TW201526701A - Light-emitting diode controller capable of automatically switching dimming modes - Google Patents
Light-emitting diode controller capable of automatically switching dimming modes Download PDFInfo
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本發明是有關於一種發光二極體（light-emitting diode，LED）控制器，且特別是有關於一種自動切換調光模式之LED控制器。
The present invention relates to a light-emitting diode (LED) controller, and more particularly to an LED controller that automatically switches between dimming modes.
圖1為一種現有的顯示器之背光驅動系統之電路方塊圖。請參見圖1，交流電源輸入後，經過電源供應器1轉換成多組不同準位的直流電壓輸出，以供電給顯示器內部其它元件。以小尺寸顯示器為例，電源供應器1可輸出5V的直流電壓Vo1供電給主板，並輸出12V或16V的直流電壓Vo2供電給顯示面板、音源放大器及背光驅動電路2。背光驅動電路2用於驅動作為背光的LED光源3。由於LED光源3通常包含有由多顆LED串聯組成的LED串31，而LED串31中串聯的LED數量越多就需要越高的順向電壓來驅動，因此直流電壓Vo2輸入背光驅動電路2後，通常需要先經過升壓轉換器21升壓以產生可驅動LED串31的直流電壓Vled後再輸出至LED光源3，然後LED控制器22可根據主板發送的開關信號ON/OFF開啟或關閉LED光源3，並在LED光源3被開啟時根據主板發送的調光信號DIM對LED光源3進行調光。LED光源3的調光方式或調光模式主要有類比（analogy）調光及脈寬調變（pulse-width modulation，PWM）調光兩種。類比調光直接調節流過LED串31的直流電流Iled大小，以改變LED串31的亮度，以此控制LED光源3的亮度；而PWM調光則藉由調節LED串31中固定大小的電流Iled的工作週期（duty cycle）來改變LED串31的平均電流，以改變LED串31的平均亮度，以此控制LED光源3的亮度。1 is a circuit block diagram of a backlight driving system of a conventional display. Referring to FIG. 1, after the AC power input, the power supply 1 is converted into a plurality of sets of DC voltage outputs of different levels to supply power to other components inside the display. Taking a small-sized display as an example, the power supply 1 can output a 5V DC voltage Vo1 to the main board, and output a 12V or 16V DC voltage Vo2 to the display panel, the sound source amplifier, and the backlight driving circuit 2. The backlight driving circuit 2 is for driving the LED light source 3 as a backlight. Since the LED light source 3 usually includes an LED string 31 composed of a plurality of LEDs connected in series, the higher the number of LEDs connected in series in the LED string 31, the higher the forward voltage is required to drive, so the DC voltage Vo2 is input to the backlight driving circuit 2 Generally, it is required to be boosted by the boost converter 21 to generate a DC voltage Vled that can drive the LED string 31, and then output to the LED light source 3. Then, the LED controller 22 can turn the LED on or off according to the switch signal ON/OFF sent by the main board. The light source 3, and when the LED light source 3 is turned on, dims the LED light source 3 according to the dimming signal DIM sent by the main board. The dimming mode or dimming mode of the LED light source 3 mainly includes analog modulating and pulse-width modulation (PWM) dimming. The analog dimming directly adjusts the magnitude of the direct current Iled flowing through the LED string 31 to change the brightness of the LED string 31, thereby controlling the brightness of the LED light source 3; and the PWM dimming adjusts the fixed-sized current Iled in the LED string 31. The duty cycle is used to change the average current of the LED string 31 to change the average brightness of the LED string 31, thereby controlling the brightness of the LED light source 3.
圖2為圖1所示LED光源3採用PWM調光及類比調光時的電流Iled之波形圖。請同時參見圖1及圖2，主板發送到LED控制器22的調光信號DIM通常採用PWM形式的數位信號，故又稱為PWM調光信號，以便具有較強的抗雜訊能力。當採用PWM調光時，在PWM調光信號DIM為高準位的期間，LED控制器22藉由汲入LED串31的電流Iled以啟用LED光源3，或藉由控制升壓轉換器21正常工作以啟用LED光源3，此時電流Iled為固定大小且通常採用額定電流值Ir，所謂的額定電流值是指元件在特定環境條件（如環境溫度等）下長期連續工作時可允許的最大電流值。在PWM調光信號DIM為低準位的期間，LED控制器22藉由停止汲入LED串31的電流Iled以停用LED光源3，或藉由控制升壓轉換器21停止工作以停用LED光源3，此時電流Iled為0。因此，流過LED光源3的平均電流等於PWM調光信號DIM的工作週期D乘以額定電流值Ir，即D×Ir，可提供線性的亮度變化，其中，PWM調光信號DIM的工作週期D等於其為高準位的時間（即啟用LED光源3使其工作的時間）除以其週期T。2 is a waveform diagram of a current Iled when the LED light source 3 shown in FIG. 1 adopts PWM dimming and analog dimming. Please refer to FIG. 1 and FIG. 2 at the same time, the dimming signal DIM sent by the main board to the LED controller 22 usually adopts a digital signal in the form of PWM, so it is also called a PWM dimming signal, so as to have strong anti-noise capability. When PWM dimming is employed, during the period when the PWM dimming signal DIM is at a high level, the LED controller 22 activates the LED light source 3 by breaking the current Iled of the LED string 31, or by controlling the boost converter 21 to be normal. Work to enable the LED light source 3, the current Iled is a fixed size and usually uses the rated current value Ir, the so-called rated current value refers to the maximum allowable current when the component is continuously operated under certain environmental conditions (such as ambient temperature, etc.) value. During the period when the PWM dimming signal DIM is at a low level, the LED controller 22 disables the LED light source 3 by stopping the current Iled entering the LED string 31, or stops the operation by controlling the boost converter 21 to disable the LED. Light source 3, at this time, current Iled is zero. Therefore, the average current flowing through the LED light source 3 is equal to the duty cycle D of the PWM dimming signal DIM multiplied by the rated current value Ir, ie D×Ir, which provides a linear brightness change, wherein the duty cycle D of the PWM dimming signal DIM Equal to the time at which it is at a high level (ie, the time at which LED light source 3 is enabled to operate) divided by its period T.
然而，在PWM調光信號DIM由高準位變成低準位時，電流Iled瞬間解離為0，使得電源供應器1輸出直流電壓Vo2的輸出端形同滿載瞬間變成空載，造成直流電壓Vo2發生暫態振盪；在PWM調光信號DIM由低準位變成高準位時，電流Iled極短時間內由0上升至額定電流值Ir，使得電源供應器1輸出直流電壓Vo2的輸出端形同空載瞬間變成滿載，造成直流電壓Vo2發生瞬降現象。因此，對電源供應器1而言，作為其負載的電流Iled的劇烈變化會使其輸出的直流電壓Vo2產生極大的電壓暫態振盪及瞬降現象，間接影響了其它共用此直流電壓Vo2作為電源的負載，例如顯示面板及音源放大器，常見的現象是螢幕出現水波紋及無音源輸入下喇叭出現低頻雜音。此外，負載的劇烈變化還會使電源供應器1中磁性元件的激磁電流變化過大，產生較多的散射雜訊。However, when the PWM dimming signal DIM changes from the high level to the low level, the current Iled is instantaneously disengaged to 0, so that the output end of the output voltage of the DC supply Vo2 of the power supply 1 becomes the no-load moment, causing the DC voltage Vo2 to occur. Transient oscillation; when the PWM dimming signal DIM changes from the low level to the high level, the current Iled rises from 0 to the rated current value Ir in a short time, so that the output end of the output DC voltage Vo2 of the power supply 1 is the same The load instantly becomes full, causing a transient drop in the DC voltage Vo2. Therefore, for the power supply 1 , the drastic change of the current Iled as its load causes the output DC voltage Vo2 to generate a large voltage transient oscillation and a transient phenomenon, which indirectly affects the sharing of the DC voltage Vo2 as a power source. The load, such as the display panel and the audio amplifier, is a common phenomenon in which the screen has water ripples and low-frequency noise occurs in the speaker without the input of the sound source. In addition, a drastic change in the load causes the excitation current of the magnetic component in the power supply 1 to vary too much, resulting in more scattering noise.
