Patent ID: 7495964

Claim:
A sense amplifier circuit comprising: a summer for summing a current from a memory cell and a feedback current to form a summed current; a capacitance element connected to receive the summed current and to integrate the summed current over a first time, the capacitance element being charged and discharged during the first time; an analog-to-digital converter connected to receive the integrated summed current from the capacitance element, the analog-to-digital converter comprising a plurality of inverter circuits and at least two switches, each switch being connected between an output of a first associated inverter circuit and an input of a second associated inverter circuit, an output of a last inverter circuit of the plurality of inverter circuits being a digital output corresponding to an average current and a count of a number of times the capacitance element is discharged during the first time; and a digital-to-analog converter connected to receive the digital average current and to output the feedback current to the summer.