201130376 六、發明說明： 【發明所屬之技術領域】 且特別是關於一種 本發明係關於一種基本電子電路 脈衝技術控制電路。 【先前技術】 -般對全彩發光二極體燈具驅動電路的需求，除 高之外，其動態控制（個別亮度調整）亦須具有一定的 與速度，才能展現豐富的色彩。由於發光二極體的亮^ 電流的對應曲線並不全是線性，因此近乎所有全彩發乂 極體燈具的亮度均係以脈衝寬度調變方式來驅動。/ 一 若以線性脈衝寬度觀方式來驅動發光二極體，會 發光-極體在低階時亮度變化過大，但在高階時亮度變化 反而不明顯。因此’為展現出更佳的色彩效果必須增加 脈衝寬度調變的分解度(例如達到1000:1或更高），這對開 關式發光二極體驅動電路而言具有一定難度。 汗 一般開關式發光二極體驅動電路的開關頻率約在 100KHZ〜500KHZ纟右，由於一般開關式發光二極體驅動 電路的操作頻率與自外部輸人之脈衝寬度調變控制信號的 頻率不同步’為避免控制上的誤差以及頻率不同步所產生 的拍頻現象’開關式發光二極體驅動電路大都限制脈衝寬 度調麦佗號的最小頻寬為其操作頻率的1/1〇以上。因此開 關式發光二極體驅動電路的操作頻率若沒有達到1MHZ以 上，只能提供較低的脈衝寬度調變分解度，效能因此不佳。 201130376 【發明内容】 為解決習知技術之問題， 一種可變週期脈衝寬度調變控制=之ί要目的在於提供 應的特定週期;== 不同計 =-極體的每，舆其前-色階二發量〜二= 為達上述目的，本發 變控制電路。根據本發明可變週期脈衝寬度調 寬度調變控制電路包含万式，前述可變週期脈衝 脈衝寬度調變計數器、暫存器=期分除^器、時脈選擇器、 以產生時脈;週期分除器連接於震=器用其中震盪器用 進行週期分除，以產 ^盗，用以對前述時脈 擇器連接於週期分除器，用以^供=期之時脈；時脈選 相應於計數參數的一者。 八别述不同週期之時脈中 前述=參計數f連接於時脈選擇器，根據 前述不同週期的時二之計:參數相對應之 暫存亮度資二週期計數參數，·暫存器用3 調變計數器與暫存器，用數’比較器連接於脈衝寬度 前述亮度參數，跡山 較則述可變週期計數參數血 本發明出可變脈衝寬度調變控制信號: 度調變控制電路的發=包含可變週期脈衝寬 變週期脈衝寬度調變控制電路與發光二極體 [si 201130376 . 驅動電路，以使可變週期脈衝寬度調變控制電路與發光二 極體驅動電路同步操作。 為達上述目的，本發明提供一種包含可變週期脈衝寬 度調變控制電路的發光二極體驅動電路。根據本發明另一 實施方式，前述包含可變週期脈衝寬度調變控制電路的發 光二極體驅動電路包含參考電壓產生胃、感測電路、可變 週期脈衝寬度調變控制電路、驅動電路比較器以及開關。 其中參考電壓產生器，用以產生參考電壓；感測電路，用 # 喊測流經複數個發光二極體之電流，並提供隨前述電流 變化之偏壓。 見厌碉變控制電路，用以產生 3=寬度調變控制信號；驅動電路比較 器與刖述複數個發光二極體，用 開關之切換；震盪器同時提供時脈予可衝 變控制電路與發光二極體驅動電路 週观衝寬度1 度調變控制電路與發光二極體驅動電路^變週期脈衝: 本發明之再-目的在於提供 二：作。 變控制方法，藉由於每次計數 脈衝寬度1 同的參數值以改變下一計數週期的:數:間給予計時器; 為達上述g的，本發明提供一 :、a 變控制方法。根據本發明再一實施方可變週期脈衝寬度t 之計數值溢位時，將中斷計數器之式，首先，當計時i 斷中斷計數器之計數值是否溢位，二數值加1，接著，多 右中斷計數器之計數名 201130376 未溢位，則比較亮度參數與中斷計 脈衝寬度調變控制信號，用以控 ^數值，以產生 間。然後，將中斷計數器之計數二值疒务光二極體的發光時 一計數週期的計數時間，並於下一計時器，以改變下 期脈衝寬度調變控制信號，用以控;週期時產生可變週 二極體的發光時間。 】下计數週期之發光 【實施方式】 第1圖係繪示依照本發明一實 脈衝寬度調變控制電路1〇〇示竟:式的一種可變週期 度調變控制電路100 ,包含震'盈器丨。前述可變週期脈衝寬 時脈選擇器130、脈衝寬度調變:數：：期：除器12〇、 及比較器17G。其t震㈣u 暫存器150以 除器120連接於震盪器11〇 二生時脈；週期分 除，以產生複數個具不同週期之時脈别日 =夺ί進行週期分 :於週期分除器！20,用來提供前述不=擇請連 應於計數參數的一者。 週功之時脈中相 脈衝寬度調變計數器140連接於 據則述計數參數由時脈選擇器13得前數:艮 :紅前述不同週期之時脈中之特定週于期：== 行計數以輸出可變週期計數參數；^器 連接於存免度資料，並輸出亮度參數；比較器170 度調變計數器刚與暫存器150，用來比較 月\〇 =週期計數參數與前述亮度參數，以輪出可變週期 脈衝寬度調變控制信號；鎖存器160連接於暫存器15〇與 201130376 比較器170之間，用λ仅 參數予比較器Π0,其;述亮度參數並提供前述亮度 參數需經觸發而變更儲存於鎖存器⑽中之前述亮度 所產ίΐΠ:分除器120是用來將震盪器11。 分別為具# 1/zs’,2分:為8個具有不同週期之時脈， "s m 100 4/zs、8/ZS、16/zs、32//S、64 脈:隨後，時脈™ 前述罝有不鬥、月# 田脈衝寬度調變計數器140對 時即度時=：：者？行計數並產生計數參數 時脈選擇器130版❶7 、计數器14〇的末二個輸出端由 脈’其對應關係將於：尤:數參數相對應的特定週期時 _中洋述。 第2圖係纟會示依昭★從 器參數與具有不同=實補之脈職度調變計數 照第1圖和第2圖心氏之對應關係參照表。同時參 為8位元計數器，則复/寬度調變計數器140例示性地 8個不同的參數值二复出端Q5'Q6、Q7可輪出 器130取得具有 〃 > 值為〇00時，可由時脈選擇 可由時脈選擇器13〇取^的時脈，當其參數值為001時， 推’當其參數值為lu Z具有2/zs週期的時脈，以此類 128"s週期的時脈 /可由時闕擇II 13G取得具有 調變計數器140之東圖中可以看出’每當脈衝寬度 原先週期之時脈—雨出端的參數值加1時，對具有 脈中，具有更長:二::得前述8個具有不同週期4 例不的脈衝寬度調變計數器14G為8位元計數 201130376 f :其係根據末三個輸出端Q5、Q 6、Q 7的參數值來取 ^特定週期時脈’因此，每當脈衝寬度調變計數器140之 j數參數進位到輸出端Q5時’即可由時脈選擇器130取 知具有下一週期之時脈。因此，可將脈衝寬度調變計數器 〇之计數參數以每32個計數值為—組而务為8組，分別 為〇 31、32〜63、…以此類推，最後一組為224〜255。前述 、、且中之最低階組〇〜31所對應之時脈為具有週期之時 脈，而最高階組224〜255所對應之時脈為具有128//s週期 鲁 之時脈’其對應關係如第2圖所示。 從而’當脈衝寬度調變計數器14〇之計數參數為例如 31時，其所對應之末三個輸出端的參數值為〇〇〇，此時脈 衝寬度調變計數器140將由時脈選擇器13〇取得具有1"s 週期之時脈’是故計數參數為例如31時，其所對應之特定 週期時脈即為具有…週期之時脈。然後，脈^度調變 ^器14G可對具有1/zs週期之時脈進行計數，相較於脈 衡寬度調變計數器14〇之計數參數為例如255時係對具有 鲁 週期之時脈進行計數，可使輸出之可變週期脈衝寬 度調變控制信號於料二極體色階之低階(例如：色 =控制發光二極體發出較低之亮度，而於高階(例如：色階 為255)時控制發光二極體發出較高之亮度。 _暫存器15〇是用來儲存外部輸入之亮度資料，由於例 暫存器15〇為8位元暫存器，因此其可輪出8位元亮 度參數至鎖存器160，由鎖存器160保持^ =前述亮度參數予比較請，直到==數 4合事件發生時所產出之觸發信號)輸入鎖存器⑽時，鎖 201130376 存器160再根據觸發信號接收當前輸入的另一亮度參數並 保持另一亮度參數，直到再度被觸發。比較器Π0是用來 比較前述可變週期計數參數與前述亮度參數，當前述可變 週期計數參數大於前述亮度參數時，比較器17〇輸出高電 壓準位信號。 第3圖係繪示依照先前技術的一種線性脈衝寬度調變 控制電路的輸入參數與輸出脈衝寬度調變之佔空比的曲線 圖。如第3圖所示，一般脈衝寬度調變信號產生電路為線 性計數，即整個週期内每一個時脈都是一樣的寬度，因此 脈衝寬度調變信號產生電路輸出的脈衝寬度正比於輸入參 數。如此，應用在發光二極體燈具會產生問題，亦即在低 階時每一階較前一階的亮度增量較大（以256階為例，第1 階的亮度值為1/256，第2階的亮度值為2/256，第3階的 亮度值為3/256，則第2階較第1階的亮度增量為100%， 而第3階較第2階的亮度增量為50%…），而在高階時每一 階較前一階的亮度增量變小（以256階為例，第253階的亮 度值為253/256，第254階的亮度值為254/256，第255階 的亮度值為255/256,則第254階較第253階的亮度增量為 約0.4%，而第255階較第254階的亮度增量為約0.4°/。…）。 因此，以發光二極體做混色時，其低階的亮度變化較大， 而其高階的亮度變化卻不太明顯，將造成發光二極體的亮 度增量不均。 然而，本發明實施例之可變週期脈衝寬度調變控制電 路100，可使發光二極體的亮度增量趨近一致。