- * 九、發明說明： ， 【發明所屬之技術領域】 本發明係指一種直流電源轉換電路，尤指一種用來驅動發光 裝置，具有自體輔助電壓源及負載開路及短路保護功能的直流電 . 源轉換電路。 【先前技術】 _ 近年來’發光二極體（LightEmittingDi〇de，LED)已普遍應 用使用於資訊、通訊及消費性電子產品的指示燈與顯示裝置上， 如父通號諸燈等等。不同於一般白熾燈泡，發光二極體係屬冷發 光το件’因此具有減量低、元件壽命長、無猶燈時間以及反 應速度快等優點，再加上其體積小、耐震動、適合量產，因此容 易配合應用需求而製成極小或陣列式的元件。在發光二極體的物 轉財’騎發光二極體之電鱗著發光二鋪之—順向偏壓 • I指數型的增加，而發光二極體之發光程度係與通過的電流成正 比，也就是說’當通過的電流越大，二極體發光_度也越高。 因此’-般來說’魏二極體需要—電祕換電路來控制其順向 偏壓，以穩定發光亮度。 、 請參考第1圖，帛1圖為一習知直流對直流電壓轉換器1〇 之示意圖。直流對直流電壓轉換器1〇包含有一直流電塵源1〇〇、 —開關電晶體102、-電阻104、一二極體1〇6、一電感⑽、一 控制訊號產生器110、-負載112及一線性調壓器（line_糾咖） 1325675 \ 器不僅耗費书月匕’亦可能因為線性調壓器過熱而損壞電路。 【發明内容】 因此’本發明之主要目的即在於提供一種具有自體輔助電壓 源及負载開路及短路倾魏的直流電轉換電路。 士么本發明係揭露一種具有自體輔助電壓源及負载開路及短路保 瘦功月b的直流電轉換電路。該直流電_換電路包含有一直流 電塵源、-驅動電路及—辅助電路。該直流電壓源係絲提供一 ，原：驅動電路包含有-開關、-第-電阻、-控制訊號 叙接電阻、—二極體及—電感。該糊具有一第一端 麵接於該錢龍源，—第二端絲接收-控觀號，以及-第 =第該Γ請用來根據該第二端所接收之控制訊號，導通或關 =2 賴。鮮—树㈠—翻接於 逐開闕之第二h ’及一黛-^山.> J,., 電阻之第-端及L 11產生11祕於該第一 一鳊，用來感測該第一電阻之電壓，以產峰哕 控制訊號。該第二電阻具有 “ 關之第-端，及―第一姓論_接於該直流輕源及該開 有當心社 該控制訊號產生器。該二極體且 於該第，且之第二端，及—第接 地知。該電感具有-第一端_於該第 及= 二端耦接於一負載。 罘一知，及一第 助電容及-輔助-極:=聯於該電感' 其包含有-輔 電阻之第η:::電容具有-第，接於該第- 喊接於該第二電阻之第二端。該辅助 、75 才。體/、有第一端耗接於該輔助電容之第二端，及一第二端. 接於該電感之第二端。 > 【實施方式】 °月參考第2圖’第2圖為本發明具有自體輔助電壓源及負載 開路及短路保護魏流電源轉觀路2G之示意目。直流電源 轉換電路20包含有一直流電壓源2〇〇、-負载212、-驅動電路 22及一辅助電路24。直流電壓源200耦接於一接地端GND，用 來提供-直流電源Vin。負載212係為發光裝置，通常由至少_發 光二極體（LightEmittingDiode，LED)組成，其亦耦接於接地端 GND。驅動電路22之構成元件類似於第丨圖之直流對直流電壓轉 換器ίο,包含有一開關202、一第一電阻2〇4、一二極體2〇6、一 電感208、一第二電阻21〇及一控制訊號產生器26。開關2〇2用 來根據一第二端2024所接收之一控制訊號&，導通或關閉一第一 端2022至一第三端2026之連結。開關202通常為一金屬氧化半 導體琢效電阳體（metal-oxide-semiconductor field-effect transistor， MOSFET)，其第一端2022係汲極，第二端2024係閘極，第三端 2026係源極。或者，開關202亦可為一雙極性接面電晶體（Bip〇lar- * Nine, the invention description: , [Technical field of the invention] The present invention refers to a DC power conversion circuit, especially a DC device for driving a light-emitting device, having a self-assisted voltage source and a load open circuit and short circuit protection function. Source conversion circuit. [Prior Art] _ In recent years, LightEmitting Diode (LED) has been widely used in indicator lights and display devices for information, communication and consumer electronics, such as the father's number lamps. Different from ordinary incandescent light bulbs, the light-emitting diode system is a cold-emitting light-emitting device. Therefore, it has the advantages of low reduction, long component life, no lamp time and fast response speed, plus its small size, vibration resistance and mass production. Therefore, it is easy to make a very small or array type component in accordance with the application requirements. In the light-emitting diode, the material is turned into a 'light-emitting diode', and the light-emitting diode is illuminated. The forward bias is increased. The I-index is increased, and the luminous level of the light-emitting diode is proportional to the current passing through. That is to say, 'the greater the current passing through, the higher the luminescence of the diode. Therefore, the 'well-like' Wei-polar body needs to be electrically switched to control its forward bias to stabilize the brightness of the light. Please refer to Figure 1, which is a schematic diagram of a conventional DC-to-DC voltage converter. The DC-to-DC voltage converter 1A includes a DC power source 1〇〇, a switching transistor 102, a resistor 104, a diode 1〇6, an inductor (10), a control signal generator 110, a load 112, and A linear regulator (line_correcting coffee) 1325675 \ not only costs the book