201109681 六、發明說明： 【發明所屬之技術領域】 [0001] 本發明涉及一種電壓偵測電路。 【先前4支術】 [0002] 先前各種電子設備的電源模組中包含一欠壓保護電路及 一過壓保護電路，以在電源輸入的電壓低於一第一臨界 值或高於一第二臨界值時對該電子設備進行保護。當電 源的電壓低於該第一臨界值或高於該第二臨界值時，該 欠壓保護電路或過壓保護電路將會斷開該電子設備與該 電源的連接。另，電子設備還會因其他原因斷電，故當 該電子設備因電源的電壓過低或過高而斷電時，使用者 不能知道該電子設備斷電的原因，亦即無法立刻作提高 電壓或降低電壓的決定。 【發明内容】 [0003] [0004] [0005] 鑒於以上内容，有必要提供一種偵測一電子設備的電源 是否處於欠壓或過壓狀態且能在電源處於欠壓或過壓狀 態時提示使用者的電壓偵測電路。 一種電壓偵測電路，包括： 一欠壓偵測電路，包括一第一比較器、一第一穩壓二極 體及一第一發光二極體，該第一穩壓二極體的陰極透過 一第一電阻與該電源連接、陽極接地，該第一比較器的 負輸入端與該第一穩壓二極體的陰極相連、正輸入端透 過一第二電阻與該電源連接且透過一第三電阻接地、輸 出端透過一第四電阻與該第一發光二極體的陰極相連， 098130318 該第一發光二極體的陽極與該電源相接，該第一穩壓二 表單編號A0101 第4頁/共12頁 0982052030-0 201109681 極體的穩定電壓V-dwl滿足關係： R2/(R1+R2) ’其中V_min為該電源的下限電壓，μ、μ 分別為第二電阻、第三電阻的阻值；及 [0006] 一過壓偵測電路，包括—筮_ 私μ 枯第一比較器、—第二穩壓二極 體及一第二發光二極體，嗜笛_ μ第一穩壓一極體的陰極透過 -第五電阻與該電源連接、陽極接地，該第二比較器的 正輸入端與該第二穩壓二極體的陰極相連、負輸入端透 過一第六電阻與該電源連接且透過一第七電阻接地、輸 Ο [0007] Ο 出端透過一第八電阻與該第二發光二極體的陰極相連， 該第二發光二極體的陽極與該電源相接，該第二穩壓二 極體的穩定電壓V-dw2滿足關係：v-dw2=V-maxx R3/(R3 + R:4.) ’其中V-max為該電源的上限電堅，R4、R3 -I 5丨 r I*'、？ T羞-<· ρ Λζ. 分別為第六電阻、第七電阻的阻值。 本發明電壓偵測電路將該電源的電壓經電阻分壓後透過 第一比較器與第一穩壓二極體的穩定電壓.比較，並將 ·; # 1 ： - * * · ' 該電源的電壓經電阻分壓後逶過第二比較器與第二穩壓 二極體的穩定電壓作比較，進一步控制該第一發光二極 體或第二發光二極體，以表示該電源處於欠壓、過壓或 正常狀態。 [0008] 【實施方式】 請參閱圖1，本發明電壓偵測電路用於偵測一電#v_in的 電壓，該電壓偵測電路的較佳實施方式包括一欠壓债測 電路10及一過壓偵測電路20。 [0009] 098130318 該欠壓偵測電路10包括一比較器、一穩壓二極體DW1 一發光二極體LED1及複數電阻Rl、R2、R5、R7 表單編號A0101 第5頁/共12頁 0982052030-0 201109681 [0010] 該電阻R1的一端連接一電源V-in，另一端透過該電阻R2 接地。 [0011] 該穩壓二極體Ml的陰極透過該電阻R5與該電源V-in連 接，陽極接地。 [0012] 該比較器U1的負輸入端與該穩壓二極體DW1的陰極相連， 正輸入端連接於該電阻R1及R2之間的節點A，輸出端透過 該電阻R7與該發光二極體LED1的陰極相連，電源端與該 電源V - i η相連，接地端接地。 [0013] 該發光二極體LED1的陽極與該電源V-in相接。 [0014] 該過壓偵測電路20包括一比較器U2、一穩壓二極體DW2、 一發光二極體LED2及複數電阻R3、R4、R6、R8。 [0015] 該電阻R4的一端連接該電源V-in，另一端透過該電阻R3 接地。 [0016] 該穩壓二極體DW2的陰極透過該電阻R6與該電源V-in連 接，陽極接地。 [0017] 該比較器U2的正輸入端與該穩壓二極體DW2的陰極相連、 負輸入端連接於該電阻R3及R4之間的節點B、輸出端透過 該電阻R8與該發光二極體LED2的陰極相連、電源端與該 電源V - i η相連、接地端接地。 [0018] 該發光二極體LED2的陽極與該電源V-in相接。 [0019] 下面對本發明電壓偵測電路的工作原理進行說明。 [0020] 該電源V- in正常是指其電壓處於一上限電壓與一下限電 098130318 表單編號A0101 第6頁/共12頁 0982( 201109681 [0021] [0022] [0023] ❹ [0024] [0025] Ο [0026] 壓之間。該電源V-in的欠壓狀態是指其電壓低於該下限 電壓。該電源V-in的過壓狀態是指其電壓高於該上限電 壓。 該穩壓二極體DW1的穩定電壓V-dwl及穩壓二極體DW2的 穩定電壓V-dw2與該電阻Rl、R2 、R3及R4滿足以下關係 V-dwl=V-minxR2/(Rl+R2); V-dw2=V-maxxR3/(R3+R4)。 其中V-min為該電源V-in的下限電壓，V-max為該電源 V-in的上限電:艟。 當該電源V-in正常，即該電源V-in的電摩處於該上限電 壓與該下限電壓之間時：A點的電壓Va=V-inx R2/(R1+R2)高於該穩壓二極體DW1的穩定電壓，即該比 較器U1的正輸入端的電壓高於負輸入端的t壓，該比較 器U1的輸出端輸出高電平，該發光二g體LED1不亮；B點 的電壓Vb=V-inxR3/(R3 + R4)低於_穩壓二極體DW2的穩 定電壓，即該比較器U2的正輸入端的電壓高於負輸入端 的電壓，該比較器U2的輸出端亦輸出高電平，該發光二 極體LED2不亮。此時該發光二極體LED1及發光二極體 LED2均不亮，表示該電源V-in正常。 當該電源V-in處於欠壓狀態，即其電壓低於該下限電壓 時：B點的電壓Vb=V-inxR3/(R3+R4)低於該穩壓二極體 DW2的穩定電壓，即該比較器U2的正輸入端的電壓高於負 輸入端的電壓，該比較器U2的輸出端輸出高電平’該發 098130318 表單編號A0101 第7頁/共12頁 0982052030-0 201109681 光二極體LED2不亮；A點的電壓Va = V-inxR2/(R1+R2)低 於忒穩壓二極體DW1的穩定電壓，即該比較器耵的正輸入 端的電壓低於負輸入端的，該比較器Μ的輸出端輪 出低電平，該發光二極體LED1發光。此時表示該電源v— i η為欠壓狀態。 [0027] 當該電源V-in處於過壓狀態，即其電壓高於該上限電壓 時：A點的電壓Va = V-inxR2/(Rl+R2)高於該穩壓二極體 DW1的穩定電壓，即該比較器Μ的正輸入端的電壓高於負 輸入端的電壓，該比較器U1的輸出端輪出高電平，該發 光二極體LED1不亮；Β點的電壓Vb=V-inxR3/(R3+R4)高 於該穩壓二極碰DW2的穩定電壓，即該敦較器们的正輪入 端的電壓低於負輸入端的電壓，該比較器U2的輸出端輸 出低電平，該發光二極體LED2發光。此時表示該電源v_ in為過壓狀態。 [0028] 本實施方式中，該穩壓二極體1)们的穩定電壓為該下限電 壓的一半，該電阻R1及R2的阻值相同，即A點的電壓為該 電源V-in的電壓的一半。