1296409 玖、發明說明： 發明領域 本發明是有關於一種具有複數個光源的光碟機，且特 別是有關於一種使用單一設備偵測由複數個光源產生之光 束功率的裝置與方法。 發明背景 在光碟機中通常具有複數個光源，而能夠以不同波長 紀錄或讀取光學媒體之資料。如果要以一台光碟機於兩種 不同光碟片上(例如光碟(Compact Disc，CD)及數位多功能 光碟(Digital Versatile Disc，DVD))紀錄或讀取資料，則此 光碟機則必須具備有CD用光源及DVD用光源。這是因 爲從CD及DVD上記錄或讀取資料必須使用不同之標準 波長。 然而，當光碟機內之溫度上升後，則光碟機之輸出光 源將減弱。爲了解決此問題，光碟機通常包括有可以監視 光束功率、並自動控制光源功率的自動功率控制器（AutoBACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an optical disk drive having a plurality of light sources, and more particularly to an apparatus and method for detecting the power of a beam generated by a plurality of light sources using a single device. BACKGROUND OF THE INVENTION Optical disc drives typically have a plurality of light sources that are capable of recording or reading data from optical media at different wavelengths. If you want to record or read data on two different optical discs (such as Compact Disc (CD) and Digital Versatile Disc (DVD)), you must have a CD. Use a light source and a light source for DVD. This is because different standard wavelengths must be used to record or read data from CDs and DVDs. However, when the temperature inside the optical disk unit rises, the output light source of the optical disk drive will be weakened. In order to solve this problem, the optical disk drive usually includes an automatic power controller that can monitor the beam power and automatically control the power of the light source (Auto
Power Control，APC) 〇 通常，光碟機是使用單一裝置監視光束功率。換言之， 藉由一個監視光二極體Monitor photo Diode，MPD)偵測 由複數個光源產生的光束功率°如此’對於複數個光源而 言，MPD之增益放大(或敏感度)需設置爲均一的。但是， 如果由複數個光源所產生的最大光束功率不同，則MPD 將很難具有足夠的雲力態範圍以^便於偵測』每一個1光源所產生 之光束功率。因此，必須提供一個APC以便於供給連續 9681pifl.doc/008 6 1296409 一致的光源功率。 第1圖所繪示爲具有CD及DVD光源的光碟機所需 的光束功率與MPD所偵測到的光束功率之關係圖。請參 照第1圖，CD光源的最大光束功率看似較DVD光源兩倍 大’同時MPD的增益放大對兩光源而言也是相同的。在 此實例中’ CD光源具有足夠動態範圍偵測光束功率，但 是DVD光源只有所需動態範圍的一半。爲了解決此問題， 必須使MPD依據光碟機之不同光源而具有相對不同的放 大增益。然而，此種光碟機必須具有更多空間以容納多出 的MPD，同時於光碟機中多裝MPD也會增加製造成本。 發明槪述 有鑑於此，爲了解決上述問題，本發明之一目的係提 供一種以單一設備偵測具有複數個光源之光碟機的光束功 率，並可以控制複數個光源之光束功率增益，以確保偵測 複數個光源之最大光束功率的動態範圍之裝置與方法。 本發明之另一目的係提出一種以單一設備偵測具有複 數個光源之光碟機之光束功率，並可以依據不同光源決定 所產生之光束功率的放大增益之裝置與方法。 爲達成上述目的，本發明較佳實施例係提出一種在具 有複數個光源的光碟機中偵測光束功率之裝置。此裝置包 括：接收從複數個光源之其中之一所產生的光束功率之光 源接收單元、以及選擇一增益，根據選擇之增益而放大以 光源接收單元所接收光束功率，並輸出已放大爲檢測光束 功率的光束功率之放大單元。 9681pifl.doc/008 7 1296409 增益較佳是由依據使用光學媒之形式所產生之不同增 益選擇信號來調整。 由可變電阻與一回授增益電阻所決定的第一增益，或 由可變電阻與另一回授增益電阻所決定的第二增益之其中 之一較佳是選自放大單元內之增益。 由第一可變電阻、第一固定電阻和一回授增益電阻所 決定的第一增益，或由第二可變電阻'第二固定電阻和相 同的回授增益電阻所決定的第二增益之其中之一較佳是選 自放大單元內之增益。 爲了達成上述目的，本發明另一較佳實施例提出一種 於具有複數個光源的光碟機中偵測光束功率之裝置。此裝 置包括：接收由複數個光源之其中之一發射的光束功率之 光源接收單元、依據第一設定增益而放大光源接收單元所 接收光束，並輸出經放大之光束功率的第一放大單元、依 據第二設定增益而放大光源接收單元所接收光束，並輸出 經放大之光束功率的第二放大單元、以及選擇和輸出第一 放大單元輸出的光束功率或第二放大單元輸出的光束功率 之其中之一作爲檢測光束功率的切換開關。 切換開關較佳是由依據使用光學媒體之型式所產生之 不同的選擇信號來控制。 第一設定增益較佳是由第一可變電阻與第一回授增益 電阻所決定，且第二設定增益較佳是由第二可變電阻與第 二回授增益電阻所決定。 爲達成上述目的，本發明另一較佳實施例係提出一種 9681pifl.doc/008 8 1296409 於具有複數個光源的光碟機中偵測光束功率的方法。此方 法包括：接收由複數個光源之一所發射的光、以及依據使 用光學媒體之型式所決定之增益而放大所接收的光束功 率，並輸出作爲檢測光束功率之經放大的光束功率。 爲了達成上述目的，本發明另一較佳實施例係提供一 種於具有複數個光源的光碟機中檢測光束功率的方法。此 方法包括：接收由複數個光源之其中之一所產生的光束、 依據第一設定增益而放大所接收光束，並輸出經放大之光 束功率、依據第二設定增益而放大所接收光束，並輸出已 放大之光束功率、以及依據使用光學媒體之型式選擇由第 一設定增益放大之光束功率或由第二設定增益放大之光束 功率，並輸出選擇作爲檢測光束功率之光束功率。 