Current sense circuit and semiconductor memory device provided with this

摘要

To provide a current sensing circuit that detects a difference between a cell current and a reference current. The current sensing circuit includes: current mirror circuits of which the input terminal is connected with a reference current source; a differential amplifier of which the one input terminal is supplied with a potential of an electrical connection point between an output terminal of the current mirror circuit and a memory cell and of which the other input terminal is supplied with a reference potential; and an equalizing circuit that short-circuits the both input terminals of the differential amplifier in response to an equalizing signal. Thereby, the both input terminals can be kept at the same potential immediately before a sensing operation starts, and thus, even when the cell current is weak, a highly sensitive sensing operation can be performed at high speed.