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天津巨冉軸承銷(xiāo)售有限公司，公司銷(xiāo)售INA軸承德國(guó)INA軸承銷(xiāo)售德國(guó)INA軸承銷(xiāo)售INA德國(guó)軸承銷(xiāo)售商－－宇瑞通捷主要銷(xiāo)售德國(guó)INA進(jìn)口軸承銷(xiāo)售、德國(guó)INA軸承銷(xiāo)售、德國(guó)進(jìn)口軸承銷(xiāo)售、德國(guó)INA軸承銷(xiāo)售、IN德國(guó)INA軸承銷(xiāo)售、德國(guó)INA軸承銷(xiāo)售，提供的德國(guó)INA軸承品種、型號(hào)齊全，價(jià)格低廉，質(zhì)量。主要銷(xiāo)售范圍有:工礦企業(yè)用德國(guó)INA進(jìn)口軸承銷(xiāo)售,鋼廠用德國(guó)INA進(jìn)口軸承銷(xiāo)售,機(jī)械設(shè)備用德國(guó)INA進(jìn)口軸承銷(xiāo)售,鐵路用德國(guó)INA進(jìn)口軸承銷(xiāo)售,工程機(jī)械用德國(guó)INA進(jìn)口軸承銷(xiāo)售，發(fā)電廠用德國(guó)INA進(jìn)口軸承銷(xiāo)售,石化機(jī)械用德國(guó)INA進(jìn)口軸承銷(xiāo)售,鉆機(jī)用德國(guó)INA進(jìn)口軸承銷(xiāo)售等。德國(guó)軸承公司所提供的標(biāo)準(zhǔn)產(chǎn)品有各類(lèi)軸承二萬(wàn)余種。品種包括深溝球德國(guó)INA進(jìn)口軸承、調(diào)心球德國(guó)INA進(jìn)口軸承、圓柱滾子德國(guó)INA進(jìn)口軸承、球面滾子德國(guó)INA進(jìn)口軸承、角接觸球德國(guó)INA進(jìn)口軸承、滾針德國(guó)INA進(jìn)口軸承及其它多種類(lèi)型。

天津巨冉軸承銷(xiāo)售有限公司網(wǎng)站：http://www.jrskf.com 聯(lián)系電話(huà)：022-27720759-8003詢(xún)價(jià)傳真：022-27720759-8007 QQ:1014271275 聯(lián)系人：陳小姐   以下軸承我們均現(xiàn)貨供應(yīng) 歡迎致電??！

一、SYL-11型苯板切割機(jī)概況

SYL-11型苯板切割機(jī)本機(jī)適用于切割各種苯板之儀器。具有切割度高使用靈活方便等特點(diǎn)。是試驗(yàn)室理想的配套設(shè)備。

二、    SYL-11型苯板切割機(jī) 技術(shù)參數(shù)

1、可切割試件尺寸：600×600mm

2、可切割試件厚度：5－300mm

3、電源：220V

4、切割絲電壓：12V

5、外形尺寸：460×410×720mm

6、整機(jī)重量：45Kg

三、SYL-11型苯板切割機(jī)安裝與使用

確認(rèn)接好電源220V并有接地。按工作臺(tái)面調(diào)整好靠尺尺寸。準(zhǔn)備好被切割試件，打開(kāi)電源開(kāi)關(guān)。根據(jù)所切割試件的厚度掌握好切割速度，切割完畢關(guān)閉電源開(kāi)關(guān)。

請(qǐng)注意在切割時(shí)頭及手部切勿接觸切割絲以防燙傷。

結(jié)束語(yǔ)

產(chǎn)品的改善永無(wú)止境，本公司歡迎所有的用戶(hù)為我們提出合理的意見(jiàn)，以便使我們的產(chǎn)品加完善，為您提供好的服務(wù)。

無(wú)論您對(duì)我們的產(chǎn)品和服務(wù)感到滿(mǎn)意或者是不滿(mǎn)意，我們都非常希望得到您的意見(jiàn)，您的意見(jiàn)對(duì)我們很寶貴。

我們期待您的批評(píng)、指導(dǎo)和支持，謝謝您的使用！

Kanomax6004日本加野麥克斯熱線(xiàn)式風(fēng)速計(jì)在很多領(lǐng)域都能靈活運(yùn)用，是難得的一種熱式風(fēng)速計(jì)

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公司名稱(chēng): 青島藍(lán)天科技環(huán)保設(shè)備有限公司

聯(lián) 系 人 : 李恒（商務(wù)經(jīng)理）

手　　機(jī): 159 668 96953

聯(lián)系電話(huà): 0532-888 68758

聯(lián)系傳真: 0532-888 68766

電子郵件: cydx8848@126.com

網(wǎng)　　址: www.leehang.com

地　　址: 青島市李滄工業(yè)園九水東路137號(hào)

郵　　編: 266100

美國(guó)華瑞PGM-1600 SearchRAE 泵吸式可燃?xì)?毒氣復(fù)合氣體檢測(cè)儀  

SearchRAE是一款可燃?xì)狻⒍練鈴?fù)合式檢測(cè)器，可選可燃?xì)釲EL及LEL/VOL雙量程傳感器、電化學(xué)氧氣/毒氣傳感器及MOS傳感器，體積小巧，攜帶方便，內(nèi)置中文菜單，方便使用，可滿(mǎn)足燃?xì)饧笆褪袠I(yè)應(yīng)用。一.基本性能：♦采樣方式 泵吸式♦外殼材質(zhì) 工程塑料，橡膠外套♦防護(hù)等級(jí) IP65，防水，防塵♦抗電磁輻射 EMI/RF等級(jí)：EMC Directive 89/336/EEC♦環(huán)境溫度 -20o C ～ 50o C♦環(huán)境濕度 0% ～ 95%相對(duì)濕度（無(wú)冷凝）二.傳感器參數(shù):♦傳感器配置 1個(gè)LEL或LEL/VOL傳感器、1個(gè)EC傳感器檢測(cè)CO/H2S/O2、1個(gè)MOS傳感器檢測(cè)甲烷*♦傳感器 檢測(cè)范圍（%） 分辨率 （%） 響應(yīng)時(shí)間（T90秒） 檢測(cè)誤差（標(biāo)定點(diǎn)）O2            0-30                0.1                 15                        <±3％LEL          0-100               1                    15LEL/VOL 0-100/0-100    1                    15♦傳感器 檢測(cè)范圍（ppm） 分辨率 （ppm） 響應(yīng)時(shí)間（T90秒） 檢測(cè)誤差（標(biāo)定點(diǎn)）CO              0-500                1                            25                       <±3％H2S            0-100               0.1                          30CO*            0-2000              1                            25H2S*          0-1000              1                            30MOS*         0-2000               1                            60*供貨時(shí)間待定三..顯示及操作:♦顯示屏 圖形液晶顯示器、帶自動(dòng)背光♦顯示語(yǔ)言 中文/英語(yǔ)+符號(hào)♦顯示內(nèi)容 同時(shí)顯示兩個(gè)傳感器及實(shí)時(shí)檢測(cè)值、峰值、電池電壓、存儲(chǔ)狀態(tài)、泵狀態(tài)♦按鍵 1個(gè)操作鍵、2個(gè)功能鍵、1個(gè)照明燈開(kāi)關(guān)♦報(bào)警方式 95dB@30cm蜂鳴器、LED閃爍♦報(bào)警信號(hào) 高/低濃度報(bào)警、電池電量不足報(bào)警、傳感器故障報(bào)警、泵阻塞報(bào)警♦報(bào)警點(diǎn)設(shè)置 單獨(dú)設(shè)置高/低報(bào)警限值♦報(bào)警模式 鎖定或自動(dòng)重置♦數(shù)據(jù)存儲(chǔ)及通訊參數(shù)♦數(shù)據(jù)存儲(chǔ) 使用SD卡數(shù)據(jù)存儲(chǔ)，EXCEL數(shù)據(jù)格式♦采樣間隔 1-3600秒可調(diào)♦數(shù)據(jù)通訊 通過(guò)SD讀卡器下載檢測(cè)數(shù)據(jù)，通過(guò)USB（通過(guò)底座）、RS232（通過(guò)旅行充電器）下載儀器參數(shù)♦泵方式 內(nèi)置♦泵流速 450-550cc/min♦電池 3.7V可充電鋰離子電池♦堿性電池適配器，使用4節(jié)AA堿性電池♦運(yùn)行時(shí)間 可連續(xù)工作16小時(shí)（視工作環(huán)境和使用頻率）♦鋰電池充電時(shí)間 8小時(shí)♦標(biāo)定方式 零點(diǎn)/擴(kuò)展標(biāo)定♦尺寸 21×8.5×6.5 cmv 重量 700g（含鋰電池）

