Sgs-thomson Microelectronics Limited

Stmicroelectronics Gmbh

Stmicroelectronics S.a.

Stmicroelectronics S.r.l.

Medtronic, Inc.

Medtronics, Inc.

David C McClure

Mark A Lysinger

Thomas A Teel

Tom Youssef

William C Slemmer

Thomas A Coker

Yamu Hu

Deyou Fang

Mehdi Zamanian

Rong Yin

Sooping Saw

Naren K Sahoo

James Brady

François Jacquet

Milad Alwardi

Chao-Ming Tsai

Tsiu Chiu Chan

Larry Earl Tyler

Paul F Gerrish

Kevin K Walsh

Huantong Zhang

Robert Alan Wadsworth

Michael Joseph Brannigan

Alessandro Tocchio

Philippe Roche

Francois Jacquet

Pavan Nallamothu

Marco Garbarino

Frank J Sigmund

Narasimhan Iyengar

Robert Mikyska

Anthony Junior Casillan

John A Michlowsky

William D Bishop

At start-up of a microelectromechanical system (MEMS) gyroscope, the drive signal is inhibited, and the phase, frequency and amplitude of any residual mechanical oscillation is sensed and processed to determine a process path for start-up. In the event that the sensed frequency of the residual mechanical oscillation is a spurious mode frequency and a quality factor of the residual mechanical oscillation is sufficient, an anti-phase signal is applied as the MEMS gyroscope drive signal in order to implement an active dampening of the residual mechanical oscillation. A kicking phase can then be performed to initiate oscillation. Also, in the event that the sensed frequency of the residual mechanical oscillation is a resonant mode frequency with sufficient drive energy, a quadrature phase signal with phase lock loop frequency control and amplitude controlled by the drive energy is applied as the MEMS gyroscope drive signal in order to induce controlled oscillation.

MEMS gyroscope start-up process and circuit

A microelectromechanical system (MEMS) gyroscope includes a driving mass and a driving circuit that operates to drive the driving mass in a mechanical oscillation at a resonant drive frequency. An oscillator generates a system clock that is independent of and asynchronous to the resonant drive frequency. A clock generator circuit outputs a first clock and a second clock that are derived from the system clock. The drive loop of the driving circuit including an analog-to-digital converter (ADC) circuit that is clocked by the first clock and a digital signal processing (DSP) circuit that is clocked by the second clock.

MEMS gyroscope control circuit

A microelectromechanical system (MEMS) gyroscope sensor has a sensing mass and a quadrature error compensation control loop for applying a force to the sensing mass to cancel quadrature error. To detect fault, the quadrature error compensation control loop is opened and an additional force is applied to produce a physical displacement of the sensing mass. A quadrature error resulting from the physical displacement of the sensing mass in response to the applied additional force is sensed. The sensed quadrature error is compared to an expected value corresponding to the applied additional force and a fault alert is generated if the comparison is not satisfied.

MEMS gyroscope self-test using a technique for deflection of the sensing mobile mass

A microelectromechanical system (MEMS) accelerometer sensor has a mobile mass and a sensing capacitor. To self-test the sensor, a test signal is applied to the sensing capacitor during a reset phase of a sensing circuit coupled to the sensing capacitor. The test signal is configured to cause an electrostatic force which produces a physical displacement of the mobile mass corresponding to a desired acceleration value. Then, during a read phase of the sensing circuit, a variation in capacitance of sensing capacitor due to the physical displacement of the mobile mass is sensed. This sensed variation in capacitance is converted to a sensed acceleration value. A comparison of the sensed acceleration value to the desired acceleration value provides an indication of an error in operation of the MEMS accelerometer sensor if the sensed acceleration value and desired acceleration value are not substantially equal.

