1345360 099年12月14日修正替換頁 六、發明說明： 【發明所屬之技術領域】 [0001] 本發明係關於一種直流電壓轉換電路。 【先前技術】 ’ [0002] 目前，直流電壓轉換電路作為驅動電源，已被廣泛應用 於便攜式液晶顯示器中。一般，便攜式液晶顯示器正常 工作需要一穩定之8V直流電壓及一穩定之3. 3V直流電壓1345360 Revised replacement page on December 14, 099. VI. Description of the Invention: [Technical Field of the Invention] [0001] The present invention relates to a DC voltage conversion circuit. [Prior Art] [0002] At present, a DC voltage conversion circuit has been widely used as a driving power source in a portable liquid crystal display. Generally, a portable liquid crystal display requires a stable 8V DC voltage and a stable 3. 3V DC voltage.
[0003] 請參閱圖1，係一先前技術直流電壓轉換電路之示意圖。 該直流電壓轉換電路10包括一電源（1. 5V)11、一升压式 直流电源变换積體電路（Step-up Dc-dc Convert-er)13、一第一調壓電路12、一第二調壓電路14、一第 一輸出端15及一第二輸出端16。 [0004] 該第一調壓電路1 2用於將該電源11之1. 5 V直流電壓轉換 為一8V直流電壓，並經由該第一輸出端15輸出。該第一 調壓電路12包括一低噪音負輸出電荷泵穩壓器121、一第 • 一反饋支路122及一第一電容123。該第一電容123與該 第一反饋支路122並聯，其一端接地，另一端連接至該第 一輸出端15。該第一反饋支路122包括串聯之一第一電阻 124及一第二電阻125。 [0005] 該低噪音負輸出電荷泵穩壓器121用於接收該第一反饋支 路122反饋之電壓，並穩定該第一輸出端15之電壓。該低 噪音負輸出電荷泵穩壓器121之型號為MAX853，其包括 一輸入端1210、一第一反饋接收端1211及一負壓輸出端 096132576 1212。該輸入端1210連接至該電源11，該負壓輸出端 表單編號A0101 第5頁/共21頁 0993445888-0 1345360 099年12月14日修正替換百 1212連接至該第一輸出端15。該第一反饋接收端1211連 接於該第一電阻124與該第二電阻125之間。 [0006] 該第二調壓電路14用於將該電源11之1. 5 V直流電壓轉換 為3. 3V直流電壓，並經由該第二輸出端16輸出。該第二 調壓電路14包括一電感141、一二極體142、一第二反饋 支路143及一第二電容144。該電源11依序經由該電感 141、該二極體142之陽極（未標號）、陰極（未標號）連接 至該第二輸出端16。該第二電容144與該第二反饋支路 143並聯，其一端接地，另一端連接至該第二輸出端16。 該第二反饋支路143包括串聯之一第三電阻145及一第四 電阻146。 :V ^ [0007] 該升壓式直流電源變換積體I電路少3救於七散該第二反饋 支路143反饋之電壓，並穩定該第二輸出端16之電壓。該 升壓式直流電源變換積體電路13之型號為ΜΑΧ856，其包 括一第二反饋接收端131及一控制輸出端132。該控制輸 出端132連接至該二極體142之障極η”該第二反饋接收端 131連接於該第三電阻145輿該策四：：電阻146之間。 [0008] 惟，該直流電壓轉換電路10之第一調壓電路12係藉由該 低噪音負輸出電荷泵穩壓器12達到一8V之直流電壓。通 常該低噪音負輸出電荷泵穩壓器12之成本較高，因此該 直流電壓轉換電路10之成本較高。 【發明内容】 [0009] 有鑑於此，提供一種成本較低且體積較小之直流電壓轉 換電路實為必需。 096132576 表單編號A0101 第6頁/共21頁 0993445888-0 1345360 [0010]Please refer to FIG. 1, which is a schematic diagram of a prior art DC voltage conversion circuit. The DC voltage conversion circuit 10 includes a power supply (1.5 V) 11, a step-up DC-DC convert-er circuit 13, a first voltage regulator circuit 12, and a second The voltage regulating circuit 14 has a first output end 15 and a second output end 16. [0004] The first voltage regulating circuit 12 is configured to convert a 1.5 V DC voltage of the power source 11 into an 8 V DC voltage, and output through the first output terminal 15. The first voltage regulating circuit 12 includes a low noise negative output charge pump regulator 121, a first feedback branch 122 and a first capacitor 123. The first capacitor 123 is connected in parallel with the first feedback branch 122, one end of which is grounded, and the other end of which is connected to the first output terminal 15. The first feedback branch 122 includes a first resistor 124 and a second resistor 125 connected in series. The low noise negative output charge pump regulator 121 is configured to receive the voltage fed back by the first feedback branch 122 and stabilize the voltage of the first output terminal 15. The low noise negative output charge pump regulator 121 is of the type MAX853 and includes an input