聯(lián)系人：孟陽(yáng)手機(jī)   ：13520399001設(shè)備類(lèi)型  開(kāi)關(guān)電源

設(shè)備廠家  華為

華為T(mén)P48600B機(jī)柜尺寸：

寬mm    深mm     高mm

650毫米 450毫米 1600號(hào) 

設(shè)備型號(hào)  CPMU01

接口類(lèi)型  DB9 公頭，232 接口

接線(xiàn)說(shuō)明  2 接 TX，3 接 RX，5 接 GND

協(xié)議名稱(chēng)  CPMU01華為T(mén)P48600B開(kāi)關(guān)電源機(jī)柜，48v通信電源 （CPMU01 ）華為T(mén)P48600B-N16A2

串口參數(shù)  地址 1,數(shù)據(jù)位 8,停止位 1，無(wú)校驗(yàn)，波特率 9600

注：舊版本 FSU 需配 RS232/RS485 轉(zhuǎn)換器。新版本 FSU 自帶 RS232（串口 7、8 為 232 接口）

可直接接入（2 接 TX，3 接 RX，5 接 GND）。需要將地址改為 1，通信方式改為，開(kāi)關(guān)

電源參數(shù)設(shè)置密碼：000001

鐵塔智能設(shè)備接入指導(dǎo)

6

7)  TP48600B-N16B2 （CPMU01 ）

設(shè)備類(lèi)型  開(kāi)關(guān)電源

設(shè)備廠家  華為

設(shè)備型號(hào)  CPMU01

接口類(lèi)型  RJ45 水晶頭，232 接口

接線(xiàn)說(shuō)明  水晶頭 3 接 TX，7 接 RX，6 接 GND

協(xié)議名稱(chēng)  CPMU01

串口參數(shù)  地址 1,數(shù)據(jù)位 8,停止位 1，無(wú)校驗(yàn)，波特率 9600

注：舊版本 FSU 需配 RS232/RS485 轉(zhuǎn)換器。新版本 FSU 自帶 RS232（串口 7、8 為 232 接口）

可直接接入（3 接 TX，7 接 RX，6 接 GND）。

TP4606B；產(chǎn)品概述2產(chǎn)品框架；功能；模塊可通過(guò)本地操作、后臺(tái)網(wǎng)絡(luò)管理等功能實(shí)現(xiàn)；管理功能、整流模塊和分發(fā)管理；表2-4監(jiān)控模塊功能表；2產(chǎn)品拱TCP466B產(chǎn)品概述；LCD顯示；監(jiān)控模塊可通過(guò)LCD液晶顯示界面實(shí)時(shí)顯示。顯示電源系統(tǒng)；運(yùn)行參數(shù)、運(yùn)行狀態(tài)、報(bào)警狀態(tài)、設(shè)定參數(shù)和控制；可通過(guò)四個(gè)按鍵操作；（紅色），提供一種驅(qū)動(dòng)柜燈報(bào)警的方法，TP466B產(chǎn)品概述2產(chǎn)品架構(gòu)功能監(jiān)控模塊可通過(guò)實(shí)際LOC實(shí)現(xiàn)。AL操作、后臺(tái)網(wǎng)絡(luò)管理等。介紹了環(huán)境監(jiān)測(cè)、異常報(bào)警、管理、整流模塊和配電管理的功能。該函數(shù)如表2-4所示。

表2-4監(jiān)控模塊功能表2產(chǎn)品結(jié)構(gòu)TP466B產(chǎn)品概述

華為T(mén)P48600B開(kāi)關(guān)電源機(jī)柜，48v通信電源 （CPMU01 ）華為T(mén)P48600B-N16A2

監(jiān)控模塊通過(guò)LCD LCD接口實(shí)時(shí)顯示電力系統(tǒng)的AC、DC、模塊和電池。

項(xiàng)目運(yùn)行參數(shù)、運(yùn)行狀態(tài)、報(bào)警狀態(tài)、設(shè)定參數(shù)和控制參數(shù)。參數(shù)設(shè)置與功能控制

它可以用四把鑰匙操作。監(jiān)控模塊提供運(yùn)行指示燈（綠色）和報(bào)。

（紅色）同時(shí)提供驅(qū)動(dòng)柜照明警示指示器輸出和監(jiān)控模塊報(bào)警蜂鳴器輸出。華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

TP46600

產(chǎn)品概述3產(chǎn)品和應(yīng)用場(chǎng)景

通過(guò)調(diào)整所安裝的整流模塊的數(shù)量，可以靈活地將產(chǎn)品和應(yīng)用場(chǎng)景的TP48 600 B電力系統(tǒng)應(yīng)用到室內(nèi)基站、室內(nèi)中央機(jī)房、BSC等。TP4606B電力系統(tǒng)安裝安裝在機(jī)房?jī)?nèi)，支撐墻（距墻100mm以上），通過(guò)調(diào)整安裝整流模塊的數(shù)量，可靈活應(yīng)用于-48伏直流、34.8kW的負(fù)載場(chǎng)景。例如：BTS39 00 BTS3012室內(nèi)基站BSC室內(nèi)中心室。

圖3-1 TP426B電力系統(tǒng)應(yīng)用示意圖

3產(chǎn)品和應(yīng)用場(chǎng)景TP466B產(chǎn)品概述TP48 6600電力系統(tǒng)和交流電源、ATS、電池等設(shè)備的典型應(yīng)用，以形成現(xiàn)場(chǎng)能源解決方案，其在典型的現(xiàn)場(chǎng)解決方案中的應(yīng)用如圖3-2所示。圖3-2 TP4266B電力系統(tǒng)應(yīng)用在典型的現(xiàn)場(chǎng)解決方案TP466B產(chǎn)品概述4產(chǎn)品的運(yùn)行和維護(hù)中采用多個(gè)優(yōu)化的維護(hù)設(shè)計(jì)，使維護(hù)簡(jiǎn)單方便。操作和維護(hù)支持上、下線(xiàn)路。支持預(yù)維護(hù)。整流模塊和監(jiān)控模塊都支持熱插拔。監(jiān)控模塊的維護(hù)不會(huì)影響正常供電。內(nèi)部模塊可以獨(dú)立拆卸和維護(hù)。華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜， 華為T(mén)P48600B開(kāi)關(guān)電源機(jī)柜48v通信電源 

