Abstract: A method of sensing a data value stored at a memory cell according to a dual mode sensing scheme includes determining, at a sensing circuit, whether a resistance of a magnetic tunnel junction (MTJ) element is within a first range of resistance values, within a second range of resistance values, or within a third range of resistance values. The MTJ element is included in the memory cell. The method also includes determining the data value stored at the memory cell according to a first mode of operation if the resistance of the MTJ element is within the first range of resistance values or within the third range of resistance values. The method further includes determining the data value stored at the memory cell according to a second mode of operation if the resistance of the MTJ element is within the second range of resistance values.

Abstract: Error detection and correction decoding apparatus performs single error correction-double error detection (SEC-DED) or double error correction-triple error detection (DEC-TED) depending on whether the data input contains a single-bit error or a multiple-bit error, to reduce power consumption and latency in case of single-bit errors and to provide powerful error correction in case of multiple-bit errors.

Abstract: A sensing system may include a sense amplifier, a sensing circuit configured to sense a current difference, a data cell selectively coupled to the sensing circuit, a first reference cell selectively coupled to the sensing circuit, and a second reference cell selectively coupled to the sensing circuit. The resistance of the first reference cell and the second reference cell are different.

Abstract: Systems and methods relate to providing a constant sensing current for reading a resistive memory element. A load voltage generator provides a load voltage based on a current mirror configured to supply a constant current that is invariant with process-voltage-temperature variations. A data voltage is generated based on the generated load voltage, by passing a sensing current mirrored from the constant current, through the resistive memory element. A reference voltage is generated, also based on the generated load voltage and by passing reference current mirrored from the constant current, through reference cells. A logical value stored in the resistive memory element is determined based on a comparison of the data voltage and the reference voltage, where the determination is free from effects of process-voltage-temperature variations.

Abstract: A read circuit for a memory cell may include an integrated logic circuit for sensing a current change. The integrated logic sensing circuit may be an offset cancelling single ended integrated logic sensing circuit. The circuit may include an offset canceling single ended sensing circuit coupled to a supply voltage, an offset canceling single ended sense amplifier circuit having a sense amplifier input coupled to the offset canceling single ended sensing circuit and a sense amplifier output, and a cell array coupled to a sensing circuit output and a ground.

Abstract: A method includes sensing a state of a data cell to generate a data voltage. The state of the data cell corresponds to a state of a programmable resistance based memory element of the data cell. The method further includes sensing a state of a reference cell to generate a reference voltage. The state of the data cell and the state of the reference cell are sensed via a common sensing path. The method further includes determining a logic value of the data cell based on the data voltage and the reference voltage.

Abstract: An offset cancelling sense amplifier according to some examples of the disclosure may use a double sensing margin structure and positive feedback to achieve better performance characteristics and read stability without a multistage operation. For example, a sense amplifier may include a second pair of sensing switches cross coupled in parallel with a first pair of sensing switches and a pair of degeneration transistors coupled in line before a pair of load transistors.

Abstract: Systems and methods for reducing a probability of read disturbance during a read operation on a resistive memory bit cell include a dual stage sensing scheme, which is used to reduce pulse widths of sensing currents for reading the resistive memory bit cell. During a first stage of the read operation on the resistive memory bit cell, a first sensing current is passed in a first direction through the resistive memory bit cell, and during a second stage of the read operation, a second sensing current is passed in an opposite, second direction through the resistive memory bit cell. Durations of the first and second stages are each equal to half of the duration of the read operation, which reduces pulse width of the first and second sensing currents. Probability of read disturbance occurring is limited to at most one of the first or second stages.

Abstract: Systems and methods relate to providing a constant sensing current for reading a resistive memory element. A load voltage generator provides a load voltage based on a current mirror configured to supply a constant current that is invariant with process-voltage-temperature variations. A data voltage is generated based on the generated load voltage, by passing a sensing current mirrored from the constant current, through the resistive memory element. A reference voltage is generated, also based on the generated load voltage and by passing reference current mirrored from the constant current, through reference cells. A logical value stored in the resistive memory element is determined based on a comparison of the data voltage and the reference voltage, where the determination is free from effects of process-voltage-temperature variations.