terminal 1210, a first feedback receiving terminal 1211 and a negative voltage output terminal 096132576 1212. The input terminal 1210 is connected to the power source 11, the negative voltage output terminal form number A0101, page 5 of 21, 0993445888-0 1345360, December 14, 2004, the correction replacement hundred 1212 is connected to the first output terminal 15. The first feedback receiving end 1211 is connected between the first resistor 124 and the second resistor 125. The second voltage regulating circuit 14 is configured to convert the 1.5 V DC voltage of the power source 11 into a 3.3 V DC voltage, and output through the second output terminal 16. The second voltage regulating circuit 14 includes an inductor 141, a diode 142, a second feedback branch 143, and a second capacitor 144. The power source 11 is sequentially connected to the second output terminal 16 via the inductor 141, an anode (not labeled) of the diode 142, and a cathode (not labeled). The second capacitor 144 is connected in parallel with the second feedback branch 143, one end of which is grounded and the other end of which is connected to the second output terminal 16. The second feedback branch 143 includes a third resistor 145 and a fourth resistor 146 in series. :V ^ [0007] The boosted DC power conversion integrated circuit I saves the voltage fed back by the second feedback branch 143 and stabilizes the voltage of the second output terminal 16. The boost DC power conversion integrated circuit 13 is model 856, which includes a second feedback receiving end 131 and a control output 132. The control output 132 is connected to the barrier η of the diode 142. The second feedback receiving end 131 is connected between the third resistor 145 and the resistor 146. [0008] The first voltage regulating circuit 12 of the conversion circuit 10 reaches a DC voltage of 8 V by the low noise negative output charge pump regulator 12. Generally, the low noise negative output charge pump regulator 12 has a high cost, so The cost of the DC voltage conversion circuit 10 is relatively high. SUMMARY OF THE INVENTION [0009] In view of the above, it is necessary to provide a DC voltage conversion circuit with a lower cost and a smaller volume. 096132576 Form No. A0101 Page 6 of 21 0993445888-0 1345360 [0010]
[0011][0011]
099年12月14日按正替換頁 一種直流電壓轉換電路，其包括一電源、一第一輸出端 、一第二輸出端、一變壓器 '一第一調壓電路、一第二 調壓電路及一升压式直流电源变换積體電路。該第一调 壓電路包括一電晶體、一第一電容及一第一二極體。該 第一電容一端接地，另一端連接至該第一輸出端。該第 一輸出端依序經由該第一二極體之陽極、陰極、該變壓 器及該電晶體之汲極、源極接地。該電源依序經由該變 壓器及該第二調壓電路為該第二輸出端提供一第二電壓 。該升压式直流电源变换積體電路用於接收該第二輸出 端之反饋電壓，並穩定該第二輸出端之電壓，亦用於接 收該第一輸出端之反饋電壓，控制該電晶體之導通或關 / " ; 閉，以穩定該第一輸出端之電屋。 , r .· Si £ -i —4 一種直流電壓轉換電路，其包括一電源、/一第一輸出端 、一第二輸出端、一變壓器、一第一調壓電路、一第二 調壓電路及一升压式直流电源变换積體電路。該第一调 + - Ά 2 心 * . Λ··. ( 壓電路包括一電晶體、一第一電容及一第二二極體。該• ， ， 第一電容一端接地，另一端連接至該第一輸出端。該第 一輸出端依序經由該第一二極體之陽極、陰極、該變壓 器及該電晶體之汲極、源極接地。該電源依序經由該變 壓器及該第二調壓電路連接至該第二輸出端。該升压式 直流电源变换積體電路包括一第一反饋端、一第二反饋 端、一第一控制輸出端及一第二控制輸出端。該第一反 饋端連接至該第一輸出端。該第二反饋端連接至該第二 輸出端。該第一控制輸出端連接至該電晶體之閘極，用 於根據該第一反饋端之電壓，穩定該第一輸出端之電壓 096132576 表單編號Α0101 第7頁/共21頁 0993445888-0 1345360 [0012] 099年12月14日梭正巷換頁 »該第二控制輸出端連接至該第二調壓電路，用於根據 該第二反饋端之電壓，穩定該第二輸出端之電壓。 