1310665 ，九、發明說明： 【發明所屬之技術領域】 本發明涉及一種照明電路。 【先前技術】 習知技術中，利用一些產生脈寬調製波（pwM波）的 晶片驅動發光體時，晶片輸出PWM波的引腳會由於某些 原因產生故障，加電後會一直處於高電平狀態，因此，晶 _ 片相當於輸出占空比為100%的PWM波驅動發光體。致使 發光體-直處於高亮度狀態，此時，若用戶未開關該照明 電路’其無法儘快獲知㈣單元故障情況，無法儘快維修， 導致電能過度消耗。 【發明内容】 有鑒如此，提供一種照明電路，以解決先前技術中用 戶無法儘快獲知照明電路故障的問題。 _其中’所述照明電路包括一連接至一電源的發光單 •所述發光單元包括多個並聯的發光支路，所述發光支 —控制單元輸出脈寬調製波控制—開關電路導通截止 來控制’所述脈寬調製波輸出至一微分電路並經該微分電 路微分以產生尖脈衝波控制所述開關電路。 / 所述照明電路還包括一電勢提升電路，用於提升尖脈 衝波的電勢。 所述照明電路還包括一取樣電路，所述取樣電路獲取 發光單元的實際亮度資訊，旅將該實際亮度資訊回饋回控 制單元，所述控制單元根據所述實際亮度資訊調節輸出脈 6 1310665 寬調製波的占空比。 每一發光支路包括一發光體以及與一發光艤串接的阻 性元件’所述阻性元件平衡各發光支路的阻值。 【實施方式】 請參閱圖1 ’是一利用本發明照明電路的電子裝置一 示意圖。所示電子裝置為一便攜式無紙書1。所述便攜式 無紙書1包括一顯示區11與一按鍵區12。戶斤述顯示區11 周圍區域13殻體内部裝設有多個發光體14»所述發光體 14發出亮光經由一導光板（未示出）照亮顯斧區11。使用 戶在黑暗環境中仍能閱讀該便攜式無紙書1所顯示資料。 請參閱圖2及圖3 ’是本發明照明電路/具體實施方 式的電路框圖與部分開關連接示意圖。包含發光體14的發 光單元7利用一控制單元3產生脈寬調製波（pWM波）來 控制發光亮度。所述發光單元7與所述控制單元3均從一 直流電源（VDD) 2處接受電能供應。所述控制單元3主 要包括有：一 VDD輸入口 3〇1，用於從直流電源2處接受 直流電能供應控制單元3内各部分利用；一 Pwm輸出口 302 ’用於輸出具占空比的pWM波控制發光單元7的 發光π度，- VSS輸入口 3〇3，與一公共低電勢（如圖所 不為-地電勢）相連；—回饋輸入口 3〇4，與一取樣電路8 相連，用於接收脉樣電路8獲取的發光單元7的實際亮 度資訊；-環境域測輪人口撕，與—環境光感測單元9 相連’接收％境光感測單元9感測的環境光強度值；一發 光開關輸人口 306 ’與—發光開關單元搬相連，用於接 7 1310665 收用戶操作發光開關單元1〇2產生的照明電路開關命令； 及一亮度選取輪入口 307，與一亮度選取單元103相連， 用於接收用戶操作亮度選取單元103選取的亮度訊號。該 亮度選取單元103、發光開關單元1〇2以及一環境光感測 開關單元101共同組成一供用戶控制照明電路的用戶控制 單元组10 ’該用戶控制單元組10設置於便攜式無紙書1 的外殼上’例如設置於便攜式無紙書1的按鍵區12，便於 用戶操作。環境光感測開關單元1〇用於用戶根據需要開關 環境光感測單元9。在本實施方式中，環境光感測開關單 元101鉗制發光開關單元1〇2產生開關開關照明電路的命 令’當用戶操作環境光感測開關單元101啟動環境光感測 單元感測環境光’以使控制單元3自動根據環境光強度值 開關與調節發光單元7的發光亮度時，照明電路已處於自 動控制的狀態’此時操作發光開關單元102無法產生開關 照明電路的命令；反之，當根據需要選取通過發光開關單 元102開關照明電路時，需先利用環境光感測開關單元1〇1 關閉環境光感測單元9。在另一實施方式中，也可利用發 光開關單元102鉗制環境光感測開關單元ιοί，此時只有 在利用發光開關單元1〇2關閉照明電路後，才能利用環境 光感測開關單元101啟動環境光感測單元9,使控制單元3 自動控制照明電路。此外，發光開關單元102亦控制亮度 選取單元103，在發光開關單元1〇2啟動照明電路後，用 戶才可通過亮度選取單元1〇3輸入亮度訊號。 從PWM輸出口 302輸出的PWM波經一微分電路4與 8 1310665 電位麵：升電路5後進入一開關電路6，控制該開關電路6 的導通與截止。該開關電路6的導通與截止又進一步控制 發光單元7經取樣電路8後與一公共低電勢，如圖所示為 一地電勢的連接，從而控制發光單元7的發光亮度。 睛參閱圖4所示，是控制單元3的具體框圖。控制單 几3包括—開關模組311，該開關模組311接收從環境光感 、J輸入口 305輸入的ί哀境光強度值與從發光開關輸入口 302輸入的開關照明電路的命令，當所接收的環境光強度 值低於某一預設水準時，或者接收到開照明電路的命令 時該開關模組311輸出訊號啟動一亮度選取模組31〇。 該亮度選取模組310接收從環境光感測輸入口 3〇5輸入的 環境光強度值或從亮度選取輸入口 3〇7輸入的亮度訊號， 並根據該環境光強度值或亮度訊號從一存儲單元3〇8内選 取相應的預设免度，根據該預設亮度驅動一 ρ產生電 路309產生具相應占空比的Pwm波。在本實施方式中， 根據需要在存儲單元308内預存有η (其中η為大與工的 自然數）個預設亮度值，另’在存儲單元3〇5内還預存有 η個環境光強度區間，該n個環境光強度區間與n個預設 亮度值 對應。當亮度選取模組310所接收的環境光強 度值落入η個環境光強度區間中某一個環境光強度區間 時’冗度選取模組310選取與該壤境光強度區間相對應的 預設亮度值，利用該預設亮度值控制PWM废生電路309 產生具相應占空比的PWM波，從而達到控制發光單元7 發出接近預設亮度值亮度的亮光。此外，利用亮度選取單 9 1310665 元103選取預設亮度時，根據用戶操作的不同’該亮度選 取單元103可產生η種亮度訊號’該等受度说说與存儲單 元308内預存的η個預設亮度值一一對應。當亮度選取模 組310從亮度選取輸入口 307接收到一亮度訊號時’其在 存儲單元308内選取與該亮度訊號相對應的預設亮度值’ 利用該預設亮度值控制發光單元7發出接近預設亮度值亮 度的亮光。 當開關模組311接收從發光開關輸入口 302輸入的開 照明電路的命令啟動亮度選取模組310後，若亮度選取模 組310未從亮度選取輸入口 307接收到任何亮度訊號，則 亮度選取模組310在存儲單元308内選取一默認預設亮 度，利用該默認預設亮度值控制發光單元7發出接近默認 預設亮度值亮度的亮光。 PWM產生電路還接受從回饋輸入口 304輸入的發光單 元7的實際亮度資訊，並將該實際亮度值與預設亮度值比 較’根據比較結果來調節產生PWM波的占空比，最終控 制發光單元7的實際亮度值接近甚至等於預設亮度值。 請參閱圖5所示’是圖2所示照明電路中部分具體電 路圖。在該具體電路圖中’發光單元7包括多個並聯於直 流電源2與開關電路6之間的發光支路Ll、L2...Ln。每一 發光支路Ln包括一發光體14 (如圖4所示為一發光二極 體）與一與該發光體14串接的阻性元件15，所述阻性元 件15平衡各發光支路Ln的阻值。所述開關電路6例舉為 一 MOS管S，所述MOS管S汲源兩極連接于發光單元7 1310665 與取樣電路8之間，閘極連接於微分電路4。所述取樣電 路8由一小阻值阻性元件R 2串接於開關電路6與公共低電 勢（地電勢）之間構成。發光單元7的實際亮度資訊經由 阻性元件R2連接開關電路8的一端回饋至控制單元3的回 饋輸入口 304。所述微分電路4由一容性元件c與一阻性 元件R1構成，所述容性元件C連接於PWM輸出口 3〇2 與開關電路6閘極之間，阻性元件R1連接於開關電路6 閘極與公共低電勢（地電勢）之間。所述電位提升電路5 包括一二極體D，所述二極體D陰極連接開關電路6閘極， 陽極連接公共低電勢（地電勢）。從PWM輸出口 3〇2輸出 的矩形PWM波經微分電路4微分後產生尖脈衝波，該尖 脈衝波經電位提升電路5提升電勢後進入開關電路6，控 制開關電路6導通截止。 : 在使用中，當控制單元3内部或PWM輸出口 3〇2處 產生故障，導致PWM輸出口 302持續輸出高電平（即輸 出占空比為100%的PWM波）時，此時發光單元7會一直 處於高亮度的狀態。若用戶未開關該照明電路，並且也未 調節發光單元7的亮度，因而無法儘快獲知控制單元故障 情況，無法儘快維修，導致電能過度消耗。利用微分電路 4’若控制單元3產生故障，其pWM輸出口 3〇2持續輸出 同電平，則由於微分電路4對該PWM輸出口 302輸出p\VM 波的微分作用，發光單元7點亮後迅速熄滅，自動通知用 戶控制單元3處於故障狀態，達到節能的目的。 【圖式簡單說明】 11 1310665 圖1是一利用本發明照明電路的電子裝置一示意圖。 圖2是本發明照明電路一具體實施方式的電路框圖。 圖3是圖2所示照明電路部分開關連接示意圖。 圖4疋圖2所不照明電路中控制單元的一具體框圖。 是圖2所示照明電路中部分具體電路圖。 