TW201525972A - Backlight module - Google Patents
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- TW201525972A TW201525972A TW102149388A TW102149388A TW201525972A TW 201525972 A TW201525972 A TW 201525972A TW 102149388 A TW102149388 A TW 102149388A TW 102149388 A TW102149388 A TW 102149388A TW 201525972 A TW201525972 A TW 201525972A
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本發明係關於一種背光模組，尤指一種利用脈衝寬度調變訊號來控制背光源強弱的背光模組。 The present invention relates to a backlight module, and more particularly to a backlight module that uses a pulse width modulation signal to control the strength of a backlight.
發光二極體因為其節省電力及高亮度的特性成為常見的背光模組發光元件，而一般控制發光二極體亮度的驅動方式有兩種，類比調光(Analog dimming)及數位調光(Digital diming)。類比調光係透過控制流經發光二極體的電流大小，來調整發光二極體的亮度，而數位調光則係透過脈衝訊號寬度的調變，增減發光二極體導通的時間，以達成調整明暗的目的。由於數位調光的導通電壓電流較為固定，所以在低亮度時不會發生色彩偏移的問題，也因此成為一種受歡迎的調光模式。 The light-emitting diode has become a common backlight module light-emitting element because of its power saving and high-brightness characteristics, and generally has two driving modes for controlling the brightness of the light-emitting diode, analog dimming and digital dimming (Digital). Diming). The analog dimming system adjusts the brightness of the light emitting diode by controlling the current flowing through the light emitting diode, and the digital dimming increases or decreases the time of the light emitting diode through the modulation of the pulse signal width. Achieve the purpose of adjusting the shading. Since the on-voltage current of the digital dimming is relatively fixed, the problem of color shift does not occur at low luminance, and thus it becomes a popular dimming mode.
然而隨著使用者對於顯示器的品質要求越來越高，畫面亮暗的對比程度也成為顯示器品質的一項重要指標，顯示器因此被要求要將最高亮度做到比以前更亮，最低亮度則要做到比以前更暗，以達到較大的對比。對於利用脈衝訊號寬度調變來調整發光二極體亮度的顯示器而言，當操作在偏低亮度時，脈衝訊號的工作週期(Duty cycle)也相對較小，而脈衝訊號較小的工作週期將有可能導致發光二極體的驅動電壓不穩定，甚至造成螢幕閃爍不穩的情形。也因此如何利用脈衝訊號寬度調變操作在低亮度的情境下，並能使發光二極體維持穩定發光，成為一項挑戰。 However, as the user's quality requirements for the display become higher and higher, the degree of contrast between the brightness and the brightness of the screen becomes an important indicator of the quality of the display. Therefore, the display is required to make the highest brightness brighter than before, and the minimum brightness is required. Be darker than before to achieve a larger contrast. For a display that uses the pulse signal width modulation to adjust the brightness of the LED, when operating at a low brightness, the duty cycle of the pulse signal is relatively small, and the duty cycle with a small pulse signal will be There is a possibility that the driving voltage of the light-emitting diode is unstable, and even the screen flicker is unstable. Therefore, how to use the pulse signal width modulation operation in a low-brightness situation and to enable the LED to maintain stable illumination becomes a challenge.
本發明之一實施例提供一種背光模組，包含一轉換器；一組發光二極體，耦接於該轉換器，用以提供背光；一微控制器，耦接於該轉換器，用以根據一輸入訊號產生一脈衝寬度調變訊號至該轉換器；一電阻調變模組，耦接於該轉換器及該微控制器，用以根據該脈衝寬度調變訊號之一工作週期輸出一對應之阻值；及一升壓電路，耦接於該轉換器及該組發光二極體，用以將一第一直流電壓升壓至一第二直流電壓，以對該組發光二極體提供該第二直流電壓，該升壓電路包含一第一開關，該第一開關係根據該阻值對應之一操作訊號及該脈衝寬度調變訊號被開啟及關閉。 An embodiment of the present invention provides a backlight module including a converter, a set of light emitting diodes coupled to the converter for providing backlights, and a microcontroller coupled to the converter for Generating a pulse width modulation signal to the converter according to an input signal; a resistance modulation module coupled to the converter and the microcontroller for outputting a duty cycle according to one of the pulse width modulation signals Corresponding resistance value; and a boosting circuit coupled to the converter and the group of light emitting diodes for boosting a first DC voltage to a second DC voltage to the group of LEDs Providing the second DC voltage, the boosting circuit includes a first switch, and the first open relationship is turned on and off according to the one of the operation signals corresponding to the resistance value and the pulse width modulation signal.