該穩壓二極體DW2的穩定電壓為 該上限電壓的一半，該電阻R3及R4的阻值相同，即B點的 電壓也為該電源V-in的電壓的一半。 [0029] 本發明電壓偵測電路將該電源V - i η的電壓經電阻R丨> | 後透過比較器U1與穩壓二極體DW1的穩定電壓作比較，& 將該電源V-in的電壓經電阻R4分壓後透過比較器 壓二極體DW2的穩定電壓作比較，進一步控制該發光二極 體LED1或LED2，以表示該電源V-in處於欠壓、過壓或正 常狀態。 098130318 表單編號A0101 第8頁/共12頁 0982052030 201109681 [0030] 综上所述，本發明符合發明專利要件，爰依去提出專， 申請。惟，以上所述者僅為本發明之較佳實;=出= 热悉本案技藝之人士，於爰依本發明精神所作之等效修 飾或變化，皆應涵蓋於以下之申請專利範圍内。^ 【圖式簡單說明】 _] ®1係本發明電Μ«路_佳實財式的電路圖。 【主要元件符號說明】 [0032] 欠壓偵測電路：1 〇 〇201109681 VI. Description of the Invention: [Technical Field of the Invention] [0001] The present invention relates to a voltage detecting circuit. [Previous 4 Techniques] [0002] The power module of various electronic devices previously includes an undervoltage protection circuit and an overvoltage protection circuit, so that the voltage input to the power supply is lower than a first threshold or higher than a second The electronic device is protected at a critical value. When the voltage of the power source is lower than the first threshold or higher than the second threshold, the undervoltage protection circuit or the overvoltage protection circuit disconnects the electronic device from the power source. In addition, the electronic device may be powered off for other reasons. Therefore, when the electronic device is powered off due to the voltage of the power supply being too low or too high, the user cannot know the reason for the power failure of the electronic device, that is, the voltage cannot be immediately increased. Or the decision to lower the voltage. SUMMARY OF THE INVENTION [0003] In view of the above, it is necessary to provide a method for detecting whether an electronic device is under voltage or overvoltage and can prompt for use when the power supply is undervoltage or overvoltage. Voltage detection circuit. A voltage detecting circuit includes: an undervoltage detecting circuit comprising a first comparator, a first voltage stabilizing diode, and a first light emitting diode, wherein the cathode of the first voltage stabilizing diode is transmitted a first resistor is connected to the power source, and the anode is grounded. The negative input end of the first comparator is connected to the cathode of the first voltage stabilizing diode, and the positive input terminal is connected to the power source through a second resistor and transmits through the first resistor. The three-resistor grounding and the output end are connected to the cathode of the first light-emitting diode through a fourth resistor, 098130318, the anode of the first light-emitting diode is connected to the power source, and the first voltage-stabilized two form number A0101 is 4 Page / Total 12 pages 0982052030-0 201109681 The stable voltage of the polar body V-dwl satisfies the relationship: R2/(R1+R2) 'where V_min is the lower limit voltage of the power supply, μ and μ are the second resistance and the third resistance respectively Resistance value; and [0006] an overvoltage detection circuit, including - 筮 _ private μ dry first comparator, - second voltage regulator diode and a second light emitting diode, whistle _ μ first stable