圖式之簡單說明 第1圖所繪示爲有CD光源及DVD光源的光碟機之 所需光源功率與MPD輸出之光束功率關係圖； 第2圖所繪示爲依據本發明第一實施例之偵測光束功 率裝置的電路圖； 第3圖所繪示爲依據本發明第二實施例之偵測光束功 率裝置的電路圖； 第4圖所繪示爲依據本發明第三實施例之偵測光束功 率裝置的電路圖； 第5圖所繪示爲依據本發明在光碟機中偵測光束功率 的方法流程圖；以及Power Control, APC) 〇 Normally, the optical drive monitors the beam power using a single device. In other words, the power of the beam generated by the plurality of light sources is detected by a monitor photodiode (MPD) such that for a plurality of light sources, the gain amplification (or sensitivity) of the MPD needs to be set to be uniform. However, if the maximum beam power produced by a plurality of light sources is different, it will be difficult for the MPD to have a sufficient range of cloud power states to facilitate detection of the beam power produced by each of the 1 light sources. Therefore, an APC must be provided in order to supply a consistent source power of 9681pifl.doc/008 6 1296409. Figure 1 is a graph showing the relationship between the beam power required for a CD player with CD and DVD sources and the beam power detected by the MPD. Referring to Figure 1, the maximum beam power of the CD source appears to be twice as large as that of the DVD source. Meanwhile, the gain amplification of the MPD is the same for both sources. In this example, the CD source has sufficient dynamic range to detect beam power, but the DVD source has only half the required dynamic range. In order to solve this problem, the MPD must have a relatively different amplification gain depending on the different light sources of the optical disk drive. However, such a disc player must have more space to accommodate an extra MPD, and the addition of an MPD to the disc player also increases manufacturing costs. SUMMARY OF THE INVENTION In view of the above, in order to solve the above problems, an object of the present invention is to provide a single device for detecting the beam power of an optical disk drive having a plurality of light sources, and to control beam power gain of a plurality of light sources to ensure detection. Apparatus and method for measuring the dynamic range of the maximum beam power of a plurality of light sources. Another object of the present invention is to provide a device and method for detecting the beam power of a disk drive having a plurality of light sources by a single device, and determining the amplification gain of the generated beam power according to different light sources. In order to achieve the above object, a preferred embodiment of the present invention provides an apparatus for detecting beam power in an optical disk drive having a plurality of light sources. The apparatus includes: a light source receiving unit that receives a beam power generated from one of the plurality of light sources, and a gain selected to amplify the received beam power of the light source receiving unit according to the selected gain, and the output is amplified to the detection beam Amplifying unit of beam power of power. 9681pifl.doc/008 7 1296409 Gain is preferably adjusted by different gain selection signals generated in the form of optical media. One of the first gain determined by the variable resistor and a feedback gain resistor, or the second gain determined by the variable resistor and the other feedback gain resistor is preferably a gain selected from the amplification unit. a first gain determined by the first variable resistor, the first fixed resistor, and a feedback gain resistor, or a second gain determined by the second variable resistor 'the second fixed resistor and the same feedback gain resistor One of them is preferably a gain selected from the amplification unit. In order to achieve the above object, another preferred embodiment of the present invention provides an apparatus for detecting beam power in an optical disk drive having a plurality of light sources. The device comprises: a light source receiving unit that receives the beam power emitted by one of the plurality of light sources, a first amplifying unit that amplifies the received light beam according to the first