201238392 六、發明說明： 【發明所屬之技術領域】 本發明係有關一種發光元件控制電路與控制方法，特別是 指一種能減少積體電路接腳數目並能動態調整輸出電壓以= 最佳電源運用效率的發光元件控制電路與控制方法。本發明也 有關於應用在發光元件控制電路與控制方法中的積體電路。 【先前技術】 請參閱第1圖’先前技術之發光元件控制電路包括積體電 路20，其中包含一個功率級控制電路2卜控制功率級電路6〇 中功率電晶體的切換’以將輸人電壓vin轉換為輸出電壓 V〇ut，供應給多串發光二極體(LED) cm_CHn。功率級電路 6〇例如但*限於可為第2A_2G圖所*的同步或非同步降壓、 升壓、升降壓、反壓、返驰電路。其中，視應用場合而定，在 某些情況下轉級電路6G中的功率電晶體或二極體可以整合 至積體電路20的内部。 為了控制各串LED的亮度，帛丨圖中係以運算放大器 OP卜電晶體Q1、電阻R1構成的電流職路CS1來控制第一 LED通道CH1的電流’以運算放A|| 〇p2、電晶體、電阻 ^構成的電麵電路CS2來㈣帛二LED通道CH2的電流， 等等。由;^在每-led ϋ道上串接多個LED之故，輸出電壓 V〇ut相當* ’因此電晶體⑼你必須使用高耐壓元件，無法 整合在積體電路20之内而必須設置在積體電路外部。然而， 如此一來積體電路20必須設置通道數目兩倍的接腳PJ.-P2N’ 才能控制N串的LED電路。 在某些應用場合中，更如第3圖所示，需將電晶體Q1_Qn 201238392 的沒極電壓取人積體電路2G㈣，如此更將此部份所需的接 腳數目增加到通道數目的三倍。 有鑑於此，本發明乃提出一種能減少積體電路接腳數目的 發光元件控制電路與控制方法。 此外’本發明亦提出一種能動態調整輸出電壓以達最佳電 源運用效率的發光元件控制電路與控制方法。 【發明内容】 本發明目的之-在提供—種發光元件控制電路。 本發明的另一目的在提供一種發光元件控制方法。 本發明的再一目的在提供一種用於發光元件控制電路中 之積體電路。 為達上述之目的，就其中一個觀點言，本發明提供了一 種發光元件控制電路，包含：辨級㈣電路，其控制一功率 級電路’以將-輸人電壓轉換為—輸出電壓，供應給至少一個 發光元件通道，該發技件通道中包括至少—個發光元件；位 於該發光元件通道上的電晶體卿，此電晶體關接收一控制 電壓VG ;控制該發光树通道電流的電流源電路，該^原 電路正吊工作所需之最低電壓為VR;以及動態磨差控制電 路’、將》亥電B曰體開關電流流出端之電壓％與電壓他相比 較，判斷在該控制電壓VG大於—參考電壓VH的情況下電壓 VS與電壓VR間之關係，而產生控制訊號提供給功率級控制 電路’以控繼功輪電路而調整輸出電麼。 就另一個觀點言’本發明提供了-種祕發光元件控制 電路中之㈣電路’該發光元件控制·控制至少—個發光元 件通道’此發光元件通道中包括至少一個發光元件及一個與該 201238392 . 發光元件耦接的電晶體開關，此電晶體開關接收一控制電壓201238392 VI. Description of the Invention: [Technical Field] The present invention relates to a control circuit and a control method for a light-emitting element, and more particularly to a method for reducing the number of integrated circuit pins and dynamically adjusting the output voltage to optimize the power supply efficiency. Light-emitting element control circuit and control method. The present invention is also related to an integrated circuit applied to a light-emitting element control circuit and a control method. [Prior Art] Please refer to FIG. 1 'The prior art light-emitting element control circuit includes an integrated circuit 20 including a power stage control circuit 2 for controlling the switching of the power transistor in the power stage circuit 6 以 to input the voltage Vin is converted to an output voltage V〇ut and supplied to a plurality of strings of LEDs cm_CHn. The power stage circuit 6 is, for example, but limited to a synchronous or non-synchronous buck, boost, buck-boost, back-pressure, flyback circuit that can be the 2A_2G diagram. Among them, depending on the application, the power transistor or the diode in the conversion circuit 6G may be integrated into the inside of the integrated circuit 20 in some cases. In order to control the brightness of each string of LEDs, the current of the first LED channel CH1 is controlled by the current path CS1 composed of the operational amplifier OP, the transistor Q1 and the resistor R1, to calculate the A|| 〇p2, the electricity Crystal, resistor ^ composed of electrical circuit CS2 to (four) 帛 two LED channel CH2 current, and so on. Since ^^ is connected in series with each LED on each-led ramp, the output voltage V〇ut is equivalent*'. Therefore, the transistor (9) must use a high withstand voltage component and cannot be integrated in the integrated circuit 20 and must be set in External to the integrated circuit. However, in this way, the integrated circuit 20 must set the pins PJ.-P2N' twice the number of channels to control the N-string LED circuits. In some applications, as shown in Figure 3, the gate voltage of the transistor Q1_Qn 201238392 needs to be taken into the integrated circuit 2G (4), so that the number of pins required for this part is increased to three of the number of channels. Times. In view of the above, the present invention proposes a light-emitting element control circuit and control method capable of reducing the number of integrated circuit pins. Further, the present invention also proposes a light-emitting element control circuit and control method capable of dynamically adjusting an output voltage to achieve optimum power utilization efficiency. SUMMARY OF THE INVENTION It is an object of the present invention to provide a light-emitting element control circuit. Another object of the present invention is to provide a light emitting element control method. A further object of the present invention is to provide an integrated circuit for use in a light-emitting element control circuit. In order to achieve the above object, in one aspect, the present