Atmel Corporation

Invensense, Inc.

Gabriele Pelli

Lorenzo Bedarida

Simone Bartoli

Massimiliano Frulio

Davide Manfre′

Mauro Chinosi

Giorgio Bosisio

Andrea Bettini

A motion sensor with sigma-delta analog-to-digital converter (ADC) having improved bias instability is presented herein. Differential outputs of a differential amplifier of the sigma-delta ADC are electrically coupled, via respective capacitances, to differential inputs of the differential amplifier. To minimize bias instability corresponding to flicker noise that has been injected into the differential inputs, the differential inputs are electrically coupled, via respective pairs of electronic switches, to feedback resistances based on a pair of switch control signals. In this regard, a first feedback resistance of the feedback resistances is electrically coupled to a first defined voltage, and a second feedback resistance of the feedback resistances is electrically coupled to a second defined reference voltage. The differential outputs are electrically coupled to differential inputs of a differential comparator of the sigma-delta ADC, and complementary outputs of the differential comparator comprise the pair of switch control signals.

Motion sensor with sigma-delta analog-to-digital converter having resistive continuous-time digital-to-analog converter feedback for improved bias instability

A sensing circuit with current offset functionality. In one embodiment, the sensing circuit includes a memory circuit having a first offset circuit operative to offset a first current. The sensing circuit also includes a reference circuit coupled to the memory circuit, where the reference circuit includes a second offset circuit operative to offset a second current. The sensing circuit also includes a compare circuit coupled to the memory circuit and the reference circuit, where the compare circuit determines the state of a memory cell based on first current and the second current. According to the system disclosed herein, the first and second offset circuits optimize the performance of the sensing circuit and prevent errors when determining the state of the memory cell.

Compensated current offset in a sensing circuit

A memory system is disclosed. In one embodiment, the memory system includes a first bitline, where the first bitline produces a first transient current. The memory system also includes a sense amplifier coupled to the first bitline. The memory system also includes a second bitline coupled to the sense amplifier, where the second bitline produces a second transient current that is equal to the first transient current. The sense amplifier enables the first and second transient currents to be canceled. According to the system disclosed herein, the state of a memory cell may be determined without being adversely affected by transient currents.

Sense architecture

A current mirror circuit includes a first current-mirror transistor coupled to a second current-mirror transistor. A load is coupled to the second current-mirror transistor. A first current source is coupled to the first current-mirror transistor to cause a bias current to flow through the first current-mirror transistor and a second current source is coupled to the second current-mirror transistor and in parallel with the load to shunt the bias current away from the load.

Biasing current to speed up current mirror settling time

A sense amplifier circuit for reading the state of memory cells. In one aspect of the invention, the sense amplifier circuit includes a first stage receiving a cell current derived from the memory cell and a reference current derived from a reference cell, and a second stage receiving the cell current and the reference current. A comparator, coupled to the first stage and the second stage, provides an output indicative of the state of the memory cell based on a difference of the voltages provided by the first stage and the second stage, where the state indicated by the comparator is substantially unaffected by capacitive current components provided by transient behavior of the first and second stages.

Growing community of inventors

Mortara, Italy

Gabriele Pelli