201137593 六、發明說明: 【發明所屬之技術領域】 本發明係有關於液晶電視之電源管理別於 =面信號_裝置降舰晶電視待機雜 、_ 一輸201137593 VI. Description of the invention: [Technical field to which the invention pertains] The present invention relates to power management of a liquid crystal television, which is different from the = surface signal
【先前技術】 % τ &I 近年來,隨著經濟成長,資訊、家電產品 城數位化、轉化及舒舰_。越出二; =豕電,於待機時仍具備遙控、顯示、定時、觸控[Prior Art] % τ &I In recent years, with the economic growth, information, home appliances, digital city, transformation and Shu ship _. More than two; = 豕, still have remote control, display, timing, touch during standby
電器 電器 以^咖應使用者之指示—如细遙控器啟動錢。於此 待機狀態下系統所消耗之電力稱為「待機功耗」。雖^一於此 =在待機模式下之耗電量不大,但長久下來累積及多樣性电 產品之乘積,其耗損的電量亦相當可觀 與二氧化職,峨賴雜深㈣源浪費 =資,、家電產品中,LCD電視佔了很大比例,故其工作盘 待機時之耗電量已成為節能技術之騎議題。近年 ,為了,低LCD電視之待機電力’紛_職效率城式^ 術、尚效轉組件及高效料統控㈣路,例如零賴或零電流 切換之共振式操作雜,及糊—次微控制器制咖電視 入信號以控制電源之供應模式。 則 但其仍難以達成使LCD電視之待機功耗低於1W.以下之要 求’其原因如下。請參照圖1 ’其繪示習知液晶電視之基本架構方 塊圖。如圖1所示,該液晶電視具有一電源模組1〇〇、一^系統 模組110、一變頻器120、一 LCD面板13〇及一喇叭14〇。其中 該電源模組100包含一待機電源單元101及一主電源單元彳〇2, 該主系統模組彳彳〇包含一次級微控制器彳彳彳、一具微控制器之縮 =器丨C 112及一音頻放大器113。在待機狀態下,該次級微控制 器111 ’接受該待機電源早元ιοί所輸出之vSUB之供電,其輸出 之主電源控制信號S〇n會禁能該主電源單元1〇2其va、Vaud及 201137593 VINv^電壓之輪出,而使該具微控制器之縮放器丨c 112、該音頻 放,器113及該變頻器12Q停止操作,從而使該lcd面板13〇 及輔队140停止工作。然而該次級微控制器川在待機下之耗 電並無法達成小於05W之規格(一般次級微控制器之功耗約 0.5W〜0.9W) ’且該次級微控制器川之成本可達卜2美金(依次 級微控制器的功能規格而有差異)。 故亟需一低成本之解決方案以降低液晶電視之待機功耗。 【發明内容】 本發明之主要目的在於提供一具低功耗、低成本之輸入介面 • 信號偵測電路,以使LCD電視之待機功耗低於0 5W。 為達成上述目的,本發明提出一種用於液晶電視電源管理之 輸入介面#號偵測電路,其係一硬佈線電路以依至少一輸入介面 信號產生一主電源控制信號,其中:當該至少一輸入介面信號中 有任一信號被偵測到時,該主電源控制信號即呈現一致能狀態以 致能一液晶電視之主電源單元;當該至少一輸入介面信號中^任 一信號被偵測到時,該主電源控制信號即呈現一禁能狀態以禁能 該液晶電視之主電源單元。 為使貝審查委員能進一步瞭解本發明之結構、特徵及其目 鲁的’茲附以圖式及較佳具體實施例之詳細說明如后。 【實施方式】 為了達成待機功耗低於0.5W,及降低成本之目的,本發明提 出以硬佈線方式實施之一輸入介面信號偵測電路。請參照圖2,其 繪示包含本發明輸入介面信號偵測電路一較佳實施例之液晶電視 架構方塊圖。如圖2所示,該液晶電視架構具有一電源模組2〇〇、 一主系統模組210、一變頻器220、一 LCD面板230及一制〇八 240。其中該電源模組200包含一待機電源單元201及—主電源 單元202 ’該主系統模組210包含一輸入介面信號偵測電路211、 一具微控制β之縮放IC.212及一音頻放大器213。在待機狀束| 201137593 下,該輸入介面信號偵測電路211,接受該;择機電源單元2〇ι所 輸出之VSUB之供電,其輸出之主電源控制信號s0N會禁能該主電 源單元2Q2其Va、Vaud及VINV等電壓之輸出,而使該具微控制器 之縮放器IC 212、該音頻放大器213及該變頻器220停止操作, 從而使該LCD面板230及該喇叭240停止工作。 該輸入介面信號偵測電路211係分別耦接至一電源開關信號 sP0WER、一影音信號Sav、一高解析多媒體影音指示信號Shd:;、u 一電版>彳§號Spc及一遙控信號Sir等輸入介面信號,以在該等輸入 介面信號中有任一信號被偵測到時,使該主電源控制信號s〇n呈 •.現一致能狀態以致能該主電源單元202。若該等輸入介面信號中 無任一信號被偵測到時,該主電源控制信號s〇n即呈現一禁能狀 態以禁能該主電源單元202而使該液晶電視進入待機狀態。由於 該輸入介面信號偵測電路211係以硬佈線(Hard_Wired)之方式,' 由些電阻、電谷、電晶體及二極體所組成,其所消耗之功率及 成本均遠低於習知之次級微控制器所具者。以下茲就該輸入介面 信號偵測電路211提出說明。 請參照圖3’其繪示本發明輸入介面信號偵測電路其電源開關 狀態指號偵測電路一較佳實施例之電路圖。如圖3所示,該電源 •開關狀態信號偵測電路具有電阻3〇1_3〇2、- PNP電晶體3〇3及 一二極體304。 。該電阻301-302及該PNP電晶體303之組合係用作一反相 器而該二極體304則用作一單向開關,以在該電源開關信號 Sp0WER為,電位時(代表開啟電源開關),使第一主電源控制信號 ONM呈現而電位,以及在該電源開關信號sp〇WER為高電位時(代 表開^電_斷),使該第—主電雜制信號Sqni呈現高阻抗。 凊參照圖4’其繪示本發明輸入介面信號偵測電路其影音 偵測電路一較佳實施例之電路圖。 ) 如圖4所示’該影音信號偵測電路具有一電容401、電阻 201137593Electrical appliances Electric appliances should be instructed by the user - such as a fine remote control to start the money. The power consumed by the system in this standby state is called "standby power consumption". Although this is the case, the power consumption in standby mode is not large, but the product of long-term accumulation and diversity of electrical products, the power consumption is also considerable and the second-oxidation job, relying on the deep (four) source waste = capital Among the home appliances, LCD TVs account for a large proportion, so the power consumption of the work disk during standby has become the