200919880 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、 /肖耗功率小、使用壽命長、以及容易由電流大小來控制其 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 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（vertical 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。 200919880 -般雷射二極體必須使用雷射二極體驅動器一犷 diode driver，LDD)驅動之。雷射二極體驅動電路是用來 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， 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羯 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= L *Δί/Δί。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。 在使用咼頻、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 月述問題。 本發明之目的係於電流切換的上昇時間（rise 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。 200919880 本發明係揭露一種雷射二極體驅動電路，包含一第一 路徑，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 徑，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，第二供電路徑且 有一提供電壓脈衝之裝置、一第二電感以及第二儲^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 M〇dulati〇n，pwM)控制器轉合至半導體元件 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壓至第一電容以及雷射二極體。利 用一脈波寬度調變控^器傳送控制信一半導體元件開 ^以及f壓脈衝產生_。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|爸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-極體驅動電路只在電流切換上昇時間（rise ㈣追加 200919880 額外正電壓或負電壓的短脈衝驅動雷射二極體，達到快速 電流切換目的；在電流穩態時電壓快速的回復到較原準 位，將額外的功率損耗減到最小。本發明之雷射二極體驅 動電路可k幵應用於低電壓、高頻、大電流方波驅動型高 功率（g5〇0mW)半導體雷射二極體及高功率發光二極體= 的電源轉換器能量轉換效率。 本發明之雷射二極體驅動電路在不增高輸入電壓的情 況:，於電流切換上昇期間提供另一條較低阻抗路徑，= 電流上昇期間使電感端有較高的分壓，使得電流上昇率增 大。在電流准位達到所需求值時’將前述所提供的低阻^ 路徑開路’使電流准位保持在原需求准位；達到加快速電 流上昇速度目的。 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10示意圖^雷射二極體驅動電路包括兩 個MOSFET開㈣i與Q2所形成的第一路徑12以第二路 徑14。第一路徑12之阻抗係大於第二阻抗14。本發明係 提供-較低阻抗的路徑14’於電流切換期 具有較高的分壓，以致電流上升率增加。 软端200919880 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to circuit design, and more particularly to a laser diode driving circuit and method therefor. [Prior Art] A laser diode or a semiconductor laser has the characteristics of light weight, high efficiency, small power consumption, long service life, and easy control of its 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 features of the laser diode is its ability to control the intensity of its output light directly 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 device according to the junction structure. 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 ranging from 39 nanometers to 950 nanometers. They are mainly used in optical information and display applications such as optical disc printers, laser printers, bar code printers, scanners and indicators; long wavelengths The laser covers lasers with emission wavelengths from 980 nm to 1550 nm, mainly for fiber optic communications. 200919880 The general laser diode must be driven by a laser driver, LDD). The laser diode drive circuit is used to supply the current required by the laser diode to convert the originally electrical energy into light energy. In today's technology, the driver often consumes too much power, and the photoelectric conversion efficiency of the laser diode. _ On the laser diode drive circuit, except for the fact that each electronic component has a stray capacitance, there is a parasitic inductance on the contact point on the connector and on the conductive pad of the printed circuit board. When the power converter is performing current switching, the inductance produces a voltage drop of Δν = L * Δί / Δί. The voltage drop is proportional to the parasitic inductance value and the amount of current variation ' and is inversely proportional to the switching time. When a rake-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 additional voltage is applied 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 problems described in the month. 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 to achieve fast current switching and reduce power consumption. 200919880 The present invention discloses a laser diode driving circuit comprising a first path 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 power supply path coupled to the first path to provide 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 provides The first voltage is to the first storage device. A second power supply path is coupled to the first path, the second power supply path and a means for providing a voltage pulse, a second inductor, and a second memory device, wherein the voltage pulse is supplied to the first storage device. A pulse width modulation (Pulse Width M〇dulati〇n, pwM) controller is coupled to the semiconductor component switch and means for providing a voltage pulse. . The invention also provides a method of driving a laser diode comprising a power converter to provide a first voltage to a first capacitor and a laser diode. A pulse width modulation controller is used to transmit a control signal, a semiconductor element is turned on, and a f-pulse pulse is generated. And the voltage pulse generator supplies 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. And the present invention is not limited to any embodiment's which should be based on the accompanying patent application|Daddy and its equivalent fields. The invention discloses a laser diode driving circuit. The laser-polar body driving circuit of the invention only drives the laser diode with a short pulse of additional positive voltage or negative voltage in the current switching rise time (rise) to achieve fast current switching purpose; the voltage is fast at current steady state Reverting to the original level, the additional power loss is minimized. The laser diode driving circuit of the invention can be applied to low voltage, high frequency, high current square wave driving type high power (g5〇0mW) Power converter energy conversion efficiency of semiconductor laser diode and high power light emitting diode = The laser diode drive circuit of the present invention does not increase the input voltage: another one is provided during the current switching rise Lower impedance path, = higher voltage at the inductor end during current rise, which increases the rate of current rise. When the current level reaches the required value, 'open the low impedance path provided above' to make the current The bit is maintained at the original demand level; the purpose of increasing the speed of the fast current is reached. The first figure is a schematic diagram of the laser diode driving circuit 10 of the present invention according to a preferred embodiment of the present invention. The emitter diode drive circuit includes a first path 12 formed by two MOSFETs (4) i and Q2 with a second path 14. The impedance of the first path 12 is greater than the second impedance 14. The present invention provides a path of lower impedance. 14' has a higher partial voltage during the current switching period, so that the current rising rate increases.