The cathode of the one-pole body is connected to the power source through the fifth resistor, and the anode is grounded. The positive input end of the second comparator is connected to the cathode of the second voltage stabilizing diode, the negative input end is connected to the power source through a sixth resistor, and is grounded through a seventh resistor, and the output is transmitted through the ground [0007] The eighth resistor is connected to the cathode of the second light emitting diode, the anode of the second light emitting diode is connected to the power source, and the stable voltage V-dw2 of the second voltage stabilizing diode satisfies the relationship: v-dw2 =V-maxx R3/(R3 + R:4.) 'Where V-max is the upper limit of the power supply, R4, R3 -I 5丨r I*',? T shame-<· ρ Λζ. The resistance values of the sixth resistor and the seventh resistor, respectively. The voltage detecting circuit of the present invention compares the voltage of the power supply through a resistor and then passes through the first comparator to compare the stable voltage of the first voltage stabilizing diode, and will: #1 : - * * · ' The voltage is divided by the resistor and then passed through the second comparator to compare the stable voltage of the second voltage regulator diode to further control the first light emitting diode or the second light emitting diode to indicate that the power source is under voltage , overvoltage or normal state. [0008] Referring to FIG. 1, a voltage detecting circuit of the present invention is used for detecting a voltage of an electric #v_in. The preferred embodiment of the voltage detecting circuit includes an undervoltage detecting circuit 10 and a pass. Voltage detection circuit 20. [0009] 098130318 The undervoltage detecting circuit 10 includes a comparator, a voltage stabilizing diode DW1, a light emitting diode LED1, and a plurality of resistors R1, R2, R5, and R7. Form No. A0101 Page 5 / 12 pages 0982052030 -0 201109681 [0010] One end of the resistor R1 is connected to a power source V-in, and the other end is grounded through the resistor R2. [0011] The cathode of the voltage stabilizing diode M1 is connected to the power source V-in through the resistor R5, and the anode is grounded. [0012] The negative input terminal of the comparator U1 is connected to the cathode of the voltage stabilizing diode DW1, the positive input terminal is connected to the node A between the resistors R1 and R2, and the output terminal is transmitted through the resistor R7 and the light emitting diode The cathode of the body LED1 is connected, the power terminal is connected to the power source V - i η , and the ground terminal is grounded. [0013] The anode of the LED LED1 is connected to the power source V-in. [0014] The overvoltage detecting circuit 20 includes a comparator U2, a voltage stabilizing diode DW2, a light emitting diode LED2, and a plurality of resistors R3, R4, R6, and R8. [0015] One end of the resistor R4 is connected to the power source V-in, and the other end is grounded through the resistor R3. [0016] The cathode of the Zener