month 'may also damage the circuit due to overheating of the linear regulator. SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a DC power conversion circuit having a self-assisted voltage source, a load open circuit, and a short circuit. The invention discloses a direct current conversion circuit having a self-assisted voltage source and a load open circuit and a short circuit protection function b. The DC power conversion circuit includes a DC power source, a drive circuit, and an auxiliary circuit. The DC voltage source wire provides a first: the drive circuit includes a - switch, - a - resistance, - a control signal, a resistor, a diode and an inductor. The paste has a first end face connected to the Qianlong source, the second end wire receiving-control view number, and - the first = the first requesting to be turned on or off according to the control signal received by the second end =2 Lai. Fresh-tree (1)--connected to the second h' and the 黛-^山.> J,., the first end of the resistor and the L 11 produce 11 secrets to the first one, for the sense The voltage of the first resistor is measured to generate a peak 哕 control signal. The second resistor has a "closed end", and a "first name" is connected to the DC light source and the controller has a control signal generator. The diode is in the second and second The first and second ends of the inductor are coupled to a load at the first and second ends. A first aid, and a first auxiliary capacitor and an auxiliary-pole: = coupled to the inductor The η::: capacitor having a secondary resistor has a -th. The second terminal connected to the second resistor is connected to the second resistor. The auxiliary is 75. The first terminal is connected to the first terminal. The second end of the auxiliary capacitor and the second end are connected to the second end of the inductor. [Embodiment] ° month reference to FIG. 2' is a self-assisted voltage source and load according to the present invention. Open circuit and short circuit protection Wei flow power transfer road 2G. The DC power conversion circuit 20 includes a DC voltage source 2, - load 212, - drive circuit 22 and an auxiliary circuit 24. The DC voltage source 200 is coupled to A grounding terminal GND is provided for supplying a DC power source Vin. The load 212 is a light emitting device, usually by at least a light emitting diode (Light Emitting Di The ode (LED) is also coupled to the ground GND. The components of the driving circuit 22 are similar to the DC-to-DC voltage converter of the first drawing, and include a switch 202, a first resistor 2〇4, and a second. The pole body 2〇6, an inductor 208, a second resistor 21〇, and a control signal generator 26. The switch 2〇2 is used to turn on or off a control signal according to a second terminal 2024. The connection 202 is generally a metal-oxide-semiconductor field-effect transistor (MOSFET), and the first end 2022 is a drain, the second The terminal 2024 is a gate, and the third terminal 2026 is a source. Alternatively, the switch 202 can also be a bipolar junction transistor (Bip〇lar).
