TW200301881A - LED driving circuit - Google Patents

Abstract

The present invention provides a LED driving circuit. The circuit structure includes a supplying power, a current guiding control circuit composed of one to several common-ground current control units, and a voltage detection circuit for detecting the voltage level of the supplying power. The supplying power is serially connected to one to several LED sets. Each LED set is composed of one to several LEDs. The current control unit of the current guiding control circuit is sequentially connected to the N electrode (negative electrode) of each LED set. According to the voltage detection circuit, the voltage level for supplying the positive part of the power is determined. Then, different current guiding control circuits are respectively driven for being turned on based on various voltage levels. A suitable number of LED sets are driven by turning on different current guiding control circuits. Such a circuit design allows the voltage of positive part of the supplying power to directly drive the LED set to light a maximum number of LED sets based on the voltage value without the design of filtering capacitor, thereby achieving the purpose of fully utilizing electricity power, increasing power factor and reducing power loss.

Description

A kind of component rectification that can drive the loss directly. Generally, there are two types of lighting, high and brake lights. ^ The primary colors are used for street advertising. The screen is large. 〖From the honeycomb polar body, it is smaller and saves part of the lighting. 200301881 V. Description of the invention (1) [ The technical field to which the invention belongs] The present invention relates to a driving circuit 'especially the county, the design of the non-filter capacitor by the forward part of the power supply +, | ⑺ voltage light-emitting diodes, and can make full use of power Power and reduced power Opto-polar driver circuit. Μ [Previous technology] A semiconductor diode is one of the most basic parts in various electronic systems at the same time. 'At the same time, its characteristics are similar to ordinary switches and also useful.' Therefore, it also plays a very important role in electronic systems-its The scope of application can be extended from simple to complex electrical appliances in Fan f. The rectification of electrical appliances relies on the power of diodes. When we look at the advertisements we see on the road, it is also the function of ^ f. And done. The application of visible light-emitting diodes is mainly the application of traffic signs and vehicle indicators; the full-color light-emitting diode system uses red, green, and blue to form a display screen. Widely used in stadiums, such as the most significant application examples of giant diodes outside the Nasdaq Building in Times Square, New York, USA; this screen is the world's most: > & Composition of light-emitting diodes. Phones and other portable electronics produce e-light-emitting diodes: light-emitting devices with dots or missing. Due to the body of the light emitting diode light source. With the advantages of fast speed and long life, it will be able to replace the K takazumi H t ^ in the future, and the lighting and light-emitting diode industry on each side of the market ...

200301881 V. Description of the invention (2) According to the survey data of the Economic and Trade Center of the Academy, the global lighting market grows steadily at a growth rate of about 4.8 to 8.8 every year. In 1998, the world's Zhaoming No. 2 market size was about 140. US $ 100 million in 2000; j = light source Sisi US dollars, and the visible light emitting diode market has grown steadily at about 8% to 10%. In 1998, the visible light emitting diode market regulations Changyi /, US $ 410 million. In 1999, it was 18.13 billion yuan. In 2002, it exceeded US $ 2 billion. In general, as the application of LEDs has become popular, various driving circuits and mobile chips have emerged. Please refer to Figure 1. Figure A shows the voltage and current characteristics of a _ pole. Except for some specific applications, the two bodies generally operate under forward voltage, and the relationship between voltage and current is described by the index e. When the voltage across the diode's poles exceeds a certain voltage (= the start-up voltage or the on-voltage, its value is between about 0.5 and 0.8 volts, = the material and impurity doping concentration depending on the diode And it is different), the current of the diode increases rapidly, and before this starting voltage, the current of the diode is extremely small. The characteristics of light-emitting diodes are the same as ordinary diodes. As its name * indicates, it can emit visible light when it is excited. The light emitting diode is made of arsenic gallium phosphide or gallium phosphide. When the materials used for manufacturing are different, the wavelength of the emitted light is different and the color is naturally different. For example, gallium arsenic phosphide emits red light, while gallium phosphide is between yellow and green. The luminosity (lumens) emitted by the light-emitting body is directly proportional to the on-current, as shown in Figure 1B. Therefore, in practical applications, in order to maintain a brightness, the driving circuits are mostly designed to be driven with a fixed current, & extended The purpose of the life of the light-emitting diode. If using AC power:

200301881

In the segment rp of the 4 ′ community father and the forward part of the light emitting monopole, the voltage level of the AC power source exceeds the light emitting diode conduction, so the light emitting diode will emit light in this segment. As shown in Figure C. At present, ― A ^ means 刖, 彺 In general applications, in order to make more effective use of easily available AC power, the bridge rectifier circuit Rec shown in Figure 2A is used to transpose the reverse part of the power supply to the forward direction: After further stabilizing the voltage waveform through the filter capacitor C, it will be connected to the two “polar body” and related circuits. At this time, the waveform of the power supply is shown in Figure 2 and the corresponding on-current is shown in Figure 2C. In order to make the on-state current value constant and constant, a constant-current source circuit is usually added to ensure that the brightness and color of the light-emitting diode ~ pole body can be kept consistent. The on-state current is shown in Figure 2D. In the presence of inductive components such as capacitors or inductors, the voltage and current% will not be synchronized, and the two will have a phase difference. As shown in Figure 2E, it is the current with the phase Θ after the voltage. Situation, that is, when the voltage eac is' "

When EmSin is expressed, the current lac is lmsin (ω t-Θ). At this time, because the voltage and current are not synchronized, the power will be smaller than the voltage when the voltage and current are synchronized due to the multiplication of the voltage and current at any time. The power is smaller than the voltage when the voltage and current are synchronized. The mathematical expression of the power is VmlmCos Θ / 2, where Cos Θ is generally called the power factor.

There are many patents for light-emitting diode driving circuits, such as U.S. Patent 5,936,599¾ ^ AC POWERED LIGHT EMITTING DIODE ARRAY CIRCUITS FOR USE IN TRAFFIC SIGNAL DISPLAYS ", and its circuit structure is shown in Figure 3. The patent is an array composed of an AC power supply E connected in series with the inductor L, and then supplying power to a plurality of parallel pairs of opposite light emitting diodes Dpair (Polarized LEDS). Inductance l is

Page 7 20031881 V. Description of the invention (4) It is used to replace the current limiting resistor in the general drive circuit, and can achieve the purpose of limiting the current under the condition of low loss power. In addition, in order to reduce the power loss, the patent A capacitor C is designed in parallel with the light-emitting diode array. The capacitance and inductance in the patent are designed according to the frequency of the AC power supply E (Tuning). However, although this patent improves the power loss caused by conventional current-limiting resistors, it also reduces the power factor due to the presence of capacitor C and inductor L (p 0 w e r F a c t 0 r). In addition, the patent also has the disadvantage that the capacitance and inductance need to be adjusted at different frequencies of the AC power supply E, and the number of LED groups connected to the AC power supply V s The voltage level is related.

In addition, it is also a US patent for a light emitting diode driving circuit

No. 5,457,450 nLED TRAFFIC SIGNAL LIGHT WITH AUTOMATIC LOW-LINE VOLTAGE COMPENSATING CIRCUIT " Its circuit structure is shown in Figure 4 ’and its improvement lies in the design of the low voltage compensation circuit 8 2, 8 4 (the number of the original patent scheme). Under the low power supply, in order to make the light emitting diode still emit enough light, the patent is designed to drive the part that is turned on with a larger current when the power is low without adding extra power loss. Diodes, but this rule detracts from the life of the light-emitting diode. As mentioned above, the diode driving circuit that responds to various needs arises at the historic moment, and it is necessary to maintain the voltage level of the power supply by filtering capacitors to increase the on-time of the light emitting diode, in addition to the power factor factor 'In addition to the reduction, as the frequency of the power supply changes, the capacitor value also needs to be adjusted. This ’affects the life of the capacitor under the severe high temperature environment where the light emitting diode is located and