第4圖係 繪示依照本發明實施例的一種非線性脈衝寬度調變控制電 201130376 路的輸入參數與輸出脈衝寬度調變之佔空比的曲線圖。如 第4圖所示’請同時參照本發明實施例第2圖之記述，應 用本發明實施例之可變週期脈衝寬度調變控制電路〗〇〇， 在低階時其每一階的亮度增量為3%(例如：1/32、2/64…）， 在高階時每一階的亮度增量也接近3%(例如：128/4096)， 因此可以維持較平均的亮度增量。 第5圖係繚示依照本發明實施方式的一種具有可變週 期脈衝寬度調變控制電路1〇〇之發光二極體驅動電路5〇〇 示意圖。前述發光二極體驅動電路5〇〇包含參考電壓產生 器510、感測電路520、可變週期脈衝寬度調變控制電路 100、驅動電路比較器530以及開關54〇。其中參考電壓產 生器510是用來產生參考電壓；感測電路52〇是用來感測 流經複數個發光二極體502之電流n，並提供隨前述電流 II變化之偏壓；可變週期脈衝寬度調變控制電路1〇〇是用 來產生可變週期脈衝寬度調變控制信號。 此外，驅動電路比較器53〇是用來比較前述參考電壓 與刖述偏Μ ’並根據可變週期脈衝寬度調變㈣信號產生 開關㈣，開關54G連接於驅動電路比較器53〇與前述發 光二極體5G2，用來接收開關信號以進行切換；第i圖所 之震盪器110同時提供時脈予可變週期脈衝寬度調變控 1GG與發光二極體驅動電路·，以使可變週期脈 =度調變控㈣路HK)與發光二極體驅動電路 細作。 201130376 所示，一般脈衝寬度調變控制信號係自發光二極體驅動電 路之外部輸入，由於發光二極體驅動電路的操作頻率與自 其外部輸入之脈衝寬度調變信號的頻率不同步，在控制上 會產生誤差且可能產生拍頻現象。 二 第7圖係繪示依照本發明實施例的一種發光二極體驅 動電路與脈衝寬度調變控制電路同步操作示意圖。如第7 圖所示，本發明實施例將脈衝寬度調變控制電路内建於發 光二極體驅動電路中，藉由震盪器同時提供時脈予脈衝寬 度調變控制電路與發光二極體驅動電路，以使脈衝寬度調 變控制電路與發光二極體驅動電路同步操作。 請參照第5圖，在本實施例中前述感測電路52〇包含 感測電阻522、感測電路放大器524、感測電路開關526、 内部電阻528。其中感測電阻522連接於串聯的發光二極 體502 ’感測電阻522將隨流經發光二極體502之電流II 的變化於其兩端產生感測電壓；感測電路放大器524連接 於感測電阻522兩端，根據前述感測電壓產生感測開關信 號；感測電路開關526是用來接收前述感測開關信號而進 行切換；内部電阻528連接於感測電路開關526，並透過 感測電路開關526來連接驅動電路比較器53〇’以於驅動 電路比較器530之反相輸入端532產生前述偏壓。本實施 例可更包含關閉電路550 ’連接於參考電壓產生器510與 驅動電路比較器530之間’當驅動電路比較器530的非反 相輸入端534之輸入電壓小於閥值時，關閉電路550將關 閉開關540。 如第1圖中所述之可變週期脈衝寬度調變控制電路， t S'j 12 201130376 其係利用硬體的方式來完成町變週期脈衝寬度調變的控 制。如此’可縮短發光二極體於低階時的發光時間，且^ 較於低階的發光時間可延長高階時的發光時間，以解決如 第3圖中所述之存在於先前技術中的問題。然而，除使用 硬體的方式外，亦可使用軟體的方式來完成可變週期脈衝 寬度調變的控制。有關軟體的控制方法將於第8圖的記述 中說明。 第8圖係繪示依照本發明實施例的一種可變週期脈衝 寬度調變控制流程圖。如第8圖所示’首先當計時器之計 數值溢位時，將中斷計數器之計數值加1。接著，判斷中 斷計數器之計數值是否溢位，若中斷計數器之計數值溢 位’則輸出關閉信號(隨後，可執行例如將中斷計數器之計 數值存入計時器的步驟），若中斷計數器之計數值未溢位， 則比較亮度參數與中斷計數器之計數值’以產生脈衝寬度 調變控制信號，用來控制發光二極體的發光時間。此外， 將中斷§十數器之s十數值存入計時器’以改變下一計數週期 的計數時間，並於下一計數週期時產生可變週期脈衝寬度 調變控制信號，用來控制下一計數週期之發光二極體的發 光時間。 本實施例係例示性地應用於微處理機，係利用微處理 機之韌體來執行。當計時器之計數值溢位時，微處理機中 斷目前所執行的程序，並執行中斷服務程式。前述中斷服 務程式如下所述，執行將中斷計數器之計數值加丨的程 序，隨後判斷中斷計數器之計數值是否溢位，若中斷計= 器之計數值溢位’則輸出關閉信號以控制發光二極體關 [S] 13 201130376 閉，若中斷計數器之計數值未溢位，則比較亮度參數與中 斷計數器之計數值，以產生脈衝寬度調變控制信號，用來 控制發光二極體的發光時間。然後，將中斷計數器之計數 值存入計時器。 其中，中斷計數器可為8位元計數器，其計數值之溢 位將發生於計數值為255加1(即255至〇)時。當存入計時 器中之中斷計數H計數值不同時，計時器控制下—計數週 期的計數時間相應於中斷計數器計數值而有所不同。因 生可變週期脈衝寬度調變控制信號。此外，上 供I;度ίί為—相應於所需控制發光二極體之亮度而提 點。：實施方式可知’應用本發明具有下列優 係基於時脈選擇J之可變週期脈衝寬度調變控制電路 制電路於不^ = 2 =提供可變_脈衝寬度調變控 ==發=的每，舆其 衝寬度調變控含脈 =:;:予可變週期脈衝寬度調變控制 發光二極體驅動電==期脈衝寬度調變控制電路與 頻現象的產生而避免操作上的錯誤與拍 調變控制方法，衝寬度 器不同的參數值計數週期完成後，給予計時 使發光二極趙每-色階間的増量十=:+數時間’亦可 201130376 雖然本發明已以實施方式揭露如上，然其並非用以限 定本發明，任何熟習此技藝者，在不脫離本發明之精神和 範圍内，當可作各種之更動與潤飾，因此本發明之保護範 圍當視後附之申請專利範圍所界定者為準。 【圖式簡單說明】 為讓本發明之上述和其他目的、特徵、優點與實施例 能更明顯易懂，所附圖式之說明如下： 第1圖係繪示依照本發明一實施方式的一種可變週期 脈衝寬度調變控制電路示意圖。 第2圖係繪示依照本發明實施例之脈衝寬度調變計數 器參數與具有不同週期的時脈之對應關係參照表 第3圖係繪示依照先前技術的一種線性脈衝寬度調變 控制電路的輸入參數與輸出脈衝寬度調變之佔空比的曲線 圖。 第4圖係繪示依照本發明實施例的一種非線性脈衝寬 度調變控制電路的輸入參數與輸出脈衝寬度調變之佔空比 的曲線圖。 第5圖係繪示依照本發明另一實施方式的一種具有可 變週期脈衝寬度調變控制電路之發光二極體驅動電路示意 圖。 第6圖係繪示依照先前技術的一種發光二極體驅動電 路與脈衝寬度調變控制電路非同步操作示意圖。 第7圖係繪示依照本發明實施例的一種發光二極體驅 動電路與脈衝寬度調變控制電路同步操作示意圖。 [s] 15 201130376 第8圖係繪示依照本發明實施例的一種可變週期脈衝 寬度調變控制流程圖。 【主要元件符號說明】201130376 VI. Description of the invention: [Technical field to which the invention pertains] and in particular to a invention relates to a basic electronic circuit pulse technology control circuit. [Prior Art] Generally, the demand for full-color LED light-emitting diode driving circuits, in addition to high, dynamic control (individual brightness adjustment) must also have a certain speed and speed to display rich colors. Since the corresponding curves of the bright currents of the light-emitting diodes are not all linear, the brightness of almost all full-color hair-emitting lamps is driven by pulse width modulation. / A If the LED is driven in a linear pulse width manner, the luminance of the polar body will be too large at the low order, but the brightness will not be noticeable at the high order. Therefore, in order to exhibit a better color effect, it is necessary to increase the degree of decomposition of the pulse width modulation (for example, up to 1000:1 or higher), which is difficult for the switching type LED driving circuit. The switching frequency of the general switch type LED driving circuit is about 100KHZ~500KHZ纟, because the operating frequency of the general switching type LED driving circuit is not synchronized with the frequency of the pulse width modulation control signal from the external input. 