Patent ID: 9064590
Filing Date: 2015-06-23
Classification: G11C

Abstract:
1. A semiconductor storage device comprising: a plurality of resistance change storage elements; a signal holder holding a plurality of voltages according to data stored in the storage elements; a sense amplifier detecting the data stored in the storage elements based on the voltages held in the signal holder; a write driver writing data to the storage elements; and a busy signal controller controlling a busy signal, the busy signal determining whether to permit or reject reception of a read enable signal enabling data to be read from the storage elements or whether to permit or reject reception of a write enable signal enabling data to be written to the storage elements, wherein in a period during which the busy signal controller controls the busy signal to reject the reception of the read enable signal or the write enable signal, the signal holder holds a first voltage, a second voltage and a third voltage, the first voltage corresponding to target data stored in a first storage element selected from among the storage elements, the second voltage corresponding to first sample data of first logic written to the first storage element, the third voltage corresponding to second sample data of second logic opposite to the first logic, the second sample data being written to the first storage element, the sense amplifier detects logic of the target data stored in the first storage element by comparing a read signal based on the first voltage with a reference signal generated based on the second and the third voltages, and the write driver writes the target data or write data to the first storage element, and after the write driver writes the write data, the busy signal controller controls the busy signal to permit the reception of the read enable signal or the write enable signal.