‧驅動電路
741‧‧‧第一開關單元
743‧‧‧第二開關單元
80‧‧‧驅動電路
845‧‧‧第三開關單元
861‧‧‧二極體
90‧‧‧時間軸
901‧‧‧第一時間
902‧‧‧第二時間
903‧‧‧第三時間
904‧‧‧第四時間
905‧‧‧第五時間
906‧‧‧第六時間
91‧‧‧電源電壓
93‧‧‧電容器電壓
943‧‧‧第二開關單元開關曲線
945‧‧‧第三開關單元開關曲線
95‧‧‧第二發光二極體電流
97‧‧‧電容器電流
99‧‧‧電源電流101‧‧‧Power supply
103‧‧‧Rectifier
121‧‧‧First Light Emitting Diode
123‧‧‧Second light-emitting diode
125‧‧‧ Current limiting components
127‧‧‧ capacitor
20‧‧‧ timeline
201‧‧‧First time
203‧‧‧ second time
21‧‧‧Power supply voltage
23‧‧‧Capacitor voltage
25‧‧‧Lighting diode current
27‧‧‧Capacitor current
29‧‧‧Power supply current
30‧‧‧Lighting diode drive circuit
301‧‧‧Power supply
303‧‧‧Rectifier
305‧‧‧ input
307‧‧‧output
321‧‧‧First Light Emitting Diode
323‧‧‧Second light-emitting diode
341‧‧‧First switch unit
361‧‧‧First Diode
363‧‧‧Secondary
38‧‧‧ capacitor
40‧‧‧ timeline
401‧‧‧First time
402‧‧‧Second time
403‧‧‧ third time
404‧‧‧ fourth time
41‧‧‧Power supply voltage
43‧‧‧Capacitor voltage
471‧‧‧First diode current
473‧‧‧Second diode current
49‧‧‧Power supply current
50‧‧‧ drive circuit
509‧‧‧Control circuit
543‧‧‧Second switch unit
60‧‧‧ timeline
601‧‧‧First time
602‧‧‧ second time
603‧‧‧ third time
604‧‧‧ fourth time
605‧‧‧ fifth time
606‧‧‧ sixth time
61‧‧‧Power supply voltage
63‧‧‧ capacitor voltage
65‧‧‧Second light-emitting diode current
66‧‧‧First diode current
67‧‧‧Second diode current
69‧‧‧Power supply current
70‧‧‧ drive circuit
741‧‧‧First switch unit
743‧‧‧Second switch unit
80‧‧‧ drive circuit
845‧‧‧third switch unit
861‧‧‧ diode
90‧‧‧ timeline
901‧‧‧First time
902‧‧‧ second time
903‧‧‧ third time
904‧‧‧ fourth time
905‧‧‧ fifth time
906‧‧‧ sixth time
91‧‧‧Power supply voltage
93‧‧‧ capacitor voltage
943‧‧‧Second switch unit switching curve
945‧‧‧ Third switch unit switch curve
95‧‧‧Second light-emitting diode current
97‧‧‧Capacitor current
99‧‧‧Power supply current
第１圖：係習用發光二極體驅動電路之示意圖。
第２圖：係如第１圖所示驅動電路之電壓電流示意圖。
第３圖：係本發明一實施例之示意圖。
第４圖：係如第３圖所示實施例之電壓電流示意圖。
第５圖：係本發明另一實施例之示意圖。
第６圖：係如第５圖所示實施例之電壓電流示意圖。
第７圖：係本發明又一實施例之示意圖。
第８圖：係本發明又一實施例之示意圖。
第９圖：係如第８圖所示實施例之電壓電流示意圖。
Fig. 1: Schematic diagram of a conventional LED driving circuit.
Fig. 2 is a diagram showing the voltage and current of the driving circuit as shown in Fig. 1.
Fig. 3 is a schematic view showing an embodiment of the present invention.
Fig. 4 is a schematic diagram showing the voltage and current of the embodiment shown in Fig. 3.
Figure 5 is a schematic view of another embodiment of the present invention.
Fig. 6 is a diagram showing the voltage and current of the embodiment shown in Fig. 5.
Figure 7 is a schematic view showing still another embodiment of the present invention.
Figure 8 is a schematic view showing still another embodiment of the present invention.
Fig. 9 is a diagram showing the voltage and current of the embodiment shown in Fig. 8.
