1 ^5784 九、發明說明： * 【發明所屬之技術領域】 本發明係有關電路設計，特別係關於雷射二極體驅動 電路及其方法。 【先前技術】 雷射二極體或稱半導體雷射具有體積輕巧、效益高、 消耗功率小、使用壽命長、以及容易由電流大小來控制其 鲁輸出功率、頻率等特性。這些特性使它廣泛應用於資訊處 理、光纖通訊、家電用品及精密測量上。 雷射二極體的注入電流必須大於臨界電流密度，才能 2 發出雷射光。雷射二極體的特色之一，是能直接從電流控 ， 制其輸出光的強弱。 雷射二極體和一般的二極體有相似的P-N接面結 構’而其差異主要是半導體雷射具有一對鏡面做為共振 腔。目前雷射二極體依照接面結構分類一般包括單異質結 _ 構（single heterostructure )、雙異質結構（double heterostructure )、量子井（quantum well )結構以及垂直共 振腔面射型雷射（verticai cavity surface emitting laser)。 半導體雷射依波長及應用，大致可分為短波長與長波 長雷射兩大類。短波長雷射包含發光波長由39〇奈米到 950奈米的雷射’主要使用於光碟機、雷射印表機、條碼 機、掃描器及指示器等光資訊及顯示的應用；長波長雷射 則涵蓋發光波長由980奈米至1550奈米之雷射，主要用 於光纖通訊。 5 1355784 λ J 一般雷射二極體必須使用雷射二極體驅動器〇aser ， diode driver，LDD)驅動之。雷射二極體驅動電路是用來提 供給予雷射二極體所需的電流，將原本是電能轉換為光 能。於現今技術中，其驅動器常會消耗過多的功率，降低 雷射二極體的光電轉換效率。 於雷射二極體驅動電路上，除了每個電子元件都有雜 散電容外，於連接器上的接觸點以及印刷電路板的導電箔 φ 上都有寄生電感。在電源轉換器做電流切換時，電感會產 生電壓降；即Δν=；1 電壓降正比於寄生電感值 及電流變動量’並與切換時間成反比。 在使用高頻、大電流方波電源轉換器供給雷射二極體 趨動電路時，要求快速的電流切換，即在很短的上昇及下 降時間切換電流準位。在電流切換時，在電流流通路徑上 的寄生電感會產生可觀的電壓降，須有額外的電壓降來驅 動雷射二極體，以達到快速電流切換的需求。但追加額外 • 的電壓在電流穩態時，相對的產生額外的功率損耗，使能 量轉換效率大幅降低。 【發明内容】 本發明之目的係提供一雷射二極體驅動電路，以克服 前述問題。 本發明之目的係於電流切換的上昇時間（rjse time) 中’增加額外正電壓或負電壓的脈衝，達到快速電流切換， 並減少功率耗損。 6 〒784 本發明係揭露一種雷射二極體驅動電路，包含一第一 路杈，具有一雷射二極體以及半導體元件開關，其中半導 體元件開關係用於導通或關閉第一路徑。一第一供電路 裎，耦合至第一路徑，提供一第一電壓至第一路徑，其中 第一供電路徑具有一電源轉換器、一第一電感以及一第一 儲存之裝置，其中電源轉換器提供第一電壓至第一儲存裝 置。一第二供電路徑，耦合至第一路徑，第二供電路徑具 φ有一提供電壓脈衝之裝置、一第二電感以及第二儲存裝 置，其中提供電壓脈衝至第一儲存裝置。一脈波寬度調變 (Pulse Width Modulation，PWM)控制器耦合至半導體元件 開關以及提供電壓脈衝之裝置。。 本發明亦提供一種驅動雷射二極體之方法，包含一電 源轉換器提供一第一電廢至第一電容以及雷射二極體。利 用-脈波寬度調變控制器傳送控制信號至一半導體元件開 關以及-電歷脈衝產生器。以及電壓脈衝產生器依照控制 • 信號提供一第二電壓至一第二電容器。 【實施方式】 本發明將配合其較佳實施例與隨附之圖示詳述於下。 應可理解者為本發明中所有之較佳實施例僅為例示之用， 並非用以限制。因此除文中之較佳實施例外，本發明亦可 廣泛地應用在其他實施例中。且本發明並不受限於任何實 施例，應以隨附之申請專利範圍及其同等領域而定。 本發明係揭露一種雷射二極體驅動電路。本發明之雷 射二極體驅動電路只在電流切換上昇時間time)追加 H«784 第一路徑12包括電阻R1以MOSFET開關Q1 ;第二 路梭14包括電阻R2以及MOSFET開關Q2。第一路徑12 中的電阻R1電阻值較第二路徑14的電阻R2°Q1以及Q2 的間極個別地接收外部的PWM(Puls0 Width Modulation) 控制器16所傳送的控制信號控制開關qi及Q2的頻率以 及工作週期（duty circle)。 參照第二至二C圖，為第一圖雷射二極體驅動電路1〇 φ 之時序圖，用以說明其電路的操作狀態。當t=0-Tl時，外 部PWM控制器16個別傳送控制信號至第一路徑12的開 關Q1閘極以及第二路徑的開關Q2閘極，使開關Q1以及 Q2皆導通，則流經雷射二極體ld之電流為： 當t=Tl-T2時，開關Q2已關閉，開關Q1仍導通，故 八剩第一路徑12有電流流過，則流經雷射二極體LD之電 鲁流為： i(t)=(^)x(l-exp(.^x(t-Tl))+i(Tl)x(exp(-^><(t.T1))) 若 t>3(L/R)，則 i(t) = 2 R1 當kT2時’開關Q1及Q2皆關閉。因此，第一路徑 12以及第二路徑14皆開路。 由上述可知，於t=〇_T1時，增加了一阻抗較低的第二 路徑14，使雷射二極體驅動電路1〇在電流上昇期間使得 9 1355784 電流上昇率變快，達到增加電流上昇之速度。於上升時間 (riSetime)，本發明之輸出電流較習知技術所需之時間缩 短約 20-30%。 第三圖根據本發明之另一較佳實施例，為本發明之雷 射二極體驅動電路30示意圖。參照第三圖以及第四圖，雷 射二極體趨動電路30包括—第—供電路徑31以及第二供 電路徑33。第—供電路徑31與第二供電路徑33個別地鵪 合至由雷射二極體LD、電阻、電感以及半導體元件開關 所組成的第一路徑35。 、直流/直流轉換器（DC/DC c〇nverter)32連接至電感 L!並提供振幅為Vdcl之直流電壓至第一路徑％。電容& 由直流/直流轉換器32所供給之電壓充電。二極體順 $導通，電流透過二極體D2、寄生電感^流至雷射二極 體1^因此電容之電壓等於二極體〇2之順向偏壓VFD2 加上郎點A之電壓v .1 ^ 5784 IX. Description of the invention: * Technical field to which the invention pertains The present invention relates to circuit design, and more particularly to a laser diode driving circuit and method therefor. [Prior Art] Laser diodes or semiconductor lasers have the characteristics of light weight, high efficiency, low power consumption, long service life, and easy control of their output power and frequency by current. These features make it widely used in information processing, fiber optic communications, home appliances and precision measurement. The injection current of the laser diode must be greater than the critical current density to emit laser light. One of the characteristics of the laser diode is that it can directly control the intensity of the output