本發明之另一實施例提供一種背光模組之控制方法，其包含根據一輸入訊號產生一脈衝寬度調變訊號；根據該脈衝寬度調變訊號之一工作週期調整一電阻調變模組之一阻值；根據該阻值產生一操作訊號；及根據該操作訊號及該脈衝寬度調變訊號控制一升壓電路之一第一開關的開啟及關閉，以控制耦接於該升壓電路之一組發光二極體產生背光。 Another embodiment of the present invention provides a control method for a backlight module, which includes generating a pulse width modulation signal according to an input signal, and adjusting one of the resistance modulation modules according to a duty cycle of the pulse width modulation signal. a resistance value; generating an operation signal according to the resistance value; and controlling opening and closing of one of the first switches of the boosting circuit according to the operation signal and the pulse width modulation signal to control coupling to one of the boosting circuits The group of light emitting diodes produces a backlight.
100、200‧‧‧背光模組 100, 200‧‧‧ backlight module
110‧‧‧轉換器 110‧‧‧ converter
114‧‧‧操作訊號產生模組 114‧‧‧Operation signal generation module
120‧‧‧多串發光二極體 120‧‧‧Multiple strings of LEDs
130‧‧‧微控制器 130‧‧‧Microcontroller
140、240‧‧‧電阻調變模組 140, 240‧‧‧Resistor Modulation Module
142‧‧‧第一電阻 142‧‧‧First resistance
144‧‧‧第二電阻 144‧‧‧second resistance
146‧‧‧第二開關 146‧‧‧second switch
150‧‧‧升壓電路 150‧‧‧Boost circuit
151‧‧‧第一開關 151‧‧‧First switch
152‧‧‧電感 152‧‧‧Inductance
153‧‧‧齊納二極體 153‧‧‧Zina diode
154‧‧‧電容 154‧‧‧ Capacitance
160‧‧‧直流電壓源 160‧‧‧DC voltage source
242‧‧‧可變電阻 242‧‧‧Variable resistor
第1圖係為本發明一實施例之背光模組之示意圖。 FIG. 1 is a schematic diagram of a backlight module according to an embodiment of the present invention.
第2圖為第1圖背光模組的相關操作訊號圖。 Figure 2 is a related operation signal diagram of the backlight module of Figure 1.
第3圖為本發明另一實施例之背光模組之示意圖。 FIG. 3 is a schematic diagram of a backlight module according to another embodiment of the present invention.
第4圖為第1圖及第三圖的背光模組之控制方法流程圖。 Fig. 4 is a flow chart showing the control method of the backlight module of the first and third figures.
請參考第1圖，第1圖係為本發明一實施例之背光模組100之示意圖，背光模組100包含轉換器110，多串發光二極體120，微控制器130，電阻調變模組140，及升壓電路150。微控制器130電連接於轉換器110，用 以根據輸入訊號產生脈衝寬度調變訊號至轉換器110。電阻調變模組140耦接於轉換器110及微控制器130，用以根據脈衝寬度調變訊號之工作週期(Duty cycle)輸出對應之阻值。升壓電路150耦接於轉換器110及多串發光二極體120，用以將輸入電壓源160之輸入電壓Vin升壓至較高電位之輸出電壓，並對多串發光二極體120提供其輸出電壓。升壓電路150包含開關151，而開關151係根據電阻調變模組140的阻值所對應之操作訊號及脈衝寬度調變訊號被開啟及關閉。 Please refer to FIG. 1 . FIG. 1 is a schematic diagram of a backlight module 100 according to an embodiment of the present invention. The backlight module 100 includes a converter 110 , a plurality of strings of LEDs 120 , a microcontroller 130 , and a resistor modulation module . Group 140, and boost circuit 150. The microcontroller 130 is electrically connected to the converter 110 for use The pulse width modulation signal is generated according to the input signal to the converter 110. The resistance modulation module 140 is coupled to the converter 110 and the microcontroller 130 for outputting a corresponding resistance value according to a duty cycle of the pulse width modulation signal. The boosting circuit 150 is coupled to the converter 110 and the plurality of LEDs 120 for boosting the input voltage Vin of the input voltage source 160 to a higher potential output voltage, and providing the plurality of strings of LEDs 120 Its output voltage. The booster circuit 150 includes a switch 151, and the switch 151 is turned on and off according to the operation signal and the pulse width modulation signal corresponding to the resistance of the resistance modulation module 140.