請參閱第３圖及第４圖，係本發明一實施例之示意圖及其電壓電流示意圖。如圖所示，本實施例發光二極體之高功率因數驅動電路30包含有一輸入端305、一輸出端307、一第一發光二極體321、一第一開關單元341、一第二發光二極體323、一電容器38、一第一二極體361及一第二二極體363。
在本實施例中，電源301經一橋式整流器303而形成一全波整流之直流電源。輸入端305連接該整流器303之正端，輸出端307連接整流器303之負端。
第一發光二極體321、第一開關單元341及第二發光二極體323依序串接於輸入端305與輸出端307之間，其中第一發光二極體321之正極連接輸入端305，負極連接第一開關單元341，第二發光二極體323之正極連接第一開關單元341，負極連接輸出端307。
第一二極體361及電容器38依序串接於第一發光二極體321之負極與輸出端307之間，其中第一二極體之正極連接第一發光二極體321之負極，負極連接電容器38。第二二極體363連接於輸入端305與電容器38之間，其正極連接電容器，負極連接輸入端。
根據本實施例發光二極體之高功率因數驅動電路30，其電壓及電流之變化趨勢係如第４圖所示。其中，電源電壓41 (Vs)、電容器電壓43 (Vc)、第一二極體電流471 (Id1)、第二二極體電流473 (Id2)及電源電流49 (Is)分別以對應於時間軸40 (t)的方式繪製。其中，第一發光二極體321之順向偏壓為Vf1，第二發光二極體323之順向偏壓為Vf2。
其中，假設電源電壓41為弦波的形式，則在第一時間401之前，由於電容器電壓43高於電源電壓41，通過發光二極體321、323之電流I1由電容器38放電，並經由第二二極體363提供(Id2)。在第一時間401至第二時間402之間，由於電源電壓41已高於電容器電壓43，因此通過發光二極體321、323之電流I1由電源301提供，通過第二二極體363之電流Id2為0。
由於電容器38之充電路徑係由電源301通過第一發光二極體321及第一二極體361。此時，電流由電源301通過第一發光二極體321以後之電壓為Vs－Vf1，仍低於電容器38之電壓Vc，因此無法對電容器38進行充電，通過第一二極體361之電流Id1及通過第二二極體363之電流Id2皆為0。
通過第二時間402後，Vs－Vf1已大於電容器之電壓，因此開始有電流Id1通過第一二極體361對電容器38進行充電。
至第三時間403時，電源電壓41到達頂點並開始下降，此時電容器38之電壓43亦達到最高電壓(Vs－Vf1)而停止充電。此時，由於電源301在輸入端305之電壓仍高於電容器38放電路徑之電壓，因此通過發光二極體321、323之電流I1仍由電源301提供。
至第四時間404時，電源電壓41在輸入端305已低於電容器38放電路徑之電壓，電容器38開始通過第二二極體363放電，放電電流Id2通過發光二極體321、323而驅動發光二極體321、323發光，直至下一循環。
利用本實施例發光二極體之高功率因數驅動電路30，可加長電源提供電流的時間，對於提高電路的功率因數具有相當的幫助。
在本發明中，各電壓電流之示意圖中，為方便解釋說明並令電流及電壓的變化較為明確清析，各項數值，例如Vf1、Vf2、Id1、I1、Is及各時間點等，並未依真實的比例繪製，其中進行調整之處並不影響電路運作的正確性。
在本發明之一實施例中，其中電源電壓之最大值需大於2Vf1+Vf2。
在本發明之一實施例中，其中該第一開關單元可為一限流元件。
請參閱第５圖及第６圖，係本發明另一實施例之示意圖及其電壓電流之示意圖。如圖所示，本實施例發光二極體之高功率因數驅動電路50，其電路構造與第３圖所示實施例大致相同，惟，本實施例之高功率因數驅動電路50尚包含有一第二開關單元543及一控制電路509。
其中，第二開關單元543連接於輸入端305與第二發光二極體323之正極之間，控制電路509連接第一開關單元341及第二開關單元543，用以控制各開關單元341、543為導通或斷路。
在本發明之一實施例中，其中各開關單元341、543之初始狀態皆為導通，當第一開關單元341有電流通過時，控制電路509控制第二開關單元543為斷路；當第一開關單元341無電流通過時，控制電路509控制第二開關單元543為導通。
根據本實施例發光二極體之高功率因數驅動電路50，其電壓及電流之變化趨勢係如第６圖所示。其中，電源電壓61 (Vs)、電容器電壓63 (Vc)、第二發光二極體電流65 (I1)、第一二極體電流66 (Id1)、第二二極體電流67 (Id2)及電源電流69 (Is)分別以對應於時間軸60 (t)的方式繪製。其中，第一發光二極體321之順向偏壓為Vf1，第二發光二極體323之順向偏壓為Vf2。
其中，假設電源電壓61為弦波的形式，則在第一時間601之前，由於電容器電壓63高於電源電壓61，通過發光二極體323之電流I1由電容器38放電，並經由第二二極體363提供(Id2)。此時，由於電容器電壓63已低於Vf1＋Vf2，電流無法通過第一開關單元341，故控制電路令第二開關單元543為導通。電流由電容器38經由第二二極體363及第二開關單元543通過第二發光二極體323。
在第一時間601至第四時間604之間，由於電源電壓61皆高於電容器電壓63，因此通過發光二極體321、323之電流I1由電源301提供。其中，在第一時間601至第二時間602之間，由於電源電壓61低於Vf1＋Vf2，電流無法通過第一開關單元341，故控制電路令第二開關單元543為導通。電流由電源301經由輸入端305及第二開關單元543通過第二發光二極體323。通過第一二極體361之電流Id1及通過第二二極體363之電流Id2皆為0。
在第二時間602至第三時間603之間，電源電壓61已高於Vf1＋Vf2，開始有電流通過第一開關單元341，因此控制電路509控制第二開關單元543為斷路。電流由電源301經輸入端305、第一發光二極體321及第一開關單元341通過第二發光二極體323。此時，電流通過第一發光二極體321後之電壓(Vs－Vf1)仍低於電容器電壓63，無法對電容器38進行充電。因此，通過第一二極體361之電流Id1及通過第二二極體363之電流Id2仍為0。
在第三時間603至第四時間604之間，電流通過第一發光二極體321後之電壓(Vs－Vf1)已高於電容器電壓63，因此開始有電流(Id1)通過第一二極體361對電容器38進行充電。
至第四時間604時，電源電壓61達到最高點，電容器38之電壓亦達到最高點而停止充電。
在第四時間604至第五時間605之間，電源電壓61開始下降，但在輸入端305仍高於電容器電壓63。因此電流仍由電源301提供，經輸入端305、第一發光二極體321及第一開關單元341通過第二發光二極體323。此時通過第一二極體361之電流Id1及通過第二二極體363之電流Id2皆為0。
在第五時間605之後，電容器38在輸入端305之電壓已高於電源電壓，因此通過發光二極體321、323之電流I1轉由電容器38放電，電流Id2通過第二二極體363、第一發光二極體321及第一開關單元341通過第二發光二極體323。
到達第六時間606時，由於電容器電壓63已低於Vf1＋Vf2，電流無法通過第一開關單元341，故控制電路令第二開關單元543為導通。電流由電容器38經由第二二極體363及第二開關單元543通過第二發光二極體323，直至下一循環。
利用本實施例發光二極體之高功率因數驅動電路50，可大幅加長電源提供電流的時間，同時可大幅提高電路的功率因數。
在本發明之一實施例中，其中各開關單元341、543係可分別以一電晶體實施。
在本發明之一實施例中，其中各發光二極體321、323係可分別以一燈串取代，其中各燈串分別包含有複數個串接的發光二極體。
請參閱第７圖，係本發明又一實施例之示意圖。如圖所示，本實施例發光二極體之高功率因數驅動電路70，包含有一輸入端305、一輸出端307、一第一發光二極體321、一第一開關單元741、一第二發光二極體323、一電容器38、一第二開關單元743及一控制電路509。
在本實施例中，電源301經一橋式整流器303而形成一直流電源。輸入端305連接該整流器303之正端，輸出端307連接整流器303之負端。