set gain, and outputs the amplified beam power, a second amplification unit that amplifies the received light beam by the light source receiving unit, and outputs the amplified beam power, and selects and outputs the beam power output by the first amplification unit or the beam power output by the second amplification unit. A switch that detects the power of the beam. The switch is preferably controlled by a different selection signal generated in accordance with the type of optical media used. Preferably, the first set gain is determined by the first variable resistor and the first feedback gain resistor, and the second set gain is preferably determined by the second variable resistor and the second feedback gain resistor. In order to achieve the above object, another preferred embodiment of the present invention provides a method for detecting beam power in an optical disk drive having a plurality of light sources, 9681pifl.doc/008 8 1296409. The method includes receiving light emitted by one of the plurality of light sources, and amplifying the received beam power according to a gain determined using a pattern of the optical medium, and outputting the amplified beam power as the detected beam power. In order to achieve the above object, another preferred embodiment of the present invention provides a method of detecting beam power in an optical disk drive having a plurality of light sources. The method comprises: receiving a light beam generated by one of a plurality of light sources, amplifying the received light beam according to a first set gain, and outputting the amplified beam power, amplifying the received light beam according to a second set gain, and outputting The amplified beam power, and the beam power amplified by the first set gain or the beam power amplified by the second set gain are selected according to the type using the optical medium, and the beam power selected as the detected beam power is output. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the relationship between the required light source power of an optical disk drive having a CD light source and a DVD light source and the beam power of the MPD output; FIG. 2 is a view showing the first embodiment of the present invention. A circuit diagram of a device for detecting a beam power; FIG. 3 is a circuit diagram of a device for detecting a beam power according to a second embodiment of the present invention; and FIG. 4 is a view showing a power of a detection beam according to a third embodiment of the present invention. Circuit diagram of the device; Figure 5 is a flow chart showing a method for detecting beam power in an optical disk drive according to the present invention;
第6圖所繪示爲依據本發明在具有CD光源及DVD 9681pifl.doc/008 9 1296409 光源的光碟機之光束功率與MPD輸出之光束功率關係圖。 圖式之標記說明： 201、 301、401 :電流-電壓放大器 202、 302 :放大單元 402 :第一放大單元 403 :第二放大單元 AMP1、AMP2、AMP3、AMP4、AMP5 :放大器 Gl、G2、G3、G4、G5 :回授增益電阻 PD1、PD2、PD3 :光二極體 Rl、R2 :電阻 R3、R6、R7、R8 :偏壓電阻 R4、R5 :固定電阻 SW1、SW2、SW3 :切換開關 VR1、VR2、VR3、VR4、VR5 :可變電阻 Vref :參考電壓 較佳實施例之詳細說明 第2圖所繪示爲依據本發明第一實施例之偵測光束功 率裝置的電路圖。 請參照第2圖所示，依據所使用光學媒體之型式而產 生之增益選擇信號所對應之增益而放大光束功率到一預設 的値，並將經放大光束功率作爲檢測光束功率而輸出。 請參照第2圖，在光碟機中偵測光束功率的裝置包括 有光二極體PD1、電流-電壓放大器(以下I/V放大器表示 之)201與放大單元202。光二極體PD1之功能係作爲用以 9681pifl.doc/008 10 1296409 接收光碟機中複數個光源之其中之一所產生的光（圖中未 顯示）的光源接收單元。如果光碟機可使用CD的碟片或是 DVD的碟片，那麼複數個光源即包括CD的光源及DVD 的光源，而且由CD光源或DVD光源所產生的光束功率 可由光二極體PD1所接收。 I/V放大器201包括從輸入端輸入參考電壓Vref，且 電阻Rl、R2連接到回授電路上的放大器AMP1。I/V放大 器201將依據接收光源的光二極體PD1所產生的電流轉換 爲電壓並輸出之。 放大單元202中之放大器AMP2包括連接在可輸入參 考電壓Vref之輸入端的偏壓電阻R3、以及對應所供給之 增益選擇信號而選擇其中之一構成回授迴路的回授增益電 阻G卜G2。而且，在I/V放大器201之輸出電壓的輸出 端連接有可變電阻VR1，並連接到放大器AMP2。