light from the current. The laser diode has a similar P-N junction structure as the general diode, and the difference is mainly that the semiconductor laser has a pair of mirrors as a resonant cavity. At present, laser diodes generally include a single heterostructure, a double heterostructure, a quantum well structure, and a vertical cavity surface-emitting laser (verticai cavity) according to the junction structure. Surface emitting laser). Semiconductor lasers can be roughly classified into short wavelengths and long wavelength lasers depending on the wavelength and application. Short-wavelength lasers contain lasers with wavelengths from 39 nanometers to 950 nanometers. They are mainly used in optical information and display applications such as CD players, laser printers, barcode printers, scanners and indicators; long wavelengths The laser covers lasers with emission wavelengths from 980 nm to 1550 nm, mainly for fiber optic communications. 5 1355784 λ J The general laser diode must be driven by a laser diode driver 〇aser, diode driver, LDD). The laser diode drive circuit is used to provide the current required to power the laser diode, converting the originally electrical energy into light energy. In today's technology, its driver often consumes too much power and reduces the photoelectric conversion efficiency of the laser diode. On the laser diode drive circuit, in addition to the stray capacitance of each electronic component, there is parasitic inductance on the contact point on the connector and on the conductive foil φ of the printed circuit board. When the power converter is switching current, the inductor will produce a voltage drop; that is, Δν =; 1 The voltage drop is proportional to the parasitic inductance value and the current variation amount' and is inversely proportional to the switching time. When a high-frequency, high-current square-wave power converter is used to supply a laser diode driving circuit, fast current switching is required, that is, switching the current level in a short rise and fall time. At current switching, the parasitic inductance in the current path will produce a significant voltage drop, and an additional voltage drop is required to drive the laser diode for fast current switching. However, when the additional voltage is added to the current steady state, the relative power loss is generated, and the energy conversion efficiency is greatly reduced. SUMMARY OF THE INVENTION An object of the present invention is to provide a laser diode driving circuit to overcome the aforementioned problems. The object of the present invention is to increase the pulse of an additional positive or negative voltage during the rise time of the current switching (rjse time) to achieve fast current switching and reduce power consumption. 6 784 The present invention discloses a laser diode driving circuit including a first transistor having a laser diode and a semiconductor element switch, wherein the semiconductor element opening relationship is for turning on or off the first path. a first supply circuit, coupled to the first path, providing a first voltage to the first path, wherein the first power supply path has a power converter, a first inductor, and a first storage device, wherein the power converter A first voltage is provided to the first storage device. A second power supply path is coupled to the first path. The