invention provides a light-emitting element control circuit comprising: a level-adjusting (four) circuit that controls a power stage circuit to convert a-input voltage to an output voltage for supply to At least one light-emitting element channel, the method component channel includes at least one light-emitting element; a transistor located on the light-emitting element channel, the transistor is turned off to receive a control voltage VG; and a current source circuit for controlling the light-emitting tree channel current The minimum voltage required for the positive working of the original circuit is VR; and the dynamic wear difference control circuit', the voltage % of the current output end of the "Hui B body switch" is compared with the voltage, and the control voltage VG is judged. More than - the relationship between the voltage VS and the voltage VR in the case of the reference voltage VH, and the generation of a control signal to the power stage control circuit to control the power wheel circuit to adjust the output power. According to another aspect, the present invention provides a circuit in which a light-emitting element controls and controls at least one light-emitting element channel. The light-emitting element channel includes at least one light-emitting element and one with the 201238392. a transistor switch coupled to the light emitting element, the transistor switch receiving a control voltage
VG，且該發光元件控制電路包含一功率級電路，所述積體電 路包含.功率級控制電路，其控制該功率級電路以將一輸入電 壓轉換為一輸出電壓，供應給該至少一個發光元件通道；以及 控制該發光元件通道電流的電流源電路，該電流源電路正常工 作所需之最低電壓為VR ;以及動態壓差控制電路，其將該電 晶體開關電流流出端之電壓VS與電壓VR相比較，判斷在該 控制電壓VG大於-參考電壓VH的情況下電壓vs與電壓VR 間之關係，而產生控制訊號提供給功率級控制電路，以控制該 功率級電路而調整輸出電壓。 上述控制電路或積體電路中，該動態壓差控制電路可包 括·最低值選擇電路，自各發光元件通道上的電晶體開關電流 流出端之電壓VS中選擇最低者；比較電路，將最低值選擇電 路所選電壓與電壓VR比較；計數器，計數比較電路之比較結 果；以及數位類比轉換電路，其將計數器之計數值轉換為類比 的控制城，提供給功輪㈣電路。 今類比 .上述控制電路或積體電路巾，軸紐差㈣電路可包 2·最低值選擇電路’自各發光元件通道上的電晶體開關電流 k出端之電壓vs中選擇最低者；味電路，將最健選擇電 =所選電壓與電壓VR比較；以及低通紐器，其將計數器之 s數值轉換為類比的控制訊號，提供給功率級控制電路。 . 八上述控制電路或積體電路中，該動態壓差控制電路可更包 • 短路_電路，將該電晶體«電赫出端之電壓vs 考電壓VH t匕較’以決定該發光元件通道上是否發生短 ㈣輪電壓供應給至少_發光元件通道時，該控制電 201238392 路或積體電路中可更包含有—電壓控制電路，此電壓控制電 路分開提供控制電壓VG給各發光元件通道上的電晶體開 關，當偵測到任一發光元件通道上發生短路時 ，此電壓控制電 路使對應之發光元件通道上的電晶體開關不導通。 上述控制電路或積體電路中，該動態壓差控制電路可更包 含有-斷路侧電路，將該電晶體開關電流流人端之電壓VD 與電壓VR比較’以蚊該發光元件通道上是碰生斷路。 就另一個觀點言，本發明提供了一種發光元件控制方 法，該發光元件位於一發光元件通道上，所述方法包含：在該 發光兀件通道上設置電晶體開關，此電晶體開關接收一控制電 壓VG ;以一電流源電路控制該發光元件通道的電流，該電流 源電路正常工作所需之最低電壓為w ;使該控制電壓vg大 於-參考電壓VH ;判斷該電晶體開關電流流出端之電壓％ 與電壓VR間之關係；以及根據判斷結果，調整供應給該發光 元件通道的供應電壓。 底下藉由具體實施例詳加說明，當更容易瞭解本發明之 目的、技術内容、特點及其所達成之功效。 【實施方式】 請參考第4圖，其中顯示本發明的第一個實施例。本發 明將電流源電路CSl-CSn整合至積體電路20的内部，並另外 在各LED通道CHl-CHn上設置電晶體開關，這些電 晶體開關Ml-Mn的閘極受電壓VG控制。電壓VG例如以 為固定電壓或職性的方波訊號。當電壓VG為方波訊號時， 可根據電壓VG的佔空比(duty ratio)來調整各LED通道的平均 電流’亦即達成調整LED亮度的作用。由於電晶體酬⑽她 201238392 的閉極電壓為VG，因此電晶體開關Μ1·Μη的源極電壓最高 不會超過VG ’亦即電晶體開關Ml-Mn祕了阻播高壓的作 用使得電流源電路csl_CSn内的元件可使用低壓元件來製 作’便利於整合至積體電路2G的内部。如騎示，根據本發 月就控制各LED通道而言，積體電路2〇僅需要設置N+1 個接腳’遠較第卜3圖數目為低。 第5圖顯示本發明的另一實施例，在本實施例中，更設 置有一個短路伽彳電路23，以供侧各LED通道是否發生 短路二如騎示，细彳各LED通道是砰生娜，並不需要 另外設置接腳自積體電路2〇的外部取訊號，而可自積體電路 20的内部取各電晶體開關Ml-Mn的源極電壓。 請對照參閱第5 _第6圖，舉—例制如何根據電晶 體開關Ml-Mn❸源極電壓來判斷對應各LED通道是否發生短 路在電/yiL導通時，電晶體開關的沒極電壓vDi_vDn 等於輸入輕Vin鱗對應通道中LED的輕總和，而電晶 ，開關Ml_Mn的源極電壓vsl_VSn則等於VG減掉電晶體的 臨界電壓ντ。若持續將呢的電歷升高，源極電壓vsi_vSn 也會跟著升高，直到源極電壓VSl-VSn約等於汲極電壓 Vm-VDn為止，此時源極電壓vsl_VSn的電位會被籍位在電 壓VDl-VDn，不會再隨著VG升高而升高。 參閱第5圖與第6圖，假設第-LED通道CH1為正常 工作’而帛η $ LED ifif CHn發生短路，則由於短路之故， 及極電壓VDn、約等於輸出電壓v〇ut，遠高於正常狀況下的汲 極電壓VD卜因此，我們可任意設定—個位於正常没極電壓 和輸出賴Vo狀間的參考電壓VH，並拉高電壓vg至高於 此參考電壓VH。如前所述，#電壓VG升高時，電晶體開關 201238392VG, and the light-emitting element control circuit comprises a power stage circuit, the integrated circuit comprising: a power stage control circuit that controls the power stage circuit to convert an input voltage into an output voltage, and supplies the at least one light-emitting element a channel; and a current source circuit for controlling the current of the light-emitting element, the minimum voltage required for the normal operation of the current source circuit is VR; and a dynamic differential pressure control circuit for voltage VS and voltage VR of the transistor switch current output terminal In comparison, it is judged that the relationship between the voltage vs and the voltage VR in the case where the control voltage VG is greater than the -reference voltage VH, and a control signal is generated to be supplied to the power stage control circuit to control the power stage circuit