200301881 V. Description of the invention (5) Stability is very short. [Summary of the invention] In view of the fact that for many years, the value of the power supply of the present invention has been driven by the value of the power supply to light up the maximum number of power losses, and other drive circuits are omitted. For any type, the number of wave capacitors in the present invention can be mixed, but this value is relatively close. This is the following design attached [implement the first design, so the light emission stray resistance to reduce the general drive point is more capable Let the diagram and this way] Referring to the embodiment of the diagram, the stability of the driving circuit is not good. There are imperfections in the integrated diode driving circuit. 'Invented research and development, and finally developed such a filter capacitor that directly drives the light emitting diode in the forward part of the voltage. The light emitting diode can be improved according to the voltage. Power factor, reduced purpose LED driver circuit. The polar body drive circuit directly supplies a large power supply filter capacitor with the forward part of the power supply, so the power factor is higher. The photodiode driving circuit uses a power supply of any wave shape, stable or unstable power supply. Because there is no filter, it can light up the most light-emitting light-emitting diodes according to the voltage value. Generally there are many driving circuits. The power loss of the polar body, without calculating the leakage resistance, the loss of stray electricity (these losses are stored in various types of drive circuits), the voltage drop to the on-current X current-directed control circuit, the drive circuit is low, and this value and supply The type of power supply is unmatched by other driving circuits. Examiners can more easily understand the features of the present invention, please refer to the description of the embodiments of the invention. 5. Fig. 5A is a structural diagram of a light emitting diode driving circuit of the present invention. The light-emitting diode driving circuit of the present invention has a circuit III 111 1 111 119 page 9 200301881 V. Description of the invention (6): Department of power supply, current-oriented control circuit, and voltage detection = current source can be any-type The heart is like a sine wave AC power circuit, and you = 5 疋 is a stable or non-stable power supply; a current-oriented control electric detection circuit: ϋ, composed of several common ground current control units; and voltage ', /, is used to Detect the voltage level of the power supply. ί ΐ J ^ ^ ^ # Μ, Ι ^ ^ t #nvs,; D | T Λ ^ Ι η, 12, 13 links, and the current control unit N (β) ia of the current steering control circuit 10, I (n —1), In sequentially with the forward part of each light-emitting diode group :; the same power on the power supply is determined by the voltage detection circuit 2 ° = direction = road;: ί; Γ…: different To drive the non-control circuit to be turned on respectively, by turning on different current conducting circuits, a proper number of light emitting diode groups can be spotted. The power supply :::: light: f ΐ The supply required for the light-emitting diode in the drive circuit, such as the bridge type ΐ :: The power supply passes through the rectifier circuit 3 first. For example, the present invention sends: electricity 'for negative voltage transpose. Control circuit I: Body: Ϊ: Road: Supply bank for M detection circuit and current-guiding polar body; can be provided separately, or it is controlled by light-emitting two-way: supply =: regardless of voltage detection circuit and current conduction source Supply, such as :: m :, 疋 shared power supply or another independent radio circuit can only :: ϊ ΐ ί ΐ: 1 prototype ☆, you must first pass the rectifier filter-as a current-oriented control circuit and voltage measurement circuit Supply

200301881 V. Description of the invention (7) Power supply. Take the sine wave AC power supply as an example. When the forward part of the sine wave parent current power supply, the voltage detection circuit is designed to be when the AC voltage is higher than the on-state voltage Vt hi of the light emitting diode (this value is exactly equal to the light emitting diode The sum of the turn-on voltages of all series-connected light-emitting diodes in the body group. If the light-emitting diodes in the light-emitting diode group are all of the same type, the value of Vthl is multiplied by the light-emitting diode Number of stages in series), the voltage detection circuit will turn on the 11 current control unit, while the other current control units remain inactive. At this time, the current and path are supplied by the power supply, the light emitting diode group D1, and the current control Unit 丨 丨, then ^ is grounded, and when the power supply voltage continues to rise to Vthl + Vth2 (if the number and type of light-emitting diodes of the light-emitting diode group D2 are exactly the same as D1, then vth2 = =, which is voltage detection When the circuit detects the power of the power supply, when 咼 = 2Vth, the 12 current control unit is turned on and 棹 η is turned off at the same time. This current path is provided by the power supply and the light-emitting diode group]), D2, ii T 9 u electricity / melon's heart ground; when supplied The voltage of the power supply continues to rise: According to the analogy, at the same time, only one current is maintained to control the brightness of the U-conducting and constant-current light-emitting diodes. Generally, the current control unit is designed privately. of. It is worthwhile to follow the current control of the unit, basin, the light emitting diode driving circuit of the present invention, and it can be achieved by two buckets, and the structure can be achieved by any current control circuit. Most of them should be controlled by current, or It is designed for current limiting control. In order to maintain the brightness of the light-emitting diode, the current Δ 囡 疋 is equal to two but can be adjusted as needed. Electricity-to-solids, teeth, and applications' are connected in series to produce various colors of light.