issue of energy-saving technology. In recent years, in order to reduce the standby power of low-LCD TVs, the efficiency of the city, the efficiency of the components, and the high-efficiency control (four), such as zero-lying or zero-current switching, the resonant operation, and the paste - micro The controller makes a television TV signal to control the power supply mode. However, it is still difficult to achieve the requirement that the standby power consumption of the LCD TV is less than 1 W. The reason is as follows. Please refer to FIG. 1 ' for a basic architectural block diagram of a conventional LCD television. As shown in FIG. 1, the LCD TV has a power module 1 , a system module 110 , a frequency converter 120 , an LCD panel 13 , and a speaker 14 . The power module 100 includes a standby power unit 101 and a main power unit ,2, and the main system module 一次 includes a primary-level microcontroller 彳彳彳, and a microcontroller 缩C 112 and an audio amplifier 113. In the standby state, the secondary microcontroller 111' accepts the power supply of the vSUB output by the standby power supply, and the output main power control signal S〇n disables the main power supply unit 1〇2, va, Vaud and 201137593 VINv^ voltage wheeling, so that the microcontroller's scaler 丨c 112, the audio amplifier 113 and the frequency converter 12Q stop operating, so that the lcd panel 13 and the auxiliary team 140 stop jobs. However, the power consumption of the secondary microcontroller in standby is not able to achieve a specification of less than 05W (the power consumption of a general secondary microcontroller is about 0.5W~0.9W) and the cost of the secondary microcontroller can be reduced. Dab 2 US dollars (there are differences in the functional specifications of the sequential microcontrollers). Therefore, a low-cost solution is needed to reduce the standby power consumption of the LCD TV. SUMMARY OF THE INVENTION The main object of the present invention is to provide a low power consumption, low cost input interface • signal detection circuit, so that the standby power consumption of the LCD TV is less than 0 5W. In order to achieve the above object, the present invention provides an input interface ## detecting circuit for liquid crystal television power management, which is a hard wiring circuit for generating a main power control signal according to at least one input interface signal, wherein: at least one When any signal in the input interface signal is detected, the main power control signal presents a consistent energy state to enable a main power supply unit of the liquid crystal television; when any signal of the at least one input interface signal is detected When the main power control signal is in a disabled state, the main power supply unit of the liquid crystal television is disabled. The detailed description of the structure and features of the present invention and the detailed description of the preferred embodiments of the present invention are set forth below. [Embodiment] In order to achieve standby power consumption of less than 0.5 W and cost reduction, the present invention proposes to implement an input interface signal detecting circuit in a hard wiring manner. Referring to FIG. 2, a block diagram of a liquid crystal television architecture including a preferred embodiment of the input interface signal detecting