• M363016 五、新型說明： ^ 【新型所屬之技術領域】 ' 本新型涉及光源驅動，尤其涉及一種發光二極體均流 電路及驅動電路。 【先前技術】 . 隨著發光二極體（Light Emitting Diode，LED)的技術 - 發展，發光二極體在光源領域應用日益廣泛。通常，在採 φ 用大量發光二極體組成光源的電路中，需要連接一均流電 路到每一發光二極體，以控制流經該發光二極體的電流。 目前常見的均流電路有多種實現方式，如直接採用一 般的電阻或一般的電晶體，直接連接于每一發光二極體， 起均流作用，然，該等實現方式的均流效果皆較差。另， 還可利用運算放大器或帶均流功能的積體電路（Integrated Circuit，1C)來達到均流作用，但這些方式卻因運算放大 φ 器或1C的價格高而具有成本高的缺點。 【新型内容】 有鑒於此，有必要提供一種發光二極體均流電路，其 對發光二極體的均流效果好，且具有較低的成本。 ' 另，還需提供一種發光二極體驅動電路，其對發光二 極體的均流效果好，且具有較低的成本。 一種發光二極體均流電路，用於平衡流經發光二極體 電路的電流。該發光二極體均流電路包括第一電晶體、第 4 M363016 •二電晶體、限流電阻及感測電阻。第—電晶體的沒極連接 于批光-；^體電路。第二電晶體的基極連接於該第—電 -晶體的射極，其汲極連接於該第一電晶體的基極，其射極 接地限抓電阻連接於該第一電晶體的基極與外部電壓源 之間’用於為該第-電晶體提供工作電壓。感測電阻的一 •端連接該第-電晶體的射極與第二電晶體的基極，另—端 •接地，、中’該第二電晶體透過感測該第一電晶體射極電 • μ的灸化來凋g“亥第二電晶體汲基極間的電壓進而調節第 % B曰體及射極間的電壓，從而使流經該感測電阻的電流 維持穩定，以此平衡流經該發光二極體電路的電流。 一種發光二極體驅動電路，祕驅動並均流複數發光 二極體電路。該發光二極體,_電路包姉換電路與複數 均抓電路。轉換電路與該等發光二極體電路的一端連接， 用於向該等發光一極體電路提供直流訊號以驅動該等發光 ❿二極體妨。每—均流電路對應連接每—㈣二極體電路 的另-端，用於平衡流經該發光二極體電路的電流。每一 均流電=包括第-電晶體、第二電晶體、限流電阻及感測 电阻帛電晶體的汲極連接于該發光二極體電路。第二 電晶體的基極連接於該第—電晶體的射極，其沒極連接於 "亥第電30體的基極’其射極接地。限流電卩且連接於該第 -電晶體的基極與外部電壓源之間，用於為該第—電晶體 提供工作電壓。感測電阻的—端連接該第一電晶體的射極 5 M363016 與第二電晶體的基極，另〜山 透過感測該第―電晶體射極:：地：其中，該第二電晶體 體汲基極間的電壓^的變化來調節該第二電晶 nk 网郎第一畲曰 攸而使流經該感測電 明體汲射極間的電壓， 电丨且的電流維持奸〜 枭光二極體電路的電流。 、’思欠，以此平衡流經該 用兩個電晶體及兩 / 的電路連接關係， 冑㈣成有回饋作用• M363016 V. New description: ^ [New technology field] 'This new type relates to light source driving, especially to a light-emitting diode current sharing circuit and driving circuit. [Prior Art] With the development of the technology of the Light Emitting Diode (LED), the light-emitting diode is increasingly used in the field of light sources. Generally, in a circuit that uses a large number of light-emitting diodes to form a light source, it is necessary to connect a current sharing circuit to each of the light-emitting diodes to control the current flowing through the light-emitting diodes. At present, the current current sharing circuit has various implementation modes, such as direct use of a general resistance or a general transistor, which is directly connected to each of the light-emitting diodes, and functions as a current sharing. However, the current sharing effects of the implementations are poor. . In addition, an operation amplifier or an integrated circuit with integrated current (1C) can be used to achieve current sharing. However, these methods have the disadvantage of high cost due to the high price of the operational amplifier or 1C. [New content] In view of this, it is necessary to provide a light-emitting diode current sharing circuit which has a good current sharing effect on the light-emitting diode and has a low cost. In addition, it is also necessary to provide a light-emitting diode driving circuit which has a good current sharing effect on the light-emitting diode and has a low cost. A light-emitting diode current sharing circuit for balancing current flowing through a light-emitting diode circuit. The light-emitting diode current sharing circuit comprises a first transistor, a fourth M363016 • two transistors, a current limiting resistor and a sensing resistor. The first pole of the first transistor is connected to the batch-light circuit. a base of the second transistor is connected to the emitter of the first electro-crystal, and a drain is connected to the base of the first transistor, and an emitter grounding resistor is connected to the base of the first transistor. 