於第1圖之實施例中，轉換器110包含操作訊號產生模組114電連接於電阻調變模組140，操作訊號產生模組114係根據電阻調變模組140的阻值來產生對應之操作訊號；轉換器110將脈衝寬度調變訊號及操作訊號以邏輯積(logical product)的方式運算產生升壓控制訊號，而升壓電路150的開關151即由此升壓控制訊號來控制。於此實施例中，電阻調變模組140的阻值越大時，操作訊號產生模組114對應產生之操作訊號具有越低的頻率。 In the embodiment of FIG. 1 , the converter 110 includes an operation signal generation module 114 electrically connected to the resistance modulation module 140 , and the operation signal generation module 114 generates a corresponding value according to the resistance of the resistance modulation module 140 . The operation signal is generated by the converter 110 to generate a boost control signal in a logical product manner, and the switch 151 of the boost circuit 150 is controlled by the boost control signal. In this embodiment, when the resistance of the resistance modulation module 140 is larger, the operation signal generated by the operation signal generation module 114 has a lower frequency.
於第1圖之實施例中，升壓電路150包含電感152，齊納二極體153及電容154。電感152電連接於輸入電壓源160和齊納二極體153的正端之間；齊納二極體153的負端則為升壓電路150之輸出端並與多串發光二極體120電連接；而電容154的兩端則分別與齊納二極體153的負端及接地端電連接。第一開關151為電晶體，其具有汲極、源汲極及閘極，其汲極耦接於齊納二極體正端，源極耦接至接地電壓，而閘極則耦接於轉換器110。於另一實施例中，第一開關151可為一電子式開關，其具有第一端，第二端及控制端，其第一端耦接於齊納二極體正端，第二端耦接至接地電壓，而控制端則耦接於轉換器110。開關151係根據轉換器110輸出之升壓控制訊號來導通或截止。當開關151導通時，將自輸入電壓Vin導入電流Ii流經電感152及開關151，此時導入電流Ii會對電感152充能，而電容154則處於放能狀 態；當開關151截止時，因為電容154的端電壓Vc高過輸入電壓Vin，直流電壓源160將不再導入電流進入電感152之中，然而由於電感的電性特性，在導通時期的導入電流Ii並不會立刻截止，而會流入電容154，此時電感152處於放能狀態，電容154則處於充能狀態，而電容154的端電壓Vc因此可維持在高於輸入電壓Vin的高電位。 In the embodiment of FIG. 1, the booster circuit 150 includes an inductor 152, a Zener diode 153, and a capacitor 154. The inductor 152 is electrically connected between the input voltage source 160 and the positive terminal of the Zener diode 153; the negative terminal of the Zener diode 153 is the output terminal of the booster circuit 150 and is electrically connected to the plurality of LEDs 120. The two ends of the capacitor 154 are electrically connected to the negative terminal and the ground terminal of the Zener diode 153, respectively. The first switch 151 is a transistor having a drain, a source drain and a gate. The drain is coupled to the positive terminal of the Zener diode, the source is coupled to the ground voltage, and the gate is coupled to the switch. 110. In another embodiment, the first switch 151 can be an electronic switch having a first end, a second end, and a control end, the first end of which is coupled to the positive end of the Zener diode, and the second end is coupled Connected to the ground voltage, the control terminal is coupled to the converter 110. The switch 151 is turned on or off according to the boost control signal output from the converter 110. When the switch 151 is turned on, the current Ii is introduced from the input voltage Vin through the inductor 152 and the switch 151. At this time, the current Ii is charged to charge the inductor 152, and the capacitor 154 is in the discharge state. When the switch 151 is turned off, since the terminal voltage Vc of the capacitor 154 is higher than the input voltage Vin, the DC voltage source 160 will no longer introduce current into the inductor 152. However, due to the electrical characteristics of the inductor, the current is introduced during the conduction period. Ii does not immediately turn off, but will flow into the capacitor 154. At this time, the inductor 152 is in the discharging state, the capacitor 154 is in the charging state, and the terminal voltage Vc of the capacitor 154 can be maintained at a high level higher than the input voltage Vin.