【主要元件符號說明】 1 11 12 13 14 2 3 4 5 6 7 8 9 10 101 102 1031310665, IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a lighting circuit. [Prior Art] In the prior art, when a wafer is used to generate a pulse width modulated wave (pwM wave) to drive an illuminator, a pin of a PWM wave outputted by the chip may malfunction for some reason, and will always be in a high voltage after being powered. In the flat state, therefore, the crystal chip corresponds to a PWM wave driving illuminator having an output duty ratio of 100%. The illuminant is directly in a high-brightness state. At this time, if the user does not switch the lighting circuit, it cannot know (4) the unit failure condition as soon as possible, and cannot be repaired as soon as possible, resulting in excessive consumption of electric energy. SUMMARY OF THE INVENTION In view of the above, a lighting circuit is provided to solve the problem that the prior art cannot know the malfunction of the lighting circuit as soon as possible. The lighting circuit includes a light emitting unit connected to a power source. The light emitting unit includes a plurality of parallel light emitting branches, and the light emitting branch control unit outputs a pulse width modulation wave control switch circuit to turn on and off to control The pulse width modulated wave is output to a differential circuit and differentiated by the differentiating circuit to generate a sharp pulse wave to control the switching circuit. / The illumination circuit further includes a potential boosting circuit for boosting the potential of the spike. The illumination circuit further includes a sampling circuit, the sampling circuit acquires actual brightness information of the light emitting unit, and the brigade returns the actual brightness information back to the control unit, and the control unit adjusts the output pulse according to the actual brightness information. The duty cycle of the wave. Each of the illuminating branches includes an illuminant and a resistive element in series with an illuminating unit. The resistive element balances the resistance of each of the illuminating branches. [Embodiment] Please refer to Fig. 1' which is a schematic diagram of an electronic device using the illumination circuit of the present invention. The electronic device shown is a portable paperless book 1. The portable paperless book 1 includes a display area 11 and a button area 12. The display area 11 is surrounded by a plurality of illuminants 14» The illuminants 14 emit bright light to illuminate the display axe area 11 via a light guide plate (not shown). The user can still read the data displayed in the portable paperless book 1 in a dark environment. Please refer to FIG. 2 and FIG. 3' which are circuit diagrams and partial switch connections of the lighting circuit/embodiment of the present invention. The light-emitting unit 7 including the illuminator 14 uses a control unit 3 to generate a pulse width modulated wave (pWM wave) to control the light-emitting luminance. Both the light emitting unit 7 and the control unit 3 receive power supply from a direct current power source (VDD) 2. The control unit 3 mainly includes: a VDD input port 3〇1 for receiving various parts of the DC power supply control unit 3 from the DC power source 2; and a Pwm output port 302' for outputting the duty ratio The pWM wave controls the illumination π of the light-emitting unit 7, - the VSS input port 3〇3, is connected to a common low potential (as shown in the figure - the ground potential); the feedback input port 3〇4 is connected to a sampling circuit 8 For receiving the actual brightness information of the light-emitting unit 7 acquired by the pulse-like circuit 8; - the environmental domain wheel population tearing, connected with