Junction Transistor…BJT) ’ 則第一端 2022 係集極，第二端 2024 係基極，第三端2026係射極。第二電阻21〇係一高阻抗的電阻， 用來提供控制訊號產生器26的啟動電源。二極體206通常為一 pn 接面半導體元件，其第2圖中之右端為n極而左端為p極。電感 1325675 2〇8麵接於負載212 ’用來儲存或釋放直流電壓源2〇〇提供之能 置。控制訊號產生器26通常為-脈寬調變器，輕接於第一電阻2〇4 之兩端，藉此用來感測第—電阻204之電壓，以產生控制訊號&。 根據第-電阻綱之電流改變的程度，控制訊號產生器％調整控 制訊號Sc，以控制開關202之導通或關閉。 本發明直流電源轉換電路20於驅動電路22之電感208上並 φ 聯辅助電路24。辅助電路24包含有一輔助電容214及一辅助二極 體216。辅助電容214於直流電源轉換電路2〇啟動時，透過第二 電阻210，储存直流電獅2〇〇提供之能量。當儲滿電能時，輔助 電容214即形成-辅助電壓源，可提供一穩定的辅助電壓W給 控制訊號產生器26。輔助二極體216輕接於辅助電容214與電感 208之間，用來於開關202導通時，防止直流電壓源2〇〇提供之電 源的電流流入輔助電路24導致負載212的電壓發生非預期的改 變。輔助一極體216通常相同於二極體2〇6，具有相同的順向偏 •壓’其第2圖中之右端為η極而左端為p極。直流電源轉換電路 20另包含一濾波電容（未示於第2圖）耦接於一接地端GND與 電感208之間，用來濾除輸出至負載212之電流的雜訊。 本發明直流電源轉換電路20之工作原理如下。首先，於直流 電源轉換電路20啟動時’第二電阻210調降直流電源Vin至一適 當的電壓準位’以啟動控制訊號產生器26，並同時提供能量給電 容214作儲能用。控制訊號產生器26於啟動後透過接線ρι及？2， 1325675 不斷地感測通過第-電阻204之電流，並根據電流變化，事實調 整控制化號Sc。接著，當開關2〇2導通時，二極體施及輔助二 極體216皆承叉反偏壓，分別阻斷迴路[2及迴路。直流電壓 源200對電感208儲能’此時第一電阻2〇4的電流隨著電感2〇8 的電流逐步往上升。當電阻2〇4的電流上升至一預定最大值時， 控制訊號產生器26透過控制訊號Se關閉開關2Q2。一旦開關2〇2 關閉，二極體206及辅助二極體216皆運作於順向偏壓時，分別 • 導通迴路L2及U。由於直流電麗源200之供電被截斷，電感208 產生極性相反的電壓，同時提能量給負載212及辅助電容214，使 通過負載212之電流不會發生劇烈變化，亦可使辅助電容214維 持穩定的電壓，維持控制訊號產生器26之正常運作。因此，無論 在開關202導通或關閉的情形下，對控制訊號產生器％來說，辅 助電谷214如一穩定的電壓源，提供輔助電壓Vcc給控制訊號產 生器26。最後，當第一電阻2〇4的電流下降至一預定最小值時， 控制訊號產生器26再透過控制訊號Sc開啟開關2〇2，使直流電源 轉換電路20之工作因開關202導通及關閉不斷循環下去。 在直流電源轉換電路20中，若負載212、電感208及辅助電 谷214的電壓大小分別為vLD、VL及Vc，並根據迴路L2及L3， 可得出關係式·： ------ VL=二極體216的順向偏壓+ Vld=二極體2〇6的順向偏壓Junction Transistor...BJT) ’ then the first end 2022 is the collector, the second end 2024 is the base, and the third end 2026 is the emitter. The second resistor 21 is a high impedance resistor for providing a startup power to the control signal generator 26. The diode 206 is typically a pn junction semiconductor device, the second end of which is n pole and the left end is p pole. Inductor 1325675 2〇8 is connected to load 212 ’ to store or release the DC voltage source 2〇〇. The control signal generator 26 is typically a pulse width modulator that is coupled across the first resistor 2〇4 to sense the voltage of the first resistor 204 to generate a control signal & The control signal generator % adjusts the control signal Sc to control the on or off of the switch 202 according to the degree of change of the current of the first-resistance. The DC power conversion circuit 20 of the present invention is coupled to the inductor 208 of the drive circuit 22 and coupled to the auxiliary circuit 24. The auxiliary circuit 24 includes an auxiliary capacitor 214 and an auxiliary diode 216. When the DC power conversion circuit 2 is activated, the auxiliary capacitor 214 transmits the energy supplied by the DC lion 2 through the second resistor 210. When fully charged, the auxiliary capacitor 214 forms an auxiliary voltage source that provides a stable auxiliary voltage W to the control signal generator 26. The auxiliary diode 216 is lightly connected between the auxiliary capacitor 214 and the inductor 208, and is used to prevent the current of the power supply provided by the DC voltage source 2 from flowing into the auxiliary circuit 24 when the switch 202 is turned on, so that the voltage of the load 212 is unexpected. change. The auxiliary diode 216 is generally identical to the diode 2〇6 and has the same forward bias voltage. In the second figure, the right end is the η pole and the left end is the p pole. The DC power conversion circuit 20 further includes a filter capacitor (not shown in FIG. 2) coupled between a ground GND and the inductor 208 for filtering noise of the current output to the load 212. The working principle of the DC power conversion circuit 20 of the present invention is as follows. First, when the DC power conversion circuit 20 is activated, the second resistor 210 lowers the DC power source Vin to an appropriate voltage