由可變 電阻VR1與選定的回授增益電阻Gl、G2之其中之一決定 I/V放大器201輸出電壓的增益。 依據使用光學媒體之型式而產生增益選擇信號使回授 增益電阻Gl、G2連接到放大器AMP2。舉例來說，當光 碟機中使用的光學媒體之光束功率需要以回授增益電阻 G1和可變電阻VR1放大時，發出一增益選擇信號使回授 增益電阻G1連接放大器AMP2形成回授電路。另一方面， 當光碟機中使用的光學媒體之光束功率需要以由回授增益 電阻G2和可變電阻VR1增益放大時，發出一增益選擇信 號使回授增益電阻G2連接放大器AMP2形成回授電路。 9681pifl.doc/008 11 1296409 如上述，爲了藉由增益選擇信號決定放大器AMP2所 構成之回授電路，因此在回授增益電阻Gl、G2與放大器 AMP2輸出端設置一切換開關SW1。在光碟機中之伺服控 制器（圖中未顯示）同時也可以產生增益選擇信號。調整可 變電阻VR1可使得複數個光源減少散射並且具有線性特 性。 如此，當增益選擇信號選擇回授增益電阻G1時，放 大單元202以一增益(亦即回授增益電阻G1除以可變電阻 VR1，就是G1/VR1)放大所接收之光束功率的電壓到一 個預設電位。當增益選擇信號選擇回授增益電阻G2時， 放大單元202以一增益(亦即回授增益電阻Gi除以可變電 阻VR1，就是G2/VR1)放大接收之光束功率的電壓到一 個預設値。經放大之電壓可作爲檢測光束功率輸出，並且 可用於自動功率控制(APC)。而且，檢測光束功率也可供 給至伺服控制器。 第3圖所繪示爲依據本發明第二實施例之偵測光束功 率裝置的電路圖。如第3圖所示之裝置可依據光碟機使用 光學媒體之型式而產生不同增益選擇信號所對應之增益而 放大光束功率，並將經放大光束功率作爲爲檢測光束功率 輸出。請參照第3圖，此裝置包括有光二極體PD2、I/V 放大器301與一放大單元302。 由於光二極體PD2、I/V放大器301的結構與操作方 式均與第2圖的光二極體PD1、一 I/V放大器201相同， 因此省略其說明。 9681pifl.doc/008 12 1296409 放大單元302包括放大器AMP3。放大器AMP3包括 連接在可輸入參考電壓Vref之輸入端的偏壓電阻R6、以 及連接至回授電路上之回授增益電阻G3。在I/V放大器301 之輸出電壓的輸出端連接有藉由增益選擇信號而選擇的可 變電阻VR2、VR3與固定電阻R4、R5，並連接到放大器 AMP3。 依據光碟機中使用光學媒體之型式、可變電阻VR2、 VR3以及固定電阻R4、R5而產生增益選擇信號。亦即’ 當光學媒體之光束功率需要以回授增益電阻G3、可變電 阻VR2與固定電阻R4增益放大時，發出一增益選擇信號 使得可變電阻VR2、固定電阻R4在I/V放大器301與放 大器AMP3之間構成通路。另一方面，當光學媒體之光束 功率需要以回授增益電阻G3、可變電阻VR3與固定電阻 R5增益放大時，發出一增益選擇信號使得可變電阻VR3 與固定電阻R5在I/V放大器301與放大器AMP3之間構 成通路。 固定電阻R4、R5與放大器AMP3之輸出端設置有一 切換開關SW2，使增益選摄信號可以決定放大器AMP3與 I/V放大器301中間連接可變電阻VR2及固定電阻R4或 是可變電阻VR3及固定電阻R5。此時，調整可變電阻VR2 及VR3値可使得被選擇的複數個光源之其中之一減少散 射並且具有線性特性，同時依據不同光源的最大光束功率 比例決定固定電阻R4及R5之値。 如此，當增益選擇信號選擇可變電阻VR2及固定電 9681pifl.doc/008 13 1296409 阻R4時，放大單元302之增益爲一個數値，亦即回授增 益電阻G2除以可變電阻VR2與固定電阻R4之和，就是 G3/(VR2+R4)。當增益選擇信號選擇可變電阻VR3及固 定電阻R5時，放大單元302之增益爲一個數値，亦即回 授增益電阻G3除以可變電阻VR3與固定電阻R5和’就 是G3/(VR3+R5)。然後，放大單元302可依據增益放大 所接收之光束功率的電壓値至一預設電位。經放大之電壓 可作爲檢測光束功率輸出。如同第2圖的說明，檢測光束 功率也可使用在APC。 第4圖所繪示爲依據本發明第三實施例偵測光束功率 裝置的電路圖。如第4圖所示之裝置可檢測根據光碟機使 用之光學媒體之型式，依據光源特性所需的預設値使用複 數個放大單元之其中之一，而放大經接收之光源到一預定 値之光束功率。 第4圖中的裝置包括：光二極體PD3、I/V放大器401、 第一放大單元402、第二放大單元403與轉換器SW3。 由於光二極體PD3、I/V放大器401的結構與操作方 式均與第2圖的光二極體PD1、一 I/V放大器201相同， 因此省略其說明。 第一放大單元402包括一放大器AMP4。放大器AMP4 包括連接在可輸入參考電壓Vref之輸入端的偏壓電阻 R7、以及連接至回授電路之回授增益電阻G4。在I/V放 大器401之輸出電壓的輸出端連接有藉由增益選擇信號而 選擇的可變電阻VR4，並連接到放大器AMP4輸入端。調 9681pifl.doc/008 14 1296409 整可變電阻VR4可使得相對的光源減少散射並具有線性 特性。 第一放大單元402根據一增益（亦即回授增益電阻G4 除以可變電阻VR4,就是（G4/VR4)放大從I/V放大器401 輸出之電壓至一個預設値，並且輸出其結果。從第一放大 單元402輸出之電壓送入切換開關SW3輸入端之其中之 -^ 〇 同時，第二放大單元403包括放大器AMP5。放大器 AMP5包括連接在可輸入參考電壓Vref之輸入端之偏壓電 阻R8、以及連接至回授電路之回授增益電阻G5。在I/V 放大器401之輸出電壓的輸出端連接有藉由增益選擇信號 而選擇的可變電阻VR5，並連接到放大器AMP5輸入端。 調整可變電阻VR5可使得相對的光源減少散射並具有線 性特性。 /如此，第二放大單元403根據一增益（亦即回授增益 電阻G5除以可變電阻VR5，就是（G5/VR4)放大從I/V 放大器401輸出之電壓至一個預設値，並且輸出其結果。 從第二放大單元403輸出之電壓送入切換開關SW3輸入 端之其中之一。 切換開關SW3依據選擇信號選擇從第一放大單元402 輸出之信號與從第二放大單元403輸出之信號之其中之 一，並且輸出選擇出的信號。此時，此輸出信號就是檢測 光束功率。選擇信號與增益選擇信號同樣的都是依據光碟 機使用光學媒體之型式，而產生不同。 9681pifl.doc/008 15 1296409 第5圖爲繪示本發明在光碟機中檢測光束功率方法的 流程圖。在第5圖的方法中依據光碟機中使用光學媒體之 型式而決定偵測光束功率的增益。 使用例如是光二極體的光源接收裝置偵測由複數個光 源之其中之一所產生的光之光束功率（步驟501)。接著參 考第2圖的說明，以I/V放大器201將檢測光束功率轉爲 電壓（步驟502)。然後，依據光碟機中使用光學媒體的型 式決定增益（步驟503)。接著，根據增益放大電壓到預設 電位(步驟504)。之後，輸出經放大之電壓(步驟505)。 在本發明之於光碟機中檢測光束功率方法中，當光源 接收裝置偵測到光束功率後，可以參照第4圖之說明依光 碟機中之複數個光源所對應之預定增益，將檢測光束功率 放大並輸出之。舉例來說，光碟機中包括有兩種光源，檢 測光束功率可以經由對應一光源之適當增益放大後並輸出 之’或者檢測光束功率可以經由通應另~^光源之另一^適當 增益放大後並輸出之。此外’可選擇上述之複數個經放大 並輸出之光束功率之其中之一作爲檢測光束功率而輸出 之。 第6圖所示爲本發明較佳實施例之具有CD光源與 DVD光源的光碟機中的偵測光束功率的裝置，其個別光源 所需光束功率(第6圖的X軸)與臉測光束功率(第6圖的Y 軸）關係圖。如第6圖所示藉由控制不同光源的光束功率 放大增益可以確保最大光束功率具有一定足夠的動態範 圍。 9681pifl.doc/008 16 1296409 如上所述，在具有複數個光源的光碟機中利用一設備 偵測光源所發出的光束功率時，依據各個光源之特性將檢 測光束功率放大一預定增益。於是’依每一個光源特性提 供具有足夠足夠的動態範圍之檢測光束功率，而可以有效 的實現APC。 綜上所述，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’任何熟習此技藝者，在不脫離本 發明之精神和範圍內’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爲準。 