200931757 九、發明說明： •【發明所屬之技術領域】 ’ 纟發明#及一種保護電路，丨其涉及-種佈設於電子 產品之電路板上之觸水斷電保護電路。 【先前技術】 -般之電子產品内都裝設有—電路板，其上佈設有複 數藉由預設電路電性連接之功能模組。給所述電子產品之 〇電路板提供—電源以啟動所述電路板上之各功能模組，藉 由插作電子產品上之各操作按紐、開關或手柄等以驅動其 相對應之各功能模組，從而實現該電子產品預設之各種功 能。 由於電子產品自身結構設計之缺陷或其組裝精度等因 素之影響，電子產品报難達到絕對防水之要求。用戶於使 用電子產品之過程中，·f 枉〒了此不小心將電子產品掉入水中或 由於使用不慎將水滲到雷 ,到％子產0 口内之電路板上。如果該 ©。於開機狀態或使用過程中，有水滲人到電子產 品内之電路板上時， & ρ, 了月b a使电子產品之電路板上之各功 能权組之間形成錯誤 分 、之電11連接，導致電路板發生短路甚 至起火、爆炸等事故。 【發明内容】 有鑒於此， 内之電路板上時 保護電路。 有必要提供一種可於有水滲入到電子產品 ，對電路板上之功能模組提供斷電保護之 一種保護電路 用於保護一功能模組，所述保護電路 200931757 匕：场效應電晶體、-電阻及二導電觸墊，所述場效應 .J晶體之漏極D與電源輸入端之正電極電性連接，所述功 .能模組串聯連接於場效應電晶體之源極s與電源輸入端之 負電極之間；所述電阻之一端與場效應t晶體之栅極G電 •性連接，其另一端與場效應電晶體之漏極D及電源輸入端 之正電極電性連接；所述二導電觸塾相對間隔之佈設於電 路板上，一導電觸墊與場效應電晶體之柵極g電連接，另 ❹一導電觸墊與電源輸入端之負電極電連接。 與習知技術相比，所述保護電路佈設於電子產品内之 電路板上對應之易滲水位置處，當有水滲入、覆蓋或滴入 到電路板上之所述二導電觸墊之間時，藉由該保護電路之 場效應電晶體之導通及截止特性，對電路板上之功能模組 之電源進行切斷，以實現對所述功能模組之保護。 【實施方式】 請參閱圖1及圖2’所述具保護電路2〇之電路板1〇 φ裝史於一電子產品内’該電路板1〇上佈設有一電源輪入端 11、複數個功能模組12及至少一保護電路2〇。該等功能 模組12用於實現該電子產品之各預設功能，其與保護電路 20藉由佈設於電路板10上之預設電路15電性連接。所述 保護電路20佈設於該電子產品之電路板1〇上對應之易參 水位置處’例如接近電子產品殼體接縫之位置。 所述電源輸入端11包括一正電極及一負電極，其夢由 與裝設於所述電子產品内之電池或外接式電源電性連接， 以給所述電路提供一工作電壓Vcc。所述保護電路2〇二端 200931757 分別與所U之正電極及貞電極電性連接，以 ’ 構成一連通回路。 . 所述保護電路20包括一場效應電晶體21、一可變電 阻R1及一導電觸墊25。於本實施例中，該場效應電晶體 21為一金屬氧化物半導體場效應電晶體（Metal 〇xide200931757 IX. Description of the invention: • [Technical field to which the invention pertains] ’ 纟 invention# and a protection circuit, which relates to a water- and power-off protection circuit disposed on a circuit board of an electronic product. [Prior Art] - The electronic product is usually provided with a circuit board on which a plurality of functional modules electrically connected by a predetermined circuit are disposed. Providing a power supply to the circuit board of the electronic product to activate each functional module on the circuit board, and driving each corresponding function by inserting various operation buttons, switches or handles on the electronic product The module realizes various functions preset by the electronic product. Due to the defects of the electronic product's own structural design or its assembly accuracy and other factors, it is difficult for electronic products to meet the requirements of absolute waterproofing. In the process of using electronic products, the user accidentally dropped the electronic product into the water or inadvertently drenched the water into the mine, and went to the circuit board of the 0-part product. If the ©. In the state of being turned on or in use, when water leaks into the circuit board inside the electronic product, & ρ, the monthly ba causes the wrong function of each functional group on the circuit board of the electronic product. The connection causes a short circuit or even a fire or explosion of the board. SUMMARY OF THE INVENTION In view of this, the circuit is protected on the circuit board. It is necessary to provide a protection circuit for protecting a functional module of a circuit board from water penetration into an electronic product for protecting a functional module, the protection circuit 200931757 匕: field effect transistor, - a resistor and a second conductive contact pad, wherein the drain D of the field effect transistor is electrically connected to the positive electrode of the power input terminal, and the power module is connected in series to the source s of the field effect transistor and the power input One end of the resistor is electrically connected to the gate G of the field effect t crystal, and the other end is electrically connected to the drain D of the field effect transistor and the positive electrode of the power input terminal; The two conductive contacts are disposed on the circuit board with a relatively spaced interval, and one conductive