'In order to avoid the error in control and the beat phenomenon caused by the frequency out of sync', the switching type LED driving circuit mostly limits the minimum bandwidth of the pulse width to the 1/1〇 of the operating frequency. Therefore, if the operating frequency of the switching type LED driving circuit does not reach above 1 MHz, it can only provide a low pulse width modulation decomposition degree, and the performance is therefore poor. 201130376 SUMMARY OF THE INVENTION In order to solve the problems of the prior art, a variable period pulse width modulation control has the purpose of providing a specific period of time; == different counts = each of the polar bodies, before the color The second order quantity ~ two = for the above purpose, the present variable control circuit. According to the present invention, the variable period pulse width modulation width modulation control circuit includes a variator, the variable period pulse width modulation counter, a register = a period divider, a clock selector, to generate a clock; The divider is connected to the oscillator=the oscillator is used for periodic division and division to generate the thief, and is used for connecting the clock pulsator to the period divider for use in the clock of the = period; One of the counting parameters. In the clocks of different periods, the above-mentioned = parameter count f is connected to the clock selector, according to the second period of the different periods: the parameter corresponding to the temporary storage brightness, the second period counting parameter, and the temporary register with 3 The variable counter and the temporary register are connected to the pulse width by the number of comparators, and the variable period count parameter is used to describe the variable pulse width modulation control signal. The modulation of the degree modulation control circuit is The variable period pulse wide variable period pulse width modulation control circuit and the light emitting diode [si 201130376.] drive circuit are arranged to synchronize the variable period pulse width modulation control circuit with the LED driving circuit. To achieve the above object, the present invention provides a light emitting diode driving circuit including a variable period pulse width modulation control circuit. According to another embodiment of the present invention, the foregoing LED driving circuit including the variable period pulse width modulation control circuit includes a reference voltage generating stomach, a sensing circuit, a variable period pulse width modulation control circuit, and a driving circuit comparator. And the switch. The reference voltage generator is configured to generate a reference voltage; the sensing circuit uses # to sense the current flowing through the plurality of light emitting diodes and provides a bias voltage that varies with the aforementioned current. See the anamorphic control circuit for generating the 3=width modulation control signal; the driver circuit comparator and the plurality of light-emitting diodes are switched by the switch; the oscillator simultaneously provides the clock to the variable-change control circuit and The LED driving circuit has a circumferential width of 1 degree modulation control circuit and a light-emitting diode driving circuit. The periodic pulse of the present invention is further provided. The variable control method is characterized in that: by counting the same parameter value of the pulse width 1 each time, the number of the next counting period is changed: a timer is given; for the