MEMS accelerometer self-test using an active mobile mass deflection technique

An integrated circuit includes an output pad, an alarm output pad, and a test mode output pad. A first multi-bit register is programmable to store programmable data such as data that identifies a customer for whom the integrated circuit has been manufactured. A second multi-bit register is programmable to store customer specified threshold data. A first circuit selectively couples the first and second multi-bit registers to the output pad. The first circuit is operable responsive to the integrated circuit being placed into a test mode to perform parallel-to-serial conversion of either the customer identification data stored in the first multi-bit register or the customer specified threshold data stored in the second multi-bit register and drive the converted data for output through the output pad. The integrated circuit further includes a tamper detection circuit operable responsive to the customer specified threshold data to generate a tamper alarm signal. A second circuit selectively couples the tamper alarm signal to the alarm output pad and test mode output pad depending on whether the integrated circuit is in a test mode. More specifically, the second circuit operates to drive the alarm output pad with the tamper alarm signal when the integrated circuit is not in test mode and drive the test mode output pad with the tamper alarm signal when the integrated circuit is in test mode (with the alarm output pad driven to a known state).

Test mode circuitry for a programmable tamper detection circuit

An SRAM having two capacitors connected in series between respective bit storage nodes of each memory cell. The two inverters of the memory cell are powered by a positive voltage and a low voltage. The two capacitors are connected to each other at a common node. A leakage current generator is coupled to the common node. The leakage current generator supplies to the common node a leakage current to maintain a voltage which is approximately halfway between the voltages of the high and low SRAM supplies.

Robust SRAM memory cell capacitor plate voltage generator

A battery monitor circuit. The circuit includes a control module, a resistive load having a resistive value between a first and a second terminals and a part of that resistive value between the first and an intermediate terminals, a switch configured to couple the full load between circuit input and a common potential in response a pulse signal, a first comparator having inputs separately coupled to a voltage reference and the intermediate terminal, a second comparator having inputs separately coupled to the voltage reference and an input potential, a latch, a detection module having input coupled to second comparator output, and an alarm module. The latch is configured to latch a value at output of first comparator to another input of the detection module in response to the pulse signal; if input potential is less than a preselected magnitude, detection module output is configured to activate the alarm module.

Battery monitor circuit and method for battery tamper detection

A threshold personalization circuit for a reset or supervisor chip includes personalization fuses, which shift a resistor divider to provide a variety of selectable voltage thresholds. The personalization fuses may provide hundreds of millivolts of adjustment. The threshold personalization circuit further includes trim fuses to fine tune the threshold to within a few millivolts of the target threshold voltage. The threshold personalization circuit includes a test mode to cycle through to a particular personalization trim, such that at prelaser testing the personalized value is found (the fuse blow for personalization is emulated) and then the trim fuse amount can be based on the actual final personalized voltage. This results in very accurate threshold voltages for all personalized values.

Threshold personalization testmode

A digital-to-analog converter, in response to a digital signal, selectively taps a resistor string to generate an analog output and selectively shunts around resistors in the string to voltage shift the analog output. If two supply voltage sets are present, two strings are provided. A mutually exclusively selection of outputs is made to select a source of the analog output. An integrated circuit temperature sensor uses the converter and includes a sensing circuit that determines exposure to one of a relatively low or high temperature. A measured voltage across the base-emitter of a bipolar transistor is selected in low temperature exposure and compared against a first reference for a too cold temperature condition. Alternatively, a measured delta voltage across the base-emitter is selected in high temperature exposure and compared against a second reference voltage for a too hot temperature condition. Through the comparisons, a temperature exposure detection is made.

Digital-to-analog converter circuit and method

The entire data path of a synchronous integrated circuit device is initialized in a test mode upon power-up of the synchronous integrated circuit device. Upon power-up of the integrated circuit device in the test mode, a clock signal (either an external clock signal or an associated internal clock signal) is internally clocked. As the clock signal goes to a low logic state upon power-up of the device, a master latch(flip-flop)flip-flopelement of the integrated circuit device is loaded with data and is allowed to conduct; a slave latch(flip-flop)flip-flopelement of the integrated circuit device does not conduct. As the clock signal goes to a high logic state, the data in the master latch is latched. Also upon the high logic state of the clock, the slave latch element is loaded with data and is allowed to conduct.

Synchronous test mode initialization

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Carrollton, TX, United States of America

David C McClure