第一發光二極體321、第一開關單元741及第二發光二極體323依序串接於輸入端305與輸出端307之間，其中第一發光二極體321之正極連接輸入端305，負極連接第一開關單元741，第二發光二極體323之正極連接第一開關單元741，負極連接輸出端307。
電容器38串接於第一發光二極體321之負極與輸出端307之間。第二開關單元743連接於輸入端305與第二發光二極體323正極之間。控制電路509連接第一開關單元741及第二開關單元743，用以控制各開關單元741、743為導通或斷路。
在本發明之一實施例中，令電源301之電壓為Vs，第一發光二極體321之順向偏壓為Vf1，第二發光二極體323之順向偏壓為Vf2，則當Vs＜Vf2時，控制電路509控制第一開關單元741為導通；當Vf2＜Vs＜Vf1＋Vf2時，控制電路509控制第一開關單元741為斷路，第二開關單元743為導通；當Vf1＋Vf2＜Vs時，控制電路509控制控制第一開關單元741為導通，第二開關單元743為斷路。
利用本實施例發光二極體之高功率因數驅動電路70，可根據電源301電壓之大小而改變電流路徑。當Vf2＜Vs＜Vf1＋Vf2時，電流由電源301提供，經輸入端305及第二開關單元743通過第二發光二極體323。
當Vf1＋Vf2＜Vs時，電流由電源301提供，經輸入端305、第一發光二極體321及第一開關單元741通過第二發光二極體323，同時對電容器38進行充電。
當Vs＜Vf2時，電源301已無法提供電流，此時第一開關單元741為導通，故電容器38可放電而提供電流，經第一開關單元741通過第二發光二極體323。
請參閱第８圖及第９圖，係本發明又一實施例之示意圖及其電壓電流示意圖。如圖所示，本實施例發光二極體之高功率因數驅動電路80之電路構造與第７圖所示實施例大致相同，惟，本實施例尚包含有一二極體861及一第三開關單元845。
其中，二極體861連接於第一發光二極體321負極與電容器38之間，其正極連接第一發光二極體321之負極，負極連接電容器38。第三開關單元845連接於二極體861負極與第二發光二極體323正極之間。控制電路509連接各開關單元741、743、845，用以控制各開關單元741、743、845為導通或斷路。
在本發明之一實施例中，當第一開關單元741或第二開關單元743有電流通過時，控制電路509控制第三開關單元845為斷路；當第一開關單元741有電流通過時，控制電路509控制第二開關單元743為斷路；當第一開關單元741無電流通過時，控制電路509控制第二開關單元743為導通；當第二開關單元743為導通且無電流通過時，控制電路509控制第三開關單元845為導通。
根據本實施例發光二極體之高功率因數驅動電路80，其電壓及電流之變化趨勢係如第９圖所示。其中，電源電壓91 (Vs)、電容器電壓93 (Vc)、第二發光二極體電流95 (I1)及電源電流99 (Is)，以及第二開關單元743之開關曲線943、第三開關單元845之開關曲線945分別以對應於時間軸90 (t)的方式繪製。其中，第一發光二極體321之順向偏壓為Vf1，第二發光二極體323之順向偏壓為Vf2。
其中，假設電源電壓91為弦波的形式，則在第一時間901之前，由於電源電壓91已低於Vf2，電源301已無足夠的電壓提供電流通過第二開關單元743與第二發光二極體323。此時，第二開關單元743為導通且無電流通過，控制電路509控制第三開關單元845為導通。電容器38放電，電流Ic經第三開關單元845通過第二發光二極體323。
在第一時間901至第二時間902之間，電源電壓91已高於Vf2，開始有電流通過第二開關單元743，控制電路509控制第三開關單元845為斷路。電流由電源301提供，經輸入端305第二開關單元743通過第二發光二極體323。電容器38停止放電，Ic為0。
在第二時間902至第五時間905之間，電源電壓91高於Vf1＋Vf2，有電流通過第一開關單元741，控制電路509控制第二開關單元743為斷路。電流由電源301提供，經輸入端305、第一發光二極體、第一開關單元741通過第二發光二極體323。
在第三時間903時，電源電壓通過第一發光二極體321後(Vs－Vf1)已高於電容器電壓93 (Vc)，因此開始有電流Ic通過二極體861對電容器38進行充電。在第四時間904時，電源電壓93達到最大值而開始下降，電容器電壓93亦達到最高點而停止充電。此時Ic為0。
在第五時間905時，由於電源電壓91已低於Vf1＋Vf2，電源301所提供的電流無法通過第一開關單元741，此時控制電路509控制第二開關單元743為導通。電流由電源301提供，經輸入端305及第二開關單元743通過第二發光二極體323。
至第六時間906時，電源電壓91已低於Vf2，電源301已無足夠的電壓提供電流通過第二開關單元743與第二發光二極體323。此時，第二開關單元743為導通且無電流通過，控制電路509控制第三開關單元845為導通。電容器38開始放電，電流Ic經第三開關單元845通過第二發光二極體323。
利用本實施例發光二極體之高功率因數驅動電路80，可大幅加長電源提供電流的時間，同時可大幅提高電路的功率因數。且，由於電容器38只需提供電流驅動第二發光二極體323，電容器38之電容值可大幅縮減，可降低電路整體之成本。
在本發明之一實施例中，其中各開關單元741、743、845係可分別以一電晶體實施。
在本發明之一實施例中，其中各發光二極體321、323係可分別以一燈串取代，其中各燈串分別包含有複數個串接的發光二極體。
根據上述說明，可知利用本發明之發光二極體之高功率因數驅動電路，可根據電壓之變化改變電流之路徑，並藉由開關單元的切換控制電容器的充放電時間，可提高各發光二極體之使用效率，並提高電路整體之功率因數。
以上所述者，僅為本發明之實施例而已，並非用來限定本發明實施之範圍，即凡依本發明申請專利範圍所述之形狀、構造、特徵、方法及精神所為之均等變化與修飾，均應包括於本發明之申請專利範圍內。
Please refer to FIG. 3 and FIG. 4, which are schematic diagrams of a embodiment of the present invention and a schematic diagram of voltage and current. As shown in the figure, the high power factor driving circuit 30 of the LED includes an input terminal 305, an output terminal 307, a first LED diode 321, a first switching unit 341, and a second illumination. The diode 323, a capacitor 38, a first diode 361 and a second diode 363.
In this embodiment, the power supply 301 forms a full-wave rectified DC power supply via a bridge rectifier 303. The input terminal 305 is connected to the positive terminal of the rectifier 303, and the output terminal 307 is connected to the negative terminal of the rectifier 303.