above g, the present invention provides a : a variable control method. According to still another embodiment of the present invention, when the count value of the variable period pulse width t is overflowed, the counter is interrupted. First, when the count value of the interrupt counter is overwritten, the two values are incremented by one, and then, right. When the count name of the interrupt counter 201130376 is not overflowed, the brightness parameter and the interrupt meter pulse width modulation control signal are compared to control the value to generate the interval. Then, the counting counter of the counter is counted as the counting time of the counting period of the light-emitting diode, and the next timer is used to change the next-time pulse width modulation control signal for control; Change the illuminating time of the polar body. 】Lighting of the lower counting period [Embodiment] FIG. 1 is a diagram showing a variable period modulation control circuit 100 of a real pulse width modulation control circuit 1 according to the present invention, including a shock盈 丨. The variable period pulse width clock selector 130, pulse width modulation: number:: period: divider 12 〇, and comparator 17G. The t-shock (four) u register 150 is connected to the oscillator 11 by the divider 120; the period is divided to generate a plurality of clocks with different periods: the period is divided into: the period is divided by: ! 20, used to provide the foregoing non-selection of one of the counting parameters. The cycle pulse width modulation counter 140 of the Zhou Gongzhi clock is connected to the clock selector 13 according to the counting parameter. The 周: red: the specific week in the clock of the different cycles described above: == row count The variable period counting parameter is output; the device is connected to the memory data, and the brightness parameter is output; the comparator 170 degree modulation counter is just connected with the register 150 for comparing the month\〇=cycle counting parameter with the foregoing brightness parameter. To rotate the variable period pulse width modulation control signal; the latch 160 is connected between the register 15A and the 201130376 comparator 170, using λ only parameters to the comparator Π0, which describes the brightness parameter and provides the foregoing The brightness parameter needs to be triggered to change the brightness produced by the aforementioned brightness stored in the latch (10). The divider 120 is used to turn the oscillator 11. It is #1/zs', 2 points: 8 clocks with different periods, "sm 100 4/zs, 8/ZS, 16/zs, 32//S, 64 pulses: then, clock TM The above-mentioned 罝有不斗,月# Field pulse width modulation counter 140 is the right time =::? Row Counting and Counting Parameters The clock selector 130 version 7 and the last two outputs of the counter 14〇 are pulsed. The corresponding relationship will be: especially: the specific period corresponding to the number of parameters. Fig. 2 shows the reference table of the relationship between the parameters of the instrument and the pulse of the difference between the two parameters. At the same time, as an 8-bit counter, the complex/width modulation counter 140 is illustratively 8 different parameter values. The second reset terminal Q5'Q6, Q7 can be obtained by the rounder 130 with a value of 〃 > The clock selection can be obtained by the clock selector 13 when the parameter value is 001, when the parameter value is lu Z has a clock of 2/zs period, such a 128"s period When the clock/time-selectable II 13G is obtained from the east diagram with the modulation counter 140, it can be seen that 'when the pulse width of the original period of the pulse width-the value of the rain-out terminal is increased by 1, the pair has a pulse and has a longer length. : 2:: The above 8 pulse width modulation counters 14G with different periods of 4 cases