US Patent 7826291 Precharge and evaluation phase circuits for sense amplifiers

A precharge and evaluation circuit for a memory sense amplifier includes a first precharge-phase transistor having a source coupled to a power-supply potential, a gate coupled to a precharge control line, and a drain. A second precharge-phase transistor has a drain coupled to the drain of the first precharge-phase transistor, a source, and a gate coupled to the source through a feedback circuit. A first read-phase transistor has a source coupled to the power-supply potential, and a gate and drain coupled to a comparator. A second read-phase transistor has a drain coupled to the drain of the first read-phase transistor, a source coupled to the source of the second precharge-phase transistor, and a gate coupled to the source of the second read-phase transistor through a feedback circuit. A column decoder is coupled to the sources of the second precharge-phase and second read-phase transistors.