diode DW2 is connected to the power source V-in through the resistor R6, and the anode is grounded. [0017] The positive input end of the comparator U2 is connected to the cathode of the voltage stabilizing diode DW2, the negative input end is connected to the node B between the resistors R3 and R4, and the output end is transmitted through the resistor R8 and the light emitting diode The cathode of the body LED 2 is connected, the power terminal is connected to the power source V - i η , and the ground terminal is grounded. [0018] The anode of the LED 2 is connected to the power source V-in. [0019] The working principle of the voltage detecting circuit of the present invention will be described below. [0020] The power supply V-in normally means that its voltage is at an upper limit voltage and a lower limit voltage 098130318. Form No. A0101 Page 6 / Total 12 pages 0982 (201109681 [0021] [0022] [0023] ❹ [0024] [0025] Ο [0026] Between the voltages. The undervoltage state of the power supply V-in means that its voltage is lower than the lower limit voltage. The overvoltage state of the power supply V-in means that its voltage is higher than the upper limit voltage. The stable voltage V-dwl of the diode DW1 and the stable voltage V-dw2 of the voltage stabilizing diode DW2 and the resistors R1, R2, R3 and R4 satisfy the following relationship V-dwl=V-minxR2/(Rl+R2); V-dw2=V-maxxR3/(R3+R4), where V-min is the lower limit voltage of the power supply V-in, and V-max is the upper limit of the power supply V-in: 艟. When the power supply V-in is normal That is, when the electric motor of the power source V-in is between the upper limit voltage and the lower limit voltage: the voltage of the point A Va=V-inx R2/(R1+R2) is higher than the stable voltage of the voltage stabilizing diode DW1 That is, the voltage of the positive input terminal of the comparator U1 is higher than the voltage of the negative input terminal, the output terminal of the comparator U1 outputs a high level, the LED of the light emitting body is not bright; the voltage of the point B is Vb=V-inxR3/ (R3 + R4) is lower than the stability of the voltage regulator diode DW2 Pressing, that is, the voltage of the positive input terminal of the comparator U2 is higher than the voltage of the negative input terminal, the output end of the comparator U2 also outputs a high level, and the LED 2 of the LED is not lit. At this time, the LED 2 and the LED The LEDs of the LEDs are not lit, indicating that the power supply V-in is normal. When the power supply V-in is in an undervoltage state, that is, its voltage is lower than the lower limit voltage: the voltage at point B is Vb=V-inxR3/(R3 +R4) is lower than the stable voltage of the voltage regulator diode DW2, that is, the voltage of the positive input terminal of the comparator U2 is higher than the voltage of the negative input terminal, and the output terminal of the comparator U2 outputs a high level 'the 098130318 form number A0101 Page 7 of 12 0982052030-0 201109681 The light diode LED2 is not lit; the voltage at point A Va = V-inxR2/(R1+R2) is lower