The first light-emitting diode 321 , the first switch unit 341 and the second light-emitting diode 323 are sequentially connected in series between the input end 305 and the output end 307 , wherein the anode of the first light-emitting diode 321 is connected to the input end 305 . The negative electrode is connected to the first switching unit 341, the positive electrode of the second light emitting diode 323 is connected to the first switching unit 341, and the negative electrode is connected to the output terminal 307.
The first diode 361 and the capacitor 38 are connected in series between the negative electrode of the first LED 321 and the output terminal 307. The anode of the first diode is connected to the cathode of the first LED 321 and the cathode. The capacitor 38 is connected. The second diode 363 is connected between the input terminal 305 and the capacitor 38, the positive electrode of which is connected to the capacitor, and the negative electrode of which is connected to the input terminal.
According to the high power factor driving circuit 30 of the light emitting diode according to the embodiment, the trend of the voltage and current changes is as shown in FIG. Wherein, the power supply voltage 41 (Vs), the capacitor voltage 43 (Vc), the first diode current 471 (Id1), the second diode current 473 (Id2), and the power supply current 49 (Is) respectively correspond to the time axis. 40 (t) way to draw. The forward bias of the first LED 321 is Vf1, and the forward bias of the second LED 323 is Vf2.
Wherein, assuming that the power supply voltage 41 is in the form of a sine wave, before the first time 401, since the capacitor voltage 43 is higher than the power supply voltage 41, the current I1 passing through the light-emitting diodes 321, 323 is discharged by the capacitor 38, and is passed through the second Diode 363 provides (Id2). Between the first time 401 and the second time 402, since the power supply voltage 41 is higher than the capacitor voltage 43, the current I1 through the light-emitting diodes 321, 323 is supplied from the power source 301, and the current through the second diode 363 Id2 is 0.
Since the charging path of the capacitor 38 is passed through the first light emitting diode 321 and the first diode 361 from the power source 301. At this time, the voltage of the current from the power source 301 after passing through the first light-emitting diode 321 is Vs-Vf1, which is still lower than the voltage Vc of the capacitor 38, so that the capacitor 38 cannot be charged, and the current through the first diode 361 is Id1. And the current Id2 passing through the second diode 363 is 0.
After the second time 402, Vs-Vf1 is already greater than the voltage of the capacitor, so that the current Id1 begins to charge the capacitor 38 through the first diode 361.
By the third time 403, the power supply voltage 41 reaches the apex and begins to fall. At this time, the voltage 43 of the capacitor 38 also reaches the highest voltage (Vs - Vf1) and the charging is stopped. At this time, since the voltage of the power source 301 at the input terminal 305 is still higher than the voltage of the discharge path of the capacitor 38, the current I1 passing through the light-emitting diodes 321, 323 is still supplied from the power source 301.
By the fourth time 404, the power supply voltage 41 is lower than the voltage of the discharge path of the capacitor 38 at the input terminal 305, the capacitor 38 begins to discharge through the second diode 363, and the discharge current Id2 is driven to emit light through the LEDs 321, 323. The diodes 321, 323 illuminate until the next cycle.