9681pifl.doc/008 17Figure 6 is a graph showing the relationship between beam power and MPD output of an optical disk drive having a CD light source and a DVD 9681pifl.doc/008 9 1296409 light source in accordance with the present invention. DESCRIPTION OF SYMBOLS: 201, 301, 401: Current-voltage amplifiers 202, 302: Amplifying unit 402: First amplifying unit 403: Second amplifying units AMP1, AMP2, AMP3, AMP4, AMP5: Amplifiers G1, G2, G3 , G4, G5 : feedback gain resistors PD1, PD2, PD3: photodiode Rl, R2: resistors R3, R6, R7, R8: bias resistors R4, R5: fixed resistors SW1, SW2, SW3: switch VR1 VR2, VR3, VR4, VR5: Variable Resistor Vref: Reference Voltage DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 2 is a circuit diagram of a detecting beam power device according to a first embodiment of the present invention. Referring to Fig. 2, the beam power is amplified to a predetermined chirp according to the gain corresponding to the gain selection signal generated by the type of optical medium used, and the amplified beam power is output as the detected beam power. Referring to Fig. 2, the apparatus for detecting the beam power in the optical disk drive includes a photodiode PD1, a current-voltage amplifier (hereinafter referred to as an I/V amplifier) 201, and an amplifying unit 202. The function of the photodiode PD1 serves as a light source receiving unit for receiving light (not shown) generated by one of a plurality of light sources in the optical disk drive at 9681 pifl.doc/008 10 1296409. If the disc player can use a CD disc or a DVD disc, then a plurality of light sources include a CD light source and a DVD light source, and the beam power generated by the CD light source or the DVD light source can be received by the photodiode PD1. The I/V amplifier 201 includes an amplifier AMP1 that inputs a reference voltage Vref from an input terminal and that has resistors R1, R2 connected to the feedback circuit. The I/V amplifier 201 converts the current generated by the photodiode PD1 of the receiving light source into a voltage and outputs it. The amplifier AMP2 in the amplifying unit 202 includes a bias resistor R3 connected to an input terminal to which the reference voltage Vref can be input, and a feedback gain resistor Gb G2 which is selected to constitute a feedback loop corresponding to the supplied gain selection signal. Further, a variable resistor VR1 is connected to the output terminal of the output voltage of the I/V amplifier 201, and is connected to the amplifier AMP2. The gain of the output voltage of the I/V amplifier 201 is determined by one of the variable resistor VR1 and the selected feedback gain resistors G1, G2. The gain selection signal is generated in accordance with the pattern of the optical medium to connect the feedback gain resistors G1, G2 to the amplifier AMP2. For example, when the beam power of the optical medium used in the optical disk needs to be amplified by the feedback gain resistor G1 and the variable resistor VR1, a gain selection signal is issued to cause the feedback gain resistor G1 to be connected to the amplifier AMP2 to form a feedback circuit. On the other hand, when the beam power of the optical medium used in the optical disk drive needs to be amplified by the gain of the feedback gain resistor G2 and the variable resistor VR1, a gain selection signal is sent to connect the feedback gain resistor G2 to the amplifier AMP2 to form a feedback circuit. . 