'Between the external voltage source' is used to provide an operating voltage for the first transistor. One end of the sensing resistor is connected to the emitter of the first transistor and the base of the second transistor, and the other end is grounded, and the second transistor transmits the first transistor to sense the first transistor. • μ moxibustion to wither the voltage between the base of the second transistor and then adjust the voltage between the first B body and the emitter, so that the current flowing through the sensing resistor remains stable, thus balancing The current flowing through the light-emitting diode circuit. A light-emitting diode driving circuit that secretly drives and averages a plurality of light-emitting diode circuits. The light-emitting diode, the circuit pack switching circuit and the plurality of circuits are all converted. The circuit is connected to one end of the light emitting diode circuit for supplying a direct current signal to the light emitting diode circuits to drive the light emitting diodes. Each of the current sharing circuits is connected to each of the (four) diodes. The other end of the circuit is used to balance the current flowing through the LED circuit. Each current is divided into a drain including a first transistor, a second transistor, a current limiting resistor, and a sensing resistor. Connected to the LED circuit. The base connection of the second transistor The emitter of the first transistor has a pole connected to the base of the body of the body, and the emitter is grounded. The current limit is connected to the base of the first transistor and an external voltage source. For supplying the working voltage to the first transistor, the end of the sensing resistor is connected to the emitter 5 M363016 of the first transistor and the base of the second transistor, and the other is sensing the first Crystal emitter:: ground: wherein the second transistor has a change in the voltage between the bases of the second transistor, and the second transistor is adjusted to pass through the sensing body. The voltage between the emitters, the electric current and the current of the 〜 枭 二 二 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭 枭Feedback
流效果好，且具有更低的=:極體電路的均流’不僅均 【實施方式】 圖1為本新型發光二極體（Light Emitting Diode，LED) ‘驅動電路一實施方式的電路圖。在本實施方式中，發光二 極體驅動電路用於驅動複數發光二極體電路，每一發光二 極體電路包括複數串行連接的發光二極體。需要注意的 是’圖1中僅示出一發光二極體電路12 ’該發光二極體電 鲁路12包括複數串行連接的發光二極體D1.....02。下面 以發光二極體電路12與發光二極體D1.....D2為例來做 詳細闡述。在本實施方式中，該發光二極體D1、…、D2 是同向串行連接的，即後一個發光二極體的陽極連接前一 個發光二極體的陰極，以此類推。 在本實施方式中，發光二極體驅動電路包括轉換電路 10及與該發光二極體電路12數量相當的複數均流電路 14 °需要注意的是，因所有的均流電路14的電路結構及連 6 M363016 接關係均一致，圖1中僅示出一均流電路14。 ' 轉換電路10連接于發光二極體電路12的一端，用於 ’向發光二極體電路12提供直流訊號以驅動發光二極體電 路12。在本實施方式中，轉換電路10與發光二極體電路 12中第一個發光二極體D1的陽極連接，用於將所接收的 . 外部直流訊號轉換為適合該等發光二極體D1.....D2的 直流訊號，以驅動該等發光二極體D1.....D2。 φ 均流電路14連接于發光二極體電路12的另一端，用 於平衡流經發光二極體電路12的電流。前已述及，該等發 光二極體D1.....D2是同向串行連接的，因此，均流電 路14連接于發光二極體電路12中最後一個發光二極體D2 的陰極。在本實施方式中，均流電路14包括第一電晶體 Q1、第二電晶體Q2、限流電阻R1及感測電阻R2。 第一電晶體Q1的汲極連接于發光二極體電路12中最 φ 後一個發光二極體D2的陰極。 第二電晶體Q2的基極連接於第一電晶體Q1的射極， 其汲極連接於第一電晶體Q1的基極，其射極接地。 限流電阻R1連接於第一電晶體Q1的基極與外部電壓 " 源之間，用於為第一電晶體Q1提供工作電壓Vx。 感測電阻R2的一端連接第一電晶體Q1的射择與第二 電晶體Q2的基極，另一端接地。 第二電晶體Q2透過感測第一電晶體Q1射極電流的變 7 M363016 化來調節第二電晶體Q2沒基極的電墨進而調節第一電晶 體Q1汲射極間的電壓，從而使流經感測電阻R2的電流維 ' 持穩定，以此平衡流經該發光二極體電路12的電流。 詳而言之，當發光二極體D1、…、D2上的電壓處於 穩態時，利用第二電晶體Q2操作于線性區時基極與射極 - 間電壓為一定值的特性，可使得感測電阻R 2上的電壓與電 流維持穩定’並且忽略流入弟二電晶體Q 2基極的電流5 φ 因此流經感測電阻R2的電流等於流經發光二極體 D1、…、D2的電流。 當某些原因使得流經發光二極體D1.....D2的電流 下降時，經第一電晶體Q1流入感測電阻R2的電流與流入 第二電晶體Q2基極的電流會隨之下降，這將導致流經限 流電阻R1的電流及限流電阻R1兩端之間的電壓下降，第 二電晶體Q2的汲極與射極間的電壓和第一電晶體Q1的基 φ 極電壓上升。第一電晶體Q1的基極電壓上升會造成第一 電晶體Q1的汲極與射極間電壓下降，進一步使得感測電 阻R2上的電壓上升，從而使得流過感測電阻R2的電流上 升至一定值。此時，流經發光二極體D1.....D2上的電 流即得到了平衡。 同時，若在每一發光二極體電路12上都接入一均流電 路14，配以參數相同的電晶體及電阻等元件，就可使得流 經所有發光二極體電路12的電流都一樣，從而實現發光二 8 M363016 極體的均流效果。 ^ 圖2為本新型發光二極體驅動電路另一實施方式的電 路圖。 在本實施方式中，發光二極體驅動電路比圖1所不的 實施方式僅多了一個溫度補償電路16,並連於感測電阻R2 - 的兩端，用於對感測電阻R2進行溫度補償，從而進一步提 高電流均流效果。溫度補償電路16可採用具溫度變化特性 φ 的元件來實現。在本實施方式中，溫度補償電路16包括熱 敏電阻，如負溫度係數熱敏電阻、正溫度係數熱敏電阻等。 本創作所提供的均流電路的實施方式採用兩個電晶體 Ql、Q2及兩個電阻Rl、R2形成有回饋作用的電路連接關 係，即實現了發光二極體電路12的均流，製作非常簡單， 均流效果好且具有成本低等特性。 【圖式簡單說明】 φ 圖1為本新型發光二極體驅動電路一實施方式的電路 圖。 圖2為本新型發光二極體驅動電路另一實施方式的電 路圖。 【主要元件符號說明】 轉換電路 10 發光二極體電路 12 發光二極體 Dl、D2 M363016 均流電路 14 限流電阻 R1 感測電組 R2 第一電晶體 Q1 第二電晶體 Q2 溫度補償電路 16The flow effect is good, and the lowering of the current circuit of the lower body circuit is not limited. [Embodiment] FIG. 1 is a circuit diagram of an embodiment of a driving circuit of a new light emitting diode (LED). In this embodiment, the LED driving circuit is configured to drive a plurality of LED circuits, and each of the LED circuits includes a plurality of serially connected LEDs. It is to be noted that only one light-emitting diode circuit 12' is shown in Fig. 1. The light-emitting diode circuit 12 includes a plurality of serially connected light-emitting diodes D1.....02. Hereinafter, the light-emitting diode circuit 12 and the light-emitting diodes D1.....D2 will be described in detail as an example. In the present embodiment, the light-emitting diodes D1, ..., D2 are connected in the same direction in series, that is, the anode of the latter light-emitting diode is connected to the cathode of the former light-emitting diode, and so on. In the present embodiment, the LED driving circuit includes a conversion circuit 10 and a plurality of current sharing circuits 14 corresponding to the number of the LED circuits 12. It should be noted that the circuit structure of all the current sharing circuits 14 and Even the 6 M363016 connections are identical, and only one current sharing circuit 14 is shown in FIG. The conversion circuit 10 is connected to one end of the LED circuit 12 for supplying a direct current signal to the LED circuit 12 to drive the LED circuit 12. In this embodiment, the conversion circuit 10 is connected to the anode of the first LED diode D1 of the LED circuit 12 for converting the received external DC signal to be suitable for the LEDs D1. ....D2 DC signal to drive the LEDs D1.....D2. The φ current sharing circuit 14 is connected to the other end of the light-emitting diode circuit 12 for balancing the current flowing through the light-emitting diode circuit 12. As described above, the light-emitting diodes D1.....D2 are connected in the same direction in series, and therefore, the current sharing circuit 14 is connected to the cathode of the last light-emitting diode D2 in the light-emitting diode circuit 12. . In the present embodiment, the current sharing circuit 14 includes a first transistor Q1, a second transistor Q2, a current limiting resistor R1, and a sensing resistor R2. The drain of the first transistor Q1 is connected to the cathode of the most φ latter LED D2 in the LED circuit 12. The base of the second transistor Q2 is connected to the emitter of the first transistor Q1, the drain of which is connected to the base of the first transistor Q1, and the emitter of which is grounded. The current limiting resistor R1 is connected between the base of the first transistor Q1 and the external voltage source for supplying the operating voltage Vx to the first transistor Q1. One end of the sensing resistor R2 is connected to the emitter of the first transistor Q1 and the base of the second transistor Q2, and the other end is grounded. The second transistor Q2 adjusts the electrode of the second transistor Q2 without the base electrode by sensing the