With the high power factor driving circuit 30 of the light emitting diode of the embodiment, the time for supplying current by the power source can be lengthened, which is quite helpful for improving the power factor of the circuit.
In the present invention, in the schematic diagram of each voltage and current, for convenience of explanation and to make the changes of current and voltage relatively clear, various values, such as Vf1, Vf2, Id1, I1, Is, and various time points, etc., are not It is drawn according to the real scale, and the adjustments do not affect the correctness of the circuit operation.
In an embodiment of the invention, wherein the maximum value of the supply voltage is greater than 2Vf1 + Vf2.
In an embodiment of the invention, the first switching unit can be a current limiting component.
Please refer to FIG. 5 and FIG. 6 , which are schematic diagrams of another embodiment of the present invention and a schematic diagram of the voltage and current thereof. As shown in the figure, the high power factor driving circuit 50 of the light emitting diode of the present embodiment has a circuit configuration substantially the same as that of the embodiment shown in FIG. 3. However, the high power factor driving circuit 50 of the embodiment further includes a first The second switch unit 543 and a control circuit 509.
The second switch unit 543 is connected between the input terminal 305 and the positive terminal of the second LED 323, and the control circuit 509 is connected to the first switch unit 341 and the second switch unit 543 for controlling the switch units 341 and 543. To be turned on or off.
In an embodiment of the present invention, wherein the initial states of the respective switch units 341, 543 are all turned on, when the first switch unit 341 has a current, the control circuit 509 controls the second switch unit 543 to be open; when the first switch When the unit 341 has no current passing, the control circuit 509 controls the second switching unit 543 to be turned on.
According to the high power factor driving circuit 50 of the light emitting diode according to the present embodiment, the trend of the voltage and current changes is as shown in FIG. Wherein, the power supply voltage 61 (Vs), the capacitor voltage 63 (Vc), the second LED current 65 (I1), the first diode current 66 (Id1), the second diode current 67 (Id2), and The supply current 69 (Is) is drawn in a manner corresponding to the time axis 60 (t), respectively. The forward bias of the first LED 321 is Vf1, and the forward bias of the second LED 323 is Vf2.
Wherein, assuming that the power supply voltage 61 is in the form of a sine wave, before the first time 601, since the capacitor voltage 63 is higher than the power supply voltage 61, the current I1 passing through the light-emitting diode 323 is discharged by the capacitor 38, and via the second diode Body 363 provides (Id2). At this time, since the capacitor voltage 63 is lower than Vf1+Vf2, the current cannot pass through the first switching unit 341, so the control circuit causes the second switching unit 543 to be turned on. The current is passed from the capacitor 38 through the second diode 363 and the second switching unit 543 through the second LED 323.
Between the first time 601 and the fourth time 604, since the power supply voltage 61 is higher than the capacitor voltage 63, the current I1 passing through the light-emitting diodes 321, 323 is supplied from the power supply 301. Wherein, between the first time 601 and the second time 602, since the power supply voltage 61 is lower than Vf1+Vf2, the current cannot pass through the first switching unit 341, so the control circuit makes the second switching unit 543 conductive. The current is passed from the power source 301 to the second LED 323 via the input terminal 305 and the second switching unit 543. The current Id1 through the first diode 361 and the current Id2 through the second diode 363 are both zero.
Between the second time 602 and the third time 603, the power supply voltage 61 has been higher than Vf1 + Vf2, and current has passed through the first switching unit 341, so the control circuit 509 controls the second switching unit 543 to be open. The current is passed from the power source 301 through the input terminal 305, the first LED 321 and the first switching unit 341 through the second LED 323. At this time, the voltage (Vs - Vf1) after the current passes through the first light-emitting diode 321 is still lower than the capacitor voltage 63, and the capacitor 38 cannot be charged. Therefore, the current Id1 passing through the first diode 361 and the current Id2 passing through the second diode 363 are still zero.
Between the third time 603 and the fourth time 604, the voltage (Vs-Vf1) after the current passes through the first light-emitting diode 321 has been higher than the capacitor voltage 63, so that the current (Id1) starts to pass through the first diode. The capacitor 38 is charged 361.
By the fourth time 604, the power supply voltage 61 reaches the highest point, and the voltage of the capacitor 38 also reaches the highest point to stop charging.
Between the fourth time 604 and the fifth time 605, the supply voltage 61 begins to drop, but is still above the capacitor voltage 63 at the input 305. Therefore, the current is still supplied from the power source 301, and passes through the input terminal 305, the first LED 321 and the first switching unit 341 through the second LED 323. At this time, the current Id1 passing through the first diode 361 and the current Id2 passing through the second diode 363 are both zero.
After the fifth time 605, the voltage of the capacitor 38 at the input terminal 305 has been higher than the power supply voltage, so the current I1 through the light-emitting diodes 321, 323 is discharged by the capacitor 38, and the current Id2 passes through the second diode 363, The light emitting diode 321 and the first switching unit 341 pass through the second light emitting diode 323.
When the sixth time 606 is reached, since the capacitor voltage 63 has fallen below Vf1 + Vf2, the current cannot pass through the first switching unit 341, so the control circuit causes the second switching unit 543 to be turned on. The current is passed from the capacitor 38 through the second diode 363 and the second switching unit 543 through the second LED 323 until the next cycle.
By using the high power factor driving circuit 50 of the light emitting diode of the embodiment, the time for supplying current by the power source can be greatly lengthened, and the power factor of the circuit can be greatly improved.
In an embodiment of the invention, each of the switching units 341, 543 can be implemented by a transistor.
In an embodiment of the present invention, each of the light-emitting diodes 321 and 323 can be replaced by a light string, wherein each of the light strings respectively includes a plurality of light-emitting diodes connected in series.