當採用類比調光時，LED控制器22通常需要先利用電阻和電容組成的RC積分電路將主板發送的PWM形式的調光信號DIM轉換成直流形式的電流命令值，使電流命令值與PWM調光信號DIM的工作週期D成正比，再根據此電流命令值調整汲入LED串31的電流Iled大小，或藉由控制升壓轉換器21調整直流電壓Vled以改變LED串31的電流Iled大小。因此，對電源供應器1而言，作為其負載的電流Iled並不會有劇烈的變化，故輸出的直流電壓Vo2不會發生極大的電壓暫態振盪及瞬降現象，不會影響其它共用此直流電壓Vo2的負載，此外，電源供應器1中磁性元件的激磁電流也不會變化過大而產生較多的散射雜訊。然而，電阻和電容組成的RC積分電路並不能精準地將PWM調光信號DIM的工作週期D轉換成與其成正比的電流命令值，而且，由於LED本身特性的緣故，流過LED串31的電流Iled過低時會使其發出的光產生色溫偏差的問題。
When analog dimming is used, the LED controller 22 usually needs to use an RC integration circuit composed of a resistor and a capacitor to convert the PWM-type dimming signal DIM sent by the main board into a DC-type current command value, so that the current command value and the PWM tone are adjusted. The duty cycle D of the optical signal DIM is proportional to the current command value, and the current Iled size of the LED string 31 is adjusted according to the current command value, or the DC voltage Vled is adjusted by the boost converter 21 to change the current Iled size of the LED string 31. Therefore, for the power supply 1, the current Iled as its load does not change drastically, so the output DC voltage Vo2 does not cause extreme voltage transient oscillation and transient phenomenon, and does not affect other sharing. The load of the DC voltage Vo2, in addition, the excitation current of the magnetic element in the power supply 1 does not change too much and generates a large amount of scattering noise. However, the RC integrating circuit composed of the resistor and the capacitor cannot accurately convert the duty cycle D of the PWM dimming signal DIM into a current command value proportional thereto, and the current flowing through the LED string 31 due to the characteristics of the LED itself. When Iled is too low, the light emitted by it will cause a problem of color temperature deviation.
本發明的目的在提出一種自動切換調光模式之LED控制器，可改善電源供應器輸出電壓暫態振盪及瞬降現象，進而改善螢幕出現水波紋、無音源輸入下喇叭出現低頻雜音及產生較多散射雜訊的問題，且可避免LED光源因電流過低使其發出的光產生色溫偏差的問題。The object of the present invention is to provide an LED controller for automatically switching the dimming mode, which can improve the transient oscillation and the instantaneous drop phenomenon of the output voltage of the power supply, thereby improving the water ripple of the screen, the low frequency noise of the speaker under the input of no sound source, and the generation of the low frequency noise. The problem of multi-scattering noise, and avoiding the problem of color temperature deviation caused by the light emitted by the LED light source due to the low current.
為達到上述目的，本發明提出一種自動切換調光模式之LED控制器，包括調光信號偵測模組及調光控制模組。調光信號偵測模組接收PWM調光信號，在偵測到PWM調光信號的正緣時，開始計時以產生第一計時值；在第一計時值小於PWM調光信號的週期且偵測到PWM調光信號的負緣時，停止計時並讀出第一計時值，然後重置（reset）第一計時值的計時；在第一計時值達到PWM調光信號的週期時，輸出最大亮度通知信號並重新開始計時以產生第一計時值；在偵測到PWM調光信號的負緣時，開始計時以產生第二計時值；在第二計時值小於PWM調光信號的週期且偵測到PWM調光信號的正緣時，停止計時並讀出第二計時值，然後重置第二計時值的計時；在第二計時值達到PWM調光信號的週期時，輸出最小亮度通知信號並重新開始計時以產生第二計時值。調光控制模組在未收到最大亮度通知信號或最小亮度通知信號時，將第一計時值除以第一計時值及第二計時值之和以得到比值，在比值大於閾值時，採用類比調光模式控制LED光源的亮度；在比值小於閾值時，採用PWM調光模式控制LED光源的亮度；在收到最大亮度通知信號或最小亮度通知信號時，停止比值的計算，並控制LED光源發出最大亮度或不發光。To achieve the above object, the present invention provides an LED controller that automatically switches between dimming modes, including a dimming signal detection module and a dimming control module. The dimming signal detection module receives the PWM dimming signal, and when detecting the positive edge of the PWM dimming signal, starts timing to generate the first timing value; when the first timing value is less than the period of the PWM dimming signal and detecting When the negative edge of the PWM dimming signal is reached, the timing is stopped and the first timing value is read, and then the timing of the first timing value is reset; when the first timing value reaches the period of the PWM dimming signal, the maximum luminance is output. Notifying the signal and restarting the timing to generate the first timing value; when detecting the negative edge of the PWM dimming signal, starting timing to generate the second timing value; when the second timing value is less than the period of the PWM dimming signal and detecting When the positive edge of the PWM dimming signal is reached, the timing is stopped and the second timing value is read, and then the timing of the second timing value is reset; when the second timing value reaches the period of the PWM dimming signal, the minimum luminance notification signal is output and The timing is restarted to produce a second timing value. When the maximum brightness notification signal or the minimum brightness notification signal is not received, the dimming control module divides the first timing value by the sum of the first timing value and the second timing value to obtain a ratio, and when the ratio is greater than the threshold, the analogy is used. The dimming mode controls the brightness of the LED light source; when the ratio is less than the threshold, the PWM dimming mode is used to control the brightness of the LED light source; when the maximum brightness notification signal or the minimum brightness notification signal is received, the calculation of the ratio is stopped, and the LED light source is controlled. Maximum brightness or no light.
在本發明一實施例中，調光信號偵測模組包括正緣偵測器及負緣偵測器。正緣偵測器接收PWM調光信號，在偵測到PWM調光信號的正緣時，輸出正緣通知信號。負緣偵測器接收PWM調光信號，在偵測到PWM調光信號的負緣時，輸出負緣通知信號。In an embodiment of the invention, the dimming signal detection module includes a positive edge detector and a negative edge detector. The positive edge detector receives the PWM dimming signal, and outputs a positive edge notification signal when the positive edge of the PWM dimming signal is detected. The negative edge detector receives the PWM dimming signal, and outputs a negative edge notification signal when the negative edge of the PWM dimming signal is detected.
在本發明一實施例中，調光信號偵測模組還包括第一正反器（flip-flop）及第二正反器。第一正反器耦接正緣偵測器及負緣偵測器，在收到正緣通知信號時，控制調光信號偵測模組開始計時以產生第一計時值；在收到負緣通知信號時，控制調光信號偵測模組停止計時並讀出第一計時值，然後重置第一計時值的計時。第二正反器耦接正緣偵測器及負緣偵測器，在收到負緣通知信號時，控制調光信號偵測模組開始計時以產生第二計時值；在收到正緣通知信號時，控制調光信號偵測模組停止計時並讀出第二計時值，然後重置第二計時值的計時。In an embodiment of the invention, the dimming signal detection module further includes a first flip-flop and a second flip-flop. The first flip-flop is coupled to the positive edge detector and the negative edge detector. When the positive edge notification signal is received, the dimming signal detection module is controlled to start timing to generate the first timing value; When the signal is notified, the control dimming signal detection module stops counting and reads the first timing value, and then resets the timing of the first timing value. The second flip-flop is coupled to the positive edge detector and the negative edge detector, and when the negative edge notification signal is received, the dimming signal detection module is controlled to start timing to generate the second timing value; When the signal is notified, the control dimming signal detection module stops counting and reads the second timing value, and then resets the timing of the second timing value.
在本發明一實施例中，若正緣通知信號及負緣通知信號均為脈衝信號，則第一正反器及第二正反器均為邊緣敏感式（edge-sensitive）正反器。若正緣通知信號及負緣通知信號均為高或低準位信號，則第一正反器及第二正反器均為準位敏感式（level-sensitive）正反器。In an embodiment of the invention, if both the positive edge notification signal and the negative edge notification signal are pulse signals, the first flip-flop and the second flip-flop are both edge-sensitive flip-flops. If both the positive edge notification signal and the negative edge notification signal are high or low level signals, the first flip-flop and the second flip-flop are both level-sensitive flip-flops.
在本發明一實施例中，第一正反器及第二正反器均為設定重置（set-reset，SR）正反器，且均具有設定端、重置端、第一輸出端及第二輸出端，第一輸出端及第二輸出端的輸出互補。第一正反器的設定端及重置端分別耦接正緣偵測器及負緣偵測器，第二正反器的設定端及重置端分別耦接負緣偵測器及正緣偵測器。In an embodiment of the invention, the first flip-flop and the second flip-flop are both set-reset (SR) flip-flops, and each has a set end, a reset end, a first output end, and The output of the second output terminal is complementary to the outputs of the first output terminal and the second output terminal. The set end and the reset end of the first flip-flop are respectively coupled to the positive edge detector and the negative edge detector, and the set end and the reset end of the second flip-flop are respectively coupled to the negative edge detector and the positive edge Detector.