contact pad is electrically connected to the gate g of the field effect transistor, and the other conductive contact pad is electrically connected to the negative electrode of the power input end. Compared with the prior art, the protection circuit is disposed at a corresponding water-permeable position on a circuit board in the electronic product, when water penetrates, covers or drops into the two conductive contact pads on the circuit board. The power supply of the functional module on the circuit board is cut off by the on-and-off characteristics of the field effect transistor of the protection circuit to protect the functional module. [Embodiment] Please refer to FIG. 1 and FIG. 2'. The circuit board with the protection circuit 2〇 is installed in an electronic product. The circuit board 1 is provided with a power supply terminal 11 and a plurality of functions. The module 12 and at least one protection circuit 2 are. The function modules 12 are used to implement the preset functions of the electronic product, and are electrically connected to the protection circuit 20 by a preset circuit 15 disposed on the circuit board 10. The protection circuit 20 is disposed at a position corresponding to the water-repellent position on the circuit board 1 of the electronic product, for example, close to the seam of the electronic product housing. The power input terminal 11 includes a positive electrode and a negative electrode. The dream is electrically connected to a battery or an external power source installed in the electronic product to provide an operating voltage Vcc to the circuit. The second end of the protection circuit 2, 200931757, is electrically connected to the positive electrode and the 贞 electrode of the U, respectively, to constitute a communication loop. The protection circuit 20 includes a field effect transistor 21, a variable resistor R1 and a conductive pad 25. In this embodiment, the field effect transistor 21 is a metal oxide semiconductor field effect transistor (Metal 〇xide).
Semiconductor Field Effect Transistor，MOSFET)。所述場 效應電晶體21具-栅極G、—漏極D及—源極s。所述場 ❹效應電晶體21之柵極G與源極s間可藉由控制栅極g、 源極S間之電壓大小而控制栅極G、源極s間之導通及截 止，其中，柵極G與源極S間導通之門限電壓為Vgs(叫。 於本實施例中，所述場效應電晶體21之漏極D與所述電 源輸入端11之正電極電性連接。所述功能模組12串聯連 接於場效應電晶體21之源極S與電源輸入端u之負電極 之間。所述可變電阻R1 一端與場效應電晶體21之漏極d 接腳及電源輸入端11之正電極電性連接，其另一端與場效 ❿應電晶體21之栅極g電性連接。所述可變電阻R1之大小 選取取決於整個電路板1〇之負載及實際運行之需要。所述 二導電觸墊25呈矩形條狀，其由金屬等導電材料製成，其 相對間隔之佈设於電路板上易滲水位置處。一導電觸墊 25與場效應電晶體21之栅極G電連接，另一導電觸墊25 與電源輸入端11之負電極電連接。 使用時’電源輸入端11給電路提供一工作電壓Vcc， 所述工作電壓Vcc藉由R1向場效應電晶體21之柵極G提 供一電壓VGS ’同時’所述工作電壓vcc —併向場效應電 200931757 、曰曰體21之漏極D提供—電壓v〇s。當沒有水覆蓋或滴入所 述一導電觸墊25之間時，電路中之二導電觸墊25相互間 .隔處於斷開狀悲。此時，所述場效應電晶體21之拇極〇、 、 <间之電堡VGS大於場效應電晶體21之栅極 =、源極s接點之間之門限電壓Vg_，從而使得所述場 效應電晶體21之栅極G、源極s之間導通。此時，電源輸 入端u、可變電阻R1、場效應電晶體21之柵極g、源極 ❹s及功錢組12連接形成—通路，使功能模組12正常運 行。 請一併參閲圖3 ’當有水從電子產品外面滲入，而覆 蓋或滴入到電路板1G上之所述二導電觸墊25之間時，由 於水為一弱導體，此時，於整個電路中，所述二導電觸墊 25與水就相當於一串聯於場效應電晶體2ι之栅極&與電 源輸入端π之負電極之間之一電阻尺㈣。此時，由於Rpad 之分壓作用’所述場效應電晶體21之栅極G、源極s之間 ©之電壓VGS小於場效應電晶體21之栅極G、源極s之間之 門限電壓vGS(th) ’從而使得所述場效應電晶體2丨處於截止 狀，’即場效應電晶體21之栅極G、源極s之間處於斷路 狀態。此時，工力能模、址12所處之支路處於短路狀態，以保 賴述電路板H)上佈設之功能模組12。藉由於製造時調 節R1之阻值，可以確保於二導電觸墊。之間進水時構成 之Rpad阻值與R1保持適當之比例，令既可以分去 足夠之電壓，讓場效應電晶體21可以及時截止，而又不會 因阻值過大而構成實際上之斷路，從而失去分壓作用。 200931757 請參閱圖4’所示為本發明所述保護電路如之二導電 觸墊35之另一實施方式之正面示意圖。所述導電觸勢％ •由一米子型片材351及一與所述米字型片材351相互配對 之外圓内凹米字型之片材352組合而成。 請參閱圖5,所示為本發明所述保護電路如之二導電 觸墊45之又一實施方式之正面示意圖。