9681pifl.doc/008 11 1296409 As described above, in order to determine the feedback circuit constituted by the amplifier AMP2 by the gain selection signal, a switch SW1 is provided at the feedback gain resistors G1, G2 and the output of the amplifier AMP2. The servo controller (not shown) in the CD player can also generate a gain selection signal. Adjusting the variable resistance VR1 allows a plurality of light sources to reduce scattering and have linear characteristics. Thus, when the gain selection signal selects the feedback gain resistor G1, the amplification unit 202 amplifies the voltage of the received beam power to a gain (ie, the feedback gain resistor G1 divided by the variable resistor VR1, that is, G1/VR1). Preset potential. When the gain selection signal selects the feedback gain resistor G2, the amplifying unit 202 amplifies the voltage of the received beam power to a preset by a gain (ie, the feedback gain resistor Gi divided by the variable resistor VR1, that is, G2/VR1). . The amplified voltage can be used as the detection beam power output and can be used for automatic power control (APC). Moreover, the detected beam power is also available to the servo controller. Fig. 3 is a circuit diagram showing a device for detecting a beam power according to a second embodiment of the present invention. The apparatus shown in Fig. 3 can amplify the beam power according to the gain of the optical disc using different types of gain selection signals, and use the amplified beam power as the detected beam power output. Referring to FIG. 3, the device includes a photodiode PD2, an I/V amplifier 301, and an amplifying unit 302. Since the configuration and operation of the photodiode PD2 and the I/V amplifier 301 are the same as those of the photodiode PD1 and the I/V amplifier 201 of Fig. 2, the description thereof will be omitted. 9681pifl.doc/008 12 1296409 The amplification unit 302 includes an amplifier AMP3. The amplifier AMP3 includes a bias resistor R6 connected to the input terminal to which the reference voltage Vref can be input, and a feedback gain resistor G3 connected to the feedback circuit. A variable resistor VR2, VR3 selected by a gain selection signal and fixed resistors R4, R5 are connected to the output terminal of the output voltage of the I/V amplifier 301, and are connected to the amplifier AMP3. A gain selection signal is generated according to the type of optical medium used in the optical disk drive, the variable resistors VR2 and VR3, and the fixed resistors R4 and R5. That is, when the beam power of the optical medium needs to be amplified by the feedback gain resistor G3, the variable resistor VR2 and the fixed resistor R4, a gain selection signal is issued so that the variable resistor VR2 and the fixed resistor R4 are in the I/V amplifier 301 and A path is formed between the amplifiers AMP3. On the other hand, when the beam power of the optical medium needs to be gain-amplified by the feedback gain resistor G3, the variable resistor VR3, and the fixed resistor R5, a gain selection signal is issued such that the variable resistor VR3 and the fixed resistor R5 are at the I/V amplifier 301. A path is formed between the amplifier AMP3 and the amplifier. The output terminals of the fixed resistors R4 and R5 and the amplifier AMP3 are provided with a switch SW2, so that the gain selection signal can determine that the amplifier AMP3 and the I/V amplifier 301 are connected with the variable resistor VR2 and the fixed resistor R4 or the variable resistor VR3 and fixed. Resistor R5. At this time, adjusting the variable resistors VR2 and VR3 値 can reduce one of the selected plurality of light sources and have a linear