circuit of the present invention is shown. As shown in FIG. 2, the LCD TV architecture has a power module 2A, a main system module 210, a frequency converter 220, an LCD panel 230, and a system. The power module 200 includes a standby power unit 201 and a main power unit 202. The main system module 210 includes an input interface signal detecting circuit 211, a micro control β scaling IC 212, and an audio amplifier 213. . In the standby beam | 201137593, the input interface signal detecting circuit 211 accepts the power supply of the VSUB outputted by the selected power supply unit 2〇, and the output main power control signal s0N disables the main power supply unit 2Q2 The output of the Va, Vaud, and VIV voltages causes the microcontroller's scaler IC 212, the audio amplifier 213, and the inverter 220 to stop operating, thereby stopping the LCD panel 230 and the speaker 240. The input interface signal detecting circuit 211 is respectively coupled to a power switch signal sP0WER, a video signal Sav, a high-resolution multimedia video indication signal Shd:; u, an electrotype> 彳§Spc, and a remote control signal Sir. The input interface signal is such that when any of the input interface signals is detected, the main power control signal s〇n is rendered in a consistent state to enable the main power supply unit 202. If none of the input interface signals are detected, the main power control signal s〇n assumes an inactive state to disable the main power supply unit 202 to bring the liquid crystal television into a standby state. Since the input interface signal detecting circuit 211 is formed by hard wiring (Hard_Wired), the power and cost consumed by the resistors, the electric valley, the transistor and the diode are far lower than the conventional ones. The class of microcontrollers. The input interface signal detecting circuit 211 will be described below. Please refer to FIG. 3' for a circuit diagram of a preferred embodiment of the power switch state indicator detecting circuit of the input interface signal detecting circuit of the present invention. As shown in FIG. 3, the power supply/switch state signal detecting circuit has a resistor 3〇1_3〇2, a PNP transistor 3〇3, and a diode 304. . The combination of the resistors 301-32 and the PNP transistor 303 is used as an inverter and the diode 304 is used as a one-way switch to indicate that the power switch signal Sp0WER is at a potential (on behalf of turning on the power switch) The first main power control signal ONM is rendered at a potential, and when the power switch signal sp 〇 WER is at a high level (representing the power on/off), the first main electrical miscellaneous signal Sqni is rendered high impedance. Referring to FIG. 4', a circuit diagram of a preferred embodiment of the audio and video detection circuit of the input interface signal detecting circuit of the present invention is shown. As shown in Figure 4, the video signal detection circuit has a capacitor 401, resistor 201137593