在本發明一實施例中，調光信號偵測模組還包括第一計時器、第一參數讀取器、第一延遲器、第二計時器、第二參數讀取器及第二延遲器。第一計時器耦接第一正反器的第一輸出端；第一正反器在收到正緣通知信號時，控制第一計時器開始計時以產生第一計時值；第一正反器在收到負緣通知信號時，控制第一計時器停止計時；第一計時器在第一計時值達到PWM調光信號的週期時，輸出最大亮度通知信號並重新開始計時以產生第一計時值。第一參數讀取器耦接第一正反器的第二輸出端及第一計時器；第一正反器在收到負緣通知信號時，控制第一參數讀取器讀出第一計時值。第一延遲器耦接第一正反器的第二輸出端及第一計時器；第一正反器在收到負緣通知信號時，通過第一延遲器在第一參數讀取器讀出第一計時值後重置第一計時器的計時。第二計時器耦接第二正反器的第一輸出端；第二正反器在收到負緣通知信號時，控制第二計時器開始計時以產生第二計時值；第二正反器在收到正緣通知信號時，控制第二計時器停止計時；第二計時器在第二計時值達到PWM調光信號的週期時，輸出最小亮度通知信號並重新開始計時以產生第二計時值。第二參數讀取器耦接第二正反器的第二輸出端及第二計時器；第二正反器在收到正緣通知信號時，控制第二參數讀取器讀出第二計時值。第二延遲器耦接第二正反器的第二輸出端及第二計時器；第二正反器在收到正緣通知信號時，通過第二延遲器在第二參數讀取器讀出第二計時值後重置第二計時器的計時。In an embodiment of the invention, the dimming signal detection module further includes a first timer, a first parameter reader, a first delay, a second timer, a second parameter reader, and a second delay . The first timer is coupled to the first output end of the first flip-flop; the first flip-flop controls the first timer to start timing to generate the first timing value when the positive edge notification signal is received; the first flip-flop Controlling the first timer to stop timing when receiving the negative edge notification signal; the first timer outputs a maximum brightness notification signal and restarts timing to generate the first timing value when the first timing value reaches the period of the PWM dimming signal . The first parameter reader is coupled to the second output end of the first flip-flop and the first timer; the first flip-flop controls the first parameter reader to read the first timing when receiving the negative edge notification signal value. The first delay device is coupled to the second output end of the first flip-flop and the first timer; the first flip-flop reads the first edge reader through the first delay device when receiving the negative edge notification signal The timing of the first timer is reset after the first timing value. The second timer is coupled to the first output end of the second flip-flop; the second flip-flop controls the second timer to start timing to generate the second timing value when the negative edge notification signal is received; the second flip-flop Controlling the second timer to stop timing when receiving the positive edge notification signal; and outputting the minimum brightness notification signal and restarting timing to generate the second timing value when the second timing value reaches the period of the PWM dimming signal . The second parameter reader is coupled to the second output end of the second flip-flop and the second timer; the second flip-flop controls the second parameter reader to read the second timing when receiving the positive edge notification signal value. The second delay device is coupled to the second output end of the second flip-flop and the second timer; the second flip-flop reads the second edge reader through the second delay device when receiving the positive edge notification signal The timing of the second timer is reset after the second timing value.
在本發明一實施例中，調光控制模組包括計算器、乘法器、比較器、第一開關及第二開關。計算器將第一計時值除以第一計時值及第二計時值之和以得到比值。乘法器將比值乘以LED光源的額定電流值以得到電流命令值，電流命令值控制流過LED光源的電流值。比較器比較比值及閾值。第一開關具有第一端、第二端及控制端，第一開關的第一端及第二端分別耦接額定電流值及電流命令值；在比值大於閾值時，比較器通過第一開關的控制端控制其第一端及第二端斷開，使電流命令值為比值乘以額定電流值，以便調光控制模組採用類比調光模式控制LED光源的亮度；在比值小於閾值時，比較器通過第一開關的控制端控制其第一端及第二端導通，使電流命令值為額定電流值，以便調光控制模組採用PWM調光模式控制LED光源的亮度；在調光控制模組收到最大亮度通知信號時，最大亮度通知信號通過第一開關的控制端控制其第一端及第二端導通，使電流命令值為額定電流值，以便調光控制模組控制LED光源發出最大亮度。第二開關具有第一端、第二端及控制端，第二開關的第一端及第二端分別耦接電流命令值及零電流命令值；在調光控制模組收到最小亮度通知信號時，最小亮度通知信號通過第二開關的控制端控制其第一端及第二端導通，使電流命令值為零電流命令值，以便調光控制模組控制LED光源不發光。In an embodiment of the invention, the dimming control module includes a calculator, a multiplier, a comparator, a first switch, and a second switch. The calculator divides the first timing value by the sum of the first timing value and the second timing value to obtain a ratio. The multiplier multiplies the ratio by the rated current value of the LED source to obtain a current command value that controls the current value flowing through the LED source. The comparator compares the ratio and the threshold. The first switch has a first end, a second end and a control end, and the first end and the second end of the first switch are respectively coupled with a rated current value and a current command value; when the ratio is greater than the threshold, the comparator passes through the first switch The control terminal controls the first end and the second end to be disconnected, so that the current command value is multiplied by the rated current value, so that the dimming control module controls the brightness of the LED light source by using the analog dimming mode; when the ratio is less than the threshold, the comparison is performed. The first end and the second end of the first switch are controlled to be turned on, so that the current command value is a rated current value, so that the dimming control module uses the PWM dimming mode to control the brightness of the LED light source; in the dimming control mode When the group receives the maximum brightness notification signal, the maximum brightness notification signal controls the first end and the second end to be turned on by the control end of the first switch, so that the current command value is the rated current value, so that the dimming control module controls the LED light source to emit Maximum brightness. The second switch has a first end, a second end and a control end, and the first end and the second end of the second switch are respectively coupled with a current command value and a zero current command value; and the dimming control module receives the minimum brightness notification signal When the minimum brightness notification signal is controlled by the control end of the second switch, the first end and the second end are turned on, so that the current command value is a zero current command value, so that the dimming control module controls the LED light source to not emit light.
上述一個實施例中描述的技術手段可應用於上述另一個實施例中，以得到一個新的實施例，只要這些技術手段不相互矛盾。The technical means described in one embodiment above can be applied to the other embodiment described above to obtain a new embodiment as long as the technical means are not contradictory.
本發明的調光信號偵測模組藉由偵測PWM調光信號的正緣及負緣可精準地得到PWM調光信號為高準位的時間（即第一計時值）及低準位的時間（即第二計時值），使得調光控制模組將第一計時值除以第一計時值及第二計時值之和得到的比值可精準地等於PWM調光信號的工作週期；而且，調光控制模組在比值大於閾值時，即在高亮度條件下採用類比調光模式控制LED光源的亮度，可改善電源供應器輸出電壓暫態振盪及瞬降現象，且可避免LED光源因電流過低使其發出的光產生色溫偏差的問題；在比值小於閾值時，即在低亮度條件下採用PWM調光模式控制LED光源的亮度，因平均負載較低而使電源供應器輸出電壓雖有暫態振盪及瞬降現象但並不嚴重，可改善螢幕出現水波紋、無音源輸入下喇叭出現低頻雜音及產生較多散射雜訊的問題。The dimming signal detecting module of the present invention can accurately obtain the time when the PWM dimming signal is at a high level (ie, the first timing value) and the low level by detecting the positive edge and the negative edge of the PWM dimming signal. The time (ie, the second timing value) is such that the dimming control module divides the first timing value by the sum of the first timing value and the second timing value to obtain a ratio that is exactly equal to the duty cycle of the PWM dimming signal; When the ratio of the dimming control module is greater than the threshold value, that is, the brightness of the LED light source is controlled by the analog dimming mode under high brightness conditions, the transient oscillation and the instantaneous drop phenomenon of the output voltage of the power supply can be improved, and the current of the LED light source can be avoided. Too low to cause the color light to produce a color temperature deviation; when the ratio is less than the threshold, that is, the PWM dimming mode is used to control the brightness of the LED light source under low brightness conditions, because the average load is low, the power supply output voltage is Transient oscillation and transient drop phenomenon are not serious, which can improve the water ripple on the screen, low-frequency noise in the speaker without the input of the sound source, and the problem of generating more scattering noise.
