数位像机电源系统简介课件

1、數位相機電源系統 : 項目1.Digital Camera System Block Diagram2.Switch Converter System Type3.Photoflash Controllers4.AT1452/53Photoflash Capacitor Charger IC 5.DC/DC Switch Controllers for DSC6.AT1380 DC/DC Converter7.AT1382A/AT1382B DC/DC Converter8.AT1386/AT1387/AT1388 DC/DC Converter9.AT1393 DC/DC Converter

2、10.AT1202 /AT1117 數位相機系統方塊圖PC Camera控制系統方塊圖DSPCOMS SensorSCRPhoto Flash Light moduleData bufferSDRAMCode FlashPower Control &Battery detect &Data FlashOptionKey BoardOptionPC Camera 影像資料系統方塊圖DSPCMOS SensorUSB OutputSDRAM810Bits Data Bus16 bits Data busData Flash8 bits Data bus PC Camera 電源系統方塊圖 LDOA

3、T1117Flash LightAT1452 AT1453DC/DC ConverterAT1380USB InputSystem IC (DSP/SDRAM/LCD.)2.5v/3.3vFlash Capacitor300vCMOS 3.3v/5V Battery Input(0.9v1.5v or CCD Camera控制系統方塊圖DSPSensorModuleAuto Focus LensPhoto Flash Light moduleData bufferSDRAMCode bufferCode FlashMemory Card &USB Connector &CVBS Connect

4、orPower Control &Battery detect &Battery ChargerKey BoardLCD Module CCD & CMOS 影像資料系統方塊圖DSPSensorMemory card(CF/SD/MS/SM)TV Out(CVBS) &USB connectorSDRAM810Bits Data Bus16 or 32bits Data busData Bus:CF:16/8 SD:4/1 MS:4/1 SM:8TFT LCD ModuleSwitch Converter System TypeBuck Converter Circuit(Step Down)

5、 :右圖為Buck Converter 基本線路結構.此種線路最大特性是輸出電壓永遠小於輸入電壓,故又稱 :Step Down Converter.Buck Converter 輸入與輸出關係式為:CCM : DCM :CCM : continuous conduction mode.DCM : discontinuous conduction mode.DC/DC controllerBoost Converter Circuit (Step Up) :右圖為Boost Converter 基本線路結構.此種線路最大特性是輸出電壓永遠大於輸入電壓,故又稱 :Step Up Converter

6、. Boost Converter 輸入與輸出關係式為:CCM:DCM:Sepic Converter Circuit :右圖為Sepic Converter 基本線路結構.此種線路最大的特性在於它的輸出電壓可同時比輸入電壓高或低 , 而別於 Buck與 Boost Converter的線路只能純昇壓或純降壓.Flyback Converter Circuit :右圖為Flyback Converter 基本線路結構.此種線路最大的特性在於它的輸出電壓可同時比輸入電壓高或低 , 而且它的極性可正可負.Flyback Converter 輸出電壓高低,極性正負的關鍵就在於變壓器的繞線比與一二次側

7、極性 ,故當一次側的繞線小於二次側時,輸出為昇壓反之為降壓 此種電路最大的缺點在於整體體積過大 Photoflash Controllers DescriptionVin(max)On/offCharge readySoft startAuto-discharge Auto-refreshPackageAT1450Photoflash capacitor charger13SOP8AT1452A/BPhotoflash capacitor charger7TSSOP8AT1453A/BPhotoflash capacitor charger7TSSOP8系統參考線路 :1.1V電源系統設計應流

8、程:1.決定最大瞬間電流輸入量及電壓值: 因為數位相機是離線電源系統 , 設計時應考量輸入能量以求系統 穩定.2.選擇系統充電最高電壓: (選擇充電電容器) 閃光燈動作主要是因為電容放電所產生,故閃光大小取決於選擇 的電容容量大小.3.決定充電時間 : 閃光燈模組主要功能是提供即時亮度,故充電時間的長短是一個 重要的決定.因為充電的長短與所需的電流輸入成反比. 當我們有了以上的資料後就可以決定系統的參數值.parameterSymbolConditionValuesUnitMinTyp.MaxInput Supply RangeVcc2,55.5VFeedback VoltageVFBTa=2

9、5C1.0801.1001.120VFrequencyfoseA405060kHzB90100110kHzCharger ON/OFF SectionVONH2.0VVONL0.8VRecommended Operating ConditionsAT1452AT1453AT1452/AT1453 Block DiagramAT1452 Charger Toggling refresh ModeNote : AT1453 只有Toggle mode , 而沒有Auto modeAT1452 Auto Mode/Toggle Mode Timing ChartSoft-Start 功能 :主要是利