to adjust the output voltage. In the above control circuit or integrated circuit, the dynamic differential pressure control circuit may include a minimum value selection circuit, and select the lowest one among the voltages VS of the transistor switch current outflow terminals on the respective light emitting element channels; the comparison circuit selects the lowest value The selected voltage of the circuit is compared with the voltage VR; the counter, the comparison result of the counting comparison circuit; and the digital analog conversion circuit, which converts the counter value of the counter into an analog control city, and supplies it to the power wheel (four) circuit. In this analogy, the above control circuit or integrated circuit towel, the axis difference (four) circuit can be packaged. 2. The lowest value selection circuit 'selects the lowest voltage from the output of the transistor switch current k on each light-emitting element channel; the taste circuit, The most selective selection = the selected voltage is compared to the voltage VR; and a low pass converter that converts the s value of the counter to an analog control signal for supply to the power stage control circuit. In the above control circuit or integrated circuit, the dynamic differential pressure control circuit may further comprise a short circuit_circuit, and the voltage of the transistor «electrical output terminal vs. voltage VH t匕" is determined to determine the light-emitting element channel. When a short (four) wheel voltage is supplied to at least the illuminating element channel, the control circuit 201238392 circuit or integrated circuit may further include a voltage control circuit, and the voltage control circuit separately provides a control voltage VG to each of the illuminating element channels. The transistor switch prevents the transistor switch on the corresponding light-emitting element channel from being turned on when a short circuit occurs on any of the light-emitting element channels. In the above control circuit or integrated circuit, the dynamic differential pressure control circuit may further comprise a circuit with a circuit that compares the voltage VD of the current of the transistor switch current with the voltage VR. Broken road. In another aspect, the present invention provides a light-emitting element control method, the light-emitting element being located on a light-emitting element channel, the method comprising: providing a transistor switch on the light-emitting element channel, the transistor switch receiving a control Voltage VG; controlling current of the light-emitting element channel by a current source circuit, the minimum voltage required for the normal operation of the current source circuit is w; making the control voltage vg greater than - reference voltage VH; determining the transistor switch current outflow end The relationship between the voltage % and the voltage VR; and adjusting the supply voltage supplied to the light-emitting element channel according to the judgment result. The purpose, technical contents, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments. [Embodiment] Please refer to Fig. 4, which shows a first embodiment of the present invention. The present invention integrates the current source circuits CS1 - CSn into the inside of the integrated circuit 20, and additionally sets a transistor switch on each of the LED channels CH1 - CHn, and the gates of these transistor switches M1 - Mn are controlled by the voltage VG. The voltage VG is, for example, a square wave signal of a fixed voltage or a job. When the voltage VG is a square wave signal, the average current of each LED channel can be adjusted according to the duty ratio of the voltage VG, that is, the effect of adjusting the brightness of the LED is achieved. Since the transistor recharge (10) her 201238392's closed-pole voltage is VG, the source voltage of the transistor switch Μ1·Μη does not exceed VG'. That is, the transistor switch Ml-Mn secretly blocks the high voltage, making the current source circuit The components in csl_CSn can be fabricated using low voltage components to facilitate integration into the interior of integrated circuit 2G. For example, in the case of riding the display, according to the control of each LED channel in this month, the integrated