為讓本發明上述和其他目的、特徵和優點能更明顯易懂，下文特舉較佳實施例，並配合所附圖式，作詳細說明如下。The above and other objects, features and advantages of the present invention will become more <RTIgt;
1‧‧‧電源供應器
2‧‧‧背光驅動電路
21‧‧‧升壓轉換器
22‧‧‧LED控制器
3‧‧‧LED光源
31‧‧‧LED串
4‧‧‧調光信號偵測模組
41-1‧‧‧正緣偵測器
41-2‧‧‧負緣偵測器
42-1‧‧‧第一正反器
42-2‧‧‧第二正反器
S‧‧‧設定端
R‧‧‧重置端
Q‧‧‧第一輸出端
Q’‧‧‧第二輸出端
43-1‧‧‧第一計時器
43-2‧‧‧第二計時器
44-1‧‧‧第一參數讀取器
44-2‧‧‧第二參數讀取器
45-1‧‧‧第一延遲器
45-2‧‧‧第二延遲器
5‧‧‧調光控制模組
51‧‧‧計算器
52‧‧‧乘法器
53‧‧‧比較器
54‧‧‧第一開關
55‧‧‧第二開關
DIM‧‧‧PWM調光信號
D‧‧‧工作週期
ON/OFF‧‧‧開關信號
Vo1、Vo2、Vled‧‧‧直流電壓
Iled‧‧‧直流電流
T1‧‧‧第一計時值
T2‧‧‧第二計時值
Tout1‧‧‧最大亮度通知信號
Tout2‧‧‧最小亮度通知信號
Sp‧‧‧正緣通知信號
Sn‧‧‧負緣通知信號
D’‧‧‧比值
Dth‧‧‧閾值
Iset‧‧‧電流命令值
Ir‧‧‧額定電流值
t‧‧‧時間1‧‧‧Power supply
2‧‧‧Backlight drive circuit
21‧‧‧Boost Converter
22‧‧‧LED controller
3‧‧‧LED light source
31‧‧‧LED string
4‧‧‧ dimming signal detection module
41-1‧‧‧ Positive Edge Detector
41-2‧‧‧ Negative Edge Detector
42-1‧‧‧First positive and negative
42-2‧‧‧second flip-flop
S‧‧‧Setting end
R‧‧‧Reset end
Q‧‧‧ first output
Q'‧‧‧second output
43-1‧‧‧First timer
43-2‧‧‧Second timer
44-1‧‧‧First Parameter Reader
44-2‧‧‧Second parameter reader
45-1‧‧‧First retarder
45-2‧‧‧Second retarder
5‧‧‧ dimming control module
51‧‧‧Calculator
52‧‧‧Multiplier
53‧‧‧ comparator
54‧‧‧First switch
55‧‧‧Second switch
DIM‧‧‧PWM dimming signal
D‧‧‧ work cycle
ON/OFF‧‧‧ switch signal
Vo1, Vo2, Vled‧‧‧ DC voltage
Iled‧‧‧ DC current
T1‧‧‧ first timing value
T2‧‧‧ second timing value
Tout1‧‧‧Maximum brightness notification signal
Tout2‧‧‧Minimum brightness notification signal
Sp‧‧‧ positive notice signal
Sn‧‧‧ Negative notice signal
D'‧‧‧ ratio
Dth‧‧‧ threshold
Iset‧‧‧ current command value
Ir‧‧‧rated current value
t‧‧‧Time
圖1為一種現有的顯示器之背光驅動系統之電路方塊圖；
圖2為圖1所示LED光源採用PWM調光及類比調光時的電流之波形圖；
圖3為本發明的自動切換調光模式之LED控制器的一實施例之電路方塊圖；
圖4為圖3所示PWM調光信號的工作週期及電流命令值之關係曲線圖；
圖5為圖3所示調光信號偵測模組的一實施例之電路方塊圖；
圖6及圖7為圖5所示調光信號偵測模組上的信號之波形圖；
圖8為圖3所示調光控制模組的一實施例之電路方塊圖；及
圖9為圖8所示調光控制模組上的信號之波形圖。
1 is a circuit block diagram of a backlight driving system of a conventional display;
2 is a waveform diagram of currents when the LED light source shown in FIG. 1 adopts PWM dimming and analog dimming;
3 is a circuit block diagram of an embodiment of an LED controller for automatically switching a dimming mode according to the present invention;
4 is a graph showing the relationship between the duty cycle and the current command value of the PWM dimming signal shown in FIG. 3;
5 is a circuit block diagram of an embodiment of the dimming signal detecting module shown in FIG. 3;
6 and FIG. 7 are waveform diagrams of signals on the dimming signal detecting module shown in FIG. 5;
8 is a circuit block diagram of an embodiment of the dimming control module of FIG. 3; and FIG. 9 is a waveform diagram of signals on the dimming control module of FIG.
為清楚呈現本發明之特徵，所附圖式中之各元件僅為示意而並非按照實物之外形與比例繪製，且省略部份習知之元件。此外，為呈現對本發明之說明的一貫性，在不同實施例中，相同或相似的符號代表相同或相似的元件。For the sake of clarity, the various elements in the figures are only schematic and not drawn to scale and scale, and some of the conventional elements are omitted. In addition, in the different embodiments, the same or similar symbols represent the same or similar elements in order to present the consistency of the description of the present invention.
圖3為本發明的自動切換調光模式之LED控制器的一實施例之電路方塊圖，而圖4為圖3所示PWM調光信號DIM的工作週期D及電流命令值Iset之關係曲線圖。請同時參見圖3及圖4，本發明的LED控制器適用於任何採用LED光源的裝置，例如可適用於如圖1所示小尺寸顯示器之背光驅動系統以取代其中的LED控制器22，亦可適用於大尺寸顯示器之背光驅動系統。本發明的LED控制器包括調光信號偵測模組4及調光控制模組5。調光信號偵測模組4接收PWM調光信號DIM，並藉由偵測PWM調光信號DIM的正緣及負緣，以得到PWM調光信號DIM為高準位的時間（即第一計時值T1）及低準位的時間（即第二計時值T2）。此外，調光信號偵測模組4在偵測到PWM調光信號DIM為高準位的時間（即第一計時值T1）達到PWM調光信號DIM的週期T時，表示其收到的PWM調光信號DIM的工作週期D=100%，故輸出最大亮度通知信號Tout1；在偵測到PWM調光信號DIM為低準位的時間（即第二計時值T2）達到PWM調光信號DIM的週期T時，表示其收到的PWM調光信號的DIM工作週期D=0%，故輸出最小亮度通知信號Tout2。3 is a circuit block diagram of an embodiment of an LED controller for automatically switching a dimming mode according to the present invention, and FIG. 4 is a graph showing a relationship between a duty cycle D and a current command value Iset of the PWM dimming signal DIM shown in FIG. . 3 and FIG. 4, the LED controller of the present invention is applicable to any device using an LED light source, for example, a backlight driving system suitable for a small-sized display as shown in FIG. 1 to replace the LED controller 22 therein. It can be used in backlight drive systems for large size displays. The LED controller of the present invention includes a dimming signal detection module 4 and a dimming control module 5. The dimming signal detecting module 4 receives the PWM dimming signal DIM, and detects the positive and negative edges of the PWM dimming signal DIM to obtain the time when the PWM dimming signal DIM is at a high level (ie, the first timing) The value of T1) and the low level (ie, the second timing value T2). In addition, when the time when the PWM dimming signal DIM is detected to be at a high level (ie, the first timing value T1) reaches the period T of the PWM dimming signal DIM, the dimming signal detecting module 4 indicates that the PWM signal is received. The duty cycle DIM has a duty cycle D=100%, so the maximum brightness notification signal Tout1 is output; when the PWM dimming signal DIM is detected to be at a low level (ie, the second timing value T2), the PWM dimming signal DIM is reached. At the time T, it indicates that the DIM duty cycle of the PWM dimming signal received by it is D=0%, so the minimum brightness notification signal Tout2 is output.