LCD升壓反壓驅(qū)動(dòng)電路

在嵌入式系統(tǒng)里，較多場(chǎng)合需要LCD人機(jī)界面。分析以下LCD驅(qū)動(dòng)電路。

LCD_VIN是3.6~5V，經(jīng)過(guò)DC/DC burst升壓得到LCD_AVDD，LCD_AVDD為L(zhǎng)CD需要的模擬電壓，根據(jù)LCD實(shí)際情況調(diào)整FB腳電壓確定，這里假設(shè)是10V。

VGH是LCD的開(kāi)關(guān)管的開(kāi)啟電壓，假設(shè)這里需要15V，VGL是LCD開(kāi)關(guān)管的關(guān)閉電壓，假設(shè)這里需要-6.8V。

這里比較有意思的是VGH和VGL的產(chǎn)生。

以下給出綠、紅、藍(lán)三個(gè)節(jié)點(diǎn)的波形：

綠點(diǎn)為開(kāi)關(guān)電源的開(kāi)關(guān)波形，紅點(diǎn)為綠點(diǎn)向上偏移10V，藍(lán)點(diǎn)為綠點(diǎn)向下偏移10V。

綠點(diǎn)的電壓就不分析了，開(kāi)關(guān)波形。

紅點(diǎn)波形生成過(guò)程：

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

當(dāng)綠點(diǎn)“低電平”，LCD_AVDD通過(guò)二極管1-3對(duì)C165充電，經(jīng)過(guò)若干周期，C165兩端電壓約為L(zhǎng)CD_AVDD，紅點(diǎn)“低電平”。

當(dāng)綠點(diǎn)”高電平“，根據(jù)電容兩端電壓不能突變，可以知道紅點(diǎn)出現(xiàn)”高電平“，此時(shí)紅點(diǎn)電壓比LCD_AVDD高，二極管1-3斷開(kāi)，二極管3-2導(dǎo)通，C165放電。

藍(lán)點(diǎn)波形生成過(guò)程：

當(dāng)綠點(diǎn)“高電平”，此時(shí)通過(guò)二極管3-2對(duì)C171充電，經(jīng)過(guò)若干周期，C171兩端電壓約為綠點(diǎn)”高電平“即LCD_AVDD，藍(lán)點(diǎn)”高電平“。

當(dāng)綠點(diǎn)”低電平“，根據(jù)電容兩端電壓不能突變，可以知道藍(lán)點(diǎn)出現(xiàn)”低電平“，此時(shí)藍(lán)點(diǎn)電壓比GND低，二極管3-2斷開(kāi)，二極管1-3導(dǎo)通，C171放電。

在VGH和VGL輕負(fù)載的條件下，紅點(diǎn)和藍(lán)點(diǎn)經(jīng)過(guò)RC整流可以維持在20V和-10V，并經(jīng)過(guò)穩(wěn)壓管鉗壓得到目標(biāo)電壓。此升壓和反壓電路只能在清負(fù)載條件下。

LCD boost back pressure drive circuit

In embedded systems, LCD interface is needed in many occasions. The following LCD drive circuit is analyzed.

LCD_VIN is 3.6~5V, after DC/DC burst is boosted to LCD_AVDD, LCD_AVDD is the analog voltage required by LCD, ａnd the FB foot voltage is adjusted according to the actual condition of LCD, ａnd it is assumed to be 10V.

VGH is the opening voltage of the switch tube of LCD. Assuming that 15V is needed here, VGL is the closing voltage of the LCD switch tube, assuming that -6.8V is needed here.

What is more interesting here is the generation of VGH ａnd VGL.

The following three waveforms of green, red ａnd blue are given.

Green:

Red:

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

Blue:

The green point is the switching waveform of the switching power supply, the red dot shifts 10V upward to the green point, ａnd the blue point shifts 10V downward for the green dot.

The voltage of the green point is not analyzed, the switch waveform.

Red point waveform generation process:

When the green dot is "low level", LCD_AVDD charges C165 through diode 1-3. After a number of cycles, the voltage at both ends of the C165 is about LCD_AVDD, ａnd the red point is "low level".

When the green point is "high level", the voltage can not be changed according to the voltage at both ends of the capacitor. It can be known that the red point appears "high level". At this time the red point voltage is higher than the LCD_AVDD, the diode 1-3 is broken, the diode 3-2 is on, ａnd the C165 discharge.

Blue point waveform generation process:

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

When the green point is "high level", the C171 is charged by diode 3-2 at this time. After several cycles, the voltage at both ends of the C171 is about the Green Point "high level", that is, the high level of the blue point.

When the green point is "low level", according to the capacitor at both ends of the voltage can not be mutated, it can be known that the blue point appears "low level", at this time the blue point voltage is lower than GND, diode 3-2 is disconnected, diode 1-3 conduction, ａnd C171 discharge.

Under the condition of VGH ａnd VGL light load, the red dot ａnd blue dot can be maintained at 20V ａnd -10V through RC rectification, ａnd the target voltage can be pressed through the regulator clamp. This boost ａnd back voltage circuit can only be operated under clear load conditions.

■電源的安全認(rèn)證 

　　電源是電腦的心臟，品質(zhì)不好的電源不但會(huì)損壞主板、硬盤(pán)等部件，還會(huì)縮短電腦的正常使用壽命。當(dāng)然一款品質(zhì)優(yōu)良的電源的售價(jià)必定不會(huì)便宜，所以有些商家往往會(huì)采用便宜電源來(lái)消費(fèi)者，而有些用戶(hù)自己對(duì)此并不十分了解,但區(qū)區(qū)幾十元的差價(jià)可能會(huì)招致上千元的損失，這確實(shí)有些不值,所以在選購(gòu)時(shí)要特別注意電源的品質(zhì)是否優(yōu)良。 

　　安全標(biāo)準(zhǔn)以保障用戶(hù)生命和財(cái)產(chǎn)安全為出發(fā)點(diǎn)，在原材料的絕緣、阻燃等方面作出了嚴(yán)格的規(guī)定。符合安全標(biāo)準(zhǔn)的產(chǎn)品，不僅要求產(chǎn)品本身符合安全標(biāo)準(zhǔn)，而且對(duì)于制作廠家也要求有較完善的安全生產(chǎn)體系。在這些標(biāo)準(zhǔn)中，以德國(guó)基于1EC-380標(biāo)準(zhǔn)制定的VDE-0806標(biāo)準(zhǔn)最為嚴(yán)格。我國(guó)的國(guó)家標(biāo)準(zhǔn)是GB4943-1995《信息技術(shù)設(shè)備（包括電氣設(shè)備）的安全》。電源符合以上標(biāo)準(zhǔn)其安全性就有了保障。電源符合某個(gè)國(guó)家的安全標(biāo)準(zhǔn)并得到其法定部門(mén)頒發(fā)的證書(shū)，比如獲得UL機(jī)構(gòu)頒發(fā)的證書(shū)，就稱(chēng)為取得了UL認(rèn)證。中國(guó)的安全認(rèn)證機(jī)構(gòu)是CCEE。不管是哪國(guó)的安全認(rèn)證，都對(duì)爬電距離、抗電強(qiáng)度、漏電流、溫度等方面做出了嚴(yán)格規(guī)定。 