Please refer to FIG. 7, which is a schematic view of still another embodiment of the present invention. As shown in the figure, the high power factor driving circuit 70 of the light emitting diode of the present embodiment includes an input terminal 305, an output terminal 307, a first light emitting diode 321 , a first switching unit 741 , and a second The LED 323, a capacitor 38, a second switching unit 743 and a control circuit 509.
In the present embodiment, the power source 301 forms a DC power source via a bridge rectifier 303. The input terminal 305 is connected to the positive terminal of the rectifier 303, and the output terminal 307 is connected to the negative terminal of the rectifier 303.
The first LED 321 , the first switching unit 741 and the second LED 323 are serially connected between the input end 305 and the output end 307 , wherein the anode of the first LED 321 is connected to the input end 305 . The negative electrode is connected to the first switch unit 741, the positive electrode of the second light-emitting diode 323 is connected to the first switch unit 741, and the negative electrode is connected to the output terminal 307.
The capacitor 38 is connected in series between the negative electrode of the first LED 321 and the output terminal 307. The second switching unit 743 is connected between the input terminal 305 and the positive terminal of the second LED 323. The control circuit 509 is connected to the first switching unit 741 and the second switching unit 743 for controlling the switching units 741 and 743 to be turned on or off.
In an embodiment of the present invention, the voltage of the power source 301 is Vs, the forward bias of the first LED 321 is Vf1, and the forward bias of the second LED 323 is Vf2, then Vs When <Vf2, the control circuit 509 controls the first switching unit 741 to be turned on; when Vf2 < Vs < Vf1 + Vf2, the control circuit 509 controls the first switching unit 741 to be open, and the second switching unit 743 is turned on; when Vf1 + Vf2 < Vs, The control circuit 509 controls the first switching unit 741 to be turned on, and the second switching unit 743 is turned off.
With the high power factor driving circuit 70 of the light emitting diode of the present embodiment, the current path can be changed according to the magnitude of the voltage of the power source 301. When Vf2 < Vs < Vf1 + Vf2, current is supplied from the power source 301, and passes through the second LED 323 via the input terminal 305 and the second switching unit 743.
When Vf1+Vf2<Vs, the current is supplied from the power source 301, and the capacitor 38 is charged while passing through the input terminal 305, the first LED 321 and the first switching unit 741 through the second LED 323.
When Vs<Vf2, the power supply 301 is unable to supply current. At this time, the first switching unit 741 is turned on, so the capacitor 38 can be discharged to supply current, and passes through the second LED 323 via the first switching unit 741.
Please refer to FIG. 8 and FIG. 9 for a schematic view of a further embodiment of the present invention and a schematic diagram of the voltage and current thereof. As shown in the figure, the circuit structure of the high power factor driving circuit 80 of the LED is substantially the same as that of the embodiment shown in FIG. 7. However, the embodiment further includes a diode 861 and a third. Switch unit 845.
The diode 861 is connected between the negative electrode of the first light-emitting diode 321 and the capacitor 38, and has a positive electrode connected to the negative electrode of the first light-emitting diode 321 and a negative electrode connected to the capacitor 38. The third switching unit 845 is connected between the cathode of the diode 861 and the anode of the second LED 323. The control circuit 509 is connected to each of the switch units 741, 743, and 845 for controlling the respective switch units 741, 743, and 845 to be turned on or off.
In an embodiment of the present invention, when the first switching unit 741 or the second switching unit 743 has a current, the control circuit 509 controls the third switching unit 845 to be an open circuit; when the first switching unit 741 has a current, the control The circuit 509 controls the second switching unit 743 to be open; when the first switching unit 741 has no current, the control circuit 509 controls the second switching unit 743 to be turned on; when the second switching unit 743 is turned on and no current passes, the control circuit 509 controls the third switching unit 845 to be turned on.
According to the high power factor driving circuit 80 of the light emitting diode according to the embodiment, the trend of the voltage and current changes is as shown in FIG. The power supply voltage 91 (Vs), the capacitor voltage 93 (Vc), the second LED current 95 (I1), and the power supply current 99 (Is), and the switching curve 943 of the second switching unit 743, the third switching unit The switch curve 945 of 845 is drawn in a manner corresponding to the time axis 90 (t), respectively. The forward bias of the first LED 321 is Vf1, and the forward bias of the second LED 323 is Vf2.
Wherein, assuming that the power supply voltage 91 is in the form of a sine wave, before the first time 901, since the power supply voltage 91 has fallen below Vf2, the power supply 301 has no sufficient voltage to supply current through the second switching unit 743 and the second light emitting diode. Body 323. At this time, the second switching unit 743 is turned on and no current flows, and the control circuit 509 controls the third switching unit 845 to be turned on. The capacitor 38 is discharged, and the current Ic passes through the second light-emitting diode 323 via the third switching unit 845.
Between the first time 901 and the second time 902, the power supply voltage 91 has been higher than Vf2, and current has passed through the second switching unit 743, and the control circuit 509 controls the third switching unit 845 to be open. The current is supplied from the power source 301 through the second switching unit 743 via the input terminal 305 through the second LED 323. Capacitor 38 stops discharging and Ic is zero.
Between the second time 902 and the fifth time 905, the power supply voltage 91 is higher than Vf1 + Vf2, a current is passed through the first switching unit 741, and the control circuit 509 controls the second switching unit 743 to be open. The current is supplied from the power source 301, and passes through the input terminal 305, the first LED, and the first switching unit 741 through the second LED 323.