than the stable voltage of the voltage regulator diode DW1, that is, the comparison The voltage at the positive input terminal of the device is lower than the negative input terminal, and the output terminal of the comparator 轮 is turned low, and the LED of the LED is illuminated. This indicates that the power supply v_i η is undervoltage. [0027 ] When the power supply V-in is in an overvoltage state, that is, its voltage is higher than the upper limit voltage: voltage at point A Va = V-inxR 2/(Rl+R2) is higher than the stable voltage of the voltage stabilizing diode DW1, that is, the voltage of the positive input terminal of the comparator 高于 is higher than the voltage of the negative input terminal, and the output end of the comparator U1 is turned high. The LED of the LED is not bright; the voltage of the defect Vb=V-inxR3/(R3+R4) is higher than the stable voltage of the Zener diode DW2, that is, the voltage of the positive terminal of the comparator is low. At the negative input terminal, the output of the comparator U2 outputs a low level, and the LED 2 emits light. At this time, it indicates that the power source v_in is in an overvoltage state. [0028] In the present embodiment, the stabilizing voltage of the stabilizing diode 1) is half of the lower limit voltage, and the resistances of the resistors R1 and R2 are the same, that is, the voltage at the point A is the voltage of the power source V-in. Half of it. The stabilizing voltage of the stabilizing diode DW2 is half of the upper limit voltage, and the resistances of the resistors R3 and R4 are the same, that is, the voltage at the point B is also half of the voltage of the power source V-in. [0029] The voltage detecting circuit of the present invention compares the voltage of the power source V - i η through the resistor R 丨 gt | | through the comparator U1 and the stable voltage of the voltage stabilizing diode DW1, & The voltage of in is divided by the resistor R4 and then compared with the stable voltage of the comparator voltage diode DW2 to further control the LED diode 1 or LED2 to indicate that the power source V-in is under voltage, overvoltage or normal state. . 098130318 Form No. A0101 Page 8 of 12 0982052030 201109681 [0030] In summary, the present invention meets the requirements of the invention patent, and the application is filed. However, the above is only the preferred embodiment of the present invention; ======================================================================================== ^ [Simple description of the diagram] _] ® 1 is the circuit diagram of the electric Μ «路_佳实财式. [Main component symbol description] [0032] Undervoltage detection circuit: 1 〇 〇
[0033] 過壓偵測電路：20 [0034] 電源：V-in[0033] Overvoltage detection circuit: 20 [0034] Power supply: V-in
[0035]節點：A、B[0035] Node: A, B
[0036]比較器：U1、U2 [0037]穩壓二極體：DW1、DW2 [0038]發光二極體：LED1、LED2 [0039]電阻：iU~R& 098130318 表單編號A0101 第9頁/共12頁 0982052030-0Comparator: U1, U2 [0037] Regulated Diode: DW1, DW2 [0038] Light Emitting Diode: LED1, LED2 [0039] Resistor: iU~R& 098130318 Form No. A0101 Page 9 / Total 12 pages 0982052030-0