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

　　爬電距離的要求 

　　爬電距離指沿絕緣表面測(cè)得的兩個(gè)導(dǎo)電器件之間或?qū)щ娖骷c設(shè)備界面之間的最短距離。UL、CSA和VDE安全標(biāo)準(zhǔn)強(qiáng)調(diào)了爬電距離的安全要求，這是為了防止器件間或器件和地之間打火從而到人身安全。 

　　抗電強(qiáng)度的要求 

　　在交流輸入線(xiàn)之間或交流輸入與機(jī)殼之間由零電壓加到交流1500V或直流2200V時(shí)，不擊穿或拉電弧即為合格。 

　　漏電流的要求 

　　UL和CSA均要求暴露的、不帶電的金屬部分均應(yīng)與大地相接。漏電流的測(cè)量是通過(guò)在這些部分與大地之間接一個(gè)1.5千歐的電阻，測(cè)其漏電流。開(kāi)關(guān)電源的漏電流，在260V交流輸入下，不應(yīng)超過(guò)3.5mA。 

　　溫度的要求 

　　安全標(biāo)準(zhǔn)對(duì)電器的溫度要求很重視，同時(shí)要求材料有阻燃性。對(duì)開(kāi)關(guān)電源來(lái)說(shuō)，內(nèi)部溫升不應(yīng)超過(guò)65℃，如果環(huán)境溫度是25℃，電源的元器件的溫度應(yīng)小于90℃。 

　　不符合安全標(biāo)準(zhǔn)的電源在剛開(kāi)始用時(shí)對(duì)使用者并沒(méi)有什么直接的不良影響，但用久了以后，由于潮濕的空氣和灰塵的影響可能導(dǎo)致高壓區(qū)短路，不但造成電源本身?yè)p壞，還會(huì)嚴(yán)重影響電網(wǎng)，從而對(duì)其他電器造成不利影響。 

　　關(guān)于電磁干擾，國(guó)際上通用的標(biāo)準(zhǔn)有FCC-A（工業(yè)標(biāo)準(zhǔn)）、FCC-B（民用標(biāo)準(zhǔn)），電源應(yīng)符合民用標(biāo)準(zhǔn)。 開(kāi)關(guān)電源是把工頻交流整流為直流后，再通過(guò)開(kāi)關(guān)變?yōu)楦哳l交流，其后再整流為穩(wěn)定直流的一種電源，這樣就有工頻電源的整流波形畸變產(chǎn)生的噪聲與開(kāi)關(guān)波形產(chǎn)生的噪聲，在輸入側(cè)泄漏出去就表現(xiàn)為傳導(dǎo)噪聲與輻射噪聲，在輸出側(cè)泄漏出去就表現(xiàn)為紋波。 

　　電磁干擾分為傳導(dǎo)干擾和輻射干擾。傳導(dǎo)干擾通過(guò)電源線(xiàn)傳播，頻率為30MHz以下，主要干擾音頻頻段。由于計(jì)算機(jī)用開(kāi)關(guān)電源有金屬殼作屏蔽，所以主要為傳導(dǎo)干擾。傳導(dǎo)干擾的大小是衡量計(jì)算機(jī)電源品質(zhì)的重要標(biāo)準(zhǔn)，它包括兩個(gè)方面的含義：一是防止電網(wǎng)上電磁干擾通過(guò)電源本身產(chǎn)生的電磁干擾進(jìn)入電網(wǎng)，影響主機(jī)系統(tǒng)正常工作；二是防止主機(jī)本身產(chǎn)生的電磁干擾進(jìn)入電網(wǎng)，影響其它電器。我們?cè)谌粘９ぷ髦锌赡苡羞@樣的經(jīng)驗(yàn)，在微機(jī)開(kāi)機(jī)時(shí)，其附近的電器如電視、音響等不能正常使用，這是傳導(dǎo)干擾產(chǎn)生的影響。 

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

　　■電源選購(gòu)誤區(qū) 

　　由于ATX主板的日益流行，ATX電源取代了傳統(tǒng)的AT電源成為市場(chǎng)主流，價(jià)格也從以前的兩百多元降到一百多元。隨著市場(chǎng)競(jìng)爭(zhēng)越來(lái)越激烈，有些商家為了追求更高的利潤(rùn),采用一些價(jià)格較低的劣質(zhì)電源,并自圓其說(shuō)地拋出些誤導(dǎo)性言論，形成了選購(gòu)誤區(qū),讓消費(fèi)者在購(gòu)買(mǎi)時(shí)感到無(wú)所適從。 

　　誤區(qū)一：通過(guò)認(rèn)證的電源和沒(méi)有通過(guò)認(rèn)證的電源質(zhì)量相同。有的人告訴消費(fèi)者同一品牌的認(rèn)證和非認(rèn)證電源質(zhì)量相同。認(rèn)證電源和非認(rèn)證電源是從同一工廠的同一條生產(chǎn)線(xiàn)下來(lái)的，并以此認(rèn)為兩者質(zhì)量相同，甚至“中肯”地指出因?yàn)檎J(rèn)證要花錢(qián)所以認(rèn)證電源就要貴一些?？傊I(mǎi)非認(rèn)證電源可以少花不少冤枉錢(qián)。但看了以上的電源知識(shí)，大家就可以發(fā)現(xiàn)兩者有很大不同。 

　　誤區(qū)二：認(rèn)為輔助5V的輸出電流越大越好。有些商家向用戶(hù)吹噓自己的電源，輔助5V能達(dá)到1A,其時(shí)，有的主板甚至只要0.01A就夠了。但有一點(diǎn)是明確的，輔助5V能提供0.72A就保證不會(huì)有事了。輔助5V因始終處于工作狀態(tài)一般來(lái)說(shuō)比較容易發(fā)生故障,所以它能有一個(gè)較長(zhǎng)的壽命才是更重要的。 

　　誤區(qū)三：與Pentium Ⅲ配套。這根本就是一個(gè)性的誤導(dǎo)，其實(shí)電源和電腦主板配套，與CPU沒(méi)有關(guān)系，而Pentium Ⅲ的主板與Pentium Ⅱ的主板在技術(shù)上并沒(méi)有什么區(qū)別，只要升級(jí)BIOS就行了?？梢哉f(shuō)，任何一臺(tái)符合ATX 2.01的ATX電源都可和Pentium Ⅲ配套。 

　　誤區(qū)四：版本越新越好。有商家宣傳自己的電源符合最新的Intel ATX 2.03標(biāo)準(zhǔn)，似乎要比別人優(yōu)越許多。其實(shí)從ATX 2.01到ATX 2.03，只是些無(wú)關(guān)痛癢的修改，就目前來(lái)說(shuō)，滿(mǎn)足ATX 2.01標(biāo)準(zhǔn)的電源使用起來(lái)不會(huì)有問(wèn)題。 

　　誤區(qū)五：功率越大越好。有些商家向用戶(hù)吹噓自己的電源功率能達(dá)到300W甚至400W。其實(shí)普通的一臺(tái)多媒體電腦實(shí)際功率不足100W，而Intel新推出的Micro ATX標(biāo)準(zhǔn)也只有145W。對(duì)于普通用戶(hù)，2華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜00W的電源綽綽有余了。所以說(shuō)在選購(gòu)電源的時(shí)候沒(méi)有必要刻意追求電源的功率大小，只要是質(zhì)量合格的市售電源都可以滿(mǎn)足多數(shù)用戶(hù)的需要。 

Safety authentication of power supply

The power supply is the heart of the computer. The poor quality of the power supply will not only damage the motherboard, hard disk ａnd other components, but also shorten the normal service life of the computer. Of course, a good quality power supply will not be cheap, so some businesses often use cheap power to deceive consumers, ａnd some users do not know it very well, but the differential of dozens of yuan may incur a loss of thousands of yuan, which is really not worth it, so we should pay special attention to the power supply when choosing. Whether the quality is good.

