低压差稳压电源的折返式限流保护电路的设计

2007725244TelecomPowerTechnologiesJuly25,2007,Vol.24No.4:20070102:邹雪城(1964),男,教授,博士生导师,研究方向为超大规模数模混合集成电路的设计涂熙(1980),男,硕士研究生,研究方向为超大规模数模混合集成电路的设计:10093664(2007)04003102,,(,430074):为了防止因负载短路和过载对芯片造成永久性的伤害,芯片中通常需要加入限流保护电路文中从限流保护的原理出发,设计了一款用于LDO的折返式(FOLDBACK)限流保护电路该电路不仅很好地完成了限流保护功能,同时大大降低了芯片的短路功耗该设计采用0.6mBiCMOS高压工艺Hspice仿真结果表明:与常规的恒定电流限制相比,折返式限流电路在限流状态下能使系统的功耗减少70%以上:LDO;限流保护;折返式:TN433:ADesignofaFoldbackCurrentLimitCircuitinLDOZOUXuecheng,TUXi,QIANHairong(HuazhongUniversityofScience&TechnologyDeptofElectronicsofScience&Technology,Wuhan430074China)Abstract:Thecurrentlimitcircuitisusuallyusedinthechipinordertopreventchipfrombeingpermanentlydestroyedbythemasscurrent,whichiscausedbytheshortcircuitofloadorovercurrent.ThearticledesignedafoldbackcurrentlimitcircuitforLDOaccordingtotheaboveprincipal.Thisfoldbackcircuitnotonlyprovidesgoodperformanceincurrentlimiting,butalsoreducesthepowerconsumptionofthechipatheavyload.ThisdesignadoptedtheBiCMOS0.6mprocesstechnology,andtheHspicesimulatingresultshowsthatcomparingwiththeregularconstantcurrentlimit,thefoldbackcircuitcouldreducethepowerconsumptionofthesystemto30%oftheoriginalconsumption.Keywords:LDO;constantcurrentlimit,foldback0,,,,,,,LDO,,1LDO1.1LDO:,,(),,,LDO,LDO:(1),LDO(2),,(3),LDO,1.2111,MPLDO;AMPLDO312007725244TelecomPowerTechnologiesJuly.25,2007,Vol.24No.4;Rf1Rf2;UREFLDOMSENSE,;RS1RS2(RS1RS2);OCP,;MOCPLDO,MSENSE,RS1,OCP,MOCP,LDO,,MSENSE,OCP,,,MOCP,PG,,,,,,,,OCP,(FOLDBACK)2,,,OCP,,,2OCP;IBIAS;M1~M4;M6M7;M8UOUT,M72,UOUT;UOUTM8,M7,RS2,,,IBIASnIBIAS,M6(01)2OCPUINNUINP,RS2nIBIASIBIAS,UINRS1,UINN,(1),MSENSEMPUINN=UIN-nIBIASRS2(1)RS1MSENSE,UINP,UINP=UIN-ISENSERS1(2)ISENSE,(3),ISENSE=IOUTMSENSEMP(3)UINN=UINP,IMAX,(1)(2)IMAX=nIBIASMPMSENSERS2RS1(4)(4),,IMAXMPRS2,MSENSERS1,IMAX,OCP,MOCP,AMPMPUPG,MP,(ConstantCurrentLimit),UOUT,M8,M7,,,M6,(1),UINN=UIN-nIBIASRS2(5),IFOLDBACK,(2)(3)IFOLDBACK=nIBIASMPMSENSERS2RS1(6)(6),IFOLDBACK,IFOLDBACKIMAX,,,,,,,33.131.5VUoutIout1,,2(44)322007725244TelecomPowerTechnologiesJuly.25,2007,Vol.24No.4;4,:[1].[M].:,1999.[2].()[S].1997.[3].[J].,1998,13(1):2225.[4].[J].,1997,12:3235.(32)3,Uout,,70mA3.241.5VWMP41,,Uout,2,,,,,320mW80mW4,,LDO,:[1].LDO[J].,2006,5:107109.[2]CHENGXiaojie,FENGQuanyuan.AlowpowerhighreliabilityCMOScurrentlimitcircuit[C].APMC2005Proceedings,2005.[3]RobertMarnrnano,JonathanRadovsky,UnitrodeICCorp,GeorgeHarlan,PowerGeneral,Anewlinearregulatorfeaturesswitchmodeovercurrentprotection[Z].C827193/89/oooO-0159.IEEE,1989.[4]LINChuan,FENGQuan-yuan.Designofcurrentlimitingcircuitinlowdropoutlinearvoltageregulator[C].APMC2005Proceedings078039433X/05/.2005IEEE,2005.44