10、用RC充電原理,以減緩瞬間啟動時的脈衝電流.Soft-Start Setting :參數設定的公式:1.Duty Setting : The Duty resistor selection depends on Duty Cycle , choose the component using the following equation :2.Output Voltage Setting :3.Photoflash Capacitor Charger Charge Time : The energy stored in the output capacitor is : The output p

11、ower required by the flyback converter to charge the capacitor in a period of time is :222 DC/DC Switch Controllers for DSCDescriptionOutput channelMin Vin (V)Max Vin (V)Iq(mA)Short circuit protectSoft startOn/offUnder voltage detectSync.packageAT13801-Boost11.8135.58-Pin SOLAT1380A1-Boost12.51568-P

12、in SOLAT1382A4-Boost41.472LQFP48AT1382B3-Boost/1-buck41.472LQFP48AT13866-Boost61.473LQFP48AT13874-Boost/2-buck61.473LQFP48AT13885-Boost/1-buck61.473LQFP48AT13934-Boost/2-buck61.773LQFP48 AT1380 DC/DC ConverterFeatures :1.8 to 13V supply voltage operation range.Low current consumption : 5mA in operat

13、ion,1uA or less in stand-by.20kHz to 1MHz operation frequency range supply voltage fluctuations by using an external resistor to set the output current.Totem-pole output. Built-in soft-start circuit.Built-in timer latch type short circuit detection and protection (SCP) circuit.系統參考線路 :0.5V電源系統設計流程 :

14、 1.決定輸入電壓範圍 : 因為電池供電的系統輸入電壓範圍是變動且提供之能量固定, 故需要預先計算出所能提供 能量範圍,以配合最佳的控制線路及最佳的效率. 2.決定需要幾組電壓及輸出電壓範圍: 因系統IC所需的電壓範圍不同或特殊的規格需求,故設計時就需統計出所需的電壓.3.考量機構尺寸 一個完整的產品是需要機構與電子控制相互配合,而輕薄短小亦是目前潮流趨勢 , 所以電 源系統整體體積大小也是重要考量範圍. 4.選用合適的控制線路 : 不同的控制線路會有不同的狀況及不同的電氣特性.所以必須預先決定所用的應 用是純昇壓 ,純降壓或昇降壓.等.5.選用合適的Switch IC 綜合以上的限制 , 而

15、選用何種Switch controller IC. Ex:AT1380,AT1382,AT1386,AT1387 . AT1380 Block Diagram :0.1vFunction Description :Soft Start SCP :當power On 時,AT1380的SCP pin會對電容充電(1uA) , 預防電流凸波overshoot狀態.當AT1380SCP Pin充電達到0.8v時, AT1380就會從Soft-start 模式進入normal 模式而且啟動SCP 功能如果輸出負載突然被改變成重載或短路狀況,則FB Pin 會被固定在VOMax,然後SCP Pin 將小

16、於0.8v,Output Pin 將被設Low 直到從新開關電源.Setting Oscillating Frequency : 由與T所組成之三角波產生器,電壓震幅為0.1v0.8v頻率範圍為20KHz1MHz計算式如下: AT1382A/AT1382B DC/DC ConverterAT1382A Features :1.Low start-up power supply voltage: 1.4V(CH4)2.Wide supply voltage range from 1.8v to 7v(CH1CH4)3.High speed operation is possible : Maxi

17、mum 1MHz4.Supports for up ,flyback and up/down SEPIC converter (CH1CH4)5.Totem-pole type output for MOSFET6.Built-in On/Off7.Built-in Short-Circuit Protection.AT1382B Features :1.Low start-up power supply voltage: 1.4V(CH4)2.Wide supply voltage range from 1.8v to 7v(CH1CH4)3.High speed operation is

18、possible : Maximum 1MHz4.Supports for up ,flyback and up/down SEPIC converter (CH2CH4)5.Totem-pole type output for MOSFET6.Built-in On/Off7.Built-in Short-Circuit Protection.8.Supports for down and up/down zeta conversion(CH1)參考線路 :線路應用注意事項:1.如何減少輸出的OverShoot2.電池偵測注意事項AT1382A Block Diagram :AT1382B

19、Block Diagram :功能概述 : 1.電源轉換功能:a.參考電壓模塊 (Reference voltage ) : 提供IC內部的參考電壓及供給外部電路之參考電壓( typical 0.9v & Max supply current 1mA).b.三角波震盪模塊 (Triangular oscillator ): 三角波產生器主要的頻率乃由CT與RT駔程產生 CT :0.3v0.7v ; CT1 :0.2v0.65v且與CT同相 ; CT2: 0.2v0.65v且與CT反相.c.迴授放大比較器 (Error amplifier): 迴授比較器乃是比較等比例的輸出電壓與迴授參考電壓(F