Page 11 20031881 V. Description of the invention (8) The light-emitting polar group is not necessarily a light-emitting diode of a certain light color. Depending on the actual situation, different light colors (types) and numbers of light-emitting diodes can be connected in series. Through the use of different light colors (types) of light-emitting diodes, number, and luminous intensity to achieve the purpose of showing various colors. It is feasible to adopt a specific light-emitting diode array for a certain application of light color, but in order to be applicable to various applications', it is not necessary to change the type and number of light-emitting diodes. This can be achieved by controlling the magnitude of the constant current value of the current control unit, which is the second embodiment of the Maomingshe photodiode driving circuit.

In the second embodiment of the light-emitting diode driving circuit of this invention, as shown in Fig. 5B, in order to achieve a light-emitting display of any color, we will replace the original D1, D2, D3 '..., d (n — 1), the system light consisting of dn light-emitting diode groups = polar columns, changed to a multi-row light-emitting diode group array, this array is composed of three parallel light-emitting diode columns, which is The red light emitting electrode group Dal, Da2, Da3, ···, Da (nl), Dan are red light emitting electrode columns; the green light emitting diode group Dbl, Db2, j) b3, ··· D5 (nl), a green light emitting electrode column composed of Dbn, and a blue light emitting diode group "1 'DC2' Dc3, ..., Dc (n-1), blue light emitting electrode composed of Dcn = any color is acceptable The color mixing principle is divided into three primary colors, first: the current control unit Iai in the W-direction control circuit n, 12 and 13-

-a (nl) Ian, Ibl, Ib2 ... Ib (n_〇 之 雷 、 ώC n 1), Icn to control the size of the three colors of the light emitting electrode column ^^, and can achieve the emission of any color light the goal of. Since the turn-on voltage Vf of the light-emitting diodes is not necessarily the same, Tian; i sent from the Da light-emitting diode column on the three-way-this is the luminescence in the quasi-phantom armor group Diode 200301881 V. Description of the invention (9) The number of cascaded series and the series of luminescent two in the Db, Dc light-emitting diode array are not the same, so it is the same as that of the voltage measurement circuit. The number contained in the body group also depends on the light-emitting diodes = properties. In addition, the number of columns in the array is not necessarily one, one each for red, green, and blue. Figure 6 shows the relationship between the supply voltage ν s (cross-source power supply type), continuity, and ILed. Figure 6 ^ 2 = body, * The figure can clearly see that with the supply of private sources and cross-connections, the voltage drop of all ¥ through the light-emitting diode resistance, the conduction current of the diode, the current control of conduction Relationship between units. Since the present invention does not have a filter capacitor, when the power loss caused by stray resistance and capacitance is not considered, the output power of the power supply is the area of the voltage waveform of the power supply multiplied by ILed, and all the turned on light-emitting diodes The cross voltage of the group is stepped. Its power is the area of the stepped part multiplied by IL ed. The difference between the two powers is the power lost. The loss function is equal to the area Led of the dotted line. The difference Vdrop of the total voltage drop of the light emitting diode group will fall on the current control unit. If the supply power is not a stable sine wave AC power supply, the relationship between the total voltage drop VLed on the light-emitting diode Vs (cross-source power supply) and the on-state current ILed 'is shown in Figure 7, and the output of the power supply The power, the light-emitting power of the light-emitting diode, and the power loss of the driving circuit are the same as those described in FIG. The power loss value 丨 L ed is XVdrop ’This value has nothing to do with the rms voltage value of the AC power supply ’s power supply and it ’s also independent of the voltage level of the non-AC power supply ’s power supply. The above is the ideal situation, but in the actual situation, the current control