調光控制模組5在未收到最大亮度通知信號Tout1或最小亮度通知信號Tout2時，將第一計時值T1除以第一計時值T1及第二計時值T2之和以得到比值D’，即D’=T1/(T1+T2)。與現有的採用電阻和電容組成的RC積分電路不能精準地將PWM調光信號DIM的工作週期D轉換成電流命令值相比，本發明的調光信號偵測模組4藉由偵測PWM調光信號DIM的正緣及負緣可精準地得到PWM調光信號DIM為高準位的時間（即第一計時值T1）及低準位的時間（即第二計時值T2），使得調光控制模組5計算得到的比值D’可精準地等於PWM調光信號DIM的工作週期D，即D’=D。此外，調光控制模組5在收到最大亮度通知信號Tout1時，表示PWM調光信號DIM的工作週期D=100%，故停止比值D’的計算，直接控制LED光源發出最大亮度；在收到最小亮度通知信號Tout2時，表示PWM調光信號DIM的工作週期D=0%，故停止比值D’的計算，直接控制LED光源不發光。When the maximum brightness notification signal Tout1 or the minimum brightness notification signal Tout2 is not received, the dimming control module 5 divides the first timing value T1 by the sum of the first timing value T1 and the second timing value T2 to obtain the ratio D'. That is, D'=T1/(T1+T2). Compared with the existing RC integration circuit using resistors and capacitors, the dimming signal detection module 4 of the present invention can detect the PWM modulation by comparing the duty cycle D of the PWM dimming signal DIM into the current command value. The positive edge and the negative edge of the optical signal DIM can accurately obtain the time when the PWM dimming signal DIM is at a high level (ie, the first timing value T1) and the time of the low level (ie, the second timing value T2), so that the dimming The ratio D' calculated by the control module 5 can be exactly equal to the duty cycle D of the PWM dimming signal DIM, that is, D'=D. In addition, when the maximum brightness notification signal Tout1 is received, the dimming control module 5 indicates that the duty cycle of the PWM dimming signal DIM is D=100%, so the calculation of the ratio D′ is stopped, and the maximum brightness of the LED light source is directly controlled; When the minimum brightness notification signal Tout2 is reached, the duty cycle D=0 of the PWM dimming signal DIM is indicated, so the calculation of the ratio D' is stopped, and the LED light source is directly controlled to emit no light.
調光控制模組5在比值D’大於閾值Dth時，表示偵測到PWM調光信號DIM的工作週期D大於閾值Dth（如30%），故採用類比調光模式控制LED光源的亮度，此時調光控制模組5輸出電流命令值Iset為比值D’乘以LED光源的額定電流值Ir，即Iset=D’×Ir=D×Ir，以便LED控制器根據此電流命令值Iset直接調整LED光源的電流大小，以改變LED光源的亮度。由於在較高亮度條件下採用類比調光模式，電源供應器因作為其負載的LED光源的電流不會有劇烈變化，故輸出的電壓不會發生極大暫態振盪及瞬降現象，進而可改善螢幕出現水波紋、無音源輸入下喇叭出現低頻雜音及產生較多散射雜訊的問題，且可避免LED光源因電流過低使其發出的光產生色溫偏差的問題。When the ratio D′ is greater than the threshold Dth, the dimming control module 5 indicates that the duty cycle D of the PWM dimming signal DIM is greater than the threshold Dth (eg, 30%), so the analog dimming mode is used to control the brightness of the LED light source. The dimming control module 5 outputs the current command value Iset as the ratio D' multiplied by the rated current value Ir of the LED light source, that is, Iset=D'×Ir=D×Ir, so that the LED controller directly adjusts according to the current command value Iset. The current of the LED light source is used to change the brightness of the LED light source. Since the analog dimming mode is adopted under higher brightness conditions, the power supply does not change drastically due to the current of the LED light source as its load, so the output voltage does not undergo extreme transient oscillation and transient phenomenon, which can be improved. There are water ripples on the screen, low-frequency noise in the speaker input without sound source, and more scattering noise. It can avoid the problem of color temperature deviation caused by the light emitted by the LED light source due to low current.
調光控制模組5在比值D’小於閾值Dth時，表示偵測到PWM調光信號DIM的工作週期D小於閾值Dth（如30%），故採用PWM調光模式控制LED光源的亮度，此時調光控制模組5輸出電流命令值Iset為額定電流值Ir，即Iset=Ir，以便LED控制器根據電流命令值Iset使LED光源的電流為額定電流值Ir，並根據比值D’調節LED光源中固定大小的電流的工作週期來改變LED光源的平均電流，以改變LED光源的平均亮度。由於在較低亮度條件下採用PWM調光模式，LED光源的電流雖然會有劇烈變化，但其平均電流較低，對電源供應器而言即平均負載較低，故其輸出的電壓雖然會有暫態振盪及瞬降現象但相對較不嚴重，進而可改善螢幕出現水波紋、無音源輸入下喇叭出現低頻雜音及產生較多散射雜訊的問題，且LED光源的電流為額定電流值Ir而可避免LED光源因電流過低使其發出的光產生色溫偏差的問題。When the ratio D′ is less than the threshold Dth, the dimming control module 5 indicates that the duty cycle D of the PWM dimming signal DIM is less than the threshold Dth (eg, 30%), so the PWM dimming mode is used to control the brightness of the LED light source. The dimming control module 5 outputs the current command value Iset to the rated current value Ir, that is, Iset=Ir, so that the LED controller makes the current of the LED light source be the rated current value Ir according to the current command value Iset, and adjusts the LED according to the ratio D'. The duty cycle of the fixed magnitude current in the source changes the average current of the LED source to change the average brightness of the LED source. Due to the PWM dimming mode under lower brightness conditions, the current of the LED light source will change drastically, but the average current is lower. For the power supply, the average load is lower, so the output voltage will be Transient oscillation and transient drop phenomenon are relatively less serious, which can improve the water ripple on the screen, the low frequency noise of the speaker under the input of no sound source and the problem of generating more scattering noise, and the current of the LED light source is the rated current value Ir. It can avoid the problem that the LED light source produces color temperature deviation due to the current caused by the low current.
圖5為圖3所示調光信號偵測模組4的一實施例之電路方塊圖，而圖6及圖7為圖5所示調光信號偵測模組4上的信號之波形圖。請同時參見圖5、圖6及圖7，調光信號偵測模組4包括正緣偵測器41-1及負緣偵測器41-2。正緣偵測器41-1接收PWM調光信號DIM，在偵測到PWM調光信號DIM的正緣時，輸出正緣通知信號Sp。負緣偵測器41-2接收PWM調光信號DIM，在偵測到PWM調光信號DIM的負緣時，輸出負緣通知信號Sn。調光信號偵測模組4還包括第一正反器42-1及第二正反器42-2。在本實施例中，正緣通知信號Sp及負緣通知信號Sn均為脈衝信號，故第一正反器42-1及第二正反器42-2均採用邊緣敏感式正反器，但並非僅限於此，例如正緣通知信號及負緣通知信號可均為高準位信號或均為低準位信號，而第一正反器及第二正反器則可均為準位敏感式正反器。在本實施例中，第一正反器42-1及第二正反器42-2均為SR正反器，且均具有設定端S、重置端R、第一輸出端Q及第二輸出端Q’，第一輸出端Q及第二輸出端Q’的輸出互補。第一正反器42-1的設定端S及重置端R分別耦接正緣偵測器41-1及負緣偵測器41-2，第二正反器42-2的設定端S及重置端R分別耦接負緣偵測器41-2及正緣偵測器41-1。FIG. 5 is a circuit block diagram of an embodiment of the dimming signal detecting module 4 of FIG. 3, and FIG. 6 and FIG. 7 are waveform diagrams of signals of the dimming signal detecting module 4 of FIG. Referring to FIG. 5, FIG. 6, and FIG. 7, the dimming signal detecting module 4 includes a positive edge detector 41-1 and a negative edge detector 41-2. The positive edge detector 41-1 receives the PWM dimming signal DIM, and outputs a positive edge notification signal Sp when the positive edge of the PWM dimming signal DIM is detected. The negative edge detector 41-2 receives the PWM dimming signal DIM, and outputs a negative edge notification signal Sn when the negative edge of the PWM dimming signal DIM is detected. The dimming signal detecting module 4 further includes a first flip-flop 42-1 and a second flip-flop 42-2. In this embodiment, the positive edge notification signal Sp and the negative edge notification signal Sn are both pulse signals, so the first flip-flop 42-1 and the second flip-flop 42-2 both use edge-sensitive flip-flops, but It is not limited to this. For example, the positive edge notification signal and the negative edge notification signal may all be high level signals or both low level signals, and the first flip flop and the second flip flop may be level sensitive. Positive and negative. In this embodiment, the first flip-flop 42-1 and the second flip-flop 42-2 are both SR flip-flops, and both have a set terminal S, a reset terminal R, a first output terminal Q, and a second The output Q', the outputs of the first output terminal Q and the second output terminal Q' are complementary. The set end S and the reset end R of the first flip-flop 42-1 are respectively coupled to the positive edge detector 41-1 and the negative edge detector 41-2, and the set end S of the second flip-flop 42-2 And the reset terminal R is coupled to the negative edge detector 41-2 and the positive edge detector 41-1, respectively.