相較於先前技術，該直流電壓轉換電路僅需一升壓式直 流電源變換積體電路，再配合二調壓電路便可使該二輸 出端達到二電壓，因此該直流電壓#換電路之成本較低 [0013] 【實施方式】 請參閱圖2，係本發明直流電壓轉換電路第一實施方式之 示意圖。該直流電壓轉換電路20包括一電源21、一變壓 器22、一升压式直流电源变换積體電路23、一第一調壓 電路25、一第二調壓電路24^1第二遍 每|7及一第二A DC voltage conversion circuit comprising a power source, a first output terminal, a second output terminal, a transformer 'a first voltage regulating circuit, a second voltage regulating circuit and A boost DC power conversion integrated circuit. The first voltage regulating circuit includes a transistor, a first capacitor and a first diode. The first capacitor is grounded at one end and connected to the first output terminal at the other end. The first output terminal is grounded via the anode and cathode of the first diode, the transformer, and the drain and source of the transistor. The power supply sequentially supplies a second voltage to the second output terminal via the transformer and the second voltage regulating circuit. The step-up DC power conversion integrated circuit is configured to receive a feedback voltage of the second output end, and stabilize a voltage of the second output end, and is also configured to receive a feedback voltage of the first output end, and control the transistor Turn on or off / " Close to stabilize the first output of the electric house. , r .· Si £ -i — 4 A DC voltage conversion circuit comprising a power source, a first output terminal, a second output terminal, a transformer, a first voltage regulating circuit, and a second voltage regulating circuit And a boost DC power conversion integrated circuit. The first tone + - Ά 2 heart * . Λ ··. ( The voltage circuit comprises a transistor, a first capacitor and a second diode. The first capacitor is grounded at one end and connected to the other end The first output end is connected to the anode of the first diode, the cathode, the transformer, and the drain and source of the transistor are grounded. The power source sequentially passes through the transformer and the second The voltage regulating circuit is connected to the second output end. The boosting DC power conversion integrated circuit comprises a first feedback end, a second feedback end, a first control output end and a second control output end. a feedback end is connected to the first output end. The second feedback end is connected to the second output end. The first control output end is connected to the gate of the transistor, according to the voltage of the first feedback end, Stabilize the voltage of the first output 096132576 Form No. 1010101 Page 7 / Total 21 Page 0993445888-0 1345360 [0012] On December 14, 099, the shuttle is changing pages » The second control output is connected to the second voltage regulator a circuit for stabilizing the voltage according to the second feedback terminal Compared with the prior art, the DC voltage conversion circuit only needs a boost DC power conversion integrated circuit, and the second voltage regulating circuit can make the two output terminals reach the two voltages, so the DC The cost of the voltage circuit is lower [0013] [Embodiment] Please refer to FIG. 2, which is a schematic diagram of a first embodiment of a DC voltage conversion circuit of the present invention. The DC voltage conversion circuit 20 includes a power source 21, a transformer 22, and a The step-up DC power conversion integrated circuit 23, a first voltage regulating circuit 25, a second voltage regulating circuit 24^1, the second pass, each of the |7 and a second