second power supply path has a means for providing a voltage pulse, a second inductor, and a second storage device, wherein the voltage pulse is supplied to the first storage device. A Pulse Width Modulation (PWM) controller is coupled to the semiconductor component switch and means for providing a voltage pulse. . The present invention also provides a method of driving a laser diode comprising a power converter to provide a first electrical waste to a first capacitor and a laser diode. The pulse width modulation controller is used to transmit control signals to a semiconductor component switch and to an electrical pulse generator. And the voltage pulse generator provides a second voltage to a second capacitor in accordance with the control signal. [Embodiment] The present invention will be described in detail with reference to the preferred embodiments thereof and the accompanying drawings. It should be understood that all of the preferred embodiments of the present invention are intended to be illustrative only and not limiting. Therefore, the invention may be applied to other embodiments in addition to the preferred embodiments described herein. The present invention is not limited to any embodiment, and should be determined by the scope of the appended claims and their equivalents. The invention discloses a laser diode driving circuit. The laser diode driving circuit of the present invention adds H«784 only at the current switching rise time time. The first path 12 includes a resistor R1 to the MOSFET switch Q1, and the second shuttle 14 includes a resistor R2 and a MOSFET switch Q2. The resistance of the resistor R1 in the first path 12 is different from the resistance of the second path 14 by R2°Q1 and Q2, and the external PWM (Puls0 Width Modulation) controller 16 controls the switches qi and Q2. Frequency and duty circle. Referring to Figures 2 to 2C, a timing diagram of the first laser diode driving circuit 1 〇 φ is used to illustrate the operational state of the circuit. When t=0-T1, the external PWM controller 16 individually transmits the control signal to the gate of the switch Q1 of the first path 12 and the gate of the switch Q2 of the second path, so that the switches Q1 and Q2 are both turned on, then the laser flows through The current of the diode ld is: When t=Tl-T2, the switch Q2 is turned off, and the switch Q1 is still turned on, so the first path 12 of the eight remaining current flows, and then flows through the laser diode LD. The stream is: i(t)=(^)x(l-exp(.^x(t-Tl))+i(Tl)x(exp(-^><(t.T1))) if t> ; 3 (L / R), then i (t) = 2 R1 When kT2 'switch Q1 and Q2 are closed. Therefore, the first path 12 and the second path 14 are open. As can be seen from the above, at t = 〇 _ At T1, a second path 14 with a lower impedance is added, so that the laser diode driving circuit 1 变 makes the current rising rate of 9 1355784 faster during the current rising period, and increases the speed of increasing the current. In the rise time (riSetime) The output current of the present invention is shortened by about 20-30% compared to the time required by the prior art. Third Embodiment In accordance with another preferred embodiment of the present invention, a schematic diagram of a laser diode driving circuit 30 of the present invention is shown. Referring to the third and fourth figures, the laser The diode driving circuit 30 includes