the ambient light sensing unit 9 'receiving the ambient light intensity sensed by the % ambient light sensing unit 9 a light-emitting switch input population 306' is connected to the light-emitting switch unit for connecting 7 1310665 to receive a lighting circuit switch command generated by the user to operate the light-emitting switch unit 1〇2; and a brightness selection wheel inlet 307, and a brightness selection The unit 103 is connected to receive the brightness signal selected by the user operation brightness selecting unit 103. The brightness control unit 103, the light switch unit 1〇2 and an ambient light sensing switch unit 101 together form a user control unit group 10 for the user to control the lighting circuit. The user control unit group 10 is disposed in the portable paperless book 1. The housing is provided, for example, on the button area 12 of the portable paperless book 1, which is convenient for the user to operate. The ambient light sensing switch unit 1 is used for the user to switch the ambient light sensing unit 9 as needed. In the present embodiment, the ambient light sensing switch unit 101 clamps the light-emitting switch unit 1〇2 to generate a switch switch lighting circuit command 'When the user operates the ambient light sensing switch unit 101 to activate the ambient light sensing unit to sense the ambient light' When the control unit 3 automatically switches and adjusts the light-emitting brightness of the light-emitting unit 7 according to the ambient light intensity value, the lighting circuit is already in an automatic control state. At this time, the operation of the light-emitting switch unit 102 cannot generate a command to switch the lighting circuit; When the illumination circuit is switched through the illumination switch unit 102, the ambient light sensing unit 9 is first turned off by the ambient light sensing switch unit 1〇1. In another embodiment, the ambient light sensing switch unit ιοί can also be clamped by the light-emitting switch unit 102. At this time, the ambient light sensing switch unit 101 can be used to start the environment only after the lighting circuit is turned off by the light-emitting switch unit 1〇2. The light sensing unit 9 causes the control unit 3 to automatically control the lighting circuit. In addition, the illumination switch unit 102 also controls the brightness selection unit 103. After the illumination switch unit 1〇2 activates the illumination circuit, the user can input the brightness signal through the brightness selection unit 1〇3. The PWM wave outputted from the PWM output port 302 passes through a differentiating circuit 4 and 8 1310665 potential plane: the rising circuit 5 enters a switching circuit 6, and controls the switching circuit 6 to be turned on and off. The turning on and off of the switching circuit 6 further controls the light-emitting unit 7 to pass through the sampling circuit 8 and a common low potential, as shown in the figure, to establish a ground potential, thereby controlling the light-emitting luminance of the light-emitting unit 7. Referring to FIG. 4, it is a specific block diagram of the control unit 3. The control unit 3 includes a switch module 311 that receives the ί 光 light intensity value input from the ambient light sensation, the J input port 305, and the switch lighting circuit input from the illuminating switch input port 302, when When the received ambient light intensity value is lower than a certain preset level, or the command to open the lighting circuit is received, the switch module 311 outputs a signal to activate a brightness selection module 31〇. The brightness selection module 310 receives the ambient light intensity value input from the ambient light sensing input port 3〇5 or the brightness signal