輸入電壓端Vin电读一私 > 雨#， 端連接至輸入電感Lil 端接地。電感L之一 另一端連接至第一路;5 極體LD之電流丨(〇等 的電流值IQ1以及1〇2。 200919880 第一路徑12包括電阻R1以MOSFET開關Q1 ;第二 路徑14包括電阻R2以及]VI0SFET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 的閘極個別地接收外部的PWM(Pulse 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 之時序圖’用以說明其電路的操作狀態。當t=〇_T1時，外 邛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 剩第一路徑12有電流流過，則流經雷射二極體LD之雷 流為： 1⑴=(|^x(l-exP(-早 x(t_T1))+i(T1)x(exp(•早 若 t>3(L/R)，則 i(t) = 2 R1 當時’開關Q1及Q2皆關閉。因此 以及第二路徑14皆開路。 此第-路控 由上述可知，於t=〇_T1時，增加了 一阻抗 路徑14’使雷射二極體驅動電路1〇在電流上昇期間使; 200919880 電流上昇率變快，達到增加電流上昇之速度。於上升時間 (rise time)，本發明之輸出電流較習知技術所需之時間縮 短約 20-30%。 第一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 電路彺33。第一供電路m貞第二供電路徑個別地耦 合至由雷射二極體LD、I ^ .> 電阻、電感以及半導體元件開關 所組成的第一路徑3 5。 、直流/直流轉換n(DC/DC⑶nve刪32連接至電感 b並提供振幅為Vdel<直流電壓至第一路徑35。 c 由直流/直流轉換器32戶f 磁 1 么尸τ t、給之電壓充電。二極體d2順 :導通，電流透過二極體d2、寄生電感屮流至雷射二極 LD"因此電| Cl之電壓等於二極體之順向偏壓％ 加上節點A之電壓νΔ.The input voltage terminal Vin reads a private > rain #, and the terminal is connected to the input inductor Lil terminal ground. The other end of one of the inductors L is connected to the first path; the current of the 5 LD is 丨 (the current values IQ1 and 1〇2 of the 〇 etc.) 200919880 The first path 12 includes the resistor R1 with the MOSFET switch Q1; the second path 14 includes the resistor R2 and ]VI0SFET switch Q2. The resistance of the resistor R1 in the first path 12 is smaller than the resistance of the second path 14 R2°Q1 and the gate of Q2 is individually received by the external PWM (Pulse Width Modulation) controller 16 The frequency of the signal control switches qi and q2 and the duty cycle. Refer to the second to second C diagram 'for the first diagram of the laser diode driving circuit timing diagram' to illustrate the operating state of its circuit. When 〇_T1, the external 邛 PWM controller 16 individually transmits a 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 passes through The current of the polar body LD is ·· When t=Tl-T2, the switch Q2 is turned off, the switch Q1 is still turned on, so the current flows through the first path 12, and the lightning flow flowing through the laser diode LD is : 1(1)=(|^x(l-exP(- early x(t_T1))+i(T1)x(exp(•as early as t>3(L/R), then i(t) = 2 R1 At that time, 'switches Q1 and Q2 are both closed. Therefore, and the second path 14 is open. This first path is known from above. When t=〇_T1, an impedance path 14' is added to drive the laser diode. Circuit 1〇 is made during the current rise; 200919880 The current rise rate is faster, increasing the speed of the current increase. At the rise time, the output current of the present invention is shortened by about 20-30% compared to the time required by the prior art. The first diagram is a schematic diagram of a laser diode driving circuit 30 according to another preferred embodiment of the present invention. Referring to the third and fourth figures, the laser diode driving circuit 30 includes a power supply path 31 and a second supply circuit 33. The first supply circuit m贞 the second power supply path is individually coupled to the first of the group consisting of the laser diodes LD, I^> resistors, inductors, and semiconductor component switches A path 3 5, DC / DC conversion n (DC / DC (3) nve delete 32 connected to the inductor b and provide amplitude Vdel < DC voltage to the first path 35. c by DC / DC converter 32 household f magnetic 1 t, the voltage is charged. The diode d2 is smooth: conduction, The current flows through the diode d2, the parasitic inductance turbulence to the laser diode LD" therefore the voltage of the electricity | Cl is equal to the forward bias % of the diode plus the voltage νΔ of the node A.