a first power supply path 31 and a second power supply path 33. The first power supply path 31 and the second power supply path 33 are individually coupled to the laser diode LD, the resistor, the inductor, and the semiconductor. The first path of the component switch is 35. The DC/DC converter (DC/DC converter) 32 is connected to the inductor L! and provides a DC voltage of amplitude Vdcl to the first path %. Capacitance & The voltage supplied by the DC converter 32 is charged. The diode is turned on, the current is transmitted through the diode D2, and the parasitic inductance flows to the laser diode. Therefore, the voltage of the capacitor is equal to the forward bias of the diode 〇2. Press VFD2 plus the voltage of the point A.
vci= Vdcl=VFD2+vAVci= Vdcl=VFD2+vA
、外部PWM控制器34連接至M〇SFET開關qi之閉極 以？電壓脈衝產生器36。外部pWM控制器％傳送同步控 =號至聰FET開關Q1以及電壓脈衝產生器％。開關 1依照外部PWM控制器34的控制信號導通或關閉。電 2衝產生器36連接至電感L2。電感另-端連接至 ' 3、及電阻Rcs2。電壓脈衝產生器3ό依照外部pwM 制器34所傳送之控制信號提供電麼脈衝至電容^。者 外部PWM控制器34所傳送的控制信號於非工作週期（0^ 1355784 4 i y)時脈衝產生器36提供振幅為vDC2的電壓至電容匸3 ， 充電。於上述控制信號處於工作週期時，停止供給電壓給3 電谷C3以及電感l2 開關Q1依照外部PWM控制器34傳送的控制信號調 整開關頻率與工作週期。當開關Q1導通時，自電容。輸 出之電流1灿流經電阻RCS2以及雷射二極體LD至開關qi 至等電位端，其中電感Lpr2以及Lpr3為寄生電容。電容A 籲充電。輸出電流Iout的上升斜率取決於電流流過路徑之寄 生電容及寄生電感的電壓降。輸出電流匕之最大值： Ι〇ω ---Vpc2__ (RCS2 +RCS1 +RQlon) 其中RQl〇n為開關Q1導通時的電阻值。 電容c3持續放電。當放電至其電壓小於（ν·υ時， 則由電容。供給電流。因此’此時的輸出電流最大值‘為: lour =JYdC1~VFD2) (Rcsi + Rqioi1 ) 直到開關Q1關閉，則電容C2藉由Di放電。 由上述可知，電壓脈衝產生器36開始再提供電壓脈衝至電 容C3充電，並持續重複上述動作。由第四圖可知，本發明 之雷射二極體驅動電路可有效減少開M Q1料時的功 損失 PL{)SS。 參照第五圖，根據本發明之另—較佳實施例，為 本發明之雷射二極體驅動電路4G示意圖。雷射二極體驅動 電路40與第三圖之電路30類似，故相似部分不再資述。 1355784 »♦· ♦ 4 驅動電路40係利用負電壓脈衝產生器4 .«加快電流切換之速度，不需要二極體D”如此= 由一極體D2導通的功率損耗以及電流切換延遲。 、本發，亦揭露一種雷射二極體驅動之方法，應用於脈 波驅動型面功率半導體雷射二極體及高功率發光二極體。 首先’直流/直流轉換器提供一第一電壓VDC1至第一電容 ，以及雷射二極體負載。利用外部PWM控制器傳送控制 籲信號控制輕合至雷射二極體負載之半導體元件開關以及電 壓脈衝產生器。電壓脈衝產生器接收上述控制信號後，依 照外PWM控制器所傳送的控制信號提供-第二電壓 VDC2至第二電容器。於上述控制信號處於非工作週期時， 電廢脈衝產生器提供電壓至第二電容器。半導體元件開關 接收上述控制信號後，於上述控制信號處於工作週期時導 通。 虽半導體兀件開關導通時’第二電容器提供之電流流 •過由電阻、電感、雷射二極體、半導體元件開關所組成之 路徑，藉以驅動雷射二極體。參照第四圖，當上述流經雷 射二極體之驅動電流Iout介於一第一電流值A1上升至第二 電流值八2之間時，第二電容器提供一第二電壓VDC2，以 驅動雷射二極體。 當雷射二極體驅動電流1_上升至第二電流值A2 時，此時第二電容器已放電至其第二電壓值VDC2小於第一 電儲存器所提供的第-電壓值VDC1，則輸出電壓V。』保 持為第一電壓值VDC1。 12 1355784 ，· 因半導體元件開關導通瞬間’在其流過的路徑上的寄 生電感將產生反電勢vL’為解決上述問題，本發明於驅動 電流lout的上升時間加入額外的第二電壓值VDC2以驅動雷 射二極體，達到快速電流切換之目的，並可改善電源轉換 器的轉換效率，減少功率耗損。 本發明之雷射二極體驅動電路在電流切換上昇時間增 加額外之正電壓或負電壓脈衝，以加速電流切換，並有^ 減少功率損耗。 本發明之雷射一極體驅動電路可應用於脈波驅動型高 功率半導體雷射二極體及高功率發光二極體等。可使低電 壓、高頻、大電流方波電源轉換器達到高電流切換（大於 200A//z Sec)要求及提高功率轉換效率的效果。 對熟悉此領域技藝者’本發明雖以較佳實例閣明如 上，然其並非用以限定本發明之精神。在不脫離本發明之 精神與範圍内所作之修改與類似的配置，均應包含在下述 •之申請專利範圍内，此範圍應覆蓋所有類似修改與類似結 構，且應做最寬廣的詮釋。 【圖式簡單說明】 第一圖根據本發明之較佳實施例，為本發明之雷射二 極體驅動電路示意圖；第二A圖-二C圖根據本發明之較 佳實施例，為第一圖電路之時序圖，用以說明其電路的操 作狀態，第二圖根據本發明之另一較佳實施例，為本發明 之雷射二極體驅動電路示意圖；第四圖根據本發明之較佳 實施例，為第三圖電路之時序圖，用以說明其電路的操作 13 1355784 I * I i- 狀態；第五圖根據本發明之另一較佳實施例，為本發明 之雷射二極體驅動電路示意圖。 【主要元件符號說明】 010 雷射二極體驅動電路 012 第一路徑 014 第二路徑 016 PWM控制器 030 雷射二極體驅動電路The external PWM controller 34 is connected to the closed end of the M〇SFET switch qi. Voltage pulse generator 36. The external pWM controller % transmits the synchronous control = number to the Cong FET switch Q1 and the voltage pulse generator %. The switch 1 is turned on or off in accordance with a control signal from the external PWM controller 34. The electric rush generator 36 is connected to the inductor L2. The other end of the inductor is connected to '3' and the resistor Rcs2. The voltage pulse generator 3 is supplied with a pulse to the