所述導電觸墊c 由一大致呈矩形且二侧均對應間隔之設有缺口之片材々Η 〇及-與所片#451才目互配對之大致呈矩形之外方内相對間Semiconductor Field Effect Transistor, MOSFET). The field effect transistor 21 has a gate G, a drain D and a source s. The gate G and the source s of the field effect transistor 21 can control the conduction and the off between the gate G and the source s by controlling the voltage between the gate g and the source S, wherein the gate The threshold voltage of the conduction between the pole G and the source S is Vgs. In this embodiment, the drain D of the field effect transistor 21 is electrically connected to the positive electrode of the power input terminal 11. The module 12 is connected in series between the source S of the field effect transistor 21 and the negative electrode of the power input terminal u. One end of the variable resistor R1 and the drain d pin of the field effect transistor 21 and the power input terminal 11 The positive electrode is electrically connected, and the other end thereof is electrically connected to the gate g of the field effect transistor 21. The size of the variable resistor R1 depends on the load of the entire circuit board and the actual operation. The two conductive contact pads 25 are in the form of a rectangular strip, which is made of a conductive material such as metal, and is disposed at a relatively spaced position on the circuit board at a water-permeable position. A conductive contact pad 25 and a gate of the field effect transistor 21 G is electrically connected, and another conductive contact pad 25 is electrically connected to the negative electrode of the power input terminal 11. The input terminal 11 provides a working voltage Vcc to the circuit, and the working voltage Vcc provides a voltage VGS 'to the gate G of the field effect transistor 21 through R1 while the operating voltage vcc is parallel to the field effect power 200931757, The drain D of the body 21 provides a voltage v 〇 s. When there is no water covering or dropping between the conductive pads 25, the two conductive pads 25 in the circuit are disconnected from each other. At this time, the bucking poles of the field effect transistor 21, and the electric gate VGS between the gates of the field effect transistor 21 are greater than the gate voltage of the field effect transistor 21 and the threshold voltage Vg_ between the contacts of the source s, thereby causing the said The gate G and the source s of the field effect transistor 21 are turned on. At this time, the power input terminal u, the variable resistor R1, the gate g of the field effect transistor 21, the source ❹s, and the power group 12 are connected to each other. - the path to enable the function module 12 to operate normally. Please refer to FIG. 3 together when there is water infiltrating from the outside of the electronic product and covering or dropping between the two conductive pads 25 on the circuit board 1G. Since the water is a weak conductor, at this time, in the entire circuit, the two conductive pads 25 and water are equivalent to one a resistor (4) connected in series between the gate of the field effect transistor 2 and the negative electrode of the power input terminal π. At this time, due to the voltage division of the Rpad, the gate G of the field effect transistor 21, The voltage VGS between the source s is less than the threshold voltage vGS(th) ' between the gate G and the source s of the field effect transistor 21, so that the field effect transistor 2 is in a cut-off state, ie, the field The gate G and the source s of the effect transistor 21 are in an open state. At this time, the branch of the working force mode and the address 12 is in a short-circuit state, so as to protect the functional mode disposed on the circuit board H). Group 12. By adjusting the resistance of R1 during manufacture, it is possible to secure the two conductive pads. The Rpad resistance formed between the water inlet and R1 maintain an appropriate ratio, so that sufficient voltage can be divided, so that the field effect transistor 21 can be cut off in time without forming an actual disconnection due to excessive resistance. , thus losing the partial pressure effect. 