Sram column sleep circuits for leakage savings with rapid wake

Abstract

An apparatus and method for efficiently designing memory arrays in semiconductor dies. In various implementations, a memory array utilizes wake pre-charge circuitry to reduce both leakage current and a transition from an idle state. When control circuitry of the memory array determines that there are no upcoming memory accesses, it disables bit line pre-charge circuitry of columns of the array. The control circuitry enables wake pre-charge circuitry to charge the bit lines to an idle voltage level equal to a difference between the power supply voltage level and a threshold voltage of a transistor. When the control circuitry determines a memory access is pending, the control circuitry transitions the memory array to an active state. Both the amount of voltage difference and the resulting latency to charge the bit lines from the idle voltage level to the power supply reference voltage level are small.