20、B),用以控制PWM比較器的輸出狀態d.PWM比較器模塊: PWM1比較器是一個電壓對相位的轉換器而產生脈寬調變之控制.PWM比較器主要的輸入: 迴授比較輸出, DTC , Soft-start , SCP , OSC.等. e.輸出電壓模塊 : 輸出模塊為Totem pole結構, 用以控制外部的MOSFET之驅動器f.低電池偵測模塊: IC 內部提供一個定壓比較器,以利電池電壓比較之用g.類比放大模塊: IC 內部提供一個電壓放大器,放大倍率為100倍,以供系統電路應用之用. 輸出控制功能:2.保護功能: a:短路保護模塊: IC 內部每一組輸出都會有 一個短路偵測模塊,其主要的 功能是防

21、止輸出瞬間短 路時 作為保護IC裝置. b.低電壓保護模塊: 當輸入電壓未達到輸入的額定 電壓時,為防止IC輸出誤動作故 限制其輸出電壓值 為一定值3.Soft_Start 設定:輸出CH1CH4的Soft-start 完全一樣 ,但也都可以被CS所控制4.輸出電壓制設定:5.DEAD Time 設定:6.低電池偵測的線路及偵測電壓的計算 :7.同步整流參考資料: AT1386/87/88 DC/DC ConverterAT1386 Features :Low start-up power supply voltage :1.4V(CH6)Wide supply voltage range 2

22、.5V to 7V (CH16)High speed operation is possible : Maximum 1MHzSupports for up, flyback and up/down SEPIC conversion (CH16)Synchronized rectification on CH1,CH2Totem-pole type output for MOSFETBuilt-in On/Off functionBuilt-in Soft-Start function Built-in Short-Circuit Protection.AT1387 Features :Low

23、 start-up power supply voltage :1.4V(CH6)Wide supply voltage range 2.5V to 7V (CH16)High speed operation is possible : Maximum 1MHzSupports for up, flyback and up/down SEPIC conversion (CH3,4,5,6)Synchronized rectification on CH1,CH2Totem-pole type output for MOSFETBuilt-in On/Off functionBuilt-in S

24、oft-Start function Built-in Short-Circuit Protection.Support for down and up Zeta conversion(CH1,2)AT1388 Features :Low start-up power supply voltage :1.4V(CH6)Wide supply voltage range 2.5V to 7V (CH16)High speed operation is possible : Maximum 1MHzSupports for up, flyback and up/down SEPIC convers

25、ion (CH2,3,4,5,6)Synchronized rectification on CH1,CH2Totem-pole type output for MOSFETBuilt-in On/Off functionBuilt-in Soft-Start function Built-in Short-Circuit Protection.Support for down and up Zeta conversion(CH1)AT1386 Block Diagram :AT1387 Block Diagram :AT1388 Block Diagram :參考線路 :當系統關閉時為防止電

26、池耗電所建議之線路Example:可節省電池經由電阻放電,等到需要時再啟動防止系統沒啟動時電池電壓直接灌電流至負載參數設定與計算式:1.Soft-Start 設定:2. 輸出電壓設定:3.短路保護時間設定:4.Dead Time控制準位設定: AT1457Charge Management ICFeatures :Ideal for Single-Cell(4.1V or 4.2V) and Li-Ion or Li-Pol Packs.Better Than +1% Voltage Regulation Accuracy With Preset Voltages.Optional Cell-

27、Temperature Monitoring Before and During Charge.Integrated Voltage and Current Regulation With Programmable Charge-Current and High or Low-Side current Sensing.Charge Status Output for Single or Dual Led or Host Processor Interface.Automatic Battery-Recharge feature.Charge Termination by Minimum Cur

28、rent.Automatic Low-Power Sleep Mode When VCC is Removed.Requires Small Number of External Components.Packaging : 8-Pin MSOP.參考線路:Power supply voltage4.5V7VVBAT=4.1v3v for AT14574.2v3.1v for AT1457ATemperature threshold voltage :Low:30%+3VccHigh:60+3Vcc4.1v or 4.2V(for A type)3.0v or 3.1v(for A type)

29、AT1457 只支持1 cell鋰電, 因為的電壓範圍為4.23V,而AT1457輸入電壓範圍4.57v所以使用2cell鋰電則至少需要8.4v以上的輸入電壓VRCH : Vo(REG)(output voltage) 100mv+2mv如何計算 TS Pin 分壓電組 : AT1741 / AT1743 2-CH PWM Controller AT1741 Features :High-accuracy reference voltage circuit (+2%).Built-in short-circuit protection circuit.Built-in Under voltage Lockout Protection.Internal 2.5v Reference supply.Variable Dead time provides control over total Range.AT1743 Features :High-accuracy reference voltage