level to activate the control signal generator 26 and simultaneously supplies energy to the capacitor 214 for energy storage. The control signal generator 26 is connected through the wiring after the start-up? 2, 1325675 continuously senses the current through the first-resistor 204, and adjusts the control number Sc according to the current change. Then, when the switch 2〇2 is turned on, the diode application auxiliary diode 216 is biased by the reverse bias, respectively blocking the loop [2 and the loop. The DC voltage source 200 stores energy to the inductor 208. At this time, the current of the first resistor 2〇4 gradually rises with the current of the inductor 2〇8. When the current of the resistor 2〇4 rises to a predetermined maximum value, the control signal generator 26 turns off the switch 2Q2 through the control signal Se. Once the switch 2〇2 is turned off, both the diode 206 and the auxiliary diode 216 operate in the forward bias, respectively • the loops L2 and U are turned on. Since the power supply of the DC power source 200 is cut off, the inductor 208 generates a voltage of opposite polarity, and simultaneously supplies energy to the load 212 and the auxiliary capacitor 214, so that the current passing through the load 212 does not change drastically, and the auxiliary capacitor 214 can be maintained stably. The voltage maintains the normal operation of the control signal generator 26. Therefore, the auxiliary power valley 214, such as a stable voltage source, provides the auxiliary voltage Vcc to the control signal generator 26 for the control signal generator % regardless of whether the switch 202 is turned "on" or "off". Finally, when the current of the first resistor 2〇4 drops to a predetermined minimum value, the control signal generator 26 turns on the switch 2〇2 through the control signal Sc, so that the operation of the DC power conversion circuit 20 is turned on and off due to the switch 202. Loop down. In the DC power conversion circuit 20, if the voltages of the load 212, the inductor 208, and the auxiliary valley 214 are vLD, VL, and Vc, respectively, and according to the loops L2 and L3, the relationship can be obtained:: ------ VL = forward bias of the diode 216 + Vld = forward bias of the diode 2 〇 6
+ VC 由於二極體216的順向偏壓與二極體2〇6的順向偏壓幾乎相同， 1325675 最後可得到負載212、電感208及辅助電容214的電壓之間的關係 式為：vL=vLD=vc。因此，若負載212發生短路，則由上述之 關係式可知vL=vLD=o (v〇it)，❿辅助電容214則快速放電。此 日f ’換成由直流電壓源、200透過高阻抗之電阻21〇提供獅電壓 Vcc給控制訊號產生器26。由於電阻21〇之高阻抗的關係，辅助 電壓Vce將變為-很低驗準’將無法提供足夠的卫作電壓而使 • 洲喊纽11 26進人i類S (hieeup)，纽是時而啟動時 φ 酬置。另外’若負載212有開路的情況發生，則由上述之關係 式可知vLD=vc，此時直流電源轉換電路2〇可藉由辅助電容214 之電壓VC來判斷負載212的電壓&是否過高。控制訊號產生器 26根據判斷結果可自動地調整開關2〇2的導通時間，以防止負載 電壓過高而造成電路損壞。因此，無論負載212發生短路或開路， 直流電源轉換電路20可根據輔助電容2丨4輸出之輔助電屋Vcc， 調整控制訊號產生器26之工作狀態，以適時改變開關2〇2之導通 鲁 頻率，以保護直流電源轉換電路20免於損壞。 總括來說，在習知技射’ f知直流電_換電路係利用一 低效率的調壓電路來提供工作電源給訊號控制產生器，造成習知 . 直流電轉換電路浪費魏。姆於f知技術，本發明係並聯一 输助電路於電感上，使開關導通或關時，辅助電路皆可提供一 穩定的輔助電源給控制訊號產生器，以維持電路正常運作。並於 負載發生短路或斷路時，本發明可透過輔助電路提供之辅助電 壓’調整控制訊號產生器之工作狀態，以改變適時改變開關之導 12 1325675 通頻率，藉此預防電路因負載電流過高而損壞。 以上所述僅為本發明之較佳實施例，凡依本發明申請專利範 圍所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 • 【圖式簡單說明】 第1圖為一習知降壓式直流對直流電壓轉換器之示意圖。 第2圖為本發明具自體輔助電壓源及負载開路及短路保護功处 直流電源轉換電路之示意圖。 1之 【主要元件符號說明】 10 直流對直流電壓轉換器 102 開關電晶體 20 直流電源轉換電路 22 驅動電路 24 辅助電路 100、200 直流電壓源 202 開關 104、204、210 電阻 106、206、216 二極體 ..... 