多串發光二極體120係用以提供背光，其耦接於轉換器110與升壓電路150。多串發光二極體120之驅動電壓係由升壓電路150的輸出電壓提供，使發光二極體得以導通發光。於此實施例中，發光二極體的導通電流將透過回授腳位113回授給轉換器110，轉換器110根據此電流回授調整操作訊號的工作週期(duty cycle)以將驅動電壓維持在固定的電位，確保背光源的穩定。 The plurality of LEDs 120 are used to provide a backlight, which is coupled to the converter 110 and the booster circuit 150. The driving voltage of the plurality of strings of the LEDs 120 is supplied by the output voltage of the booster circuit 150, so that the light-emitting diodes are turned on. In this embodiment, the on-current of the LED is fed back to the converter 110 through the feedback pin 113. The converter 110 feedbacks the duty cycle of the operation signal according to the current to maintain the driving voltage. At a fixed potential, ensure that the backlight is stable.
於第1圖的實施例中，電阻調變模組140包含第一電阻142，第二電阻144和第二開關146。第二電阻144與第一電阻142並聯，且第二開關146串聯於第二電阻144。第二開關146為電晶體，其具有汲極、源汲極及閘極，其汲極耦接於第二電阻144，源極耦接至接地電壓，而閘極則耦接於微控制器130。於另一實施例中，第二開關146可為一電子式開關，其具有第一端，第二端及控制端，其第一端耦接於第二電阻144，第二端耦接至接地電壓，而控制端則耦接於微控制器130。 In the embodiment of FIG. 1 , the resistance modulation module 140 includes a first resistor 142 , a second resistor 144 , and a second switch 146 . The second resistor 144 is in parallel with the first resistor 142 and the second switch 146 is connected in series with the second resistor 144. The second switch 146 is a transistor having a drain, a source drain and a gate, the drain of which is coupled to the second resistor 144 , the source is coupled to the ground voltage, and the gate is coupled to the microcontroller 130 . . In another embodiment, the second switch 146 can be an electronic switch having a first end, a second end, and a control end, the first end of which is coupled to the second resistor 144, and the second end is coupled to the ground. The voltage is connected to the microcontroller 130.
於第1圖的實施例中，在脈衝寬度調變訊號的工作週期大於或等於預定值時，微控制器130會截止電阻調變模組140的第二開關146，使得電阻調變模組140的阻值即為第一電阻142之阻值；反之，在脈衝寬度調變訊號的工作週期小於預定值時，微控制器130會導通電阻調變模組140的第二開關146，使得電阻調變模組140的阻值為第一電阻142和第二電阻144 並聯之阻值。因此，透過微控制器130對第二開關146的控制，將可改變電阻調變模組140的阻值，進而改變操作訊號的週期。 In the embodiment of FIG. 1 , when the duty cycle of the pulse width modulation signal is greater than or equal to a predetermined value, the microcontroller 130 turns off the second switch 146 of the resistance modulation module 140 , so that the resistance modulation module 140 The resistance is the resistance of the first resistor 142; otherwise, when the duty cycle of the pulse width modulation signal is less than the predetermined value, the microcontroller 130 turns on the second switch 146 of the resistance modulation module 140, so that the resistance is adjusted. The resistance of the variable module 140 is the first resistance 142 and the second resistance 144. Parallel resistance. Therefore, by controlling the second switch 146 by the microcontroller 130, the resistance of the resistance modulation module 140 can be changed, thereby changing the period of the operation signal.
