文档介绍:、(HalfAdder)两个1位二进制数相加不考虑低位进位。0001101100101001真值表函数式Ai+Bi=Si(和)Ci(进位)逻辑图曾用符号国标符号半加器(HalfAdder)Si&AiBi=(FullAdder)两个1位二进制数相加,考虑低位进位。Ai+Bi+Ci-1(低位进位)=Si(和)Ci(向高位进位)1011---A1110---B+---低位进位100101111真值表标准与或式ABCi-1000001010011100101110111SiCiABCi-1SiCi0010100110010111---S高位进位←0卡诺图全加器(FullAdder)ABC01000111101111SiABC01000111101111Ci圈“0”最简与或式圈“1”逻辑图(a)用与门、或门和非门实现曾用符号国标符号ΣCOCISiAiBiCi-1CiFASiAiBiCi-1Ci&&&&&&&≥1111AiSiCiBiCi-1≥1(b)用与或非门和非门实现&≥1&≥1111CiSiAiBiCi-:74LS183CMOS:2Ai2Bi2Ci-2A2B2CIn2COn+12F1A1B1CIn1FGND1Ai1Bi1Ci-11Si地1Ci1234567141312111098C661VDD2Ai2Bi2Ci-11Ci1Si2Si1Ci-12Ci1Ai1BiVSS二、加法器(Adder):电路简单,连接方便速度低=4tpdtpd—1位全加器的平均传输延迟时间C0S0B0A0C0-,总进位信号由输入二进制数直接产生。…特点优点:速度快缺点:电路比较复杂应用举例8421BCD码→4008TTL:7428374LS283超前进位电路ΣS3ΣS2ΣS1ΣS0C3A3B3A2B2A1B1A0B0C0-1CICICICI