are 8 bit counts 201130376 f : which is based on the parameter values of the last three output terminals Q5, Q 6 and Q 7 The specific cycle clock 'Thus, whenever the j-number parameter of the pulse width modulation counter 140 is carried to the output terminal Q5', the clock selector 130 can be informed of the clock having the next cycle. Therefore, the counting parameter of the pulse width modulation counter can be set to 8 groups for every 32 count values, respectively, 〇31, 32~63, ... and so on, and the last group is 224~255. . The clock corresponding to the lowest order group 〇~31 of the foregoing, and the clock is a clock with a period, and the clock corresponding to the highest order group 224~255 is a clock with a period of 128//s. The relationship is shown in Figure 2. Therefore, when the counting parameter of the pulse width modulation counter 14 is, for example, 31, the parameter values of the corresponding three output terminals are 〇〇〇, and the pulse width modulation counter 140 will be obtained by the clock selector 13 When the clock of the 1"s period is 'when the count parameter is 31, the specific period clock corresponding to it is the clock with ... period. Then, the pulse modulation device 14G can count the clock having a period of 1/zs, and the counting parameter of the pulse width modulation counter 14 is, for example, 255, for the clock having the lu period. Counting, the variable period pulse width modulation control signal of the output can be adjusted to the lower order of the level of the material diode (for example: color = control light emitting diode emits lower brightness, and higher order (for example: color scale is 255) Controlling the light emitting diode to emit a higher brightness. The _ register 15 is used to store the brightness data of the external input. Since the example register 15 is an 8-bit register, it can be rotated. The 8-bit luminance parameter is input to the latch 160, and the latch 160 holds the above-mentioned luminance parameter for comparison, until the trigger signal generated when the ==4 event occurs, when the latch (10) is input, the lock The 201130376 buffer 160 then receives another brightness parameter currently input according to the trigger signal and maintains another brightness parameter until it is triggered again. The comparator Π0 is for comparing the variable period counting parameter with the aforementioned brightness parameter. When the variable period counting parameter is greater than the brightness parameter, the comparator 17 outputs a high voltage level signal. Figure 3 is a graph showing the input parameters of a linear pulse width modulation control circuit and the duty cycle of the output pulse width modulation in accordance with the prior art. As shown in Fig. 3, the general pulse width modulation signal generating circuit is linearly counted, that is, each clock is the same width throughout the period, and therefore the pulse width of the pulse width modulation signal generating circuit is proportional to the input parameter. As such, the application of the LED illuminator causes a problem, that is, the luminance increment of each step is higher than that of the previous step in the low order (in the case of 256 steps, the luminance value of the first order is 1/256, The second-order luminance value is 2/256, and the third-order luminance value is 3/256, and the second-order luminance is incremented by 100% from the first-order, and the third-order luminance is increased from the second-order luminance. 