Abstract: Systems and methods relate to operations on a magnetoresistive random access memory (MRAM) bit cell using a circuit configured in multiple phases. In a sensing circuit phase, the circuit configured to determine a first differential voltage between a data voltage across the bit cell and a reference voltage. In a pre-amplifying phase, the circuit is configured to pre-amplify the first differential voltage to generate a pre-amplified differential voltage, which does not have offset voltages that may arise due to process variations. In a sense amplifier phase, the circuit is configured to amplify the pre-amplified differential voltage in a latch. Generation of the pre-amplified differential voltage cancels offset voltages which may arise in the latch. In a write phase, the circuit is further configured to write a write data value to the MRAM bit cell.

Abstract: Systems and methods relate to providing a correct reference voltage for reading a resistive memory element such as a magnetoresistive random access memory (MRAM) bit cell. Two or more reference voltages are provided for each MRAM bit cell and a correct reference voltage is selected from the two or more reference voltages for reading the MRAM bit cell. The correct reference voltage meets sensing margin requirements for reading the MRAM bit cell and overcomes non-idealities and offset voltages in read circuitry for reading the MRAM bit cell. An indication of the correct reference voltage is stored in a non-volatile latch or other non-volatile programmable memory and provided to the read circuitry.

Abstract: An apparatus includes a group of data cells and a reference cell coupled to the group of data cells. The reference cell includes four magnetic tunnel junction (MTJ) cells.

Abstract: An offset canceling dual stage sensing method includes sensing a data value of a resistive memory data cell using a first load PMOS gate voltage generated by a reference value of a resistive memory reference cell in a first stage operation. The method also includes sensing the reference value of the resistive memory reference cell using a second load PMOS gate voltage generated by the data value of the resistive memory data cell in a second stage operation of the resistive memory sensing circuit. By adjusting the operating point of the reference cell sensing, an offset canceling dual stage sensing circuit increases the sense margin significantly compared to that of a conventional sensing circuit.

Abstract: A resistive memory sensing method includes sensing outputs of an offset-cancelling dual stage sensing circuit (OCDS-SC) by an NMOS offset-cancelling current latched sense amplifier circuit (NOC-CLSA). The NOC-CLSA is configured with a reduced input capacitance and a reduced offset voltage. Input transistors of the NOC-CLSA are coupled between latch circuitry and ground. A first phase output of the OCDS-SC is stored by the NOC-CLSA during a pre-charge step of the NOC-CLSA operation. A second phase output of the OCDS-SC is stored by the NOC-CLSA during an offset-cancelling step of the NOC-CLSA operation. By pipelining the OCDS-SC and NOC-CLSA, a sensing delay penalty of the OCDS-SC is overcome.

Abstract: A resistive memory sensing method includes sensing outputs of an offset-cancelling dual stage sensing circuit (OCDS-SC) by an NMOS offset-cancelling current latched sense amplifier circuit (NOC-CLSA). The NOC-CLSA is configured with a reduced input capacitance and a reduced offset voltage. Input transistors of the NOC-CLSA are coupled between latch circuitry and ground. A first phase output of the OCDS-SC is stored by the NOC-CLSA during a pre-charge step of the NOC-CLSA operation. A second phase output of the OCDS-SC is stored by the NOC-CLSA during an offset-cancelling step of the NOC-CLSA operation. By pipelining the OCDS-SC and NOC-CLSA, a sensing delay penalty of the OCDS-SC is overcome.

Abstract: An offset canceling dual stage sensing method includes sensing a data value of a resistive memory data cell using a first load PMOS gate voltage generated by a reference value of a resistive memory reference cell in a first stage operation. The method also includes sensing the reference value of the resistive memory reference cell using a second load PMOS gate voltage generated by the data value of the resistive memory data cell in a second stage operation of the resistive memory sensing circuit. By adjusting the operating point of the reference cell sensing, an offset canceling dual stage sensing circuit increases the sense margin significantly compared to that of a conventional sensing circuit.

Abstract: An apparatus includes a group of data cells and a reference cell coupled to the group of data cells. The reference cell includes four magnetic tunnel junction (MTJ) cells.

Abstract: A method includes sensing a state of a data cell to generate a data voltage. The state of the data cell corresponds to a state of a programmable resistance based memory element of the data cell. The method further includes sensing a state of a reference cell to generate a reference voltage. The state of the data cell and the state of the reference cell are sensed via a common sensing path. The method further includes determining a logic value of the data cell based on the data voltage and the reference voltage.