Safety standards are the starting point for ensuring the safety of users＇ lives ａnd property, ａnd strict regulations are made on the insulation ａnd flame retardancy of raw materials. Products that meet safety standards require not only the product itself to meet safety standards, but also a more comprehensive safety production system for manufacturers. Among these criteria, the VDE-0806 standard based on 1EC-380 standard is the most stringent in Germany. The national standard of our country is GB4943-1995 "information technology equipment (including electrical equipment) safety". The power meets the above standards, ａnd its security is guaranteed. The power supply conforms to the safety standard of a country ａnd gets the certificate issued by its statutory department, such as the certificate issued by the UL agency, which is called UL certification. China＇s security certification body is CCEE. No matter which country＇s safety certification, strict regulation has been made on creepage distance, electric strength, leakage current, temperature ａnd so on.

Requirements for creepage distance

Creepage distance refers to the shortest distance between two conductive devices along the insulation surface or between the conductive device ａnd the device interface. The safety standards of UL, CSA ａnd VDE emphasize the safety requirements of creepage distance, which is to prevent fire between devices ａnd devices ａnd thus threaten personal safety.

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

Demand for resistance to electricity

When zero voltage is added to AC 1500V or DC 2200V between AC input lines or between AC input ａnd chassis, no breakdown or arcing is acceptable.

Leakage current requirements

Both UL ａnd CSA require that exposed ａnd uncharged metal parts should be connected to the earth. The leakage current is measured by a 1 thousand ａnd 500 ohm resistor between these parts ａnd the earth, ａnd the leakage current is measured. The leakage current of switching power supply should not exceed 3.5mA under 260V AC input.

The requirement of temperature

Safety standards attach great importance to the temperature requirements of electrical appliances, while requiring flame retardancy of materials. For switching mode power supplies, the internal temperature rise should not exceed 65 degrees. If the ambient temperature is 25 degrees, the temperature of the components of the power supply should be less than 90 degrees.

The power supply that does not meet the safety standard has no direct adverse effects on the user at the beginning of use, but after a long time, the influence of wet air ａnd dust may lead to short circuit in high pressure area, which not only causes the damage of the power supply itself, but also seriously affects the power grid, thus causing adverse effects on other electrical appliances.

As for electromagnetic interference, the international standard is FCC-A (industrial standard) ａnd FCC-B (civil standard), ａnd the power supply should meet the civil standard. The switching power supply is a kind of power supply that turns the power frequency AC to DC, then turns into high frequency communication through the switch, ａnd then rectify to a stable DC power, so that the noise generated by the distortion of the power frequency power supply ａnd the noise produced by the switch waveform is shown as the conduction ａnd radiation noise on the input side.  The output side leaks out as a ripple.

Electromagnetic interference can be divided into conducted interference ａnd radiation interference. Conducted interference is transmitted through the power line, less than 30MHz, mainly interfering with the audio frequency band. Because the power supply of the computer is shielded by metal shell, it is mainly conducted by interference. The size of the conduction interference is an important standard to measure the power quality of the computer. It includes two aspects: one is to prevent electromagnetic interferen華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜ce from the power grid to enter the power grid by the electromagnetic interference produced by the power source itself, ａnd to affect the normal work of the host system; ａnd the two is to prevent the electromagnetic interference from the host itself into the power grid ａnd affect other electricity.  Apparatus. We may have such experience in our daily work. When the computer is opened, the electric appliances in the vicinity, such as TV ａnd sound, can not be used normally. This is the effect of the conduction interference.

Misunderstanding of power supply

Due to the increasing popularity of ATX motherboards, the ATX power supply has replaced the traditional AT power supply as the mainstream of the market, ａnd the price has dropped from the previous more than 200 yuan to more than 100 yuan. As the market competition is becoming more ａnd more fierce, some merchants have adopted some low quality power supplies to pursue higher profits, ａnd give out misleading remarks by themselves, forming a misunderstanding of buying ａnd buying, so that consumers feel at a loss when they buy.

Myth 1: the quality of the certified power supply is the same as that of the power without authentication. Some people tell consumers that the same brand is certified ａnd non certified power quality is the same. The authentication ａnd non - certified power sources are from the same line in the same factory, ａnd they think both of them are of the same quality, ａnd even "pertinent" point out that the authentication of the power is more expensive because of the cost of authentication. In short, buying a non certified power source can cost a lot of money. But with the above knowledge of power supply, we can see that the two are very different.

Myth two: the greater the output current of auxiliary 5V, the better. Some businesses are bragging about their power supply to users, helping 5V reach 1A. At that time, some華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜 motherboards even have enough 0.01A. But one thing is clear: auxiliary 5V can provide 0.72A to ensure that nothing will happen. Auxiliary 5V is always in work.

【導(dǎo)讀】電源電路是一個(gè)電子產(chǎn)品的重要組成部分，電源電路設(shè)計(jì)的好壞，直接牽連產(chǎn)品性能的好壞。而電源模塊最重要的是電源電路的PCB設(shè)計(jì)，本文就為大家講解兩個(gè)電源模塊電路及其PCB布局，萬(wàn)變不離其宗，只要弄通這兩個(gè)電路和PCB布局，其它的也了然于胸了。

   為什么要學(xué)習(xí)電源電路的設(shè)計(jì)? ? 

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

電源電路是一個(gè)電子產(chǎn)品的重要組成部分，電源電路設(shè)計(jì)的好壞，直接牽連產(chǎn)品性能的好壞。 

 電源電路的分類(lèi)

 我們電子產(chǎn)品的電源電路主要有線(xiàn)性電源和高頻開(kāi)關(guān)電源。從理論上講，線(xiàn)性電源是用戶(hù)需要多少電流，輸入端就要提供多少電流;開(kāi)關(guān)電源是用戶(hù)需要多少功率，輸入端就提供多少功率。   線(xiàn)性電源電路原理圖舉例   線(xiàn)性電源功率器件工作在線(xiàn)性狀態(tài)，如我們常用的穩(wěn)壓芯片LM7805、LM317、SPX1117等。下圖1是LM7805穩(wěn)壓電源電路原理圖。  圖1. 線(xiàn)性電源原理圖   從圖上可知，線(xiàn)性電源有整流、濾波、穩(wěn)壓、儲(chǔ)能等功能元件組成，同時(shí)，一般用的線(xiàn)性電源為串聯(lián)穩(wěn)壓電源，輸出電流等于輸入電流，I1=I2+I3，I3是參考端，電流很小，因此I1≈I3。我們?yōu)槭裁匆v電流，是因?yàn)镻CB設(shè)計(jì)時(shí)，每條線(xiàn)的寬度不是隨便設(shè)的，是要根據(jù)原理圖里元件節(jié)點(diǎn)間的電流大小來(lái)確定的(請(qǐng)查《PCB設(shè)計(jì)銅鉑厚度、線(xiàn)寬和電流關(guān)系表》)。電流大小、電流流向要搞清楚，做板才恰到好處。

Power circuit is an important part of an electronic product. The design of the power circuit directly affects the performance of the product. And the most important power module is the PCB design of the power circuit. This article explains two power module circuits ａnd their PCB layout. It is not separated from the power module. As long as these two circuits ａnd the PCB layout are worked out, the others are also clear.