[0014] 輸出端26。該變壓器22包械ΐ-祕逆線£圈終备1氣一次級線圈 222。該次級線圈222經由該第一調壓電路25為該第一輸 出端27提供一第一電壓。該電源21經由該初級線圈221及 該第二調壓電路24為該第；輸出，端26提供厂第二電壓。 ' ** > ' ί ^ / r 1 ' ^ ·- r ' 該第一調壓電路25包括一 # 一二極體2W1、一第一電容 252、一電晶體254及一第'反饋支路253。該第一輸出 端27依序經由該第一二極體251之陽極（未標號）、陰極（ 未標號）、該變壓器22之次級線圈222之異名端（未標號） 、同名端（未標號）及該電晶體254之汲極、源極接地。該 第一電容252與該第一反饋支路253並聯，其一端接地， 另一端連接至該第一輸出端27。該第一反饋支路253包括 二串聯之第一電阻256及第二電阻257。[0014] Output terminal 26. The transformer 22 is equipped with a ΐ-secret reverse line and a ring of 1 gas primary coil 222. The secondary coil 222 provides a first voltage to the first output terminal 27 via the first voltage regulating circuit 25. The power source 21 is the first through the primary coil 221 and the second voltage regulating circuit 24; the output terminal 26 provides a factory second voltage. ' ** > ' ί ^ / r 1 ' ^ · - r ' The first voltage regulating circuit 25 includes a # diode 2W1, a first capacitor 252, a transistor 254 and a 'feedback branch' 253. The first output end 27 sequentially passes through the anode (not labeled) of the first diode 251, the cathode (not labeled), the different end of the secondary coil 222 of the transformer 22 (not labeled), and the end of the same name (not labeled) And the drain and source of the transistor 254 are grounded. The first capacitor 252 is connected in parallel with the first feedback branch 253, one end of which is grounded, and the other end of which is connected to the first output end 27. The first feedback branch 253 includes two first resistors 256 and a second resistor 257 connected in series.
該第二調壓電路24包括一第二二極體241、一第二電容 242及一第二反饋支路243。該電源21依序經由該變壓器 096132576 表單編號A0101 第8頁/共21頁 0993445888-0 [0015] 1345360 099年12月14日修正替換頁 22之初級線圈221、該第二二極體241之陽極（未標號）、 陰極（未標號）連接至該第二輸出端26 ^該第二電容242與 該第二反饋支路243並聯，其一端接地，另一端連接至該 第二輸出端26。該第二反饋支路243包括二串聯之第三電 阻244及第四電阻245。 [0016] 該升壓式直流電源變換積體電路23包括一第一控制輸出 端232 ' —第二控制輸出端231、一第一反饋端234及一 第二反饋端233。該第一反饋端234用於接收該第一反饋 支路253反饋之電壓。該第二反饋端233用於接收該第二 反饋支路243反饋之電壓。該第一控制輸出端232連接至 該電晶體254之閘極（未標號該第乂‘制輸出端231連 接至該第二二極體241之陽極該秦丄反饋蟪234連接於 該第一電阻256與該第二電阻257之間。該第二反饋端 233連接於該第三電阻244與該第四電阻245之間。 [00Π]該升壓式直流電源變換積體電路23擇據該第一反饋端234 ..' ' i I V ·： 之電壓，控制該第一控制輸出端23么輸出高電平或低電平 ，從而控制該電晶體254之開啟或關閉。該升壓式直流電 源變換積體電路23根據該第二反饋端233之電壓，控制該 第二控制輸出端231輸出之脈衝訊號之占空比，從而控制 該變壓器22之初級線圈221之儲能時間。該第二控制輸出 端231輸出之該脈衝訊號具有一初始占空比。 [0018] 該升壓式直流電源變換積體電路23之型號可為MAX856， 其第一控制輸出端232係該MAX856之LBO接腳，該第一反 饋端234係該MAX856之LBI接腳，該第二控制輸出端231 係該MAX856之LX接腳’該第二反饋端233係該MAX856之 096132576 表單編號A0101 第9頁/共21頁 0993445888-0 1345360 099年12月14日梭正替换頁 FB接腳。 [0019] 該電源21可為1. 5 V之直流電源。該第一輸出端2 7之第一 電壓可為一8V。該第二輸出端26之第二電壓可為3. 3V。 當該二輸出端27、26之二電壓分別為一8V及3. 3V時，該 第一電阻256及該第三電阻244之阻值可為1 0K歐姆，該 第二電阻257之阻值可為1.87K歐姆，該第四電阻245之 阻值可為6.2K歐姆，第一電容252之容值可為68微法， 該第二電容242之容值可為100微法。