請參考第2圖，第2圖為背光模組100的相關操作訊號圖，其包含了脈衝寬度調變訊號，操作訊號，升壓控制訊號於第一時段T1、第二時段T2及第三時段T3內的狀態。於第一時段T1時背光模組100係操作在正常亮度的情況下，其脈衝寬度調變訊號的工作週期大於操作訊號週期的三倍，而升壓控制訊號仍能維持升壓電路的輸出電壓，使發光二極體穩定發光，此時開關146被截止，電阻調變模組140的阻值即為第一電阻142之阻值；於第二時段T2時背光模組100係操作在偏低亮度的情況下，此時脈衝寬度調變訊號的工作週期小於操作訊號週期的三倍，而升壓控制訊號的工作週期因此變得太過短暫而無法維持升壓電路150的輸出電壓，發光二極體則可能出現閃爍不穩的情形，因此在第三時段T3時，微控制器130會將開關146導通，電阻調變模組140的阻值因此降低，操作頻率產生模組114會對應該阻值產生頻率較高的操作訊號，而使得在第三時段T3時，脈衝寬度調變訊號的工作週期能維持大於操作訊號週期的三倍，使得升壓控制訊號能維持升壓電路的輸出電壓，而發光二極體能穩定發光。 Please refer to FIG. 2 . FIG. 2 is a related operation signal diagram of the backlight module 100, which includes a pulse width modulation signal, an operation signal, and a boost control signal in a first time period T1, a second time period T2, and a third time period. The status within T3. During the first time period T1, the backlight module 100 operates under normal brightness, and the duty cycle of the pulse width modulation signal is greater than three times of the operation signal period, and the boost control signal can still maintain the output voltage of the boost circuit. The light-emitting diode is stably illuminated. At this time, the switch 146 is turned off, and the resistance of the resistance modulation module 140 is the resistance of the first resistor 142; during the second time period T2, the backlight module 100 is operated at a low level. In the case of brightness, the duty cycle of the pulse width modulation signal is less than three times of the operation signal period, and the duty cycle of the boost control signal is thus too short to maintain the output voltage of the boost circuit 150. The polar body may be unstable. Therefore, during the third time period T3, the microcontroller 130 turns on the switch 146, and the resistance of the resistance modulation module 140 is reduced, and the operating frequency generation module 114 corresponds to The resistance value generates a higher frequency operation signal, so that during the third time period T3, the duty cycle of the pulse width modulation signal can be maintained to be greater than three times the operation signal period, so that the boost control signal can be maintained. Output voltage of the voltage circuit, and the light-emitting diode emitting physical stability.
於上述實施例中，該預定值係當電阻調變模組140的第二開關146為截止時，操作訊號產生模組114對應產生之操作訊號週期的三倍，而於此同一實施例中，當背光模組100自第三時段T3偏低亮度狀態回到正常亮度的狀態時，則當脈衝寬度調變訊號的工作週期大於上述之預定值時，微控制器130會將開關146截止，而電阻調變模組140的阻值會因此上升，操作訊號產生模組114會對應該阻阻值產生頻率較低的操作訊號以避免背光模組100因操作在偏高的頻率導致升壓的效率降低。須注意上述預定值乃本發明之較佳實施例，熟悉本領域者，當可根據系統運作之實際情況，修改此預定值以 符合系統需求，例如於另一實施例中，此預定值可為當電阻調變模組的第二開關為截止時，操作訊號產生模組114對應產生之操作訊號的週期。 In the above embodiment, the predetermined value is three times the period of the operation signal generated by the operation signal generating module 114 when the second switch 146 of the resistance modulation module 140 is off, and in the same embodiment, When the backlight module 100 returns to the normal brightness state from the low period of the third period T3, when the duty cycle of the pulse width modulation signal is greater than the predetermined value, the microcontroller 130 turns off the switch 146. The resistance of the resistance modulation module 140 is increased, and the operation signal generation module 114 generates an operation signal with a lower frequency corresponding to the resistance value to avoid the efficiency of the backlight module 100 due to operation at a high frequency. reduce. It should be noted that the above predetermined values are preferred embodiments of the present invention, and those skilled in the art can modify the predetermined value according to the actual operation of the system. For example, in another embodiment, the predetermined value may be a period of the operation signal generated by the operation signal generating module 114 when the second switch of the resistance modulation module is turned off.