At the third time 903, the power supply voltage has passed through the first light-emitting diode 321 (Vs-Vf1) higher than the capacitor voltage 93 (Vc), so that the current Ic is started to charge the capacitor 38 through the diode 861. At the fourth time 904, the supply voltage 93 reaches a maximum value and begins to fall, and the capacitor voltage 93 also reaches a maximum point to stop charging. At this time, Ic is 0.
At the fifth time 905, since the power supply voltage 91 has been lower than Vf1 + Vf2, the current supplied from the power source 301 cannot pass through the first switching unit 741, and the control circuit 509 controls the second switching unit 743 to be turned on. The current is supplied from the power source 301, and passes through the second LED 323 via the input terminal 305 and the second switching unit 743.
By the sixth time 906, the power supply voltage 91 has fallen below Vf2, and the power supply 301 has not supplied enough voltage to supply current through the second switching unit 743 and the second LED 323. At this time, the second switching unit 743 is turned on and no current flows, and the control circuit 509 controls the third switching unit 845 to be turned on. The capacitor 38 begins to discharge, and the current Ic passes through the second light emitting diode 323 via the third switching unit 845.
By using the high power factor driving circuit 80 of the light emitting diode of the embodiment, the time for supplying current by the power source can be greatly lengthened, and the power factor of the circuit can be greatly improved. Moreover, since the capacitor 38 only needs to supply current to drive the second light-emitting diode 323, the capacitance value of the capacitor 38 can be greatly reduced, and the cost of the entire circuit can be reduced.
In an embodiment of the invention, each of the switch units 741, 743, 845 can be implemented by a transistor.
In an embodiment of the present invention, each of the light-emitting diodes 321 and 323 can be replaced by a light string, wherein each of the light strings respectively includes a plurality of light-emitting diodes connected in series.
According to the above description, it can be seen that the high power factor driving circuit of the light emitting diode of the present invention can change the path of the current according to the change of the voltage, and can control the charging and discharging time of the capacitor by switching of the switching unit, thereby improving each of the light emitting diodes. The efficiency of the body is used, and the power factor of the circuit as a whole is improved.
The above is only the embodiment of the present invention, and is not intended to limit the scope of the present invention, that is, the equivalent changes and modifications of the shapes, structures, features, methods and spirits described in the claims of the present invention. All should be included in the scope of the patent application of the present invention.
30‧‧‧發光二極體驅動電路 30‧‧‧Lighting diode drive circuit
301‧‧‧電源 301‧‧‧Power supply
303‧‧‧整流器 303‧‧‧Rectifier
305‧‧‧輸入端 305‧‧‧ input
307‧‧‧輸出端 307‧‧‧output
321‧‧‧第一發光二極體 321‧‧‧First Light Emitting Diode
323‧‧‧第二發光二極體 323‧‧‧Second light-emitting diode
341‧‧‧第一開關單元 341‧‧‧First switch unit
361‧‧‧第一二極體 361‧‧‧First Diode
363‧‧‧第二二極體 363‧‧‧Secondary
38‧‧‧電容器 38‧‧‧ capacitor
Claims (1)
2.如申請專利範圍第1項所述之高功率因數驅動電路，其中電源電壓之最大值大於第一發光二極體順向偏壓之兩倍加上第二發光二極體之順向偏壓。
3.如申請專利範圍第1項所述之高功率因數驅動電路，其中該第一開關單元可為一限流元件。
4.如申請專利範圍第1項所述之高功率因數驅動電路，尚包含有：一第二開關單元，連接於輸入端與第二發光二極體正極之間；及一控制電路，連接第一開關單元與第二開關單元，用以控制各開關單元為導通或斷路。
5.如申請專利範圍第4項所述之高功率因數驅動電路，其中各開關單元之初始狀態皆為導通，當第一開關單元有電流通過時，控制電路控制第二開關單元為斷路；當第一開關單元無電流通過時，控制電路控制第二開關單元為導通。
6.如申請專利範圍第5項所述之高功率因數驅動電路，其中各開關單元係可分別以一電晶體實施。
7.如申請專利範圍第1項所述之高功率因數驅動電路，其中各發光二極體係可分別以一燈串取代，其中各燈串分別包含有複數個串接的發光二極體。
8.一種發光二極體之高功率因數驅動電路，包含：一輸入端，用以連接一電源之正端；一輸出端，用以連接該電源之負端；一第一發光二極體、一第一開關單元及一第二發光二極體，依序串接於輸入端與輸出端之間，其中第一發光二極體之正極連接輸入端，負極連接第一開關單元，第二發光二極體之正極連接第一開關單元，負極連接輸出端；一電容器，串接於第一發光二極體負極與輸出端之間；一第二開關單元，連接於輸入端與第二發光二極體正極之間；及一控制電路，連接各開關單元，用以控制各開關單元為導通或斷路。
9.如申請專利範圍第8項所述之高功率因數驅動電路，其中令電源之電壓為Vs，第一發光二極體之順向偏壓為Vf1，第二發光二極體之順向偏壓為Vf2，則：當Vs＜Vf2時，控制電路控制第一開關單元為導通；當Vf2＜Vs＜Vf1＋Vf2時，控制電路控制第一開關單元為斷路，第二開關單元為導通；及當Vf1＋Vf2＜Vs時，控制電路控制控制第一開關單元為導通，第二開關單元為斷路。
10.如申請專利範圍第8項所述之高功率因數驅動電路，尚包含：一二極體，其正極連接第一發光二極體之負極，負極連接電容器；及一第三開關單元，連接於二極體負極與第二發光二極體正極之間；其中控制電路連接第三開關單元，用以控制第三開關單元為導通或斷路。
11.如申請專利範圍第10項所述之高功率因數驅動電路，其中當第一開關單元或第二開關單元有電流通過時，控制電路控制第三開關單元為斷路；當第一開關單元有電流通過時，控制電路控制第二開關單元為斷路；當第一開關單元無電流通過時，控制電路控制第二開關單元為導通；當第二開關單元為導通且無電流通過時，控制電路控制第三開關單元為導通。
12.如申請專利範圍第10項所述之高功率因數驅動電路，其中各開關單元係可分別以一電晶體實施。
13.如申請專利範圍第8項所述之高功率因數驅動電路，其中各發光二極體係可分別由一燈串取代，其中各燈串分別包含有複數個串接的發光二極體。
A high power factor driving circuit for a light emitting diode, comprising: an input end for connecting a positive end of a power source; an output end for connecting a negative end of the power source; a first light emitting diode, a first a switching unit and a second LED are sequentially connected between the input end and the output end, wherein the anode of the first LED is connected to the input end, the cathode is connected to the first switch unit, and the second LED is connected The positive pole of the body is connected to the first switch unit, and the negative pole is connected to the output end; a first diode and a capacitor are sequentially connected in series between the negative pole and the output end of the first light emitting diode, wherein the first diode The positive electrode is connected to the negative electrode of the first light-emitting diode, the negative electrode is connected to the capacitor; and a second diode is connected between the input terminal and the capacitor, the positive electrode is connected to the capacitor, and the negative electrode is connected to the input end.
