A memory array structure that includes memory columns having first bit lines and second bit lines is introduced. Each of the memory columns includes a bit line pair, a pre-charge switch pair and a first switch pair. Output voltages from the first bit lines and the second bit lines are used to generated a first average voltage and a second average voltage, respectively. One of the first average voltage and the second average voltage is a lower average voltage and another one of the first average voltage and the second average voltage is a higher average voltage. The pre-charge switch pair and the first switch pair of a selected memory column among the plurality of memory columns are controlled to repeatedly perform an incremental step to increment the lower average voltage by a step voltage until the lower average voltage is greater than the higher average voltage.

A sense amplifier for a memory circuit that can sense into the deep negative voltage threshold region is described. A selected memory cell is sensed by discharging a source line through the memory cell into the bit line and sense amplifier. While discharging the source line through the memory cell into the sense amplifier, a voltage level on the discharge path is used to set the conductivity of a discharge transistor to a level corresponding to the conductivity of the selected memory cell. A sense node is then discharged through the discharge transistor. By allowing the sense amplifier to bias a memory cell being sensed to a selected one of multiple bias levels during a sensing operation, multiple target data states can be concurrently program verified, leading to higher performance when writing data.

A semiconductor device includes a line driving unit connected to a memory cell array, a switch unit including first and second output terminals electrically connected to the memory cell array through a plurality of bit lines and a plurality of source lines, and a power supply unit outputting a precharge voltage and a source voltage to the first and second output terminals. The power supply unit includes a negative voltage generation unit that charge-shares the precharge voltage to be charged with a first voltage and discharges the first voltage to one side to generate a negative voltage on the other side.

To accurately read data in a storage device provided with a cell having a variable resistance value. In a reference cell circuit, a resistance value changes to a predetermined initial value when an initialization signal exceeding a predetermined reversal threshold is input. A reference side signal source inputs a reference side read signal of a predetermined value not exceeding the predetermined reversal threshold to the reference cell circuit after the initialization signal is input to the reference cell circuit when there is an instruction to read with respect to a memory cell. A cell side signal source inputs a cell side read signal of the predetermined value to the memory cell after the initialization signal is input. A comparison unit compares a reference signal output from the reference cell circuit into which the reference side read signal has been input, and a cell signal output from the memory cell into which the cell side read current has been input, and acquires the comparison result as read data.

A semiconductor device includes a line driving unit connected to a memory cell array, a switch unit including first and second output terminals electrically connected to the memory cell array through a plurality of bit lines and a plurality of source lines, and a power supply unit outputting a precharge voltage and a source voltage to the first and second output terminals. The power supply unit includes a negative voltage generation unit that charge-shares the precharge voltage to be charged with a first voltage and discharges the first voltage to one side to generate a negative voltage on the other side.

To accurately read data in a storage device provided with a cell having a variable resistance value. In a reference cell circuit, a resistance value changes to a predetermined initial value when an initialization signal exceeding a predetermined reversal threshold is input. A reference side signal source inputs a reference side read signal of a predetermined value not exceeding the predetermined reversal threshold to the reference cell circuit after the initialization signal is input to the reference cell circuit when there is an instruction to read with respect to a memory cell. A cell side signal source inputs a cell side read signal of the predetermined value to the memory cell after the initialization signal is input. A comparison unit compares a reference signal output from the reference cell circuit into which the reference side read signal has been input, and a cell signal output from the memory cell into which the cell side read current has been input, and acquires the comparison result as read data.