50%...), and in the high order, the brightness increment of each step is smaller than that of the previous order (in the case of 256 steps, the brightness value of the 253th order is 253/256, and the brightness value of the 254th order is 254/ 256, the 255th order brightness value is 255/256, then the 254th order has a brightness increment of about 0.4% compared to the 253th order, and the 255th order has a brightness increment of about 0.4°/.... . Therefore, when the light-emitting diode is used for color mixing, the low-order brightness changes greatly, and the high-order brightness change is not so obvious, which causes the brightness of the light-emitting diode to be unevenly increased. However, the variable period pulse width modulation control circuit 100 of the embodiment of the present invention can make the luminance increment of the light emitting diodes nearly uniform. 4 is a graph showing the input parameter of the nonlinear pulse width modulation control circuit 201130376 and the duty cycle of the output pulse width modulation according to an embodiment of the invention. As shown in FIG. 4, please refer to the description of FIG. 2 of the embodiment of the present invention, and apply the variable period pulse width modulation control circuit of the embodiment of the present invention to increase the brightness of each step in the low order. The amount is 3% (for example: 1/32, 2/64...), and the luminance increment of each order is also close to 3% (for example, 128/4096) at the high order, so that a relatively average luminance increment can be maintained. Figure 5 is a schematic diagram showing a light-emitting diode driving circuit 5'' having a variable-cycle pulse width modulation control circuit 1 according to an embodiment of the present invention. The above-described light emitting diode driving circuit 5A includes a reference voltage generator 510, a sensing circuit 520, a variable period pulse width modulation control circuit 100, a driving circuit comparator 530, and a switch 54A. Wherein the reference voltage generator 510 is used to generate a reference voltage; the sensing circuit 52 is used to sense the current n flowing through the plurality of light-emitting diodes 502, and provides a bias voltage that varies with the aforementioned current II; variable period The pulse width modulation control circuit 1 is used to generate a variable period pulse width modulation control signal. In addition, the driving circuit comparator 53 is used to compare the aforementioned reference voltage with the reference bias Μ and to generate a switch (4) according to the variable period pulse width modulation (4), and the switch 54G is connected to the driving circuit comparator 53 and the foregoing two light emitting diodes The polar body 5G2 is configured to receive the switching signal for switching; the oscillator 110 of the first embodiment simultaneously provides the clock to the variable period pulse width modulation control 1GG and the LED driving circuit to make the variable period pulse = degree modulation control (four) road HK) and the light-emitting diode drive circuit. As shown in 201130376, the general pulse width modulation control signal is an external input of the self-luminous diode driving circuit. Since the operating frequency of the LED driving circuit is not synchronized with the frequency of the pulse width modulation signal input from the outside thereof, There is an error in the control and a beat phenomenon may occur. FIG. 7 is a schematic diagram showing the synchronous operation of a light-emitting diode driving circuit and a pulse width modulation control circuit according to an embodiment of the invention. As shown in FIG. 7 , in the embodiment of the present invention, the pulse width modulation control circuit is built in the LED driving circuit, and the oscillator is simultaneously provided with the pulse width modulation control circuit and the LED driving by the oscillator. a circuit for synchronizing the pulse width modulation control circuit with the LED driving circuit. Referring to FIG. 5, in the embodiment, the sensing circuit 52A includes a sensing resistor 522, a sensing circuit amplifier 524, a sensing circuit switch 526, and an internal resistor 528. The