402-405、一 NPN 電晶體 406、一電阻 407、一電容 408、一電 阻 409、一 NPN 電晶體 410、一電阻 411、電阻 412-413、一 PNP 電晶體414及一二極體415。 該電容401、電阻402-405及NPN電晶體406係用作一反 相放大器,該電阻407及電容408係用作一積分器,該電.阻409、 NPN電晶體410及電阻411係用作一反相器,以及該愈阻 412-413及該PNP電晶體414之組合係用作一反相器而該二極體 415則用作一單向開關,以在該影音信號sAV之平均電壓高於一臨 界電壓時(代表有影音信號輸入),使第二主電源控制信號s〇N2呈 # 現而電位,以及在該影音信號SAV之平均.電壓未高於該臨界電壓 時(代表無影音信號輸入)’使該第二主電源控制信號s〇N2呈現高 阻抗。 請參照圖5,其繪示本發明輸入介面信號偵測電路其高解析多 媒體影音信號偵測電路一較佳實施例之電路圖。如圖5所示,該 高解析多媒體影音信號偵測電路具有電阻5〇1_5〇2、一 npn電晶 體503、一電阻5〇4、電阻505_5〇6、一 pNp電晶體5〇7及一二 極體508。 一 如該電阻501 -502、N PN電晶體503及電阻504係用作一反相 器,2及該電阻505-506及該PNP電晶體5〇7之組合係用作一 而5亥一極體508則用作—單向開關,以在該高解析多_ 衫音指不信號S_之電壓高於一臨界電壓時(代表有高解析 =影音錢輸人)’使第三主f雜輸號s㈣呈現高電位,以 $該高解析多舰影音指示㈣Sh_之未高於該臨界雙 壓^ (代表無高解析多媒體影音信號輸入),使該第三主電源控帝 = 呈現高阻抗。其中該高解析多媒體影音指示信號S瞻 同解析多媒體影音介面(HD.MI),當其電壓等於+5Vd( I j表有高解❹賴f彡音信號,*當其電壓等於GVdc時,作 表無南解析多媒體影音信號。 201137593 請參照圖6,其繪示本發明輸入介面信號偵測電路其電腦信號 4貞測電路一較佳實施例之電路圖。如圖6所示,該電腦信號偵測 電路具有電阻601-602、一 NPN電晶體603、一電阻604、電阻 605-606、一 PNP 電晶體 607 及一二極體 608。 該電阻601 -602、NPN電晶體603及電阻604係用作一反相 器,以及該電阻605-606及該PNP電晶體607之組合係用作一 反相器而該二極體608則用作一單向開關,以在該電腦信號Spc 之電壓高於一臨界電壓時(代表有電腦信號輸入),使第四主電源 控制信號S〇n4呈現高電位,以及在該電腦信號Spc之電壓未高於 • 該臨界電壓時(代表無電腦信號輸入)’使該第四主電源控制信號 Som呈現高阻抗。其中該電腦信號Spc係來自一 pc連接器介面, 當其電壓等於+5Vdc時,代表有pc之信號,而當其電壓等於〇Vdc 時,代表無PC之信號。 請參照圖7’其繪示本發明輸入介面信號偵測電路其遙控信號 偵測電路一較佳實施例之電路圖。如圖7所示,該遙控信號偵測 電路具有電阻701-703、一 NPN電晶體704、一電阻705、一電 阻706、一電容707、一電阻708、一 NPN電晶體709、一電阻 710、電阻 711-712、一 PNP 電晶體 713、一電阻 714、一二極 # 體715、電阻716-717以及一 NPN電晶體718。 該電阻701 _703、NPN電晶體704及電阻705係用作一反相 放大器,該電阻706及電容707係用作一積分器,該電阻7〇8、 NPN電晶體709及電阻710係用作一反相器,以及該電阻 ^11-712、該PNP電晶體713及該電阻714之組合係用作一反相 器,該二極體715用作一單向開關,而該電阻7彳6_717及該NpN 電晶體718則用作一自保持迴路以在該遙控信號SIR之平均電壓 .高於-臨界電?時(代表有遙控信號輸入〉’使第五主電源控制信 號sONS呈現高電位,以及在該遙控信號S|r之平均電壓未高於該 臨界電壓時(代表無遙控信號輸入),使該第五主電源控制信號 7 201137593402-405, an NPN transistor 406, a resistor 407, a capacitor 408, a resistor 409, an NPN transistor 410, a resistor 411, a resistor 412-413, a PNP transistor 414, and a diode 415. The capacitor 401, the resistors 402-405 and the NPN transistor 406 are used as an inverting amplifier. The resistor 407 and the capacitor 408 are used as an integrator. The resistor 409, the NPN transistor 410 and the resistor 411 are used as an integrator. An inverter, and a combination of the getter 412-413 and the PNP transistor 414 are used as an inverter and the diode 415 is used as a unidirectional switch for the average voltage of the video signal sAV. When the voltage is higher than a threshold voltage (representing the input of the video signal), the second main power control signal s〇N2 is at the potential, and the average of the video signal SAV is not higher than the threshold voltage (representing no The video signal input) ' makes the second main power control signal s 〇 N2 exhibit a high impedance. Please refer to FIG. 5, which is a circuit diagram of a preferred embodiment of the high resolution multi-media audio and video signal detecting circuit of the input interface signal detecting circuit of the present invention. As shown in FIG. 5, the high-resolution multimedia video signal detecting circuit has a resistance of 5〇1_5〇2, an npn transistor 503, a resistor 5〇4, a resistor 505_5〇6, a pNp transistor 5〇7, and a second. Polar body 508. As the resistors 501-502, N PN transistor 503 and resistor 504 are used as an inverter, 2 and the combination of the resistors 505-506 and the PNP transistor 5〇7 are used as one and five hai The body 508 is used as a one-way switch, so that when the voltage of the high-resolution multi-slide tone signal S_ is higher than a threshold voltage (representing high resolution = video money input), the third main f is mixed The input signal s (four) presents a high potential, and the high-resolution multi-ship audio and video indication (four) Sh_ is not higher than the critical double voltage ^ (representing no high-resolution multimedia video signal input), so that the third main power control device exhibits high impedance . The high-resolution multimedia video indication signal S is the same as the resolution multimedia audio interface (HD.MI), when its voltage is equal to +5Vd (the I j table has a high resolution 彡 彡 彡 , signal, * when its voltage is equal to GVdc, The table has no south resolution multimedia video signal. 