Vci- Vdci=VFD2 + VA 、外部PWM控制器34連接至m〇sfet開關之間極 二及電壓脈衝產生器36。外部pwM控制器％傳送同步控 ^號至娜㈣開關Q1以及電親衝產生H 36。開關 部™控制器％的控制信號導通或關閉。電 屢脈衝產生器36連接至雷片τ ^ ^ τ ㈣至電感L”電感Lr另一端連接至Vci-Vdci = VFD2 + VA, external PWM controller 34 is connected to the pole between the m〇sfet switch and the voltage pulse generator 36. The external pwM controller % transmits the synchronization control number to the na (four) switch Q1 and the electric pro-pulse produces H 36. The control signal of the switch unit TM controller is turned on or off. The electric pulse generator 36 is connected to the laser τ ^ ^ τ (four) to the inductor L". The other end of the inductor Lr is connected to
控：二•阻、2。電壓脈衝產生器36依照外部PWM " 所傳送之控制信號提供電壓脈衝至電容合 夕PWM控制器34所傳送的控制信號於非工作週期（off 200919880 duty)時，脈衝產生器36提供振幅為％的電壓至電容a 充電。於上述控制信號處於工作週期時，停止供給電I給 電容C3以及電感l2 f 開關Qi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 2電流W流經電阻Rcs2以及雷射二極體⑺至開關⑴ 電位端，其中電感Lpr2以及L㈣為寄生電容。電容q 充電。輸出電流1_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^之最大值： out rDC2 (RCS2 +Rcsi +RQlon) 其中RQl〇n為開關Q 1導通時的電阻值。 =3，續放電。當放電至其㈣、小於（VDG1. VFD2)時 電谷C1供給電流。因此’此時的輸出電流最大值C為 _(Vpci- Vpn，） (RCS1 + RQ1〇n) L out 關閉，則電容〇2藉由R2、m放電。 可知，電壓脈衝產生器36開始再提供電壓脈衝至電 3充電’並持續重複上述動作。由第四圖可知 極體驅動電路可有效減少開關^導通時的㈣ 本發:之根據本發明之另一較佳實施例，為 月之雷射二極體驅動電路40示意圖。 電路40與第三圖之電路3。類似’故相似部分不再贅：動 200919880 驅動電路40係利用負電壓脈衝產生器42產生負電壓脈衝 以加快電流切換之速度，不需要二極體D2，如此更可減少 由二極體D2導通的功率損耗以及電流切換延遲。 本發明亦揭露一種雷射二極體驅動之方法，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。 首先，直流/直流轉換器提供一第一電壓Vdc!至第一電容 器以及雷射二極體負載。利用外部pwM控制器傳送控制 信號控制耦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 照外部PWM控制器所傳送的控制信號提供一第二電壓 VDC2至第二電容器。於上述控制信號處於非工作週期時， 電壓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。 當半導體元件開關導通時，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1_介於一第一電流值Αι上升至第二 電流值a2之間時，第二電容器提供一第二電壓n 驅動雷射二極體。Control: two resistance, 2. The voltage generator 36 provides a voltage pulse to the control signal transmitted by the external PWM " to the control signal transmitted by the capacitor PWM controller 34 during the non-working period (off 200919880 duty), the pulse generator 36 provides the amplitude of % The voltage is charged to capacitor a. When the control signal is in the duty cycle, the supply of the capacitor I to the capacitor C3 and the inductor l2 are stopped. The switch Qi adjusts the switching frequency and the duty cycle in accordance with the control signal transmitted from the external PWM controller 34. When the switch Q1 is turned on, it is self-capacitance. The current 2 flows through the resistor Rcs2 and the laser diode (7) to the potential terminal of the switch (1), wherein the inductances Lpr2 and L(4) are parasitic capacitances. Capacitor q is charged. The rising slope of the output current 1_ 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 ^: out rDC2 (RCS2 + Rcsi + RQlon) where RQl〇n is the resistance value when the switch Q 1 is turned on. =3, continuous discharge. When discharging to (4), less than (VDG1. VFD2), the electric valley C1 supplies current. Therefore, the output current maximum value C at this time is _(Vpci-Vpn,) (RCS1 + RQ1〇n) L out is turned off, and the capacitor 〇2 is discharged by R2 and m. It can be seen that the voltage pulse generator 36 begins to supply a voltage pulse to the charge 3 and continues to repeat the above actions. It can be seen from the fourth figure that the polar body driving circuit can effectively reduce the switching time when the switch is turned on. (IV) The present invention is a schematic diagram of the laser diode driving circuit 40 according to another preferred embodiment of the present invention. Circuit 40 and circuit 3 of the third figure. Similar to the 'similar part no longer 赘: move 200919880 drive circuit 40 uses negative voltage pulse generator 42 to generate a negative voltage pulse to speed up the current switching speed, does not need diode D2, so it can reduce the conduction by diode D2 Power loss and current switching delay. The invention also discloses a method for driving a laser diode, which is applied to a pulse-driven high-power semiconductor laser diode and a high-power light-emitting diode. First, the DC/DC converter provides a first voltage Vdc! to the first capacitor and the laser diode load. The semiconductor component switch coupled to the laser diode load and the voltage pulse generator are controlled by an