capacitor in accordance with a control signal transmitted from the external pwM controller 34. When the control signal transmitted by the external PWM controller 34 is in the non-working period (0^1355784 4 i y), the pulse generator 36 supplies the voltage of the amplitude vDC2 to the capacitor 匸3 for charging. When the control signal is in the duty cycle, the supply voltage is stopped to the third battery C3 and the inductor l2. The switch Q1 adjusts the switching frequency and the duty cycle according to the control signal transmitted from the external PWM controller 34. When the switch Q1 is turned on, it is self-capacitance. The output current 1 can flow through the resistor RCS2 and the laser diode LD to the switch qi to the equipotential end, wherein the inductors Lpr2 and Lpr3 are parasitic capacitances. Capacitor A calls for charging. The rising slope of the output current Iout depends on the voltage drop of the parasitic capacitance and parasitic inductance of the current flowing through the path. The maximum value of the output current 匕: Ι〇ω ---Vpc2__ (RCS2 +RCS1 +RQlon) where RQl〇n is the resistance value when the switch Q1 is turned on. Capacitor c3 continues to discharge. When discharging to a voltage less than (ν·υ, the current is supplied by the capacitor. Therefore, the maximum value of the output current at this time is: lour = JYdC1~VFD2) (Rcsi + Rqioi1) Until the switch Q1 is turned off, the capacitor C2 Discharged by Di. As can be seen from the above, the voltage pulse generator 36 starts to supply a voltage pulse to the capacitor C3 for charging, and continues to repeat the above operation. As can be seen from the fourth figure, the laser diode driving circuit of the present invention can effectively reduce the power loss PL{) SS when the M Q1 material is turned on. Referring to a fifth embodiment, a preferred embodiment of the present invention is a schematic diagram of a laser diode driving circuit 4G of the present invention. The laser diode driving circuit 40 is similar to the circuit 30 of the third figure, so similar parts will not be described. 1355784 »♦· ♦ 4 The drive circuit 40 uses a negative voltage pulse generator 4. «Accelerate the speed of current switching, no diode D is required." = Power loss and current switching delay caused by one pole D2. A method of driving a laser diode is also disclosed, which is applied to a pulse-driven surface power semiconductor laser diode and a high-power light-emitting diode. First, the DC/DC converter provides a first voltage VDC1 to a first capacitor, and a laser diode load. The external PWM controller transmits a control call signal to control a semiconductor component switch that is lightly coupled to the laser diode load and a voltage pulse generator. The voltage pulse generator receives the control signal Providing a second voltage VDC2 to the second capacitor according to a control signal transmitted by the external PWM controller. When the control signal is in a non-working period, the electric waste pulse generator supplies a voltage to the second capacitor. The semiconductor component switch receives the above control After the signal, the above control signal is turned on during the duty cycle. Although the semiconductor device switch is turned on, the second capacitor provides Flow through a path consisting of a resistor, an inductor, a laser diode, and a semiconductor