Page 13 20031881 V. Description of the invention (ίο) When the control unit operates at the desired constant current, the minimum operating voltage difference of the current control unit under this constant current must also be overcome. If the minimum operating voltage difference is V d, then The voltage value for turning on the current control unit in the voltage detection circuit must be slightly higher than the ideal situation (that is, the voltage described in the previous paragraph). This Vd value is much smaller than that of the light emitting diode group. The working voltage difference of the current control unit continues to increase with the value of the power supply until the power supply exceeds the voltage level of the next voltage detection circuit designed to reach When the maximum value (generally when the current value of the current source control unit is about 100 mA, the minimum Vd value will be designed to be less than 0.1 V). In addition, one to several light-emitting diodes in the light-emitting diode group may be connected in series, parallel, or series-parallel. Each voltage level designed in the same 'voltage detection circuit can also be adjusted as needed. There are also many implementation circuits of the voltage detection circuit. For example, the design of a comparator and a voltage dividing resistor is one of the circuit implementations. The voltage level of the control unit can be achieved by adjusting the voltage dividing resistor. ] Change and drive each current. In the above embodiment, the voltage detection circuit, the current circuit is not limited. 'Such various improvements are not limited by the following: two, electric and other methods. Moreover, the above described in the above-mentioned embodiment is merely any modification and invention made to the embodiment through better implementation. However, the number of light-emitting diodes in the embodiment is the same as that in the present invention. Without departing from the spirit and scope of the invention. The collection of bottles, and the above detailed description will make you well acquainted with this & two can achieve the aforementioned purpose, has indeed met the patent j * who understands the provisions of the present invention, according to the law on page 14 20031881 • clearly stated (11 ) Invention patent application 专利

1BI Page 15 2Q | Q301 & 84- Brief description of the diagram [Simplified description of the diagram] Figure 1A is a graph representing the voltage and current characteristics of a general diode Figure 1B is the luminosity emitted by a light-emitting diode ( Luminance) and on-current diagram. Figure 1C is the conduction state when AC power is used to drive the light-emitting diode. Figure 2A is the bridge rectifier circuit. Figure 2B is the voltage waveform diagram of the filter capacitor. Figure 2C Figure 2 is the on-current diagram corresponding to Figure 2B. Figure 2D is the on-current diagram after adding a certain current source circuit. Figure 2E is the current-lagging voltage relationship. Figure 3 is US Patent No. 5,36,599. AC POWERED LIGHT EMITTING DIODE ARRAY CIRCUITS FOR USE IN TRAFFIC SIGNAL DISPLAYS " circuit structure diagram Figure 4 is US Patent No. 5,457,450, 丨 LED TRAFFIC SIGNAL LIGHT WITH AUTOMATIC LOW-LINE VOLTAGE COMPENSATING CIRCUI T " The structure diagram of the first embodiment of the diode driving circuit. Figure 5B is the structure diagram of the second embodiment of the light-emitting diode driving circuit of the present invention. Figure 6 is the sine wave power supply. , & Amp turned on the current, and the light-emitting diode; FIG seven voltage drop relationship for any power supply system, the pressure drop across the on-state current, and the relationship between the light emitting diode of FIG.

200301881 Simple illustration of symbols Simple explanation of symbols: τ On time E Supply power I a c Parent current V s Supply power ㊀ Current and voltage phase difference V f Light-emitting diode group turn-on voltage Rec bridge rectifier circuit

Vthl Turn-on voltage of light-emitting diode group D1 Vth2 Turn-on voltage of light-emitting diode group D2 Vth3 Turn-on voltage of light-emitting diode group D3 Vth4 Turn-on voltage of light-emitting diode group D4 Vth5 Turn-on voltage of light-emitting diode group D5 IL 6 d Light-emitting diode conduction current Vdrop Current control unit across voltage D pair Polarity-opposed two light-emitting diode parallel group IL cd Light-emitting diode group conduction current ILcdl Red light-emitting diode group conduction current ILcd2 Green light-emitting diode Diode group conduction current ILcd3 Yellow light emitting diode group conduction current L Inductance C Resistance II, 12, "· Ι (η-1), In Current control unit I a 1, I a2,… la (η-1) , Ian current control unit