input from the brightness selection input port 3〇7, and stores the brightness signal according to the ambient light intensity value or the brightness signal. A corresponding preset degree is selected in the unit 3〇8, and a ρ generating circuit 309 is driven according to the preset brightness to generate a Pwm wave having a corresponding duty ratio. In the present embodiment, η (where n is a natural number of work) preset luminance values are pre-stored in the storage unit 308 as needed, and η other ambient light intensities are pre-stored in the storage unit 3〇5. The interval, the n ambient light intensity intervals correspond to n preset brightness values. When the ambient light intensity value received by the brightness selection module 310 falls within one of the ambient light intensity intervals, the redundancy selection module 310 selects a preset brightness corresponding to the boundary light intensity interval. And using the preset brightness value to control the PWM waste circuit 309 to generate a PWM wave having a corresponding duty ratio, thereby achieving control of the illumination unit 7 to emit brightness close to a preset brightness value brightness. In addition, when the preset brightness is selected by using the brightness selection sheet 9 1310665 yuan 103, the brightness selection unit 103 can generate η kinds of brightness signals according to different user operations, and the pre-stored n pre-stored in the storage unit 308. Set the brightness values one by one. When the brightness selection module 310 receives a brightness signal from the brightness selection input port 307, it selects a preset brightness value corresponding to the brightness signal in the storage unit 308. The light source unit 7 is controlled to be used to approach the brightness unit 7 by using the preset brightness value. The brightness of the brightness of the preset brightness value. After the switch module 311 receives the command to open the illumination circuit input from the illumination switch input port 302 to activate the brightness selection module 310, if the brightness selection module 310 does not receive any brightness signal from the brightness selection input port 307, the brightness selection mode is selected. The group 310 selects a default preset brightness in the storage unit 308, and uses the default preset brightness value to control the illumination unit 7 to emit light that is close to the default preset brightness value brightness. The PWM generating circuit further receives the actual brightness information of the light-emitting unit 7 input from the feedback input port 304, and compares the actual brightness value with the preset brightness value. 'According to the comparison result, the duty ratio of the generated PWM wave is adjusted, and finally the light-emitting unit is controlled. The actual brightness value of 7 is close to or even equal to the preset brightness value. Please refer to FIG. 5, which is a partial circuit diagram of the lighting circuit shown in FIG. 2. In this particular circuit diagram, the illumination unit 7 comprises a plurality of illumination branches L1, L2 ... Ln connected in parallel between the DC power supply 2 and the switching circuit 6. Each of the light-emitting branches Ln includes an illuminant 14 (shown as a light-emitting diode as shown in FIG. 4) and a resistive element 15 connected in series with the illuminant 14. The resistive element 15 balances each of the illuminating branches The resistance of Ln. The switching circuit 6 is exemplified by a MOS transistor S. The MOS transistor S is connected between the light emitting unit 7 1310665 and the sampling circuit 8 and the gate is connected to the differentiating circuit 4. The sampling circuit 8 is formed by a small resistance resistive element R 2 connected in series between the switching circuit 6 and a common low potential (ground potential). The actual luminance information of the light-emitting unit 7 is fed back to the feedback input port 304 of the control unit 3 via one end of the switching circuit 8 via the resistive element R2. The differential circuit 4 is composed of a capacitive element c and a resistive element R1 connected between the PWM output port 3〇2 and the gate of the switch circuit 6, and the resistive element R1 is connected to the switch circuit. 