The second voltage regulating circuit 24 includes a second diode 241, a second capacitor 242 and a second feedback branch 243. The power source 21 is sequentially passed through the transformer 096132576 Form No. A0101 Page 8 / Total 21 Page 0993445888-0 [0015] 1345360 December 14, 2004 Correction of the primary coil 221 of the replacement page 22, the anode of the second diode 241 (not labeled), a cathode (not labeled) is connected to the second output terminal 26. The second capacitor 242 is connected in parallel with the second feedback branch 243, one end of which is grounded and the other end of which is connected to the second output terminal 26. The second feedback branch 243 includes two third resistors 244 and a fourth resistor 245 connected in series. The boosting DC power conversion integrated circuit 23 includes a first control output 232'-second control output 231, a first feedback terminal 234 and a second feedback terminal 233. The first feedback terminal 234 is configured to receive the voltage fed back by the first feedback branch 253. The second feedback end 233 is configured to receive the voltage fed back by the second feedback branch 243. The first control output 232 is connected to the gate of the transistor 254 (the output terminal 231 is not connected to the anode of the second diode 241. The Qin 丄 feedback 234 is connected to the first resistor. Between the 256 and the second resistor 257. The second feedback terminal 233 is connected between the third resistor 244 and the fourth resistor 245. [00Π] The boost DC power conversion integrated circuit 23 selects the first A voltage of a feedback terminal 234 ..' ' i IV ·: controls the first control output terminal 23 to output a high level or a low level, thereby controlling the opening or closing of the transistor 254. The boosting DC power supply The conversion integrated circuit 23 controls the duty ratio of the pulse signal outputted by the second control output 231 according to the voltage of the second feedback terminal 233, thereby controlling the energy storage time of the primary coil 221 of the transformer 22. The second control The pulse signal outputted by the output terminal 231 has an initial duty ratio. [0018] The boosted DC power conversion integrated circuit 23 can be a MAX856 model, and the first control output terminal 232 is the LBO pin of the MAX856. The first feedback end 234 is an LBI pin of the MAX856, The second control output terminal 231 is the LX pin of the MAX856. The second feedback terminal 233 is the 096132576 of the MAX856. Form number A0101 Page 9/Total 21 page 0993445888-0 1345360 December 14, 2004 Shuttle replacement page FB 3伏。 The second voltage of the second output terminal 26 may be 3. 3V. The second voltage of the second output terminal 26 may be 3. 3V When the voltages of the two outputs 27 and 26 are respectively 8V and 3.3V, the resistance of the first resistor 256 and the third resistor 244 may be 10K ohms, and the resistance of the second resistor 257 It can be 1.87K ohms, the resistance of the fourth resistor 245 can be 6.2K ohms, the capacitance of the first capacitor 252 can be 68 microfarads, and the capacitance of the second capacitor 242 can be 100 microfarads.
