The makers of handheld medical, industrial and consumerdevices use a wide variety of high resolution, small tomedium sized color TFT LCD displays. The power supplydesigners for these displays must contend with shrinkingboard area, tight schedules, and variations in displaytypes and feature requirements. The LTC®3524 simplifi esthe designer’s job by combining a versatile, easily programmed,TFT LCD bias supply and white LED backlightdriver in a low profi le 4mm × 4mm QFN package.
上傳時(shí)間： 2013-10-26
上傳用戶：chens000
Avalanche photo diode (APD) receiver modules arewidely used in fi ber optic communication systems. AnAPD module contains the APD and a signal conditioningamplifi er, but is not completely self contained. It stillrequires signifi cant support circuitry including a highvoltage, low noise power supply and a precision currentmonitor to indicate the signal strength. The challenge issqueezing this support circuitry into applications withlimited board space. The LT®3482 addresses this challengeby integrating a monolithic DC/DC step-up converter andan accurate current monitor. The LT3482 can supportup to a 90V APD bias voltage, and the current monitorprovides better than 10% accuracy over four decades ofdynamic range (250nA to 2.5mA).
上傳時(shí)間： 2014-01-18
上傳用戶：wenyuoo
交一直一交變頻器的中間直流環(huán)節(jié)如果是用大電容平波通常稱為電壓源型變頻器。如果分開(kāi)來(lái)稱呼，則其后端逆變器部分叫電壓源逆變器(VSI)，產(chǎn)品GB和IEC標(biāo)準(zhǔn)也是這種稱呼。其前端整流部分對(duì)電網(wǎng)而言是— 個(gè)諧波源，也就叫電壓型諧波源。與此相對(duì)照，交一直一交變頻器的中間直流環(huán)節(jié)如果用大電感平波就分別稱為電流源型變頻器、電流源逆變器(CSD、電流源型諧波源。之所以要特別區(qū)分變頻器為電壓源和電流源兩大類是因?yàn)樗麄兊慕涣鬏斎腚娏鞑ㄐ魏妥冾l后輸出的交流電壓和交流電流的波形及性能都有很大的不同。
上傳時(shí)間： 2013-11-03
上傳用戶：xitai
High voltage buck DC/DC controllers such as the LTC3890(dual output) and LTC3891 (single output) are popular inautomotive applications due to their extremely wide 4V to60V input voltage range, eliminating the need for a snubberand voltage suppression circuitry. These controllersare also well suited for 48V telecom applications whereno galvanic isolation is required.
上傳時(shí)間： 2013-10-31
上傳用戶：wwwe
Avalanche photodiodes (APDs) are widely utilized in laserbased fiberoptic systems to convert optical data intoelectrical form. The APD is usually packaged with a signalconditioning amplifier in a small module. An APD receivermodule and attendant circuitry appears in Figure 1. TheAPD module (figure right) contains the APD and a transimpedance(e.g., current-to-voltage) amplifier. An opticalport permits interfacing fiberoptic cable to the APD’sphotosensitive portion. The module’s compact constructionfacilitates a direct, low loss connection between theAPD and the amplifier, necessary because of the extremelyhigh speed data rates involved
標(biāo)簽： 雪崩 光電二極管 偏置電壓 電流檢測(cè)電路
上傳時(shí)間： 2013-10-25
上傳用戶：brain kung
Telecommunication, satellite links and set-top boxes allrequire tuning a high frequency oscillator. The actualtuning element is a varactor diode, a 2-terminal device thatchanges capacitance as a function of reverse bias voltage.1 The oscillator is part of a frequency synthesizingloop, as detailed in Figure 1. A phase locked loop (PLL)compares a divided down representation of the oscillatorwith a frequency reference. The PLL’s output is levelshifted to provide the high voltage necessary to bias thevaractor, which closes a feedback loop by voltage tuningthe oscillator. This loop forces the voltage controlledoscillator (VCO) to operate at a frequency determined bythe frequency reference and the divider’s division ratio.