201137593 Please refer to FIG. 6 , which is a circuit diagram of a preferred embodiment of the computer signal 4 detection circuit of the input interface signal detecting circuit of the present invention. As shown in FIG. The measuring circuit has a resistor 601-602, an NPN transistor 603, a resistor 604, a resistor 605-606, a PNP transistor 607 and a diode 608. The resistor 601-602, the NPN transistor 603 and the resistor 604 are used. An inverter is used, and a combination of the resistors 605-606 and the PNP transistor 607 is used as an inverter, and the diode 608 is used as a one-way switch to high voltage at the computer signal Spc. At a threshold voltage (representing a computer signal input), the fourth main power control signal S〇n4 is at a high potential, and when the voltage of the computer signal Spc is not higher than the threshold voltage (representing no computer signal input) 'Making the fourth main power control signal Som presents a high impedance. The computer signal Spc comes from a pc connector interface. When its voltage is equal to +5Vdc, it represents the signal of pc, and when its voltage is equal to 〇Vdc, it represents the signal without PC. 7' is a circuit diagram showing a preferred embodiment of the remote control signal detecting circuit of the input interface signal detecting circuit of the present invention. As shown in FIG. 7, the remote signal detecting circuit has a resistor 701-703 and an NPN transistor 704. a resistor 705, a resistor 706, a capacitor 707, a resistor 708, an NPN transistor 709, a resistor 710, a resistor 711-712, a PNP transistor 713, a resistor 714, a diode 715, and a resistor. 716-717 and an NPN transistor 718. The resistor 701_703, the NPN transistor 704 and the resistor 705 are used as an inverting amplifier, and the resistor 706 and the capacitor 707 are used as an integrator, the resistor 7〇8, NPN. The transistor 709 and the resistor 710 are used as an inverter, and the combination of the resistor 11-11-712, the PNP transistor 713, and the resistor 714 is used as an inverter, and the diode 715 is used as a single To the switch, and the resistor 7彳6_717 and the NpN transistor 718 are used a self-holding loop to cause the fifth main power control signal sONS to assume a high potential when the average voltage of the remote control signal SIR is higher than -critical power (representing a remote control signal input), and at the remote control signal S|r When the average voltage is not higher than the threshold voltage (representing no remote control signal input), the fifth main power control signal 7 201137593