200931757 Please refer to FIG. 4' for a front view of another embodiment of the protection circuit, such as the second conductive pad 35, of the present invention. The conductive potential % is composed of a one-meter sub-sheet 351 and a sheet 352 which is paired with the m-shaped sheet 351 and has a concave inner shape. Referring to FIG. 5, a front view of another embodiment of the protective circuit, such as the second conductive pad 45, of the present invention is shown. The conductive contact pad c is formed by a substantially rectangular shape and a correspondingly spaced apart sheet 々Η - - - - 与 与 与 与 与 大致 451 451 451 451 451 451 451 451 451 451 451 451 451 451 451
隔凹設缺口之片材452組合而成。上述導電㈣MWA sheet 452 is formed by dividing the notched sheets. The above conductive (four) MW
二種結構，可以增加水進入電路板時與導電觸墊35、M 之接觸面積，使得即使少量水進入電子產品時，該導電觸 墊35、45亦可及時導通，從而增加了該保護電路2〇之靈 敏性。 可以理解，所述保護電路2〇並不限於本實施例中所述 之佈設方式’其佈設位置及數量可根據整個電路板1〇之實 ❿際需要而確定。 ' 可以理解’本發明所述保護電路2〇佈設於電子產品内 之電路板10上對應之易滲水位置處，當有水滲入、覆蓋或 滴入到電路板10上之所述二導電觸墊25之間時，藉由利 用該保護電路20之場效應電晶體21之導通及截止^性， 對電路板10上之功能模組12之電源進行切斷，以實現對 所述功能模組12之保護。 、 綜上所述’本發明符合發明專利要件，爰依法提出專利 申請。惟，以上所述者㈣本發明之較佳實施例，本發明之 11 200931757 範圍並不以上述實施例為限，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】 圖1為本發明保護電路之較佳實施例裝設於電路板上 之電路佈設示意圖； 圖2為圖1所示電路板正常工作情況下之電路示意圖； 圖3為圖1所不電路板有水渗入時之電路不意圖， Θ 圖4為本發明保護電路之導電觸塾之另一實施方式之 不意圖； 圖5為本發明保護電路之導電觸塾之又一實施方式之 示意圖。 主要元件符號說明 電路板 10 電源輸入端 11 功能模組 12 預設電路 15 保護電路 20 場效應電晶體 21 導電觸墊 25,35,45 片材 351The two structures can increase the contact area of the water with the conductive pads 35 and M when entering the circuit board, so that even when a small amount of water enters the electronic product, the conductive pads 35 and 45 can be turned on in time, thereby increasing the protection circuit 2 The sensitivity of cockroaches. It can be understood that the protection circuit 2 is not limited to the layout mode described in the embodiment, and the layout position and the number thereof can be determined according to the actual needs of the entire circuit board. It can be understood that the protection circuit 2 of the present invention is disposed on the corresponding water-permeable position on the circuit board 10 in the electronic product, and the two conductive touch pads are infiltrated, covered or dropped onto the circuit board 10 with water. The power supply of the function module 12 on the circuit board 10 is cut off by using the conduction and the turn-off of the field effect transistor 21 of the protection circuit 20 to realize the function module 12 Protection. In summary, the invention conforms to the patent requirements of the invention, and the patent application is filed according to law. However, the above-mentioned (4) preferred embodiments of the present invention, the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art will be able to make equivalent modifications or variations in accordance with the spirit of the present invention. All should be covered by the following application. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a circuit arrangement of a preferred embodiment of a protection circuit of the present invention mounted on a circuit board; FIG. 2 is a circuit diagram of the circuit board of FIG. 1 under normal operation; FIG. FIG. 4 is a schematic diagram of another embodiment of the conductive contact of the protection circuit of the present invention; FIG. 5 is still another embodiment of the conductive contact of the protection circuit of the present invention; Schematic diagram of the way. Main component symbol description Board 10 Power input 11 Function module 12 Preset circuit 15 Protection circuit 20 Field effect transistor 21 Conductive contact pad 25, 35, 45 Sheet 351
Q 12Q 12