circuit 2〇 only needs to set N+1 pins ′ farther than the number of the third figure. FIG. 5 shows another embodiment of the present invention. In this embodiment, a short-circuiting gamma circuit 23 is further provided for short-circuiting of the LED channels on the side, such as riding, and each LED channel is a twin. That is, it is not necessary to separately provide an external signal of the pin self-integration circuit 2, and the source voltage of each of the transistor switches M1-Mn can be taken from the inside of the integrated circuit 20. Please refer to the 5th_6th figure, how to judge whether the corresponding LED channel is short-circuited according to the source voltage of the transistor switch Ml-Mn❸. When the electric/yiL is turned on, the gate voltage vDi_vDn of the transistor switch is equal to The input light Vin scale corresponds to the light sum of the LEDs in the channel, while the electron crystal, the source voltage vsl_VSn of the switch Ml_Mn is equal to VG minus the threshold voltage ντ of the transistor. If the power level is continuously increased, the source voltage vsi_vSn will also rise until the source voltage VSl-VSn is approximately equal to the drain voltage Vm-VDn. At this time, the potential of the source voltage vsl_VSn will be at the home position. The voltage VDl-VDn will no longer rise as the VG rises. Referring to Fig. 5 and Fig. 6, assuming that the first LED channel CH1 is in normal operation' and the 帛n$LED ifif CHn is short-circuited, the pole voltage VDn is approximately equal to the output voltage v〇ut due to the short circuit. The bucker voltage VD under normal conditions, therefore, we can arbitrarily set a reference voltage VH between the normal step voltage and the output VO, and pull the voltage vg higher than the reference voltage VH. As mentioned before, when the voltage VG rises, the transistor switch 201238392
Ml-Mn的源極電壓會跟著升高 壓，故正常工作的第-LED通道中，== 及極電 電壓VSn將尚於參考電壓VH。因此，短路伯丨 7=極電壓VS1_VSn，便可獲知對應通道的狀況。 LED通道是否發生短路，可以f g進行或間歇進 VG的田為方波訊號時’請參閱第7、8圖，若使電壓 位準兩於參考_ VH，即為常態進行短路_。若 =固週期後才拉高電壓VG超過參考電壓VH，則為間歇性 也進仃崎侧。或者，電路亦可僅在_時進行單— =貞測。當電壓VG為固定電壓時，若保持使其高於參考電壓 即為常態進行短路侧，或如第9圖，可在職時使電壓 VG超過參考電壓VH，之後再使賴VG降為一個低於 電壓VH的固定電壓，進行單一次的短路偵測。 請再參閱第5圖，在正常操作而非進行短路偵測的情況 下，電壓VG的位準應低於參考電壓VH，且任一 led通道 CHl-CHn中電晶體開關Ml-Mn的源極電壓VSi_VSn應高於 某-電壓VR，此電壓VR為電流源電路csl_CSn正常工作所 需的最低電壓。因此，在正常工作時，應該具有以下關係：The source voltage of Ml-Mn will follow the boost voltage, so in the normal working first LED channel, == and the pole voltage VSn will be at the reference voltage VH. Therefore, short-circuiting 7 = pole voltage VS1_VSn, the status of the corresponding channel can be known. Whether the LED channel is short-circuited, can be f g or intermittently enter the VG field as a square wave signal. Please refer to Figures 7 and 8. If the voltage level is two in the reference _ VH, it is the normal state short circuit _. If the pull-up voltage VG exceeds the reference voltage VH after the solid cycle, the intermittent side also enters the Sakizaki side. Alternatively, the circuit can also perform a single-only test at _. When the voltage VG is a fixed voltage, if it is kept higher than the reference voltage, it is normal to perform the short-circuit side, or as shown in Fig. 9, the voltage VG can be exceeded in the reference voltage VH during the service, and then the VG is lowered to a lower level. The fixed voltage of the voltage VH is subjected to a single short-circuit detection. Please refer to Figure 5 again. In normal operation instead of short-circuit detection, the level of voltage VG should be lower than the reference voltage VH, and the source of the transistor switch Ml-Mn in any of the led channels CH1-CHn. The voltage VSi_VSn should be higher than a certain voltage VR, which is the minimum voltage required for the current source circuit csl_CSn to operate normally. Therefore, in normal work, you should have the following relationship:
VR<VS<VG<VH 其中，以VS表示任一源極電壓vsi-VSn。 另一方面，當任一源極電壓VS (代表vSl-VSn)低於電壓 VR時’對應的電流源電路CSi_CSn將無法正常工作，此時表 示對應的該串LED通道CHl-CHn中，LED的屢降較大，使 得對應的源極電壓VSl-VSn過低，換言之即表示目前的輸出 8 201238392 足而必須增加。第10圖分別顯示輸出電壓V⑽ 蓉於pm#與不足（右方）的情況。又’因源極電堡VS1-VSn VG減掉電晶體的臨界電愿ντ，故若發生源極 Sn過低的情況，也有可能是因為電壓不足所 致’因此在_判斷輸出糕Vout是否不足時，宜將電塵VG 拉高，例如但不限於超過參考餅VH，以排除誤判的可能。 根據以上’本發明另提出—種賴調整壓差的機制，此 P、在進行短路偵測而拉高電壓VG時，除根據第s圖方式判 =極電壓VD1_VDn是否高於正常電壓外，尚可一併偵測源 壓VSl-VSn是否過低，藉以判斷輸出電壓v〇ut是否不 足。當發現任-源極電塵vsl_VSn過低時，即可藉由反饋控 制的方式，控制功率級電路6G，調升輸出電壓v⑽直到所 有^源極電壓VSl-VSn都到達或超過電壓VR為止。又，如 果§拉尚電壓VG時，；:及極電壓vDl-VDn低於電壓VR且並 不改變（献等於源極賴vsl_VSn)，絲稍蘭該串led 通道為斷路狀態。 由上，我們可得出三種判斷機制： ⑴當VG>VH且VD(或VS)>VH時，表示發生短路。 (2) 當VG>VH且VS<VR時，表示輸出電壓Vout不足。VR<VS<VG<VH where VS represents any source voltage vsi-VSn. On the other hand, when any of the source voltages VS (representing vSl-VSn) is lower than the voltage VR, the corresponding current source circuit CSi_CSn will not operate normally, indicating that the corresponding LED channel CH1-CHn, LED The repeated drop is large, so that the corresponding source voltage VSl-VSn is too low, in other words, the current output 8 201238392 must be increased. Figure 10 shows the output voltage V(10) in pm# and insufficient (right). Also, 'the source volts VS1-VSn VG loses the critical ντ of the transistor. Therefore, if the source Sn is too low, it may be caused by insufficient voltage. Therefore, it is judged whether the output cake Vout is insufficient. When it is appropriate, the electric dust VG should be pulled high, such as but not limited to exceeding the reference cake VH, to eliminate the possibility of misjudgment. According to the above description of the present invention, the mechanism for adjusting the differential pressure is used. When P is short-circuited and the voltage VG is pulled high, it is determined whether the voltage VD1_VDn is higher than the normal voltage according to the s-th diagram. It can be detected whether the source voltage VSl-VSn is too low, thereby judging whether the output voltage v〇ut is insufficient. When the any-source electric dust vsl_VSn is found to be too low, the power stage circuit 6G can be controlled by feedback control to increase the output voltage v(10) until all of the source voltages VS1-VSn reach or exceed the voltage VR. Moreover, if § pulls the voltage VG, :: and the pole voltage vDl-VDn is lower than the voltage VR and does not change (satisfying the source depends on vsl_VSn), the string is slightly open. From the above, we can derive three kinds of judgment mechanisms: (1) When VG > VH and VD (or VS) > VH, it indicates that a short circuit has occurred. (2) When VG > VH and VS < VR, it means that the output voltage Vout is insufficient.
(3) 當VG>VH且VD<VR(或VD=VS)時，表示此串LED 通道為斷路。 其中，VS表示任一源極電壓vsl_VSn，VD表示任一汲 極電壓VDl-VDn。 根據第(2)種判斷機制來反饋控制輸出電壓v〇ut的實施方 式，說明如下。請參閱第n圖，首先說明概念，控制[ED電 凌的電流源電路CSl-CSn集合稱為電流調節電路30，由此電 201238392 路中’我們可以取得源極電麗vsl_VSn (以vs表示任一源極 電，VSl-VSn)，且我們已知使所有電流源電路csl_CSn都能 正常工作所需的最低電壓VR，因此，動態愿差控制電路4〇 便可根據帛(2)制賴制，# VG>VH並發雜—源極電壓 vs過低時’ g卩可控制功率級電路60，調升輸出電壓伽，直 到所有的源極賴vs都到達或超過賴VR、且源極電壓vs 中最低者（以VSmin表示）恰等於或略高於電壓VR為止。 另方面，當所有源極電壓VS都大於最低電壓vr時，則有 可月b輸出賴Vout過高*電源運驗率不為最佳狀態，此時 可_降輸出電壓Vout，直到所有源極電壓vs中最低者恰等於 或略高於電壓VR。亦即，動態壓差控制電路4〇可動態調整電 屢VS和電壓VR間之關係，使其差值為最佳電源運用效率下 的最低值。 須說明的是’圖中繪示動態壓差控制電路4〇接收電壓乂尺 和VS，此僅是示意表示動態壓差控制電路4〇取得有關電壓 VR和vs的資訊’並非表示動態壓差控制電路必須接收與 電壓VR和VS實質相等的類比電壓；例如，動態壓差控制電 路40可以㈣壓VR和VS以數位訊號的形式加以比較、或 以類比訊號但取分數值的方式來比較。而電壓VR既是一個已 知值，就可以在設計電路時以參考電壓的形式設定在動態壓差 控制電路40之内，而不一定需要從動態壓差控制電路4〇的外 部取得。又，圖中也繪示動態壓差控制電路40在VG>VH時 被致能，此也僅是示意表示動態壓差控制電路4〇所執行的判 斷機制是在VG>VH的狀態下進行，並不表示動態壓差控制電 路4〇必須具有一個致能開關EN，而可以用其他等效方式達 成，例如，可在VG〉VH的時間點才將動態壓差控制電路4〇 201238392 輸出的控制訊號傳遞給功率級控制電路21、或在vg>VH的 時間點產生一個訊號，在動態壓差控制電路40内部與其他電 路進行邏輯運算，等等。 此外’上述判斷與反饋控制機制，並不限於必須將電晶體 叹置在積體電路晶片的外侧；在電晶體設置於積體電路晶片内 部的實施型態中，也仍然可以應用，如第12圖。又，電晶體(3) When VG>VH and VD<VR (or VD=VS), it indicates that this string of LED channels is open. Where VS represents any source voltage vsl_VSn, and VD represents any of the anode voltages VDl-VDn. The implementation of the feedback control output voltage v〇ut according to the (2) judgment mechanism is explained below. Please refer to the nth figure, first explain the concept, control [EDI's current source circuit CSl-CSn set is called current regulation circuit 30, and thus electricity 201238392 in the road 'we can get the source electric vvsl_VSn (in vs. A source of electricity, VSl-VSn), and we know the lowest voltage VR required to make all current source circuits csl_CSn work properly. Therefore, the dynamic wish control circuit 4 can be based on 帛(2) , # VG > VH concurrently - when the source voltage vs is too low 'g卩 can control the power stage circuit 60, increase the output voltage gamma until all the sources rely on vs. or exceed the VR, and the source voltage vs. The lowest of them (in VSmin) is just equal to or slightly higher