characteristic, and determine the 固定 of the fixed resistors R4 and R5 according to the maximum beam power ratio of the different light sources. Thus, when the gain selection signal selects the variable resistor VR2 and the fixed resistor 9681pifl.doc/008 13 1296409 resistor R4, the gain of the amplifying unit 302 is a number 値, that is, the feedback gain resistor G2 is divided by the variable resistor VR2 and fixed. The sum of the resistors R4 is G3/(VR2+R4). When the gain selection signal selects the variable resistor VR3 and the fixed resistor R5, the gain of the amplifying unit 302 is a number 値, that is, the feedback gain resistor G3 is divided by the variable resistor VR3 and the fixed resistor R5 and 'is G3/(VR3+) R5). Then, the amplifying unit 302 can amplify the voltage of the received beam power according to the gain to a predetermined potential. The amplified voltage can be used as the detection beam power output. As explained in Figure 2, the detected beam power can also be used in APC. Fig. 4 is a circuit diagram showing a device for detecting a beam power according to a third embodiment of the present invention. The device as shown in FIG. 4 can detect the type of the optical medium used by the optical disc drive, and use one of the plurality of amplifying units according to the preset required by the characteristics of the light source, and amplify the received light source to a predetermined level. Beam power. The device in FIG. 4 includes an optical diode PD3, an I/V amplifier 401, a first amplifying unit 402, a second amplifying unit 403, and a converter SW3. Since the configuration and operation of the photodiode PD3 and the I/V amplifier 401 are the same as those of the photodiode PD1 and the I/V amplifier 201 of Fig. 2, the description thereof will be omitted. The first amplifying unit 402 includes an amplifier AMP4. The amplifier AMP4 includes a bias resistor R7 connected to the input terminal to which the reference voltage Vref can be input, and a feedback gain resistor G4 connected to the feedback circuit. A variable resistor VR4 selected by a gain selection signal is connected to the output terminal of the output voltage of the I/V amplifier 401, and is connected to the input terminal of the amplifier AMP4. Adjustment 9681pifl.doc/008 14 1296409 The integral variable resistor VR4 allows the relative light source to reduce scattering and has linear characteristics. The first amplifying unit 402 divides the voltage output from the I/V amplifier 401 to a preset 根据 according to a gain (that is, the feedback gain resistor G4 is divided by the variable resistor VR4, that is, (G4/VR4), and outputs the result. The voltage output from the first amplifying unit 402 is supplied to the input terminal of the switching switch SW3 while the second amplifying unit 403 includes the amplifier AMP5. The amplifier AMP5 includes a bias resistor connected to the input terminal of the inputtable reference voltage Vref. R8, and a feedback gain resistor G5 connected to the feedback circuit. A variable resistor VR5 selected by the gain selection signal is connected to the output terminal of the output voltage of the I/V amplifier 401, and is connected to the input terminal of the amplifier AMP5. Adjusting the variable resistor VR5 allows the relative light source to reduce scattering and has linear characteristics. / Thus, the second amplifying unit 403 is amplified by (G5/VR4) according to a gain (that is, the feedback gain resistor G5 is divided by the variable resistor VR5). The voltage output from the I/V amplifier 401 is supplied