請參考第3圖，第3圖為本發明另一實施例之背光模組200之示意圖，其與上述第1圖之實施例的差別僅在於電阻調變模組240。於第3圖之實施例中，電阻調變模組240包含可變電阻242。可變電阻242耦接於微控制器130，而在脈衝寬度調變訊號的工作週期大於或等於預定值時，微控制器130會調升可變電阻242之阻值，亦即電阻調變模組240之阻值，進而調降操作訊號的頻率；而於脈衝寬度調變訊號的工作週期小於預定值時，微控制器130會調降可變電阻242之阻值，亦即電阻調變模組240之阻值，進而調升操作訊號的頻率。此透過改變操作訊號的頻率來維持升壓電路150的輸出電壓的方式則與第1圖之實施例相同，在此不另贅述。 Please refer to FIG. 3 . FIG. 3 is a schematic diagram of a backlight module 200 according to another embodiment of the present invention. The difference from the embodiment of FIG. 1 is only the resistance modulation module 240 . In the embodiment of FIG. 3, the resistance modulation module 240 includes a variable resistor 242. The variable resistor 242 is coupled to the microcontroller 130. When the duty cycle of the pulse width modulation signal is greater than or equal to a predetermined value, the microcontroller 130 increases the resistance of the variable resistor 242, that is, the resistance modulation mode. The resistance of the group 240 is further reduced by the frequency of the operation signal; and when the duty cycle of the pulse width modulation signal is less than the predetermined value, the microcontroller 130 reduces the resistance of the variable resistor 242, that is, the resistance modulation mode. The resistance of group 240, which in turn increases the frequency of the operation signal. The manner of maintaining the output voltage of the booster circuit 150 by changing the frequency of the operation signal is the same as that of the embodiment of Fig. 1, and will not be further described herein.
請參考第4圖，第4圖為本發明背光模組100、200之控制方法流程圖。背光模組100、200之控制方法包含下列步驟：410：微控制器130根據輸入訊號產生脈衝寬度調變訊號；420：電阻調變模組140或240根據脈衝寬度調變訊號之工作週期調整電阻調變模組140或240之阻值；430：操作訊號產生模組114根據電阻調變模組140或240之阻值產生操作訊號；440：轉換器110根據操作訊號及脈衝寬度調變訊號控制升壓電路150之第一開關151的開啟及關閉，以控制耦接於升壓電路150之多組發光二極體120產生背光。 Please refer to FIG. 4 , which is a flow chart of a control method of the backlight modules 100 and 200 according to the present invention. The control method of the backlight module 100, 200 includes the following steps: 410: the microcontroller 130 generates a pulse width modulation signal according to the input signal; 420: the resistance modulation module 140 or 240 adjusts the resistance according to the duty cycle of the pulse width modulation signal The resistance of the modulation module 140 or 240; 430: the operation signal generation module 114 generates an operation signal according to the resistance of the resistance modulation module 140 or 240; 440: the converter 110 controls the signal according to the operation signal and the pulse width modulation signal. The first switch 151 of the booster circuit 150 is turned on and off to control the plurality of sets of the LEDs 120 coupled to the booster circuit 150 to generate a backlight.
在步驟410，輸入訊號係對應於系統所需的背光亮度，所需亮度越強，則脈衝寬度調變訊號的工作週期越大；所需亮度越低，則脈衝寬度調 變訊號的工作週期越小。步驟420係在脈衝寬度調變訊號的工作週期大於或等於預定值時，截止電阻調變模組140的第二開關146，以調升電阻調變模組140的阻值，或調升可變電阻242之阻值，以調升電阻調變模組240之阻值，而步驟430即根據此阻值，來產生一組頻率較低之操作訊號。反之，於同一實施例中，在脈衝寬度調變訊號的工作週期小於預定值時，步驟420會導通電阻調變模組140的第二開關146，以調降電阻調變模組140的阻值，或調降可變電阻242之阻值，以調降電阻調變模組240之阻值，而步驟430即根據此阻值來產生一組頻率較高之操作訊號。於一實施例中，預定值可為操作訊號週期的三倍。步驟440係根據操作訊號及脈衝寬度調變訊號控制升壓電路150之第一開關151的開啟及關閉，以控制耦接於升壓電路150之多組發光二極體120產生背光。於一實施例中，轉換器110係根據操作訊號及脈衝寬度調變訊號的邏輯積(Logical product)來控制第一開關151的開啟及關閉。 In step 410, the input signal corresponds to the backlight brightness required by the system. The stronger the required brightness, the larger the duty cycle of the pulse width modulation signal; the lower the required brightness, the pulse width modulation The smaller the duty cycle of the variable signal. Step 420: When the duty cycle of the pulse width modulation signal is greater than or equal to a predetermined value, the second switch 146 of the resistance modulation module 140 is turned off to increase the resistance of the resistance modulation module 140, or the variable temperature is adjustable. The resistance of the resistor 242 is used to increase the resistance of the resistor modulation module 240, and step 430 is based on the resistance to generate a set of lower frequency operation signals. On the other hand, in the same embodiment, when the duty cycle of the pulse width modulation signal is less than the predetermined value, step 420 turns on the second switch 146 of the resistance modulation module 140 to reduce the resistance of the resistance modulation module 140. Or, the resistance of the variable resistor 242 is lowered to lower the resistance of the resistance modulation module 240, and step 430 is based on the resistance to generate a set of higher frequency operation signals. In an embodiment, the predetermined value may be three times the period of the operation signal. Step 440 controls the opening and closing of the first switch 151 of the boosting circuit 150 according to the operation signal and the pulse width modulation signal to control the plurality of groups of the LEDs 120 coupled to the boosting circuit 150 to generate a backlight. In one embodiment, the converter 110 controls the opening and closing of the first switch 151 according to a logical product of the operation signal and the pulse width modulation signal.