6 Between the gate and the common low potential (ground potential). The potential boosting circuit 5 includes a diode D, the cathode of which is connected to the gate of the switching circuit 6, and the anode is connected to a common low potential (ground potential). The rectangular PWM wave outputted from the PWM output port 3〇2 is differentiated by the differentiating circuit 4 to generate a sharp pulse wave. The sharp pulse wave is boosted by the potential boosting circuit 5 and then enters the switching circuit 6, and the switching circuit 6 is turned on and off. : In use, when a fault occurs in the internal control unit 3 or the PWM output port 3〇2, causing the PWM output port 302 to continuously output a high level (ie, a PWM wave with an output duty ratio of 100%), the light-emitting unit at this time 7 will always be in a high brightness state. If the user does not switch the lighting circuit and the brightness of the light-emitting unit 7 is not adjusted, the failure of the control unit cannot be known as soon as possible, and the repair cannot be performed as soon as possible, resulting in excessive consumption of electric energy. If the control unit 3 generates a fault by using the differential circuit 4', and the pWM output port 3〇2 continues to output the same level, the differential unit 4 outputs a differential effect of the p\VM wave to the PWM output port 302, and the light-emitting unit 7 lights up. After being quickly extinguished, the user control unit 3 is automatically notified that the control unit 3 is in a fault state, achieving the purpose of energy saving. BRIEF DESCRIPTION OF THE DRAWINGS 11 1310665 FIG. 1 is a schematic diagram of an electronic device using the illumination circuit of the present invention. 2 is a circuit block diagram of a specific embodiment of a lighting circuit of the present invention. Figure 3 is a schematic view showing the switch connection of the lighting circuit shown in Figure 2. Figure 4 is a block diagram of a control unit in the non-illuminating circuit of Figure 2. It is a partial circuit diagram of the lighting circuit shown in Figure 2. [Main component symbol description] 1 11 12 13 14 2 3 4 5 6 7 8 9 10 101 102 103
便攜式無紙書 顯不區 按鍵區 周圍區域 發光體 直流電源 控制單元 微分電路 電位提昇電路 開關電路 發光單元 取樣電路 環境光感測單元 用戶控制單元組 環境光感測開關單元 發光開關單元 亮度選取單元 VDD輸入口 301 12 1310665Portable paperless display area around the button area illuminant DC power control unit differential circuit potential boost circuit switch circuit illuminating unit sampling circuit ambient light sensing unit user control unit group ambient light sensing switch unit lighting switch unit brightness selection unit VDD Input port 301 12 1310665
PWM輸出口 302 VSS輸入口 303 回授輸入口 304 環境光感測輸入口 305 發光開關輸入口 306 亮度選取輸入口 307 記憶模組 308 PWM產生電路 309 亮度選取模組 310 開關模組 311 發光支路 LI、L2、Ln 阻性元件 15、Rl、R2 容性元件 C 二極體 DPWM output port 302 VSS input port 303 feedback input port 304 ambient light sensing input port 305 light switch input port 306 brightness selection input port 307 memory module 308 PWM generation circuit 309 brightness selection module 310 switch module 311 light branch LI, L2, Ln resistive element 15, Rl, R2 capacitive element C diode D
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