Self-timing circuit with programmable delay and programmable accelerator circuits

Abstract

A memory has a novel self-timing circuit that generates internal memory control signals. Control signals may include an address latch enable signal, a decoder enable signal, and a sense amplifier enable signal. The circuit has a timing loop whose timing mimics the timing of an access of the real memory. The timing loop includes dummy bit cells of identical construction to bit cells in the real array being accessed, a programmable delay circuit, and a programmable accelerator circuit. The dummy bit cells cause the timing of the control signals to track speed changes in the memory array being accessed. The programmable delay and accelerator circuits are usable to slow or speed the timing loop. The programmable delay and accelerator circuits are usable to achieve a desired yield to memory access speed tradeoff. Flexibility of the timing loop allows a memory to be designed before memory access timing characteristics are fixed.