2. The high power factor driving circuit of claim 1, wherein the maximum value of the power supply voltage is greater than twice the forward bias of the first light emitting diode and the forward bias of the second light emitting diode. .
3. The high power factor driving circuit of claim 1, wherein the first switching unit is a current limiting element.
4. The high power factor driving circuit according to claim 1, further comprising: a second switching unit connected between the input terminal and the positive electrode of the second LED; and a control circuit connected A switch unit and a second switch unit are configured to control each switch unit to be turned on or off.
5. The high power factor driving circuit according to claim 4, wherein an initial state of each switching unit is conductive, and when the first switching unit has a current, the control circuit controls the second switching unit to be open; When no current flows through the first switching unit, the control circuit controls the second switching unit to be turned on.
6. The high power factor driving circuit of claim 5, wherein each of the switching units is implemented by a transistor.
7. The high power factor driving circuit of claim 1, wherein each of the light emitting diode systems is replaced by a light string, wherein each of the light strings comprises a plurality of light emitting diodes connected in series.
8. A high power factor driving circuit for a light emitting diode, comprising: an input end for connecting a positive end of a power source; an output end for connecting a negative end of the power source; a first light emitting diode, a first switching unit and a second LED are sequentially connected between the input end and the output end, wherein the anode of the first LED is connected to the input end, the cathode is connected to the first switch unit, and the second LED is illuminated. The positive pole of the diode is connected to the first switch unit, and the negative pole is connected to the output end; a capacitor is connected in series between the negative pole of the first light emitting diode and the output end; and a second switch unit is connected to the input end and the second light emitting diode Between the positive poles of the pole body; and a control circuit connecting the switch units for controlling the switching units to be turned on or off.
9. The high power factor driving circuit according to claim 8, wherein the voltage of the power source is Vs, the forward bias of the first light emitting diode is Vf1, and the forward bias of the second light emitting diode The voltage is Vf2, then: when Vs<Vf2, the control circuit controls the first switching unit to be turned on; when Vf2<Vs<Vf1+Vf2, the control circuit controls the first switching unit to be open, the second switching unit is turned on; and when Vf1+Vf2 When <Vs, the control circuit controls to control the first switching unit to be turned on, and the second switching unit to be open.
10. The high power factor driving circuit of claim 8, further comprising: a diode having a positive electrode connected to the negative electrode of the first light emitting diode, a negative electrode connecting the capacitor; and a third switching unit connected The diode is connected between the anode of the diode and the cathode of the second LED; wherein the control circuit is connected to the third switch unit for controlling the third switch unit to be turned on or off.
11. The high power factor driving circuit of claim 10, wherein the control circuit controls the third switching unit to be open when the first switching unit or the second switching unit has a current through; when the first switching unit has When the current passes, the control circuit controls the second switching unit to be open; when the first switching unit has no current, the control circuit controls the second switching unit to be turned on; when the second switching unit is turned on and no current passes, the control circuit controls The third switching unit is turned on.
12. The high power factor drive circuit of claim 10, wherein each of the switch units is implemented by a transistor.
13. The high power factor driving circuit of claim 8, wherein each of the light emitting diode systems is replaced by a light string, wherein each of the light strings comprises a plurality of light emitting diodes connected in series.
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| TW103102238A TW201531150A (en) | 2014-01-22 | 2014-01-22 | High power factor driving circuit for LED |
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| TW103102238A TW201531150A (en) | 2014-01-22 | 2014-01-22 | High power factor driving circuit for LED |
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| TW307980B (en) * | 1994-04-28 | 1997-06-11 | Toshiba Light Technic Kk | |
| CN201533442U (en) * | 2009-10-31 | 2010-07-21 | 中山市欧普照明股份有限公司 | High power factor electronic amperite |
| CN101944844A (en) * | 2009-11-16 | 2011-01-12 | 林福泳 | High power factor power correcting circuit |
| CN102105009B (en) * | 2011-03-25 | 2014-02-05 | 上海新进半导体制造有限公司 | High power factor light-emitting diode (LED) driving power supply and control circuit thereof |
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