綜上所述，本發明背光模組100、200能在背光處於偏低亮度的情況下，藉由改變電阻調變模組140、240的阻值，來提高操作訊號的頻率，以穩定維持升壓電路150的輸出電壓，並解決先前技術所述於低亮度螢幕易生之閃爍不穩的問題。同時當背光處於正常亮度的情況下，本發明背光模組100、200也能降低操作訊號的頻率，以提升升壓電路150的效率。 In summary, the backlight modules 100 and 200 of the present invention can increase the frequency of the operation signal by changing the resistance values of the resistance modulation modules 140 and 240 when the backlight is at a low brightness to stably maintain the rise. The output voltage of the circuit 150 is pressed, and the problem of flicker instability caused by the low-brightness screen described in the prior art is solved. At the same time, when the backlight is in normal brightness, the backlight module 100, 200 of the present invention can also reduce the frequency of the operation signal to improve the efficiency of the boost circuit 150.
以上所述僅為本發明之較佳實施例，凡依本發明申請專利範圍所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.
100‧‧‧背光模組 100‧‧‧Backlight module
110‧‧‧轉換器 110‧‧‧ converter
114‧‧‧操作訊號產生模組 114‧‧‧Operation signal generation module
120‧‧‧多串發光二極體 120‧‧‧Multiple strings of LEDs
130‧‧‧微控制器 130‧‧‧Microcontroller
140‧‧‧電阻調變模組 140‧‧‧Resistor Modulation Module
142‧‧‧第一電阻 142‧‧‧First resistance
144‧‧‧第二電阻 144‧‧‧second resistance
146‧‧‧第二開關 146‧‧‧second switch
150‧‧‧升壓電路 150‧‧‧Boost circuit
151‧‧‧第一開關 151‧‧‧First switch
152‧‧‧電感 152‧‧‧Inductance
153‧‧‧齊納二極體 153‧‧‧Zina diode
154‧‧‧電容 154‧‧‧ Capacitance
160‧‧‧直流電壓源 160‧‧‧DC voltage source
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| TW102149388A TWI605437B (en) | 2013-12-31 | 2013-12-31 | Backlight module |
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| TW102149388A TWI605437B (en) | 2013-12-31 | 2013-12-31 | Backlight module |
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| TWI605437B TWI605437B (en) | 2017-11-11 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI581662B (en) * | 2015-09-15 | 2017-05-01 | 高儀電子股份有限公司 | Circuit structure for adjusting led color temperature curve |
| CN108665859A (en) * | 2018-08-01 | 2018-10-16 | 合肥惠科金扬科技有限公司 | Backlight control circuit and backlight |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI581662B (en) * | 2015-09-15 | 2017-05-01 | 高儀電子股份有限公司 | Circuit structure for adjusting led color temperature curve |
| CN108665859A (en) * | 2018-08-01 | 2018-10-16 | 合肥惠科金扬科技有限公司 | Backlight control circuit and backlight |
| CN108665859B (en) * | 2018-08-01 | 2023-12-29 | 合肥惠科金扬科技有限公司 | Backlight source control circuit and backlight source |
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