調光信號偵測模組4還包括第一計時器43-1、第一參數讀取器44-1及第一延遲器45-1。第一計時器43-1耦接第一正反器42-1的第一輸出端Q，第一參數讀取器44-1耦接第一正反器42-1的第二輸出端Q’及第一計時器43-1，第一延遲器45-1耦接第一正反器42-1的第二輸出端Q’及第一計時器43-1。第一正反器42-1的設定端S在收到脈衝形式的正緣通知信號Sp時，其重置端R必然收到低準位信號，故第一正反器42-1的第一輸出端Q輸出高準位信號，且第二輸出端Q’輸出低準位信號；此時，第一輸出端Q輸出的高準位信號啟用第一計時器43-1開始計時以產生第一計時值T1，而第二輸出端Q’輸出的低準位信號停用第一參數讀取器44-1及第一延遲器45-1；此外，第一計時器43-1在第一計時值T1達到PWM調光信號DIM的週期T時，輸出最大亮度通知信號Tout1並重新開始計時以產生第一計時值T1。第一正反器42-1的重置端R在收到脈衝形式的負緣通知信號Sn時，其設定端S必然收到低準位信號，故第一正反器42-1的第一輸出端Q輸出低準位信號，且第二輸出端Q’輸出高準位信號；此時，第一輸出端Q輸出的低準位信號停用第一計時器43-1以停止計時，而第二輸出端Q’輸出的高準位信號啟用第一參數讀取器44-1及第一延遲器45-1，第一參數讀取器44-1從第一計時器43-1讀出第一計時值T1，然後第一延遲器45-1在第一參數讀取器44-1讀出第一計時值T1後輸出高準位信號以重置第一計時器43-1的計時。The dimming signal detecting module 4 further includes a first timer 43-1, a first parameter reader 44-1, and a first delay unit 45-1. The first timer 43-1 is coupled to the first output terminal Q of the first flip-flop 42-1, and the first parameter reader 44-1 is coupled to the second output terminal Q' of the first flip-flop 42-1. The first timer 43-1 is coupled to the second output terminal Q' of the first flip-flop 42-1 and the first timer 43-1. When the set terminal S of the first flip-flop 42-1 receives the positive edge notification signal Sp in the form of a pulse, the reset terminal R thereof must receive the low-level signal, so the first flip-flop 42-1 is the first The output terminal Q outputs a high level signal, and the second output terminal Q' outputs a low level signal; at this time, the high level signal outputted by the first output terminal Q enables the first timer 43-1 to start timing to generate the first Timing value T1, and the low level signal outputted by the second output terminal Q' disables the first parameter reader 44-1 and the first retarder 45-1; in addition, the first timer 43-1 is in the first timing When the value T1 reaches the period T of the PWM dimming signal DIM, the maximum brightness notification signal Tout1 is output and the timing is restarted to generate the first timing value T1. When the reset terminal R of the first flip-flop 42-1 receives the negative edge notification signal Sn in the form of a pulse, the set terminal S inevitably receives the low-level signal, so the first flip-flop 42-1 is the first The output terminal Q outputs a low level signal, and the second output terminal Q' outputs a high level signal; at this time, the low level signal output by the first output terminal Q disables the first timer 43-1 to stop timing, and The high level signal outputted by the second output terminal Q' enables the first parameter reader 44-1 and the first delay unit 45-1, and the first parameter reader 44-1 reads out from the first timer 43-1. The first timing value T1, then the first delayer 45-1 outputs a high level signal after the first parameter reader 44-1 reads the first timing value T1 to reset the timing of the first timer 43-1.
調光信號偵測模組4還包括第二計時器43-2、第二參數讀取器44-2及第二延遲器45-2。第二計時器43-2耦接第二正反器42-2的第一輸出端Q，第二參數讀取器44-2耦接第二正反器42-2的第二輸出端Q’及第二計時器43-2，第二延遲器45-2耦接第二正反器42-2的第二輸出端Q’及第二計時器43-2。第二正反器42-2的設定端S在收到脈衝形式的負緣通知信號Sn時，其重置端R必然收到低準位信號，故第二正反器42-2的第一輸出端Q輸出高準位信號，且第二輸出端Q’輸出低準位信號；此時，第一輸出端Q輸出的高準位信號啟用第二計時器43-2開始計時以產生第二計時值T2，而第二輸出端Q’輸出的低準位信號停用第二參數讀取器44-2及第二延遲器45-2；此外，第二計時器43-2在第二計時值T2達到PWM調光信號DIM的週期T時，輸出最小亮度通知信號Tout2並重新開始計時以產生第二計時值T2。第二正反器42-2的重置端R在收到脈衝形式的正緣通知信號Sp時，其設定端S必然收到低準位信號，故第二正反器42-2的第一輸出端Q輸出低準位信號，且第二輸出端Q’輸出高準位信號；此時，第一輸出端Q輸出的低準位信號停用第二計時器43-2以停止計時，而第二輸出端Q’輸出的高準位信號啟用第二參數讀取器44-2及第二延遲器45-2，第二參數讀取器44-2從第二計時器43-2讀出第二計時值T2，然後第二延遲器45-2在第二參數讀取器44-2讀出第二計時值T2後輸出高準位信號以重置第二計時器43-2的計時。The dimming signal detecting module 4 further includes a second timer 43-2, a second parameter reader 44-2, and a second delay unit 45-2. The second timer 43-2 is coupled to the first output terminal Q of the second flip-flop 42-2, and the second parameter reader 44-2 is coupled to the second output terminal Q' of the second flip-flop 42-2. The second timer 43-2 is coupled to the second output terminal Q' of the second flip-flop 42-2 and the second timer 43-2. When the set terminal S of the second flip-flop 42-2 receives the negative edge notification signal Sn in the form of a pulse, the reset terminal R thereof must receive the low level signal, so the first of the second flip-flop 42-2 The output terminal Q outputs a high level signal, and the second output terminal Q' outputs a low level signal; at this time, the high level signal output by the first output terminal Q enables the second timer 43-2 to start timing to generate a second Timing value T2, and the low level signal outputted by the second output terminal Q' disables the second parameter reader 44-2 and the second retarder 45-2; in addition, the second timer 43-2 is in the second timing When the value T2 reaches the period T of the PWM dimming signal DIM, the minimum brightness notification signal Tout2 is output and the timing is restarted to generate the second timing value T2. When the reset terminal R of the second flip-flop 42-2 receives the positive edge notification signal Sp in the form of a pulse, the set terminal S necessarily receives the low level signal, so the first of the second flip-flop 42-2 The output terminal Q outputs a low level signal, and the second output terminal Q' outputs a high level signal; at this time, the low level signal output by the first output terminal Q disables the second timer 43-2 to stop timing, and The high level signal outputted by the second output terminal Q' enables the second parameter reader 44-2 and the second delay unit 45-2, and the second parameter reader 44-2 is read from the second timer 43-2. The second timing value T2, and then the second delay unit 45-2 outputs a high level signal after the second parameter reader 44-2 reads the second timing value T2 to reset the timing of the second timer 43-2.
圖8為圖3所示調光控制模組5的一實施例之電路方塊圖，而圖9為圖8所示調光控制模組5上的信號之波形圖。請同時參見圖8及圖9，調光控制模組5包括計算器51、乘法器52、比較器53、第一開關54及第二開關55。計算器51將第一計時值T1除以第一計時值T1及第二計時值T2之和以得到比值D’，即D’=T1/(T1+T2)。乘法器52將比值D’乘以LED光源的額定電流值Ir以得到電流命令值Iset，即Iset=D’×Ir，電流命令值Iset用於控制流過LED光源的電流大小。比較器53比較比值D’及閾值Dth。第一開關54具有第一端、第二端及控制端，第一開關54的第一端及第二端分別耦接額定電流值Ir及電流命令值Iset。第二開關55具有第一端、第二端及控制端，第二開關55的第一端及第二端分別耦接電流命令值Iset及零電流命令值，在本實施例中，零電流命令值為接地電位。8 is a circuit block diagram of an embodiment of the dimming control module 5 of FIG. 3, and FIG. 9 is a waveform diagram of signals of the dimming control module 5 of FIG. Referring to FIG. 8 and FIG. 9 simultaneously, the dimming control module 5 includes a calculator 51, a multiplier 52, a comparator 53, a first switch 54, and a second switch 55. The calculator 51 divides the first timing value T1 by the sum of the first timing value T1 and the second timing value T2 to obtain a ratio D', i.e., D' = T1/(T1 + T2). The multiplier 52 multiplies the ratio D' by the rated current value Ir of the LED light source to obtain a current command value Iset, i.e., Iset = D' x Ir, and the current command value Iset is used to control the magnitude of the current flowing through the LED light source. The comparator 53 compares the ratio D' with the threshold Dth. The first switch 54 has a first end, a second end and a control end. The first end and the second end of the first switch 54 are respectively coupled with a rated current value Ir and a current command value Iset. The second switch 55 has a first end, a second end, and a control end. The first end and the second end of the second switch 55 are respectively coupled with a current command value Iset and a zero current command value. In this embodiment, the zero current command is used. The value is the ground potential.