[0020] 下面以一8V及3. 3V為例，說明該直流電壓轉換電路20之 工作原理： 〇[0020] The following describes the working principle of the DC voltage conversion circuit 20 by taking an 8V and 3.3V as an example:
[0021] 該直流電壓轉換電路2 0開始工作時.升學武直流電源 變換積體電路23之第二控制‘％‘出‘冗231籍f 一初始占空比 之脈衝訊號，該脈衝訊號係低電平期間，該第二二極體 241不導通，該電源21與該變壓器22之初級線圈221構成 一迴路，該初級線圈221產生電動勢，同該變壓器22之 次級線圈222產生感應電動鲁。:該)¾¾¾號係高電平期間 ，該第二二極體241導通，談ΐ源21及該變壓器22之初級 線圈221經由該第二二極體241之陽極、陰極為該第二電 容242充電，並為該第二輸出端26提供第二電壓。同時， 該第二電壓經由該第二反饋支路243反饋至該升壓式直流 電源變換積體電路23之第二反饋端233。 [0022] 如果該第二電壓小於3. 3V，則該第二電壓經由該第二反 饋支路243反饋至該升壓式直流電源變換積體電路23之第 二反饋端233後，該升壓式直流電源變換積體電路23減小 096132576 表單編號Α0101 第10頁/共21頁 0993445888-0 1345360 099年12月14日修正替換頁 該第二控制輸出端231輸出之脈衝之占空比，從而增大該 變壓器22之初級線圈221之儲能時間，提高該第二輸出端 26之第二電壓。 [0023] 如果該第二電壓高於3. 3V，則該第二電壓經由該第二反 饋支路243反饋至該升壓式直流電源變換積體電路23之第 二反饋端233後，該升壓式直流電源變換積體電路23增大 該第二控制輸出端231輸出之脈衝之占空比，減小該變壓 器22之初級線圈221之儲能時間，從而降低該第二輸出端 26之第二電壓。 [0024] 另，該直流電壓轉換電路20開始工作時，由於該第一輸 出端27之第一電壓瞬間為0V，該0V之第一電壓經由該-第 一反饋支路253反饋至該升壓式直流電源變換積體電路23 之第一反饋端234，該升壓式直流電源變換積體電路23控 制該第一控制輸出端232輸出高電壓，使該電晶體254導 通；由於上述該變壓器22之初級線圈221羞生電動勢之同 時，該變壓器22之次級線圈222產生有感應電動勢，因此 該次極線圈2 2 2經由該電晶.體―2 5'4.之》及極、源極為該第' 電容252充電，同時提高該第一輸出端27之第一電壓。 [0025] 如果該第一電壓高於一8V，則該第一電壓經由該第一反 饋支路253反饋至該升壓式直流電源變換積體電路23之第 一反饋端234後，該升壓式直流電源變換積體電路23控制 該第一控制輸出端232輸出低電平，該電晶體254不導通 ，該變壓器22之次級線圈222不為該第一電容252充電， 同時該第一電容252經由該第一反饋支路253放電，從而 降低該第一輸出端27之第一電壓。 096132576 表單編號A0101 第11頁/共21頁 0993445888-0 099年12月14日修正替换頁 [0026] "亥直仙_电壓轉換電路2〇之第二輸出端26之第二電壓及第 輸出端27之第一電壓並不限於3. 3V及一8V，藉由調整 。亥直流電壓轉換電路2Q之各電子元件之參數，便可調節 該第二電壓及該第一電壓。 [0027] 相較於先前技術，該直流電壓轉換電路2〇之第一調壓電 路25係採用該變壓器22之次級線圈222、該電晶體254及 該第一二極體251將該電源21之1. 5V電壓轉換為一8V直 流電壓，取代了先前技術之低嗓音負輸出電荷泵穩壓器 ，因此該直流電壓轉換電路2〇之成本較低。 [0028] 請參閱圖3，係本發明直流電壓轉換電路第二實施方式之 示意圖。該直流電壓轉換電酱30‘與第一方式之直流 電壓轉換電路20大致相同，:其:车要展別孓處:▲於：該直 流電壓轉換電路30進一步包括一第三電容354及一第四電 容353。該第三電容354—端接地，另一端連接至該第一 輸出端37。該第四電容353c端揍地I另碎端連接至該第 二輪出端36。該該第三電容，354声弟四,電容353分別用於 濾除該第一輸出端37之第一電:i與該第二輸出端36之第 一電壓之雜訊干擾。 [0029] 综上所述，本發明確已符合發明專利之要件，表依法提 出專利申請。惟，以上所述者僅為本發明之較佳實施方 式’本發明之範圍並不以上述實施方式為限，舉凡熟悉 本案技藝之人士援依本發明之精神所作之等效修飾或變 化，皆應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 [0030] 096132576 圖1係一先前技術直流電壓轉換電路之示意圖。 表單編號A0101 第12頁/共21頁 0993445888-0 1345360 099年12月14日梭正替換頁 [0031] 圖2係本發明直流電壓轉換電路第一實施方式之示意圖。 [0032] 圖3係本發明直流電壓轉換電路第二實施方式之示意圖。 【主要元件符號說明】 [0033] 低噪音負輸出電荷泵穩壓器：121 [0034] 升壓式直流電源變換積體電路：23、13 [0035] 變壓器：22 [0036] 第一反饋支路：122 [0037] 二極體：142 [0038] 輸入端：1210 [0039] 第一反饋接收端：1211 [0040] 負壓輸出端：1 21 2 [0041] 第二反饋接收端：131 [0042] 電感：141 , ；7'：»； [0043] 控制輸出端：132 [0044] 電晶體：254 [0045] 直流電壓轉換電路：20、10 [0046] 電源：21、11 [0047] 第二調壓電路：24、14 [0048] 第一調壓電路：25、12 [0049] 第二輸出端：26、16 096132576 表單編號A0101 第13頁/共21頁 0993445888-0 1345360 [0050] 第 一輸出端 ：27、 15 [0051] 初級線圈： 221 [0052] 次級線圈： 222 [0053] 第 二控制輸 出端： 231 [0054] 第 一控制輸 出端： 232 [0055] 第 二反饋端 ：233 [0056] 第 一反饋端 ：234 [0057] 第 二二極體 :241 [0058] 第 二電容： 242 ' 144 [0059] 第 二反饋支路：243、143 [0060] 第 三電阻： 244、 145 [0061] 第 四電阻： 245、 146 [0062] 第 一二極體 :251 [0063] 第 一電容： 252、 123 [0064] 第 一反饋支路：253 [0065] 第 二電阻： 257、 125 [0066] 第 一電阻： 256、 124 096132576 表單編號A0101 第14頁/共21頁 099年12月14日梭正替换頁 0993445888-0[0021] When the DC voltage conversion circuit 20 starts to operate, the second control '%' of the SF DC power conversion integrated circuit 23 outputs a pulse signal of an initial duty ratio, which is low. During the level period, the second diode 241 is non-conducting, and the power source 21 forms a loop with the primary coil 221 of the transformer 22. The primary coil 221 generates an electromotive force, and the