Why do you want to learn the design of the power circuit??

The power circuit is an important part of an electronic product. The design of the power circuit directly affects the performance of the product.

The classification of power circuit

The power circuit of our electronic products is mainly composed of linear power supply ａnd high frequency switching power supply. In theory, a linear power supply is how much current the user needs ａnd how much current the input will provide; the switching power is how much power the user needs ａnd how much power the input will provide. Linear power circuit schematic diagram, for example, linear power supply devices work in linear state, such as our commonly used regulator chip LM7805, LM317, SPX1117 華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜and so on. Figure 1 below is the schematic diagram of the LM7805 voltage regulated power supply circuit. Figure 1. the principle diagram of linear power supply shows that linear power is composed of functional components such as rectification, filtering, stabilizing, energy storage ａnd so on. At the same time, the linear power supply is generally used as a series regulated power supply, the output current is equal to the input current, I1=I2+I3, I3 is the reference end, ａnd the current is very small, so I1 I3. Why we want to speak the current is because PCB design, the width of each line is not casual, it is determined by the size of the current between the element nodes in the principle diagram (please check the PCB design of copper platinum thickness, line width ａnd current relation table). The size of the current ａnd the direction of the current must be clear.

 Cuk電路簡(jiǎn)介

  Cuk斬波電路也稱(chēng)Cuk變換器。美國(guó)加州理工學(xué)院Slobodan Cuk提出的對(duì)Buck/Boost改進(jìn)的單管不隔離直流變換器，在輸入輸出段均有電感，可以顯著減小輸入和輸出電流的脈動(dòng)，輸出電壓的極性和輸入電壓相反，輸出電壓既可以低于也可以高于輸入電壓。Cuk變換器可看做是Boost變換器和Buck變換器串聯(lián)而成，合并了開(kāi)關(guān)管。

開(kāi)關(guān)管Q為PWM控制方式。Cuk變換器有CCM和DCM兩種工作方式，但不是指電感電流，而是指流過(guò)二極管的電流連續(xù)或斷續(xù)。在一個(gè)開(kāi)關(guān)周期中開(kāi)關(guān)管Q的截止時(shí)間（1-Dy）Ts內(nèi)，若二極管電流總是大于零，則為電流連續(xù)；若二極管電流在一段時(shí)間內(nèi)為零，則為電流斷續(xù)工作；若二極管電流  Cuk變換器中有兩個(gè)電感，這兩個(gè)電感之間可以沒(méi)有耦合，也可以由耦合，耦合電感可進(jìn)一步減少電流脈動(dòng)量。

Cuk斬波電路拓?fù)?/p>

當(dāng)V通時(shí)，E-L1-V回路和R-L2-C-V回路分別流過(guò)電流    當(dāng)V斷時(shí)，E-L1-C-VD回路和R-L2-VD回路分別流過(guò)電流    輸出電壓極性與源電壓極性相反  

等效電路如圖所示，相當(dāng)于開(kāi)關(guān)S在A、B兩點(diǎn)之華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜間交替切換。  

  穩(wěn)態(tài)時(shí)電容C的電流在一周期內(nèi)的平均值應(yīng)為零，也就是其對(duì)時(shí)間的積分為零，即：∫icdt = 0  

  在圖中的等效電路中，開(kāi)關(guān)S合向B點(diǎn)時(shí)間即V處于通態(tài)的時(shí)間Ton，則電容電流和時(shí)間的乘積為i2*Ton.開(kāi)關(guān)S合向A點(diǎn)的時(shí)間為V處于斷態(tài)的時(shí)間Toff，則電容電流和時(shí)間的乘積為i1*Toff。    由此可得：i2*Ton=i1*Toff  

  從而可得：i2/i1=Toff/Ton=(T-Ton)/Ton =(1-α)/α    同理可得出輸出電壓U0與電源電壓E的關(guān)系：

Cuk斬波電路的優(yōu)點(diǎn) 

輸入電源電流和輸出負(fù)載電流都是連續(xù)的，且脈動(dòng)很小，有利于對(duì)輸入，輸出進(jìn)行濾波。 

Sepic斬波電路 

SPEIC(single ended primary inductor converter) 是一種允許輸出電壓大于、小于或者等于輸入電壓的DCDC變換器。輸出電壓由主控開(kāi)關(guān)(三極管或MOS管)的占空比控制。  

Sepic斬波電路是開(kāi)關(guān)電源六種基本DC/DC變換拓?fù)渲弧?/p>

Sepic斬波電路的基本工作原理：  

  當(dāng)V處于通態(tài)時(shí)，E—L1—V回路和C1—V—L2回路同時(shí)導(dǎo)電，L1和L2貯能。  

  V處于斷態(tài)時(shí)，E—L1—C1—VD—負(fù)載（C2和R）回路及L2—VD—負(fù)載回路同時(shí)導(dǎo)電，此階段E和L1既向負(fù)載供電，同時(shí)也向C1充電，C1貯存的能量在V處于通態(tài)時(shí)向L2轉(zhuǎn)移。  

  Sepic斬波電路的輸入輸出關(guān)系由下式給出：

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

Zeta電路 

  Zeta電路是開(kāi)關(guān)電源六種基本DC/DC變換拓?fù)渲弧?/p>

Zeta斬波電路也稱(chēng)雙Sepic斬波電路，其基本工作原理是：在V處于通態(tài)期間，電源E經(jīng)開(kāi)關(guān)V向電感L1貯能。待V關(guān)斷后，L1經(jīng)VD與C1構(gòu)成振蕩回路，其貯存的

能量轉(zhuǎn)移至C1，至振蕩回路電流過(guò)零，L1上的能量全部轉(zhuǎn)移至C1上之后，VD關(guān)斷，C1經(jīng)L2向負(fù)載供電。  

  Zeta斬波電路的輸入輸出關(guān)系為：

1. Zeta和Sepic電路相比，具有相同的輸入輸出關(guān)系。Sepic電路中，電源電流和負(fù)載電流均連續(xù)，有利于輸入、輸出濾波，反之，Zeta電路的輸入、輸出電流均是斷續(xù)的。  

 2. 兩種電路輸出電壓為正極性的。

Brief introduction of Cuk circuit

The Cuk chopper circuit is also called the Cuk converter. The Slobodan Cuk, California Institute of Technology, proposed a single tube non isolated DC converter for Buck/Boost, which has inductance in the input ａnd output section. It can significantly reduce the pulse of input ａnd output current, the polarity of the output voltage is opposite to the input voltage, ａnd the output voltage can be lower than the input voltage. The Cuk converter can be regarded as a series of Boost converter ａnd Buck converter, ａnd the sw華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜itch tube is merged.

The switch tube Q is the PWM control mode. The Cuk converter has two working modes, CCM ａnd DCM, but it does not refer to the inductance current, but refers to the continuous or intermittent current flowing through the diode. In a switching period, the switch tube Q＇s cut-off time (1-Dy) Ts, if the diode current is always greater than zero, is continuous for the current; if the diode current is zero for a period of time, the current is interrupted, ａnd if there are two inductors in the diode current Cuk converter, there is no coupling between the two inductors. The coupling current ａnd coupling inductance can further reduce the current ripple.

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

Cuk chopper circuit topology

When the V passes, the E-L1-V circuit ａnd the R-L2-C-V loop flow through the current respectively when the V is broken, the E-L1-C-VD circuit ａnd the R-L2-VD loop flow through the current output voltage polarity opposite to the source voltage polarity, respectively.

Equivalent circuit, as shown in figure, is equivalent to switch S switching between A ａnd B alternately.

In steady state, the average value of the current of capacitor C in a cycle should be zero, that is, the integral of time to zero is zero, i.e., ICDT = 0.

In the equivalent circuit of the graph, the switch S is at B point time, that is, V is in the pass state time Ton, then the product of the capacitance current ａnd time is the time of the i2*Ton. switch S to the A point, which is the time Toff of the V in the broken state, ａnd the product of the capacitance current ａnd time is i1*Toff. It can be obtained from this: i2*Ton=i1*Toff

Thus it can be obtained: i2/i1=Toff/Ton= (T-Ton) /Ton = (1- alpha) / alpha is able to get the relationship between output voltage U0 ａnd supply voltage E:

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

Advantages of Cuk chopper circuit

The input current ａnd output load current are continuous, ａnd the pulsation is very small, which helps to filter the input ａnd output.

Sepic chopper circuit

SPEIC (single ended primary inductor converter) is a DCDC converter that allows output voltage greater than, less than or equal to the input voltage. The output voltage is controlled by the duty ratio of the main switch (transistor or MOS tube).

Sepic chopper circuit is one of the six basic DC/DC transform topologies of switching power supply.

The basic working principle of Sepic chopper circuit:

When V is in a state, the E - L1 - V loop ａnd the C1 - V - L2 loop are conductive at the same time, L1 ａnd L2 store energy.

When the V is in the broken state, the E - L1 - C1 - VD - load (C2 ａnd R) circuits ａnd the L2 VD - load circuit simultaneously conduct electricity. This stage E ａnd L1 both supply the load to the load, but also charge it to the C1.

The input output relationship of the Sepic chopper circuit is given in the following way:

Zeta circuit

Zeta circuit is one of the six basic DC/DC transform topologies of switching power supply.

The Zeta chopper circuit is also known as the dual Sepic chopper circuit. Its basic working principle is that when the V is in a state, the power E can store energy through the switch V to the inductive L1. After V is shut off, L1 is constituted by VD ａnd C1, ａnd its storage circuit is 華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜stored.

The energy is transferred to C1, ａnd the current is zero across the oscillation circuit. When the energy on the L1 is transferred to C1, VD is turned off ａnd C1 is fed to the load via L2.

The input ａnd output relation of the Zeta chopper circuit is as follows:

1. Zeta ａnd Sepic circuits have the same input output relationship. In the Sepic circuit, both the supply current ａnd the load current are continuous, which is good for input ａnd output filtering. Conversely, the input ａnd output currents of the Zeta circuit are interrupted.華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

2. the output voltage of two kinds 1. classifications:

A) DC ground: DC circuit "ground", zero potential reference point;

B) AC: the zero line of the alternating current. It should be distinguished from the ground wire, but sometimes the ground wire ａnd the zero line will be connected before pulling the electricity into the home.

C) power point: zero potential reference point of large current network device ａnd power amplifier.

D) analog ground: zero potential reference point of amplifier, sample ａnd hold, A/D converter ａnd comparator.

E) digital ground: also called logic, it is the zero potential reference point of digital circuit.

F) "hot": the switching power supply does not need to use the power frequency transformer. The "ground" of the switching circuit is related to the power grid of the city, that is, the so-called "hot", ａnd the TA is charged.

G) "cold": because the high frequency transformer of the switching power supply is isolated from the input ａnd output terminals, ａnd because its feedback circuit is often used as a photoelectric coupler, it can not only transmit the feedback signal, but also separate the "ground". The output of the "ground" is "cold", not charged D.

2. signal grounding

A) single point grounding: only one physical point in the whole circuit system is defined as the grounding reference point, ａnd all other points needing grounding are received. A single point grounding is usually used in the frequency <1MHz.

The single point grounding is divided into series ａnd parallel.

​

The advantage of the series grounding is that the grounding mode ａnd the structure are simple. If the grounding wire is short, the impedance will be relatively small. The disadvantage is that if the power of a certain road is larger, the larger circuit current will be generated, ａnd a larger pressure ｄrop will be formed, which leads to the difference of the potential reference value between the circuit ａnd the base area, which affects the normal work of the system.

Parallel single point grounding, the advantage is that the ground potential of each circuit is not affected by other circuits, ａnd low impedance can effectively avoid low impedance interference between the circuit units. Disadvantages: multiple grounding lines are needed, the length of ground wire is increased, thus increasing the earth impedance, ａnd the coupling of the ground wires will also be caused.

B) multi point grounding: all the grounding points are directly connected to the nearest ground plane (i.e. the metal bottom plate) of the TA, which is usually >10MHz.

C) floats: there is no conductor connection between the earth ａnd the earth. [virtual ground: no earth, but equal potential.

D) mixed grounding

Figure 5 ａnd Figure 6 provide two kinds of mixed grounding methods. For capacitive coupled circuits, the single point grounding structure appears at low frequencies, ａnd the multi point grounding state occurs at high frequencies. This is because the capacitor diverts the high frequency current to the ground. The key to the success of this method lies in the frequency of clear use ａnd the expected direction of ground current. The use of capacitance ａnd inductance in the grounding topology enables us to control RF current in an optimized way. The wiring of PCB can be controlled by determining the path to be passed by RF current.

3. equipment grounding purpose

A) good electrical connection between metal shell ａnd grounding device in protected area.

B) prevent static electricity from grounding, release the accumulated charges on the chassis, avoid accumulation of charges ａnd raise the potential.

C) shields the device from the external electromagnetic environment, so that the potential of the equipment changes to the earth.of circuits is positive.

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

電源電路是電子產(chǎn)品的重要組成部分。電源電路的設(shè)計(jì)直接影響產(chǎn)品的性能。而最重要的電源模塊是電源電路的PCB設(shè)計(jì)。本文解釋了兩個(gè)電源模塊電路和PCB布局。它與電源模塊沒(méi)有分離。只要這兩個(gè)電路和PCB布局,其他人也清楚。

你為什么想學(xué)習(xí)電源電路的設(shè)計(jì)?