external pwM controller transfer control signal. After receiving the above control signal, the voltage pulse generator supplies a second voltage VDC2 to the second capacitor according to the control signal transmitted by the external PWM controller. The voltage pulse generator supplies a voltage to the second capacitor when the control signal is in a non-operating period. After receiving the control signal, the semiconductor element switch is turned on when the control signal is in a duty cycle. When the semiconductor element switch is turned on, the current supplied by the second capacitor flows through a path composed of a resistor, an inductor, a laser diode, and a semiconductor element switch to drive the laser diode. Referring to the fourth figure, when the driving current 1_ flowing through the laser diode is between a first current value Αι and a second current value a2, the second capacitor provides a second voltage n to drive the laser. Diode.
當雷射二極體驅動電流上升至第二電流值& 時’此時第二電容器已放電至其第二電壓值I小於第一 電儲存器所提供的第一電壓值V 持為第-電壓值W _出電壓V。』保 12 200919880 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i〇ut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，並有效 減少功率損耗。 本發明之雷射二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 200 A/ # Sec)要求及提咼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 :申：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I全釋。 【圖式簡單說明】 馮本發明之雷射 间很龈奉發明之較佳實施例When the laser diode drive current rises to the second current value &; then the second capacitor has been discharged until its second voltage value I is less than the first voltage value V provided by the first electrical storage device. The voltage value W _ is the voltage V. 』保12 200919880 The parasitic inductance on the path through which the semiconductor element switch is turned on will generate the back electromotive force vL'. To solve the above problem, the present invention adds an additional second voltage value at the rise time of the drive current i〇ut. Vdc2 drives the laser diode for fast current switching and improves the conversion efficiency of the power converter and reduces power consumption. The laser diode drive circuit of the present invention adds an additional positive or negative voltage pulse during the current switching rise time to accelerate current switching and effectively reduce power loss. The laser diode drive circuit of the present invention can be applied to a pulse wave driven high power semiconductor laser diode and a high power light emitting diode. It can achieve low current, high frequency, high current square wave power converters to achieve high current switching (greater than 200 A / # Sec) requirements and improve power conversion efficiency. It will be apparent to those skilled in the art that the present invention is not intended to limit the scope of the invention. Modifications and similar configurations made without departing from the spirit and scope of the invention are intended to be included in the following description: the scope should cover all similar modifications and similar structures and should be the broadest. [Simple description of the diagram] The preferred embodiment of the invention is in the laser room of the invention.
極體驅動電路示意圖；第二A 佳實施例，為第一圖電路之時序圖一：圖根據本發明之較 崎序圖，用以說1 作狀態；第三㈣縣發明之另—較 發明 之雷射二極體驅動電路示音 為本發明 實鈿例，為第三圖電路之時序 权佳 π固用以說明其電路的操作 13 200919880 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 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 電歷脈衝產生器 040 雷射二極體驅動電路 042 負電壓脈衝產生器 14A schematic diagram of a polar body driving circuit; a second embodiment of the first embodiment is a timing diagram of the first circuit: Figure 1 shows a state according to the invention, and a third (4) county invention. The display of the laser diode driving circuit is an example of the invention, and the timing of the circuit of the third figure is good. π is used to explain the operation of the circuit. 13 200919880 state; the fifth figure is another preferred according to the present invention. Embodiments are schematic diagrams of a laser diode driving circuit 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 First power supply path 032 DC/DC converter 033 Second power supply path 034 PWM controller 035 First path 036 Electric pulse generator 040 Laser diode drive circuit 042 Negative voltage pulse generator 14