secondary coil 222 of the transformer 22 generates an induction coil. During the period of the high level, the second diode 241 is turned on, and the primary source 221 of the source 21 and the transformer 22 is the anode and cathode of the second diode 241. Charging and providing a second voltage to the second output 26. At the same time, the second voltage is fed back to the second feedback terminal 233 of the boost DC power conversion integrated circuit 23 via the second feedback branch 243. [0022] If the second voltage is less than 3.3 V, the second voltage is fed back to the second feedback end 233 of the boost DC power conversion integrated circuit 23 via the second feedback branch 243, and the boosting is performed. The DC power conversion integrated circuit 23 is reduced by 096132576 Form No. Α0101 Page 10/Total 21 Page 0993445888-0 1345360 The correction of the replacement page is the duty ratio of the pulse outputted by the second control output 231, thereby Increasing the energy storage time of the primary coil 221 of the transformer 22 increases the second voltage of the second output terminal 26. [0023] If the second voltage is higher than 3.3 V, the second voltage is fed back to the second feedback end 233 of the boost DC power conversion integrated circuit 23 via the second feedback branch 243, the liter The voltage-type DC power conversion integrated circuit 23 increases the duty ratio of the pulse outputted by the second control output terminal 231, reduces the energy storage time of the primary coil 221 of the transformer 22, thereby reducing the second output terminal 26 Two voltages. [0024] In addition, when the DC voltage conversion circuit 20 starts to work, since the first voltage of the first output terminal 27 is instantaneously 0V, the first voltage of the 0V is fed back to the boost via the first feedback branch 253. The first feedback terminal 234 of the DC power conversion integrated circuit 23 controls the first control output 232 to output a high voltage to turn on the transistor 254; While the primary coil 221 is imaginary, the secondary coil 222 of the transformer 22 generates an induced electromotive force, so that the secondary coil 2 2 2 passes through the electro-crystal. The 'th capacitor 252 charges while increasing the first voltage of the first output terminal 27. [0025] If the first voltage is higher than one 8V, the first voltage is fed back to the first feedback end 234 of the boost DC power conversion integrated circuit 23 via the first feedback branch 253, and the boosting is performed. The DC power conversion integrated circuit 23 controls the first control output terminal 232 to output a low level, the transistor 254 is not turned on, the secondary coil 222 of the transformer 22 does not charge the first capacitor 252, and the first capacitor 252 is discharged via the first feedback branch 253, thereby reducing the first voltage of the first output terminal 27. 096132576 Form No. A0101 Page 11/Total 21 Page 0993445888-0 December 14, 2004 Revision Correction Page [0026] "Hai Zhixian_Voltage Conversion Circuit 2〇Second Voltage and Output of the Second Output Terminal 26 The first voltage of terminal 27 is not limited to 3. 