Programmable resistive circuit using magnetoresistive memory technology

Abstract

A programmable resistive circuit using magnetoresistive memory elements incorporated into one or more programmable segments coupled together between first and second terminals. Each segment includes at least one magnetoresistive memory element and at least one control input to select its state. The resistive circuit further includes select logic coupled to the control inputs of each segment to achieve a programmed resistance. A source signal is applied to the resistive circuit to develop an output signal that is a combination of signals developed by each of the memory elements in the resistive circuit. Bypass logic or switch devices may be included to selectively bypass or remove one or more segments. Each segment may include any combination of series and parallel coupled memory elements. The programmable segments may form a successive configuration to enable programming of progressive resistive values. The progressive resistive values may be linear and the successive configuration may be binary. A programmable current source is achieved by providing a voltage source in which the current is a combination of current signals developed by each of the memory elements in the resistive circuit. A programmable voltage source is achieved by forming first and second resistive circuits on either side of a voltage junction terminal and by applying a voltage source across both resistive circuits. The total resistance across the resistive circuits may be kept constant for each of multiple programmable voltages.