Auto precharge circuit in a semiconductor device

摘要

PURPOSE: An auto precharge circuit of a semiconductor device is provided, which prevents the precharge from being performed under the state of not satisfying a row address strobe minimum time(tRAS). CONSTITUTION: A command decoder(10) generates a row active start signal(rowatv6) and a column access start signal(casatv6). A row address strobe classifier(20) buffers the row active start signal according to an external active command(ACT). A column address active signal generator(40) generates a column strobe active signal as to a corresponding column by enabling the column access start signal according to a WA(Write with Autoprecharge) command. A column address strobe generator(50) generates a column address strobe signal to disable the corresponding column, when another bank is enabled according to the column address active signal or a burst operation is ended. A column burst signal generator(70) generates a column burst signal during a burst write period according to the column access start signal. A column burst end signal generator(80) generates a column burst operation end signal according to the column burst signal and a clock signal. An autoprecharge enable signal generator(60A) generates an autoprecharge enable signal according to the column address strobe active signal and the column address strobe signal and the column burst operation end signal. A row autoprecharge control signal unit(90) generates a next autoprecharge control signal according to a sensing generation signal. And an address strobe generator generates an autoprecharge signal according to the autoprecharge control signal by generating a row bank classifying signal according to an external command and the buffered row active start signal.