than the voltage VR. On the other hand, when all the source voltages VS are greater than the minimum voltage vr, there is a monthly b output that is too high * the power supply rate is not optimal, and the output voltage Vout can be lowered until all the sources The lowest of the voltages vs is just equal to or slightly higher than the voltage VR. That is, the dynamic differential pressure control circuit 4 can dynamically adjust the relationship between the voltage VS and the voltage VR so that the difference is the lowest value under the optimum power utilization efficiency. It should be noted that the figure shows the dynamic differential pressure control circuit 4 〇 receiving voltage scale and VS, which is only a schematic representation of the dynamic differential pressure control circuit 4 〇 to obtain information about the voltage VR and vs 'not indicating dynamic differential pressure control The circuit must receive an analog voltage substantially equal to the voltages VR and VS; for example, the dynamic differential pressure control circuit 40 can (4) compare the voltages VR and VS in the form of digital signals, or compare them by analog signals but with fractional values. The voltage VR is a known value, and can be set in the dynamic differential pressure control circuit 40 in the form of a reference voltage when designing the circuit, and does not necessarily need to be taken from the outside of the dynamic differential pressure control circuit 4〇. Further, the figure also shows that the dynamic differential pressure control circuit 40 is enabled at VG > VH, and this is merely a schematic representation that the determination mechanism performed by the dynamic differential pressure control circuit 4 is performed in the state of VG > VH. It does not mean that the dynamic differential pressure control circuit 4 must have an enable switch EN, but can be achieved by other equivalent means, for example, the control of the dynamic differential pressure control circuit 4〇201238392 can be controlled at the time point of VG>VH. The signal is transmitted to the power stage control circuit 21, or a signal is generated at a time point of vg > VH, a logic operation is performed with other circuits inside the dynamic differential pressure control circuit 40, and the like. In addition, the above-mentioned judgment and feedback control mechanism is not limited to having to slap the transistor on the outer side of the integrated circuit wafer; in the embodiment in which the transistor is disposed inside the integrated circuit wafer, it can still be applied, for example, the 12th. Figure. Again, the transistor
Ml-Mn不限定必須為m〇S電晶體，也可改換為雙載子電晶 體，如第13、14圖所示，此時電壓vs代表的是雙載子電晶 體的射極電壓，亦即不論電晶體為M〇s電晶體或雙 載子電晶體，電壓VS代表的是電晶體M1.的電流流出端 之電壓；帛6圖中的電壓VG代表的是電晶體奶她的控制 電壓；而第6圖中的電壓VD代表的是電晶體⑷她的電流 流入端之電壓。 擇電路41、比較電路42、計數器43 上述動態壓差㈣f路4G的具體實麵態，舉例而言請 參閱第15 ，本實施例中動態壓差控制電路4〇包括最低值選 、數位類比轉換電路44。 最低值選擇電路4丨自電壓VS1.VSn帽擇最低者，輸入比較 電路42與電壓VR比較，其比較結果由計數器幻予以計數， 再由數位紙讎電路44難轉換為_的控觀號，提供 給功率級控制電路以控制輸出電壓⑽。如此，就可根據 電壓VSl-VSn中最低者和電壓妞之間的差值，來調整輸出 電壓Vbut。其巾，比較電路42宜為磁滞比較電路，但也可為 一般比較電路；計數器43宜為上下計數器。 第16圖顯示動態壓差控制電路 施例中，以低通濾波器45來取代計數器 路44 ’也同樣可以將比較器42 〇的另一個實施例，本實 器43和數位類比轉換電 的輸出轉換成類比的控制訊 201238392 號’提供給神級控制電路21以控制輸出電壓_。 動態壓差控制電路40所輸出的控制訊號，功率級控制電 ，21可以有種種方式來烟，以調整輸出電壓偏。舉例而 吕，如功率級控制電路21是根據輸出電壓_的分壓反 後在運算放大H中與參考電壓比㈣進行調變㈣，則如第 Π圖所示，可將錢麵_電路⑽輸出的控舰號與取分 壓反饋訊號的節點祕’輸人運算放大器〇p中與參考電壓 Vref比較，或第18圖所示，可將動態壓差控制電路4()輸出的 控制訊號作為參考電壓，與分壓反饋訊號比較，皆屬可行。（功 率級控制電路2!中的其他電路為本業者所已知，且非本案重 點，故不予贅示。） 動態壓差控制電路40除了動態控制電壓Vs和電壓vr 間的壓差之外，尚可根據前述第（丨)種判斷機制來判斷各串 LED是否短路。請參閱第19圖，動態壓差控制電路4〇中可 更包含一個短路彳貞測電路46，此電路將電壓vsi-VSn與電壓 VH比較，當一或多個電壓VS1_VSn高於電壓VH時，即可輸 出切斷訊號，此切斷訊號可用以使電路停止供應輸出電壓 Vout、或是用以切斷對應的LED通道。類似地，第16圖電路 也可增加此功能，如第20圖所示。 當發現任一 LED通道短路時，如欲個別切斷對應的LED 通道，則如第21圖所示，可設置一個VG控制電路50，輸出 訊號VGl-VGn，個別控制電晶體Μ1·Μη。動態壓差控制電路 40所產生的切斷訊號可輸出給VG控制電路50，而VG控制 電路50即根據該切斷訊號而產生適當的訊號VG1 _VGn，使對 應的LED通道上的電晶體Ml-Mn不導通，亦即該LED通道 即成為斷路。當然，如第22圖所示，在電晶體Ml-Mn設置於 12 201238392 積體電路20内部的實施型態中，也同樣可實施此作法。 此外，根據第⑶種判斷機制，如第23、24圖所示，動態 壓差控制電路40中可更包含一個斷路偵測電路47，此電路將 電壓VDl-VDn與電壓VR比較，當VG>VH且VD<VR (以 VD表示任一汲極電壓VD1_VDn)時，表示對應的該串LEd 通道CHl-CHn為斷路。 以上已針對較佳實施例來說明本發明，唯以上所述者， 僅係為使熟悉本技術者易於了解本發明的内容而已，並非用 來限定本發明之權利範圍。在本發明之相同精神下，熟悉本 技術者可以思及各種等效變化。例如，電晶體開關 可為NMOS電晶體、亦可*PM〇s電晶體；又如，發光元件 不必然是發光二極體，而可為任何以電流控制亮度的發光元 件；再如，本發明不限於應用在多串LED通道的場合，亦可 應用在單_ LED通道的場合，此時轉壓差控制電路中 即可不需要設置最低值選擇電路41 ;又如，整合在積體電路 20内的電流源電路CS1_CSn，可為任何形式之電流源電路， 例如可以使用雙載子電晶體來代換其中的腦電晶體 Ql-Qn。