sensing resistor 522 is connected to the LEDs 502 in series. The sensing resistor 522 generates a sensing voltage at both ends of the current through the LED II flowing through the LED 502. The sensing circuit amplifier 524 is connected to the sensing voltage. The sensing resistor 522 generates a sensing switch signal according to the sensing voltage. The sensing circuit switch 526 is configured to receive the sensing switch signal for switching. The internal resistor 528 is connected to the sensing circuit switch 526 and transmits the sensing signal. The circuit switch 526 is coupled to the driver circuit comparator 53A to generate the aforementioned bias voltage at the inverting input 532 of the driver circuit comparator 530. The embodiment may further include a shutdown circuit 550' connected between the reference voltage generator 510 and the driver circuit comparator 530. When the input voltage of the non-inverting input terminal 534 of the driver circuit comparator 530 is less than a threshold, the circuit 550 is closed. The switch 540 will be turned off. As shown in Fig. 1, the variable period pulse width modulation control circuit, t S'j 12 201130376, uses a hardware method to perform the control of the pulse width modulation of the change cycle. Thus, the light-emitting time of the light-emitting diode at the low-order can be shortened, and the light-emitting time at the high-order time can be prolonged compared with the low-order light-emitting time, so as to solve the problem existing in the prior art as described in FIG. . However, in addition to using the hardware, software can also be used to control the variable period pulse width modulation. The method of controlling the software will be described in the description of Fig. 8. Figure 8 is a flow chart showing a variable period pulse width modulation control in accordance with an embodiment of the present invention. As shown in Figure 8, the count value of the interrupt counter is incremented by one when the count value of the timer overflows. Then, it is judged whether the count value of the interrupt counter overflows, and if the count value of the interrupt counter overflows, the shutdown signal is output (the subsequent step of storing the count value of the interrupt counter into the timer, for example), if the counter is interrupted If the value is not overflowed, the brightness parameter and the count value of the interrupt counter are compared to generate a pulse width modulation control signal for controlling the light-emitting time of the light-emitting diode. In addition, the s ten value of the § decimator is stored in the timer ' to change the counting time of the next counting period, and a variable period pulse width modulation control signal is generated at the next counting period to control the next The illuminating time of the light-emitting diode of the counting period. This embodiment is illustratively applied to a microprocessor, and is implemented using a firmware of a microprocessor. When the count value of the timer overflows, the microprocessor interrupts the currently executing program and executes the interrupt service routine. The foregoing interrupt service program executes a program for adding the count value of the interrupt counter as described below, and then determines whether the count value of the interrupt counter overflows, and if the count value of the interrupt counter = overflow, the output close signal is output to control the light emission. Polar body off [S] 13 201130376 Close, if the count value of the interrupt counter is not overflowed, compare the brightness parameter with the count value of the interrupt counter to generate a pulse width modulation control signal for controlling the light-emitting time of the light-emitting diode . Then, the count value of the interrupt counter is stored in the timer. The interrupt counter can be an 8-bit