to a predetermined threshold, and the result thereof is output. The voltage output from the second amplifying unit 403 is supplied to one of the input terminals of the switching switch SW3. The OFF SW3 selects one of the signal output from the first amplifying unit 402 and the signal output from the second amplifying unit 403 according to the selection signal, and outputs the selected signal. At this time, the output signal is the detected beam power. The same as the gain selection signal is different depending on the type of optical media used by the optical disk drive. 9681pifl.doc/008 15 1296409 FIG. 5 is a flow chart showing the method for detecting beam power in an optical disk drive according to the present invention. In the method of Figure 5, the gain of the detected beam power is determined according to the type of optical medium used in the optical disc drive. The light source power of the light generated by one of the plurality of light sources is detected using a light source receiving device such as a photodiode. (Step 501) Next, referring to the description of Fig. 2, the detected beam power is converted to a voltage by the I/V amplifier 201 (step 502). Then, the gain is determined according to the type of the optical medium used in the optical disk drive (step 503). And amplifying the voltage according to the gain to a preset potential (step 504). Thereafter, the amplified voltage is output (step 505). In the present invention, the optical disc In the method for detecting beam power, when the light source receiving device detects the beam power, the power of the detection beam can be amplified and output according to the predetermined gain corresponding to the plurality of light sources in the optical disk drive according to the description in FIG. 4. For example, It is said that the optical disc drive includes two kinds of light sources, and the detection beam power can be amplified and outputted through an appropriate gain corresponding to a light source' or the detected beam power can be amplified and outputted through another suitable gain of the other light source. In addition, 'one of the above-mentioned plurality of amplified and outputted beam powers can be selected as the detection beam power to output. FIG. 6 is a view showing a CD with a CD light source and a DVD light source according to a preferred embodiment of the present invention. The device for detecting the power of the beam in the machine, the required beam power of the individual light sources (X-axis of Fig. 6) and the power of the face beam (Y axis of Fig. 6). As shown in Figure 6, by controlling the beam power amplification gain of different sources, it is ensured that the maximum beam power has a sufficient dynamic range. 9681pifl.doc/008 16 1296409 As described above, when a device is used to detect the beam power emitted by a light source in an optical disk drive having a plurality of light sources, the power of the detection beam is amplified by a predetermined gain in accordance with the characteristics of the respective light sources. Thus, the detection beam power with a sufficiently sufficient dynamic range is provided for each of the light source characteristics, and the APC can be effectively realized. In the above, the present invention has been disclosed in the above preferred embodiments, and it is not intended to limit the invention to those skilled in the art, and various modifications may be made without departing from the spirit and scope of the invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims. 9681pifl.doc/008 17