凡此種種’均應包含在本發明的範圍之内。 【圖式簡單說明】 第1醜示先前技術之發光元件控制電路。 第2A-2G圖顯示功率級電路6〇的數個實施例。 第3圖顯示另一種先前技術。 元件控制電路的-個實施例 201238392 ί H至第9 ®舉觸示執行短路_的幾種方式。 的情況圖分別顯示輸出輕VGUt充足（左方）與不足（右方） J itr, 圖顯示可動態控制壓差的另外三個實施例。 第二:示ίΓ之動態壓差控制電路40的-個實施例。 第π 態壓差控制電路4G的另一個實施例。 一 18圖舉例顯示動態壓差控制電 ^提供給功輪_電㈣以 Γ2=，之動態壓差控制電路40的另-個實施例。 第21圖顯不本發明之發光元件控制電路的 以VG控制電路50來分開控制各電晶體。 、中 第22圖顯示本發明之發光元件控制電路的另一實施例 第23 ___差㈣祕4G巾可从H二較 47，以判斷各串LED是否斷路。 第24圖顯示本發明之動態壓差控制電路4〇的另一個實施例。 【主要元件符號說明】 2〇積體電路 21功率級控制電路 23短路偵測電路 3〇電流調節電路 40動態壓差控制電路 201238392 41最低值選擇電路 42比較電路 43計數器 44數位類比轉換電路 45低通濾、波器 46短路偵測電路 47斷路偵測電路 50 VG控制電路 60功率級電路 CHl-CHn LED 通道 CSl-CSn電流源電路 Ml-Mn電晶體開關 ΟΡ,ΟΡΙ-ΟΡη運算放大器 Ρ1-Ρ2Ν接腳 Ql-Qn電晶體 Rl-Rn電阻 15Ml-Mn is not limited to a m〇S transistor, and may be changed to a bipolar transistor, as shown in Figures 13 and 14, where the voltage vs represents the emitter voltage of the bipolar transistor. That is, whether the transistor is a M〇s transistor or a bipolar transistor, the voltage VS represents the voltage at the current outflow end of the transistor M1. The voltage VG in the figure 6 represents the control voltage of the transistor milk. The voltage VD in Figure 6 represents the voltage at the current inflow of the transistor (4). Selecting the circuit 41, the comparison circuit 42, and the counter 43 the specific real surface state of the dynamic pressure difference (four) f path 4G. For example, refer to the fifteenth. In the embodiment, the dynamic differential pressure control circuit 4 includes the lowest value selection and the digital analog conversion. Circuit 44. The lowest value selection circuit 4 丨 from the voltage VS1. VSn cap selection is the lowest, the input comparison circuit 42 is compared with the voltage VR, the comparison result is counted by the counter illusion, and then the digital paper cassette circuit 44 is difficult to convert to the _ control number. Power stage control circuitry is provided to control the output voltage (10). Thus, the output voltage Vbut can be adjusted according to the difference between the lowest voltage and the voltage VSl-VSn. Preferably, the comparison circuit 42 is a hysteresis comparison circuit, but may be a general comparison circuit; the counter 43 is preferably an up-down counter. Fig. 16 is a view showing an embodiment of the dynamic differential pressure control circuit in which the low-pass filter 45 is used in place of the counter path 44'. Similarly, the comparator 42 can be used to convert the output of the comparator 43 and the digital analogy. The control signal converted to analogy 201238392 is supplied to the god level control circuit 21 to control the output voltage _. The control signal output by the dynamic differential pressure control circuit 40, the power level control circuit, 21 can have various ways to smoke to adjust the output voltage bias. For example, if the power stage control circuit 21 is modulated according to the voltage division of the output voltage _ and then converted to the reference voltage ratio (4) in the operational amplification H (4), as shown in the figure, the surface _ circuit (10) The output control ship number is compared with the reference voltage Vref in the node input 'input operational amplifier 〇p of the partial pressure feedback signal, or the control signal outputted by the dynamic differential pressure control circuit 4() can be used as shown in FIG. The reference voltage is comparable to the partial pressure feedback signal. (Other circuits in the power stage control circuit 2! are known to the industry and are not the focus of the present invention, so they are not shown.) The dynamic differential pressure control circuit 40 has a voltage difference between the dynamic control voltage Vs and the voltage vr. According to the foregoing (丨) kind of judgment mechanism, it is determined whether each string of LEDs is short-circuited. Referring to FIG. 19, the dynamic differential pressure control circuit 4A further includes a short circuit detection circuit 46 for comparing the voltage vsi-VSn with the voltage VH when one or more voltages VS1_VSn are higher than the voltage VH. The cutoff signal can be output, and the cutoff signal can be used to stop the circuit from supplying the output voltage Vout or to cut off the corresponding LED channel. Similarly, the circuit of Figure 16 can also add this function, as shown in Figure 