counter, and the overflow of the count value will occur when the count value is 255 plus 1 (ie, 255 to 〇). When the interrupt count H count value stored in the timer is different, the timer control period - the count period of the count period differs depending on the interrupt counter count value. The control signal is modulated by a variable period pulse width. In addition, the upper I; the degree ίί--corresponding to the brightness required to control the light-emitting diode. The embodiment can be seen that the application of the present invention has the following advantages: the variable period pulse width modulation control circuit based on the clock selection J is not provided with a variable _ pulse width modulation control == fading =舆 冲 宽度 width modulation control with pulse =:;: variable period pulse width modulation control LED driving power == period pulse width modulation control circuit and frequency phenomenon to avoid operational errors and Shooting modulation control method, after the completion of the different parameter value counting period of the flush width device, the timing is given so that the amount of light between the two levels of the light-emitting diodes is equal to: + + time 'can also be 201130376. Although the invention has been disclosed by way of example As above, it is not intended to limit the invention, and any person skilled in the art can make various modifications and retouchings without departing from the spirit and scope of the invention. The scope is defined. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, advantages and embodiments of the present invention will become more <RTIgt; Schematic diagram of a variable period pulse width modulation control circuit. 2 is a diagram showing a correspondence between a pulse width modulation counter parameter and a clock having different periods according to an embodiment of the present invention. FIG. 3 is a diagram showing an input of a linear pulse width modulation control circuit according to the prior art. A plot of the parameters versus the duty cycle of the output pulse width modulation. Figure 4 is a graph showing the input parameters of a nonlinear pulse width modulation control circuit and the duty cycle of the output pulse width modulation in accordance with an embodiment of the present invention. Fig. 5 is a schematic view showing a light-emitting diode driving circuit having a variable period pulse width modulation control circuit according to another embodiment of the present invention. Figure 6 is a schematic diagram showing the asynchronous operation of a light-emitting diode driving circuit and a pulse width modulation control circuit according to the prior art. Figure 7 is a schematic diagram showing the synchronous operation of a light-emitting diode driving circuit and a pulse width modulation control circuit in accordance with an embodiment of the present invention. [s] 15 201130376 Figure 8 is a flow chart showing a variable period pulse width modulation control in accordance with an embodiment of the present invention. [Main component symbol description]
100 :可變週期脈衝寬度調 變520 :感測電路 控制電路 522 :感測電阻 110 震盪器 524 :感測電路放大器 120 週期分除器 526 :感測電路開關 130 時脈選擇器 528 :内部電阻 140 脈衝寬度調變計數器 530 :驅動電路比較器 150 暫存器 532 :反相輸入端 160 鎖存器 534 :非反相輸入端 170 比較器 540 :開關 500 發光二極體驅動電路 550 :關閉電路 502 發光二極體 810〜850 :步驟 510 參考電壓產生器100: variable period pulse width modulation 520: sensing circuit control circuit 522: sensing resistor 110 oscillator 524: sensing circuit amplifier 120 period divider 526: sensing circuit switch 130 clock selector 528: internal resistance 140 pulse width modulation counter 530: drive circuit comparator 150 register 532: inverting input terminal 160 latch 534: non-inverting input terminal 170 comparator 540: switch 500 light emitting diode drive circuit 550: shutdown circuit 502 Light Emitting Diodes 810~850: Step 510 Reference Voltage Generator