Latency control circuit and method using queuing design method

Abstract

A latency control circuit includes a FIFO controller and a register unit. The FIFO controller may generate an increase signal according to an external command, and generate a decrease signal according to an internal command. The FIFO controller may also enable a depth point signal responsive to the increase signal and the decrease signal. The register unit may include n registers. The value n (rounded off) may be obtained by dividing a larger value of a maximum number of additive latencies and a maximum number of write latencies by a column cycle delay time (tCCD). The registers may store an address received with the external command responsive to the increase signal and a clock signal, and may shift either the address or a previous address to a neighboring register. The latency control circuit transmits an address stored in a register as a column address corresponding to the enabled depth point signal.