標(biāo)簽： 開(kāi)關(guān)穩(wěn)壓器 低噪聲 上傳時(shí)間： 2013-12-20
上傳用戶：ABCDE
IC 特色 : ˙ 半諧振模式之 ZVS零電壓切換 , 能有效降低切換損失 , 提高效率 , 并具展頻功能 , 改善EMI . ˙ 輕 / 重載的 Duty Factor 皆在 CCM 與 DCM 邊緣 , 是最能發(fā)揮次級(jí) "同步整流" 效率的一種工作模式 . ˙ 空載時(shí)進(jìn)入 Cycle Skipping ( Typical 0.3W ) , 有效達(dá)成環(huán)保規(guī)範(fàn) . ˙ 內(nèi)建 "LEB前緣遮沒(méi)" 功能 , 避免電流迴授失真 . ˙ 能隨輸入電壓變化 , 自動(dòng)補(bǔ)償 OPP過(guò)功率保護(hù)點(diǎn) . ˙ 精密的 OVP 過(guò)壓保護(hù)點(diǎn)可自行設(shè)定 . ˙ 完整的保護(hù)功能 : OVP過(guò)壓保護(hù) , OCP過(guò)流保護(hù) , OPP過(guò)載保護(hù) , SWP線圈短路保護(hù) , SCP輸出短路保護(hù) , OTP過(guò)溫度保護(hù) .
上傳時(shí)間： 2014-12-24
上傳用戶：回電話#
傳統(tǒng)電源電路檢修 二、開(kāi)關(guān)電源電路檢修 •首先應(yīng)檢查F601、F602兩個(gè)保險(xiǎn)絲。 •若F601或F602熔斷，有可能是保險(xiǎn)絲本身質(zhì)量不好，但換上新保險(xiǎn)絲后再次熔斷，說(shuō)明電路有電流過(guò)大故障. •若F601再次熔斷，有可能是整流管V601、V602擊穿。 •若F602再次熔斷，有可能是穩(wěn)壓輸出12V的負(fù)載過(guò)流，也可能是調(diào)整管V603、V605的c-e極擊穿。 •若保險(xiǎn)絲好，再檢查18V直流電壓。無(wú)18V電壓，則有可能是電源變壓器繞組開(kāi)路、或電源開(kāi)關(guān)S601接觸不良，或V601、V602整流管都開(kāi)路。 若18V正常，則無(wú)12V輸出電壓的原因可能是R601、R602開(kāi)路，C604、C605擊穿，或V603、V605開(kāi)路
上傳時(shí)間： 2013-11-18
上傳用戶：蠢蠢66
簡(jiǎn)易負(fù)離子發(fā)生器負(fù)離子增加，對(duì)人有催眠、止汗、鎮(zhèn)痛、增進(jìn)食欲，使人精神爽快，消除疲勞的作用。圖1是負(fù)離子發(fā)生器電路圖。220V交流市電經(jīng)D1整流后向C3和C2充電，當(dāng)C2充電至氖泡導(dǎo)通并觸發(fā)SCR導(dǎo)通時(shí)，C3經(jīng)SCR、B的L1放電，經(jīng)B感應(yīng)升壓后，由D2反向整流得8kV直流高壓使發(fā)生器M的分子電離而產(chǎn)生負(fù)離子。調(diào)整R3的阻值可以改變觸發(fā)頻率和輸出電壓。調(diào)整時(shí)必須注意安全，更換元件需撥下電源插頭
標(biāo)簽： 負(fù)離子發(fā)生器
上傳時(shí)間： 2013-10-29
上傳用戶：731140412
復(fù)位監(jiān)控器件內(nèi)部集成精確的電壓監(jiān)控電路，可通過(guò)確定的閾值電壓?jiǎn)?dòng)復(fù)位操作，同時(shí)排除瞬間干擾的影響，又可以防止MCU在電源啟動(dòng)和關(guān)閉期間的誤操作，保證數(shù)據(jù)安全。通常，傳統(tǒng)的RC復(fù)位電路是不可靠的，如果一個(gè)計(jì)算機(jī)系統(tǒng)的復(fù)位不可靠將帶來(lái)意想不到的麻煩。選擇一款合適的復(fù)位器件有利于提高系統(tǒng)的可靠性和性價(jià)比。可是，用戶需要如何選擇才能找到一款適合自己系統(tǒng)的復(fù)位器件呢？在選擇復(fù)位器件之前，首先我們需要對(duì)系統(tǒng)需求做一剖析，如：該系統(tǒng)是多少伏的系統(tǒng)？是高電平復(fù)位還是低電平復(fù)位，還是同時(shí)需要用到高電平復(fù)位和低電平復(fù)位？除了復(fù)位功能，您的系統(tǒng)是否需要用到看門狗、E2PROM等器件？在您的PCB電路設(shè)計(jì)中給復(fù)位芯片預(yù)留了多大的空間？解決了以上問(wèn)題我們接下來(lái)看如何選擇合適的復(fù)位器件：
標(biāo)簽： 內(nèi)置 看門狗 電壓監(jiān)控器 電路設(shè)計(jì)
上傳時(shí)間： 2013-11-25
上傳用戶：lizhen9880
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