3V and one 8V, by adjustment. The second voltage and the first voltage can be adjusted by parameters of the electronic components of the DC voltage conversion circuit 2Q. [0027] Compared with the prior art, the first voltage regulating circuit 25 of the DC voltage conversion circuit 2 uses the secondary coil 222 of the transformer 22, the transistor 254, and the first diode 251 to power the power source 21. The 1.5V voltage is converted to an 8V DC voltage, which replaces the prior art low-pitched negative output charge pump regulator, so the DC voltage conversion circuit 2 has a lower cost. Please refer to FIG. 3, which is a schematic diagram of a second embodiment of a DC voltage conversion circuit of the present invention. The DC voltage conversion electric sauce 30' is substantially the same as the DC voltage conversion circuit 20 of the first mode, and is: the vehicle is to be displayed: ▲: The DC voltage conversion circuit 30 further includes a third capacitor 354 and a first Four capacitors 353. The third capacitor 354 is grounded and the other end is connected to the first output terminal 37. The fourth capacitor 353c is connected to the second wheel end 36. The third capacitor, 354, is used to filter out the noise interference of the first voltage of the first output terminal 37 and the first voltage of the second output terminal 36. [0029] In summary, the present invention has indeed met the requirements of the invention patent, and the patent application is filed according to law. However, the above description is only a preferred embodiment of the present invention. The scope of the present invention is not limited to the above-described embodiments, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention are It should be covered by the following patent application. BRIEF DESCRIPTION OF THE DRAWINGS [0030] FIG. 1 is a schematic diagram of a prior art DC voltage conversion circuit. Form No. A0101 Page 12 of 21 0993445888-0 1345360 December 14th, 2017 Page 1 [0031] FIG. 2 is a schematic diagram of a first embodiment of a DC voltage conversion circuit of the present invention. 3 is a schematic diagram of a second embodiment of a DC voltage conversion circuit of the present invention. [Main component symbol description] [0033] Low noise negative output charge pump regulator: 121 [0034] Boost DC power conversion integrated circuit: 23, 13 [0035] Transformer: 22 [0036] First feedback branch :122 [0037] Diode: 142 [0038] Input: 1210 [0039] First feedback receiver: 1211 [0040] Negative voltage output: 1 21 2 [0041] Second feedback receiver: 131 [0042 Inductance: 141, ;7':»; [0043] Control output: 132 [0044] Transistor: 254 [0045] DC voltage conversion circuit: 20, 10 [0046] Power supply: 21, 11 [0047] Voltage regulating circuit: 24, 14 [0048] First voltage regulating circuit: 25, 12 [0049] Second output terminal: 26, 16 096132576 Form number A0101 Page 13 / Total 21 page 0993445888-0 1345360 [0050] Output: 27, 15 [0051] Primary coil: 221 [0052] Secondary coil: 222 [0053] Second control output: 231 [0054] First control output: 232 [0055] Second feedback: 233 [0056] First feedback terminal: 234 [0057] Second diode: 241 [0058] Second capacitor: 242 ' 144 [0059] Second feedback branch 243, 143 [0060] Third resistor: 244, 145 [0061] Fourth resistor: 245, 146 [0062] First diode: 251 [0063] First capacitor: 252, 123 [0064] First feedback branch Road: 253 [0065] Second resistance: 257, 125 [0066] First resistance: 256, 124 096132576 Form number A0101 Page 14 / Total 21 page December 14, 099 Shuttle replacement page 0993445888-0