108、208 電感 214 電容 112 > 212 負載+ VC Since the forward bias of the diode 216 is almost the same as the forward bias of the diode 2〇6, the relationship between the voltage of the load 212, the inductor 208 and the auxiliary capacitor 214 is finally obtained: vL =vLD=vc. Therefore, if the load 212 is short-circuited, it is known from the above relationship that vL = vLD = o (v〇it), and the ❿ auxiliary capacitor 214 is rapidly discharged. On this day, f' is replaced by a DC voltage source, 200 through a high-impedance resistor 21, to provide a lion voltage Vcc to the control signal generator 26. Due to the high impedance relationship of the resistor 21〇, the auxiliary voltage Vce will become - very low accuracy - will not provide enough servo voltage to make the state 11 11 11 11 26 into the i class S (hieeup), New Zealand is At the time of startup, φ is paid. In addition, if the load 212 has an open circuit, it can be seen from the above relationship that vLD=vc. At this time, the DC power conversion circuit 2 can determine whether the voltage of the load 212 is too high by the voltage VC of the auxiliary capacitor 214. . The control signal generator 26 automatically adjusts the on-time of the switch 2〇2 according to the judgment result to prevent the circuit from being damaged due to excessive load voltage. Therefore, regardless of whether the load 212 is short-circuited or open-circuited, the DC power conversion circuit 20 can adjust the working state of the control signal generator 26 according to the auxiliary electric house Vcc outputted by the auxiliary capacitor 2丨4, so as to change the conduction Lu frequency of the switch 2〇2 in time. To protect the DC power conversion circuit 20 from damage. In summary, the conventional technique of using a low-efficiency voltage regulator circuit to provide a working power supply to the signal control generator is known. The DC conversion circuit wastes Wei. In the invention, the auxiliary circuit is connected to the inductor in parallel with the auxiliary circuit, so that the auxiliary circuit can provide a stable auxiliary power to the control signal generator to maintain the normal operation of the circuit. When the load is short-circuited or disconnected, the present invention can adjust the operating state of the control signal generator through the auxiliary voltage provided by the auxiliary circuit to change the frequency of the switch 12 1325675 in time, thereby preventing the circuit from being overloaded due to the load current. And damaged. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should fall within the scope of the present invention. • [Simple description of the diagram] Figure 1 is a schematic diagram of a conventional buck DC-to-DC voltage converter. 2 is a schematic diagram of a DC power conversion circuit with a self-assisted voltage source and a load open circuit and a short circuit protection function according to the present invention. 1 [Main component symbol description] 10 DC-to-DC voltage converter 102 Switching transistor 20 DC power conversion circuit 22 Drive circuit 24 Auxiliary circuit 100, 200 DC voltage source 202 Switch 104, 204, 210 Resistance 106, 206, 216 Polar body..... 108,208 Inductor 214 Capacitance 112 > 212 Load
13 1325675 110、26 控制訊號產生器 114 線性調壓器 Sc 控制訊號 U、L2、L3 迴路 2022'2024、 2026 端點 • GND 接地端 • Vcc 電壓 Vin 直流電源 • PI > P2 接線 • 1413 1325675 110, 26 Control Signal Generator 114 Linear Regulator Sc Control Signal U, L2, L3 Loop 2022'2024, 2026 End Point • GND Ground Terminal • Vcc Voltage Vin DC Power Supply • PI > P2 Wiring • 14