change of the emitter current of the first transistor Q1 to adjust the voltage between the emitters of the first transistor Q1, thereby The current flowing through the sense resistor R2 is stabilized to balance the current flowing through the LED circuit 12. In detail, when the voltage on the LEDs D1, . . . , D2 is in a steady state, when the second transistor Q2 is operated in the linear region, the base-to-emitter voltage is constant. The voltage and current on the sense resistor R 2 remain stable' and ignore the current flowing into the base of the second transistor Q 2 5 φ. Therefore, the current flowing through the sense resistor R2 is equal to the flow through the light-emitting diodes D1, ..., D2. Current. When the current flowing through the light-emitting diodes D1.....D2 drops for some reason, the current flowing into the sensing resistor R2 through the first transistor Q1 and the current flowing into the base of the second transistor Q2 will follow. Falling, this will cause the current flowing through the current limiting resistor R1 and the voltage drop across the current limiting resistor R1, the voltage between the drain and the emitter of the second transistor Q2 and the base φ pole of the first transistor Q1. The voltage rises. The rise of the base voltage of the first transistor Q1 causes a voltage drop between the drain and the emitter of the first transistor Q1, further causing the voltage on the sense resistor R2 to rise, so that the current flowing through the sense resistor R2 rises to A certain value. At this time, the current flowing through the light-emitting diodes D1.....D2 is balanced. At the same time, if a current sharing circuit 14 is connected to each of the LED circuits 12, and components such as transistors and resistors having the same parameters are used, the current flowing through all the LED circuits 12 can be made the same. In order to achieve the current sharing effect of the illuminating two 8 M363016 polar body. ^ Fig. 2 is a circuit diagram of another embodiment of the novel light emitting diode driving circuit. In the present embodiment, the LED driving circuit has only one temperature compensation circuit 16 than the embodiment shown in FIG. 1, and is connected to both ends of the sensing resistor R2 - for temperature sensing resistor R2. Compensation to further improve the current sharing effect. The temperature compensation circuit 16 can be realized by an element having a temperature variation characteristic φ. In the present embodiment, the temperature compensation circuit 16 includes a thermistor such as a negative temperature coefficient thermistor, a positive temperature coefficient thermistor, and the like. The implementation of the current sharing circuit provided by the present invention adopts two transistors Q1 and Q2 and two resistors R1 and R2 to form a circuit connection relationship with feedback function, that is, the current sharing of the LED circuit 12 is realized, and the fabrication is very Simple, balanced current and low cost. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a circuit diagram of an embodiment of a novel light emitting diode driving circuit. Fig. 2 is a circuit diagram showing another embodiment of the novel light emitting diode driving circuit. [Main component symbol description] Conversion circuit 10 LED circuit 12 LED diode Dl, D2 M363016 Current sharing circuit 14 Current limiting resistor R1 Sensing group R2 First transistor Q1 Second transistor Q2 Temperature compensation circuit 16
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