UCC3957 -1/-2/-3/-4
PRELIMINARY
SLUS236 - JANUARY 1999FEATURES
•Three or Four Cell Operation
•Two Tier Overcurrent Limiting
•30µA Typical Supply CurrentConsumption
•3.5µA Typical Supply Current in SleepMode
•Smart Discharge Minimizes Losses inOvercharge Mode
•6.5V to 20V VDD Supply Range
•Highly Accurate Internal VoltageReference
•Externally Adjustable Delays inOvercurrent Controller
•Detection of Loss of Cell SenseConnectionsThree - Four Cell Lithium-Ion Protector Circuit
BLOCK DIAGRAM
UDG-97060DESCRIPTION
TheUCC3957isaBiCMOSthreeorfourcelllithium-ionbatterypack
protectordesignedtooperatewithexternalP-channelMOSFETs.Uti-
lizingexternalP-channelMOSFETsprovidesthebenefitsofnolossof
systemgroundinanoverdischargestate,andprotectstheICaswellas
batterycellsfromdamageduringanoverchargestate.Aninternalstate
machinerunscontinuouslytoprotecteachlithium-ioncellfromover-
功率MOSFET管驱动芯片UC3875
功率MOSFET管驱动芯片UC3875
Unitrode公司的UC3875，它有4个独立的输出驱动端可以直接驱动四只功率MOSFET管，见图5，其中OUTA和OUTB相位相反，OUTC和OUTD相位相反，而OUTC和OUTD相对于OUTA和OUTB的相位θ是可调的，也正是通过调节θ的大小来进行PWM控制的。
图1 UC3875芯片引脚图
1 VREF 基准电压 10 VCC 电源电压
2 E/AOUT 误差放大器的输出 11 VIN 芯片供电电源
3 E/A－ 误差放大器的反相输入 12 PWRGND 电源地
4 E/A＋ 误差放大器的同相输入 16 __ 频率设置端
5 C/S＋ 电流检测 17 CLOCK/SYNC 时钟/同步
6 SOFT－START 软起动 18 SLOPE 陡度
7,15 __TA/B,C/D 输出延迟控制 19 RAMP 斜波
14,13,9,8 OUTA～OUTD 输出A～D 20 GND 信号地
UC3875各个管脚的具体使用说明
管脚1可输出精确的5V基准电压，其电流可以达到60mA。当VIN比较低时，芯片进入欠压锁定状态VREF消失。直到VREF达到4.75V以上时才脱离欠压锁定状态。最好的办法是接一个0.1μF旁路电容到信号地。
管脚2为电压反馈增益控制端，当误差放大器的输出电压低于1V时实现0°相移。
管脚3为误差放大器的反相输入端，该脚通常利用分压电阻检测输出电源电压。
管脚4为误差放大器的同相输入端，该脚与基准电压相连，以检测E/A（－）端的输出电源电压。
管脚5为电流检测端，该脚为电流故障比较器的同相输入端，其基准设置为内部固定2.5V（由VREF分压）。当该脚的电压超过2.5V时电流故障动作，输出被关断，软起动复位，此脚可实现过流保护。
792SC3857IC–VCE Characteristics (Typical)hFE–IC Characteristics (Typical)hFE–IC Temperature Characteristics (Typical)θj-a–t CharacteristicsIC–VBE Temperature Characteristics (Typical)VCE(sat)–IB Characteristics (Typical)Pc–Ta DeratingSafe Operating Area (Single Pulse)fT–IE Characteristics (Typical)032101243Base Current IB(A)Collector-Emitter Saturation Voltage VCE(sat)(V)IC=15A10A5ACollector Current IC(A)015105021Base-Emittor Voltage VBE(V)(VCE=4V)125˚C (Case Temp)25˚C–30˚C (Case Temp)11010010002000Time t(ms)0.1120.5Transient Thermal Resistance θj-a(˚C/W)1601208040500255075100125150Ambient Temperature Ta(˚C)Maximum Power Dissipation PC(W
)With Infin
ite heatsinkWithout Heatsink2101003000.110.510505Collector-Emitter Voltage VCE(V)Collector Current IC(A)3msWithout HeatsinkNatural CoolingDC100ms20ms10ms0.020.11100.55152050100300Collector Current IC(A)DC Current Gain hFE(VCE=4V)Typ00515102134Collector-Emitter Voltage VCE(V)Collector Current IC(A)1A400mA600mA200mA100mAIB=50mA1.5A(VCE=4V)0.020.55120503001000.11015Collector Current IC(A)DC Current Gain hFE125˚C25˚C–30˚C–0.02–0.1–1–10010204030Cut-off Frequency fT(MHZ)(VCE=12V)Emitter Current IE(A)TypSilicon NPN Triple Diffused Planar Transistor (Complement to type 2SA1493)Application: Audio and General PurposeSymbolVCBOVCEOVEBOICIBPCTjTstg2SC38572002006155150(Tc=25°C)150–55 to +150UnitVVVAAW°C°CsAbsolute maximum ratings sElectrical CharacteristicsSymbolICBOIEBOV(BR)CEOhFEVCE(sat)fTCOB2SC3857100max100max200min50min∗3.0max20typ250typUnitµAµAVVMHzpFConditionsVCB=200VVEB=6VIC=50mAVCE=4V, IC=5AIC=10A, IB=1A VCE=12V, IE=–0.5AVCB=10V, f=1MHz(Ta=25°C)(Ta=25°C)sTypical Switching Characteristics (Common Emitter)VCC(V)60RL(Ω) 12IC(A)5VBB2(V) –5IB2(A)–0.5ton(µs)0.3typtstg(µs)2.4typtf(µs)0.4typIB1(A) 0.5VBB1(V) 10231.05+0.2-0.1BE5.45±0.15.45±0.12-ø3.2±0.136.4±0.3924.4±0.2721.4±0.320.0min4.0max0.65+0.2-0.13.0+0.3-0.16.0±0.22.1abCExternal DimensionsMT-200Weight : Approx 18.4ga. Type No.b. Lot No.∗hFE RankO(50 to 100), P(70 to 140), Y(90 to 180)元器件交易网
Rev. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 Fax: 781.461.3113 ©2012 Analog Devices, Inc. All rights reserved.
ADI中文版数据手册是英文版数据手册的译文，敬请谅解翻译中可能存在的语言组织或翻译错误，ADI不对翻译中存在的差异或由此产生的错误负责。如需确认任何词语的准确性，请参考ADI提供的最新英文版数据手册。TYPICAL APPLICATION CIRCUIT
图1.
图2.效率与输出电流的关系(VIN = 12 V，fSW = 600 kHz)BST1