在比值D’大於閾值Dth（如30%）時，比較器53通過第一開關54的控制端控制其第一端及第二端斷開，使電流命令值Iset為比值D’乘以額定電流值Ir（Iset=D’×Ir），以便調光控制模組5採用類比調光模式控制LED光源的亮度。在比值D’小於閾值Dth（如30%）時，比較器53通過第一開關54的控制端控制其第一端及第二端導通，使電流命令值Iset為額定電流值Ir（Iset=Ir），以便調光控制模組5採用PWM調光模式控制LED光源的亮度。在調光控制模組5收到最大亮度通知信號Tout1時，最大亮度通知信號Tout1通過第一開關54的控制端控制其第一端及第二端導通，使電流命令值Iset為額定電流值Ir（Iset=Ir），以便調光控制模組5控制LED光源發出最大亮度。在調光控制模組5收到最小亮度通知信號Tout2時，最小亮度通知信號Tout2通過第二開關55的控制端控制其第一端及第二端導通，使電流命令值Iset為零電流命令值（Iset=0），以便調光控制模組5控制LED光源不發光。When the ratio D' is greater than the threshold Dth (eg, 30%), the comparator 53 controls the first end and the second end of the first switch 54 to be disconnected, and the current command value Iset is multiplied by the rated value D' by the rated current. The value Ir (Iset = D' x Ir), so that the dimming control module 5 uses the analog dimming mode to control the brightness of the LED light source. When the ratio D' is less than the threshold Dth (for example, 30%), the comparator 53 controls the first end and the second end of the first switch 54 to be turned on, so that the current command value Iset is the rated current value Ir (Iset=Ir). ), so that the dimming control module 5 uses the PWM dimming mode to control the brightness of the LED light source. When the dimming control module 5 receives the maximum brightness notification signal Tout1, the maximum brightness notification signal Tout1 controls the first end and the second end of the first switch 54 to be turned on, so that the current command value Iset is the rated current value Ir. (Iset=Ir), so that the dimming control module 5 controls the LED light source to emit maximum brightness. When the dimming control module 5 receives the minimum brightness notification signal Tout2, the minimum brightness notification signal Tout2 is controlled by the control end of the second switch 55 to turn on the first end and the second end, so that the current command value Iset is zero current command value. (Iset=0), so that the dimming control module 5 controls the LED light source to not emit light.
雖然本發明已以較佳實施例揭露如上，然其並非用以限定本發明，任何本領域技術人員，在不脫離本發明的精神和範圍內，當可作些許更動與潤飾，因此本發明的保護範圍當視所附的申請專利範圍所界定者為準。
Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. The scope of protection is subject to the definition of the scope of the attached patent application.
4‧‧‧調光信號偵測模組 4‧‧‧ dimming signal detection module
5‧‧‧調光控制模組 5‧‧‧ dimming control module
DIM‧‧‧PWM調光信號 DIM‧‧‧PWM dimming signal
T1‧‧‧第一計時值 T1‧‧‧ first timing value
T2‧‧‧第二計時值 T2‧‧‧ second timing value
Tout1‧‧‧最大亮度通知信號 Tout1‧‧‧Maximum brightness notification signal
Tout2‧‧‧最小亮度通知信號 Tout2‧‧‧Minimum brightness notification signal
D’‧‧‧比值 D’‧‧‧ ratio
Dth‧‧‧閾值 Dth‧‧‧ threshold
Iset‧‧‧電流命令值 Iset‧‧‧ current command value
Ir‧‧‧額定電流值 Ir‧‧‧rated current value
Claims (7)
一調光信號偵測模組，接收一脈寬調變調光信號，在偵測到該脈寬調變調光信號的正緣時，開始計時以產生一第一計時值；在該第一計時值小於該脈寬調變調光信號的週期且偵測到該脈寬調變調光信號的負緣時，停止計時並讀出該第一計時值，然後重置該第一計時值的計時；在該第一計時值達到該脈寬調變調光信號的週期時，輸出一最大亮度通知信號並重新開始計時以產生該第一計時值；在偵測到該脈寬調變調光信號的負緣時，開始計時以產生一第二計時值；在該第二計時值小於該脈寬調變調光信號的週期且偵測到該脈寬調變調光信號的正緣時，停止計時並讀出該第二計時值，然後重置該第二計時值的計時；在該第二計時值達到該脈寬調變調光信號的週期時，輸出一最小亮度通知信號並重新開始計時以產生該第二計時值；及
一調光控制模組，在未收到該最大亮度通知信號或該最小亮度通知信號時，將該第一計時值除以該第一計時值及該第二計時值之和以得到一比值，在該比值大於一閾值時，採用類比調光模式控制一發光二極體光源的亮度；在該比值小於該閾值時，採用脈寬調變調光模式控制該發光二極體光源的亮度；在收到該最大亮度通知信號或該最小亮度通知信號時，停止該比值的計算，並控制該發光二極體光源發出最大亮度或不發光。A light-emitting diode controller for automatically switching a dimming mode, comprising:
a dimming signal detecting module receives a pulse width modulation dimming signal, and when detecting a positive edge of the pulse width modulation dimming signal, starts timing to generate a first timing value; at the first timing value When the period of the pulse width modulation dimming signal is less than the period of the pulse width modulation dimming signal and the negative edge of the pulse width modulation dimming signal is detected, the timing is stopped and the first timing value is read, and then the timing of the first timing value is reset; When the first timing value reaches the period of the pulse width modulation dimming signal, a maximum brightness notification signal is output and the timing is restarted to generate the first timing value; when the negative edge of the pulse width modulation dimming signal is detected, Starting timing to generate a second timing value; when the second timing value is less than a period of the pulse width modulation dimming signal and detecting a positive edge of the pulse width modulation dimming signal, stopping timing and reading the second a timing value, and then resetting the timing of the second timing value; when the second timing value reaches the period of the pulse width modulation dimming signal, outputting a minimum brightness notification signal and restarting timing to generate the second timing value; And a dimming control module, in the absence When the maximum brightness notification signal or the minimum brightness notification signal is reached, the first timing value is divided by the sum of the first timing value and the second timing value to obtain a ratio, and when the ratio is greater than a threshold, an analogy is used. The dimming mode controls the brightness of the light emitting diode light source; when the ratio is less than the threshold value, the brightness of the light emitting diode light source is controlled by using a pulse width modulation dimming mode; and the maximum brightness notification signal or the minimum brightness is received When the signal is notified, the calculation of the ratio is stopped, and the light source of the light emitting diode is controlled to emit maximum brightness or no light.
一正緣偵測器，接收該脈寬調變調光信號，在偵測到該脈寬調變調光信號的正緣時，輸出一正緣通知信號；及
一負緣偵測器，接收該脈寬調變調光信號，在偵測到該脈寬調變調光信號的負緣時，輸出一負緣通知信號。The illuminating diode detecting device of the automatic switching dimming mode according to the first aspect of the invention, wherein the dimming signal detecting module comprises:
a positive edge detector receives the pulse width modulation dimming signal, and outputs a positive edge notification signal when detecting the positive edge of the pulse width modulation dimming signal; and a negative edge detector receives the pulse The wide dimming signal outputs a negative edge notification signal when the negative edge of the pulse width modulation dimming signal is detected.
一第一正反器，耦接該正緣偵測器及該負緣偵測器，在收到該正緣通知信號時，控制該調光信號偵測模組開始計時以產生該第一計時值；在收到該負緣通知信號時，控制該調光信號偵測模組停止計時並讀出該第一計時值，然後重置該第一計時值的計時；及
一第二正反器，耦接該正緣偵測器及該負緣偵測器，在收到該負緣通知信號時，控制該調光信號偵測模組開始計時以產生該第二計時值；在收到該正緣通知信號時，控制該調光信號偵測模組停止計時並讀出該第二計時值，然後重置該第二計時值的計時。The illuminating diode controller of the automatic switching dimming mode described in claim 2, wherein the dimming signal detecting module further comprises:
a first flip-flop coupled to the positive edge detector and the negative edge detector, and when the positive edge notification signal is received, controlling the dimming signal detection module to start timing to generate the first timing a value; when receiving the negative edge notification signal, controlling the dimming signal detection module to stop timing and reading the first timing value, and then resetting the timing of the first timing value; and a second flip-flop And the positive edge detector and the negative edge detector are coupled to control the dimming signal detection module to start timing to generate the second timing value when receiving the negative edge notification signal; During the positive edge notification signal, the dimming signal detection module is controlled to stop timing and read the second timing value, and then reset the timing of the second timing value.