Page 17 20031881 The diagram briefly illustrates Ibl, Ib2,… I b (n-1), Ibn current control units Icl, Ic2,… Ic (n-1), I cn current control units Da, Db, Dc light-emitting diodes Volumes D1, D2,… D (nl), Dn Light-emitting diode groups Da 1, Da2, ••• Da (n-1), Dan light-emitting diode groups Dbl, Db2, ··· Db (n- 1), Dbn light-emitting diode group Del, Dc2, ··· Dc (n-1), Den light-emitting diode group 1 0, Π, 1 2, 1 3 current steering control circuit 2 0 voltage detection circuit 3 0 Rectifier circuit

Page 18

Claims (1)

200301881 6. Scope of patent application [Scope of patent application] It includes: · the power source that a pole loves; to a number of common ground + u current control single 1 · a light emitting diode drive circuit, Fadi supply power , Which is used to supply a light-emitting private circuit, a current-oriented control circuit, which is composed of a unit; and-a voltage detection circuit 'which is used to detect and supply one to several light-emitting diodes in series ^] The photodiode group is composed of one or several light emitting diode strings connected in parallel to form a hair body column, and one or more light emitting diode columns are connected in parallel to seven light emitting diode columns, and then connected in series with the power supply. The current-conducting light-emitting diode array is sequentially connected to the heart of each light-emitting diode group (negatively controlling the voltage level of the positive part of the power supply, depending on the voltage = bit), driving different current-oriented control circuits so that It is turned on and wrong by turning on different current-oriented control circuits to illuminate an appropriate number of light-emitting diode groups. Such a circuit design can be directly driven by the forward partial voltage of the power supply without the design of a filter capacitor. The light-emitting diode group illuminates the most light-emitting diode group according to the voltage value to achieve the purpose of making full use of the power of the power source, increasing the power factor, and reducing power loss. 2 · The light emission as described in the first item of the scope of patent application Diode driving circuit, in which a bridge / rectifier circuit can be designed at the back end of the power supply, so that the reverse part of the power supply can be transposed to the forward direction. 3 · The light emission as described in item 1 or 2 of the scope of patent application A diode driving circuit, in which the power supply can be any level, any type of stable or unstable power supply. 200301881 6. Scope of patent application 4. As in the first scope of patent application, the current-steering control circuit is shared by the light-emitting diode array. 5. In the scope of patent application No. 4, the current-oriented control circuit shares the power supply or another type, it needs to be rectified first. In the scope of patent application No. 1, the current control unit can be achieved by a circuit. 7. If the scope of patent application is No. 1, among which the current control unit 8. If the scope of patent application is No. 1, where the current control unit 9. If the scope of patent application is No. 1, where the current control unit is changed in size. The light-emitting diode driving circuit described in the item, and the power required by the voltage detection circuit can be matched with the power supply, or the light-emitting diode driving circuit described in the item, and the voltage detection circuit can be provided separately. Regardless of whether the power supply is a stand-alone power supply, if the power supply is not a DC source filter circuit. The light-emitting diode driving circuit according to the item, which is configured by a transistor having a control current conduction or the light-emitting diode driving cell according to the item 6, can be designed to have a current limiting function. Or the light-emitting diode driving cell described in item 6 can be designed to have a constant current function. Or the current value of the light-emitting diode driving cell described in item 6 can be changed as needed Page 20, 20031881 VI. Patent application scope 1 2 · The light emitting diode driving circuit described in item 1 of the patent application scope, wherein each voltage level value of the voltage detection circuit can be changed in size as required. 13. The light-emitting diode driving circuit described in item 1 of the scope of patent application, wherein the types of light-emitting diodes included in the light-emitting diode group may be different. Page 21