電源電路是電子產(chǎn)品的重要組成部分。電源電路的設(shè)計(jì)直接影響產(chǎn)品的性能。

電力線(xiàn)路的分類(lèi)。

我們的電子產(chǎn)品的電源電路主要由線(xiàn)性電源和高頻開(kāi)關(guān)電源。理論上,一個(gè)線(xiàn)性電源是當(dāng)前用戶(hù)的需求和當(dāng)前輸入將提供多少;開(kāi)關(guān)電源是電力用戶(hù)需求和輸入將提供多大的權(quán)力。線(xiàn)性電源電路原理圖,例如,線(xiàn)性電源設(shè)備工作在線(xiàn)性狀態(tài),比如我們常用的調(diào)節(jié)器芯片LM7805 LM317,SPX1117華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜等等。下面的圖1是LM7805穩(wěn)壓電源電路的示意圖。圖1所示。線(xiàn)性電源的原理圖表明,線(xiàn)性功率等功能組件是由整流、濾波、穩(wěn)定、能源存儲(chǔ)等等。同時(shí),線(xiàn)性電源通常是用作系列穩(wěn)壓電源,輸出電流等于輸入電流,I1和I2 + = I3,I3是參考,和當(dāng)前很小,所以I1 I3。為什么我們想說(shuō)當(dāng)前是因?yàn)镻CB設(shè)計(jì),每一行的寬度并不是隨意的,它是由元素節(jié)點(diǎn)之間的電流的大小在原理圖中(請(qǐng)檢查銅鉑的PCB設(shè)計(jì)厚度,線(xiàn)寬與電流關(guān)系表)。電流的大小和電流的方向必須清楚。

Cuk電路簡(jiǎn)介

Cuk斬波電路也稱(chēng)Cuk變換器。美國(guó)加州理工學(xué)院斯洛博丹·Cuk提出的對(duì)巴克/提高改進(jìn)的單管不隔離直流變換器,在輸入輸出段均有電感,可以顯著減小輸入和輸出電流的脈動(dòng),輸出電壓的極性和輸入電壓相反,輸出電壓既可以低于也可以高于輸入電壓.Cuk變換器可看做是提高變換器和巴克變換器串聯(lián)而成,合并了開(kāi)關(guān)管。

開(kāi)關(guān)管問(wèn)為PWM控制方式.Cuk變換器有CCM和DCM兩種工作方式,但不是指電感電流,而是指流過(guò)二極管的電流連續(xù)或斷續(xù)。在一個(gè)開(kāi)關(guān)周期中開(kāi)關(guān)管問(wèn)的截止時(shí)間(1-Dy)Ts內(nèi),若二極管電流總是大于零,則為電流連續(xù);若二極管電流在一段時(shí)間內(nèi)為零,則為電流斷續(xù)工作,若二極管電流Cuk變換器中有兩個(gè)電感,這兩個(gè)電感之間可以沒(méi)有耦合,也可以由耦合,耦合電感可進(jìn)一步減少電流脈動(dòng)量。

Cuk斬波電路拓?fù)?/p>

當(dāng)V通時(shí),E-L1-V回路和R-L2-C-V回路分別流過(guò)電流當(dāng)V斷時(shí),E-L1-C-VD回路和R-L2-VD回路分別流過(guò)電流輸出電壓極性與源電壓極性相反

等效電路如圖所示,相當(dāng)于開(kāi)關(guān)年代在A、B兩點(diǎn)之華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜間交替切換。

穩(wěn)態(tài)時(shí)電容C的電流在一周期內(nèi)的平均值應(yīng)為零,也就是其對(duì)時(shí)間的積分為零,即:∫icdt = 0

在圖中的等效電路中,開(kāi)關(guān)年代合向B點(diǎn)時(shí)間即V處于通態(tài)的時(shí)間噸,則電容電流和時(shí)間的乘積為i2 *噸。開(kāi)關(guān)年代合向一個(gè)點(diǎn)的時(shí)間為V處于斷態(tài)的時(shí)間設(shè)備,則電容電流和時(shí)間的乘積為i1 *有錢(qián)人。由此可得:i2 = i1 * *噸設(shè)備

從而可得:i2 / i1 =設(shè)備/噸=(T-Ton)/噸=(1-α)/α同理可得出輸出電壓情況與電源電壓E的關(guān)系:

Cuk斬波電路的優(yōu)點(diǎn)

輸入電源電流和輸出負(fù)載電流都是連續(xù)的,且脈動(dòng)很小,有利于對(duì)輸入,輸出進(jìn)行濾波。

Sepic斬波電路

SPEIC(單端主電感變換器)是一種允許輸出電壓大,于小于或者等于輸入電壓的DCDC變換器。輸出電壓由主控開(kāi)關(guān)(三極管或MOS管)的占空比控制。

Sepic斬波電路是開(kāi)關(guān)電源六種基本直流/直流變換拓?fù)渲弧?/p>

Sepic斬波電路的基本工作原理:

當(dāng)V處于通態(tài)時(shí),E-L1-V回路和C1-V-L2回路同時(shí)導(dǎo)電,L1和L2貯能。

V處于斷態(tài)時(shí),E-L1-C1-VD——負(fù)載(C2和R)回路及L2-VD——負(fù)載回路同時(shí)導(dǎo)電,此階段E和L1既向負(fù)載供電,同時(shí)也向C1充電,C1貯存的能量在V處于通態(tài)時(shí)向L2轉(zhuǎn)移。

Sepic斬波電路的輸入輸出關(guān)系由下式給出:

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

ζ電路

ζ電路是開(kāi)關(guān)電源六種基本直流/直流變換拓?fù)渲弧?/p>

ζ斬波電路也稱(chēng)雙Sepic斬波電路,其基本工作原理是:在V處于通態(tài)期間,電源E經(jīng)開(kāi)關(guān)V向電感L1貯能。待V關(guān)斷后,L1經(jīng)VD與C1構(gòu)成振蕩回路,其貯存的

能量轉(zhuǎn)移至C1,至振蕩回路電流過(guò)零,L1上的能量全部轉(zhuǎn)移至C1上之后,VD關(guān)斷,C1經(jīng)L2向負(fù)載供電。

ζ斬波電路的輸入輸出關(guān)系為:

1。ζ和Sepic電路相比,具有相同的輸入輸出關(guān)系.Sepic電路中,電源電流和負(fù)載電流均連續(xù),有利于輸入,輸出濾波,反之,澤塔電路的輸入,輸出電流均是斷續(xù)的。

2。兩種電路輸出電壓為正極性的。

Cuk電路簡(jiǎn)介。

Cuk斬波電路也稱(chēng)為Cuk變換器。斯洛博丹·Cuk,加州理工學(xué)院的,提出了一種單管非隔離直流轉(zhuǎn)換器對(duì)于巴克/增加,電感的輸入和輸出部分。它可以顯著降低脈沖輸入和輸出電流,輸出電壓的極性相反的輸入電壓,輸出電壓可以低于輸入電壓。Cuk變換器可以視為一系列提高轉(zhuǎn)換器和巴克轉(zhuǎn)換器,和西南華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜癢管合并。

開(kāi)關(guān)管Q是PWM控制方式。Cuk變換器兩種工作模式,CCM和DCM,但這并不指電感電流,但指的是連續(xù)或間歇電流通過(guò)二極管。在交換期間,Q開(kāi)關(guān)管的截止時(shí)間(1-Dy)Ts,如果二極管電流總是大于零,電流是連續(xù)的;如果二極管電流為零在一段時(shí)間內(nèi),電流中斷,如果有兩個(gè)電感二極管電流Cuk變換器,沒(méi)有兩個(gè)電感之間的耦合。當(dāng)前和耦合電感的耦合可以進(jìn)一步降低紋波電流。

華為T(mén)P48600B高頻開(kāi)關(guān)電源機(jī)柜

Cuk斬波電路拓?fù)?/p>

V通過(guò)時(shí),E-L1-V電路和R-L2-C-V循環(huán)流過(guò)的電流分別當(dāng)V是破碎的,t

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