20. When any LED channel is found to be short-circuited, if the corresponding LED channel is to be individually cut off, as shown in Fig. 21, a VG control circuit 50 may be provided to output signals VG1-VGn, and the transistors Μ1·Μn are individually controlled. The cutoff signal generated by the dynamic differential pressure control circuit 40 can be output to the VG control circuit 50, and the VG control circuit 50 generates an appropriate signal VG1_VGn according to the cutoff signal to enable the transistor M1 on the corresponding LED channel. Mn is not conductive, that is, the LED channel becomes an open circuit. Of course, as shown in Fig. 22, this can also be carried out in the embodiment in which the transistor M1-Mn is disposed inside the integrated circuit 20 of 12 201238392. In addition, according to the (3) judgment mechanism, as shown in FIGS. 23 and 24, the dynamic differential pressure control circuit 40 may further include a disconnection detecting circuit 47, which compares the voltages VD1 - VDn with the voltage VR, when VG > When VH and VD < VR (indicating any of the drain voltages VD1_VDn by VD), it means that the corresponding string of LEd channels CH1-CHn is open. The present invention has been described with reference to the preferred embodiments thereof, and the present invention is not intended to limit the scope of the present invention. In the same spirit of the invention, various equivalent changes can be conceived by those skilled in the art. For example, the transistor switch can be an NMOS transistor or a *PM〇s transistor; for example, the light-emitting element is not necessarily a light-emitting diode, but can be any light-emitting element that controls brightness with current; for example, the present invention It is not limited to the application in the case of multiple strings of LED channels, and can also be applied to the single-LED channel. In this case, the lowest value selection circuit 41 need not be provided in the turn-off voltage difference control circuit; for example, integrated in the integrated circuit 20 The current source circuit CS1_CSn can be any form of current source circuit, for example, a bipolar transistor can be used to replace the brain crystal Ql-Qn therein. All such references are intended to be included within the scope of the present invention. [Simplified description of the drawings] The first ugly display of the light-emitting element control circuit of the prior art. Figures 2A-2G show several embodiments of the power stage circuit 6A. Figure 3 shows another prior art. An embodiment of the component control circuit 201238392 ί H to the 9th ® are shown in several ways to perform a short circuit. The situation diagram shows that the output light VGUt is sufficient (left) and insufficient (right) J itr, and the figure shows three other embodiments that can dynamically control the differential pressure. Second: an embodiment of the dynamic differential pressure control circuit 40. Another embodiment of the πth state differential pressure control circuit 4G. Figure 18 shows an example of a dynamic differential pressure control circuit 40 that provides dynamic differential pressure control to the power wheel _ electric (four) to Γ 2 =. Fig. 21 shows the VG control circuit 50 for controlling the respective transistors in the light-emitting element control circuit of the present invention. And Fig. 22 shows another embodiment of the light-emitting element control circuit of the present invention. The 23rd ___difference (4) secret 4G towel can be judged from H 2 to 47 to determine whether each string of LEDs is open. Fig. 24 shows another embodiment of the dynamic differential pressure control circuit 4 of the present invention. [Main component symbol description] 2 〇 体 circuit 21 power stage control circuit 23 short circuit detection circuit 3 〇 current adjustment circuit 40 dynamic differential pressure control circuit 201238392 41 lowest value selection circuit 42 comparison circuit 43 counter 44 digital analog conversion circuit 45 low Filter, waver 46 short circuit detection circuit 47 open circuit detection circuit 50 VG control circuit 60 power stage circuit CHl-CHn LED channel CSl-CSn current source circuit Ml-Mn transistor switch ΟΡ, ΟΡΙ-ΟΡη operational amplifier Ρ1-Ρ2Ν Pin Ql-Qn transistor Rl-Rn resistor 15