Sons呈現高阻抗。 、’查由SON1、S0N2、sON3、S0N4、S0N5之邏輯或纪人,一以錄 产輸入介面信號侧裝置即可在低成本、低功耗之 It/兄下’使液Βθ電視之待機功耗低於〇5vv。 於太揭示者,乃較佳實施例,舉凡局部之變更或修飾而源 ^案,術思想而為熟習該項技藝之人所易於推知者俱不脫 本案之專利權範嘴。 於羽Γ上所陳’本案無論就目的'手段與功效,在在顯示其迥異 ^ ¾知之技術特徵’且其首先發明合於實用,亦在在符合發明之 _專利要件,懇請貴審查委員明察,並祈早曰賜予專利,俾嘉* 社會,實感德便。 σ," 【圖式簡單說明】 圖1為一示意圖,其繪示習知液晶電視之基本架構 方塊圖。 圖j為一示意圖’其繚示包含本發明輸人介面信號偵測電路 一較佳實施例之液晶電視架構方塊圖。 '圖3為一示意圖,其繪示本發明輸入介面信號偵測電路其電 _ 源開關狀態信號偵測電路一較佳實施例之電路圖。 、 立圖4為一示意圖,其繪示本發明輸入介面信號偵測電路其影 音抬號偵測電路一較佳實施例之電路圖。 圖5為一示意圖,其繪示本發明輸入介面信號偵測電路其高 解析夕媒體影音信號偵測電路一較佳實施例之電路圖。 圖6為一示意圖,其繪示本發明輸入介面信號偵測電路其電 腦信號偵测電路一較佳實施例之電路圖。 ▲圖7為一不意圖’其繪示本發明輸入介面信號偵測電路其遙 控信號偵測電路一較佳實施例之電路圖。 【主要元件符號說明】 電源模組100、200 201137593 待機電源單元101、201 主電源單元102、202 主系統模組110、210 次級微控制器111 具微控制器之縮放器IC 112、212 音頻放大器113、213 變頻器120、220 LCD 面板 130、230 口刺队 140、240 φ 輸入介面信號偵測電路211 電阻 301 -302、402-405、407、409、411 -413、501 -502、504-506、 601-602、604-606、701-703、705-706、708、710-712、714、 716-717 PNP 電晶體 303、414、507、607、713 二極體 304、415、508、608、715 電容 401、408、707 NPN 電晶體 406、410、503、603、704、709、718Sons exhibit high impedance. , 'Check the logic or JI of SON1, S0N2, sON3, S0N4, S0N5, one can record the input interface signal side device can be used in the low-cost, low-power It/ brother to make the liquid Β θ TV standby power The consumption is less than 〇5vv. Yu Tai revealer is the preferred embodiment. Anyone who changes or modifies the source and the case is a person who is familiar with the skill and can easily infer the intent of the patent. Yu Yushang’s 'in this case, regardless of the purpose's means and efficacy, is showing its distinctive technical characteristics' and its first invention is practical, and it is also in compliance with the invention's patent requirements, please ask your review board And praying for the patents, the 俾嘉* society, the real sense of virtue. σ, " [Simple Description of the Drawings] Fig. 1 is a schematic diagram showing the basic structure of a conventional liquid crystal television. Figure j is a schematic diagram showing a liquid crystal television architecture including a preferred embodiment of the input interface signal detecting circuit of the present invention. FIG. 3 is a schematic diagram showing a circuit diagram of a preferred embodiment of the input signal signal detecting circuit of the present invention. FIG. 4 is a schematic diagram showing a circuit diagram of a preferred embodiment of the audio signal detection circuit of the input interface signal detecting circuit of the present invention. FIG. 5 is a schematic diagram showing a circuit diagram of a preferred embodiment of the high-resolution media image signal detecting circuit of the input interface signal detecting circuit of the present invention. FIG. 6 is a schematic diagram showing a circuit diagram of a preferred embodiment of the computer signal detecting circuit of the input interface signal detecting circuit of the present invention. ▲ Figure 7 is a circuit diagram showing a preferred embodiment of the remote control signal detecting circuit of the input interface signal detecting circuit of the present invention. [Main component symbol description] Power module 100, 200 201137593 Standby power supply unit 101, 201 Main power supply unit 102, 202 Main system module 110, 210 Secondary microcontroller 111 Scaler IC with microcontroller 112, 212 Audio Amplifier 113, 213 Inverter 120, 220 LCD panel 130, 230 Spurs 140, 240 φ Input interface signal detection circuit 211 Resistors 301 - 302, 402-405, 407, 409, 411 - 413, 501 - 502, 504 - 506, 601-602, 604-606, 701-703, 705-706, 708, 710-712, 714, 716-717 PNP transistor 303, 414, 507, 607, 713 diodes 304, 415, 508 608, 715 Capacitors 401, 408, 707 NPN transistors 406, 410, 503, 603, 704, 709, 718