component switch to drive the laser diode. Referring to the fourth diagram, when the above-mentioned driving current flowing through the laser diode is out When a first current value A1 rises to between the second current value 八2, the second capacitor provides a second voltage VDC2 to drive the laser diode. When the laser diode drive current 1_ rises to the first When the current value A2 is two, when the second capacitor has been discharged until its second voltage value VDC2 is less than the first voltage value VDC1 provided by the first electrical storage, the output voltage V is maintained at the first voltage value VDC1. 1355784, · The parasitic inductance on the path through which the semiconductor element switch is turned on will generate a back electromotive force vL'. To solve the above problem, the present invention adds an additional second voltage value VDC2 to drive at the rise time of the drive current lout. The laser diode achieves the purpose of fast current switching, and can improve the conversion efficiency of the power converter and reduce the power consumption. The laser diode driving circuit of the invention increases the additional time during the current switching rise time. Positive voltage or negative voltage pulse to accelerate current switching and reduce power loss. The laser one-pole driving circuit of the invention can be applied to pulse-driven high-power semiconductor laser diode and high-power light-emitting diode Body, etc. It can achieve low current, high frequency, high current square wave power converter to achieve high current switching (greater than 200A / / z Sec) requirements and improve power conversion efficiency. For those skilled in the art, the present invention The preferred embodiments are not intended to limit the spirit of the invention, and modifications and similar configurations made without departing from the spirit and scope of the invention are included in the scope of the following claims. All similar modifications and similar structures should be covered and the broadest interpretation should be made. [Simplified illustration of the drawings] The first figure is a schematic diagram of a laser diode driving circuit according to a preferred embodiment of the present invention; A-FIG. 2C is a timing diagram of a circuit of the first diagram for explaining an operational state of the circuit according to a preferred embodiment of the present invention, and FIG. 2 is a further preferred embodiment of the present invention. The schematic diagram of the laser diode drive circuit of the present invention; the fourth diagram is a timing diagram of the circuit of the third diagram for explaining the operation of the circuit according to the preferred embodiment of the present invention. 13 1355784 I * I i-state The fifth figure is a schematic diagram of a laser diode driving circuit according to another preferred embodiment of the present invention. [Main component symbol description] 010 Laser diode drive circuit 012 First path 014 Second path 016 PWM controller 030 Laser diode drive circuit
031 第一供電路徑 032 直流/直流轉換器 033 第二供電路徑 034 PWM控制器 035 第一路徑 036 電壓脈衝產生器 040 雷射二極體驅動電路 042 負電壓脈衝產生器 14031 First power supply path 032 DC/DC converter 033 Second power supply path 034 PWM controller 035 First path 036 Voltage pulse generator 040 Laser diode drive circuit 042 Negative voltage pulse generator 14