一第一計時器，耦接該第一正反器的第一輸出端；該第一正反器在收到該正緣通知信號時，控制該第一計時器開始計時以產生該第一計時值；該第一正反器在收到該負緣通知信號時，控制該第一計時器停止計時；該第一計時器在該第一計時值達到該脈寬調變調光信號的週期時，輸出該最大亮度通知信號並重新開始計時以產生該第一計時值；
一第一參數讀取器，耦接該第一正反器的第二輸出端及該第一計時器；該第一正反器在收到該負緣通知信號時，控制該第一參數讀取器讀出該第一計時值；
一第一延遲器，耦接該第一正反器的第二輸出端及該第一計時器；該第一正反器在收到該負緣通知信號時，通過該第一延遲器在該第一參數讀取器讀出該第一計時值後重置該第一計時器的計時；
一第二計時器，耦接該第二正反器的第一輸出端；該第二正反器在收到該負緣通知信號時，控制該第二計時器開始計時以產生該第二計時值；該第二正反器在收到該正緣通知信號時，控制該第二計時器停止計時；該第二計時器在該第二計時值達到該脈寬調變調光信號的週期時，輸出該最小亮度通知信號並重新開始計時以產生該第二計時值；
一第二參數讀取器，耦接該第二正反器的第二輸出端及該第二計時器；該第二正反器在收到該正緣通知信號時，控制該第二參數讀取器讀出該第二計時值；及
一第二延遲器，耦接該第二正反器的第二輸出端及該第二計時器；該第二正反器在收到該正緣通知信號時，通過該第二延遲器在該第二參數讀取器讀出該第二計時值後重置該第二計時器的計時。The light-emitting diode controller of the automatic switching mode of the dimming mode, as described in claim 5, wherein the dimming signal detecting module further comprises:
a first timer coupled to the first output of the first flip-flop; the first flip-flop controls the first timer to start timing to generate the first timing upon receiving the positive edge notification signal a value; the first flip-flop controls the first timer to stop timing when receiving the negative edge notification signal; the first timer is when the first timing value reaches a period of the pulse width modulation dimming signal, Outputting the maximum brightness notification signal and restarting timing to generate the first timing value;
a first parameter reader coupled to the second output end of the first flip-flop and the first timer; the first flip-flop controls the first parameter read when receiving the negative edge notification signal The reader reads the first timing value;
a first delay device coupled to the second output end of the first flip-flop and the first timer; the first flip-flop passes the first delay device when receiving the negative edge notification signal The first parameter reader resets the timing of the first timer after reading the first timing value;
a second timer coupled to the first output of the second flip-flop; the second flip-flop controls the second timer to start timing to generate the second timing when the negative-edge notification signal is received The second flip-flop controls the second timer to stop timing when the positive edge notification signal is received; the second timer when the second timer value reaches the period of the pulse width modulation dimming signal, Outputting the minimum brightness notification signal and restarting timing to generate the second timing value;
a second parameter reader coupled to the second output end of the second flip-flop and the second timer; the second flip-flop controls the second parameter read when receiving the positive edge notification signal The second flip-flop is coupled to the second output of the second flip-flop and the second timer; the second flip-flop receives the positive edge notification During the signal, the timing of the second timer is reset by the second delay after the second parameter reader reads the second timing value.
一計算器，將該第一計時值除以該第一計時值及該第二計時值之和以得到該比值；
一乘法器，將該比值乘以該發光二極體光源的一額定電流值以得到一電流命令值，該電流命令值控制流過該發光二極體光源的電流大小；
一比較器，比較該比值及該閾值；
一第一開關，具有一第一端、一第二端及一控制端，該第一開關的第一端及第二端分別耦接該額定電流值及該電流命令值；在該比值大於該閾值時，該比較器通過該第一開關的控制端控制其第一端及第二端斷開，使該電流命令值為該比值乘以該額定電流值，以便該調光控制模組採用類比調光模式控制該發光二極體光源的亮度；在該比值小於該閾值時，該比較器通過該第一開關的控制端控制其第一端及第二端導通，使該電流命令值為該額定電流值，以便該調光控制模組採用脈寬調變調光模式控制該發光二極體光源的亮度；在該調光控制模組收到該最大亮度通知信號時，該最大亮度通知信號通過該第一開關的控制端控制其第一端及第二端導通，使該電流命令值為該額定電流值，以便該調光控制模組控制該發光二極體光源發出最大亮度；及
一第二開關，具有一第一端、一第二端及一控制端，該第二開關的第一端及第二端分別耦接該電流命令值及一零電流命令值；在該調光控制模組收到該最小亮度通知信號時，該最小亮度通知信號通過該第二開關的控制端控制其第一端及第二端導通，使該電流命令值為該零電流命令值，以便該調光控制模組控制該發光二極體光源不發光。
The illuminating diode controller for automatically switching the dimming mode according to the first aspect of the invention, wherein the dimming control module comprises:
a calculator dividing the first timing value by the sum of the first timing value and the second timing value to obtain the ratio;
a multiplier, multiplying the ratio by a rated current value of the light emitting diode light source to obtain a current command value, the current command value controlling a current flowing through the light emitting diode light source;
a comparator comparing the ratio and the threshold;
a first switch having a first end, a second end, and a control end, wherein the first end and the second end of the first switch are respectively coupled to the rated current value and the current command value; wherein the ratio is greater than the first switch When the threshold is controlled, the comparator controls the first end and the second end to be disconnected by the control end of the first switch, so that the current command value is multiplied by the rated current value, so that the dimming control module adopts an analogy The dimming mode controls the brightness of the light emitting diode light source; when the ratio is less than the threshold value, the comparator controls the first end and the second end of the first switch to be turned on by the control end of the first switch, so that the current command value is The rated current value is such that the dimming control module controls the brightness of the light emitting diode light source by using a pulse width modulation dimming mode; when the dimming control module receives the maximum brightness notification signal, the maximum brightness notification signal passes The control end of the first switch controls the first end and the second end to be turned on, so that the current command value is the rated current value, so that the dimming control module controls the maximum brightness of the light emitting diode light source; Two switches, a first end, a second end, and a control end, the first end and the second end of the second switch are respectively coupled to the current command value and a zero current command value; the dimming control module receives the The minimum brightness notification signal is controlled by the control end of the second switch to control the first end and the second end to be turned on, so that the current command value is the zero current command value, so that the dimming control module controls The light emitting diode light source does not emit light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW102147313A TWI500356B (en) | 2013-12-19 | 2013-12-19 | Light-emitting diode controller capable of automatically switching dimming modes |
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|---|---|---|---|
| TW102147313A TWI500356B (en) | 2013-12-19 | 2013-12-19 | Light-emitting diode controller capable of automatically switching dimming modes |
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| TW201526701A true TW201526701A (en) | 2015-07-01 |
| TWI500356B TWI500356B (en) | 2015-09-11 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108322959A (en) * | 2017-11-03 | 2018-07-24 | 赛尔富电子有限公司 | A kind of light adjusting system of LED lamp |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR101153219B1 (en) * | 2010-03-18 | 2012-06-07 | 매그나칩 반도체 유한회사 | PWM signal generating circuit and method for DC-DC converter using diming signal and LED driving circuit for back light having the same |
| TWI434616B (en) * | 2010-06-01 | 2014-04-11 | United Power Res Technology Corp | Dimmable circuit applicable for led lighting device and control method thereof |
| TWI418245B (en) * | 2010-09-16 | 2013-12-01 | O2Micro Int Ltd | Controllers and method for controlling dimming of light source |
| WO2013014607A1 (en) * | 2011-07-25 | 2013-01-31 | Koninklijke Philips Electronics N.V. | System and method for implementing mains-signal-based dimming of a solid state lighting module |
| TWI444091B (en) * | 2011-08-12 | 2014-07-01 | Raydium Semiconductor Corp | Led driver |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108322959A (en) * | 2017-11-03 | 2018-07-24 | 赛尔富电子有限公司 | A kind of light adjusting system of LED lamp |
| CN108322959B (en) * | 2017-11-03 | 2024-03-15 | 赛尔富电子有限公司 | Dimming system of LED lamp |
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| Publication number | Publication date |
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| TWI500356B (en) | 2015-09-11 |
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