Analog Devices,inc.

Analog Devices Global

Sean B Brennan

Colin Gerard Lyden

Eoin Edward English

Mark Murphy

Denis Martin O'Connor

Tudor M Vinereanu

Javier Calpe-Maravilla

Jonathan Ephraim David Hurwitz

Dennis A Dempsey

John Jude O'Donnell

Alan Patrick Cahill

Denis O'Connor

Alan Cahill

Tudor Vinereanu

A relaxation oscillator can provide a smaller and cheaper alternative to a crystal oscillator circuit in a wide variety of applications. A sawtooth relaxation oscillator can include overshoot error integration. Separate and distinct oscillator capacitor charging, overshoot error integration, and reset phases can be provided using separate comparators for first and second oscillation capacitors. Potential advantages can include high accuracy high-frequency clock, convenient trimming during initial calibration, clock frequency stability over temperature and time, fast startup with low overshoot, high power supply rejection, low power, or low noise/jitter. The oscillator can charge an oscillation capacitor up to a target voltage, then interrupt charging before beginning an error integration phase that adjusts the target voltage by integrating an overshoot error of a voltage on the oscillation capacitor. After completing the overshoot error integration, the voltage on the oscillation capacitor can be reset. The techniques described are believed to be capable of improving clock frequency accuracy and other characteristics.

Relaxation oscillator with overshoot error integration

Embodiments of the present invention provide a motor-driven mechanical system with a detection system to measure properties of a back channel and derive oscillatory characteristics of the mechanical system. Uses of the detection system may include calculating the resonant frequency of the mechanical system and a threshold drive Drequired to move the mechanical system from the starting mechanical stop position. System manufacturers often do not know the resonant frequency and Dof their mechanical systems precisely. Therefore, the calculation of the specific mechanical system's resonant frequency and Drather than depending on the manufacturer's expected values improves precision in the mechanical system use. The backchannel calculations may be used either to replace or to improve corresponding pre-programmed values.

Control techniques for motor driven systems

An example transconductance circuit is provided in accordance with one embodiment. The transconductance circuit can comprise: an output node; at least one transistor; a variable resistance; and a differential amplifier; wherein the at least one transistor and the variable resistance are in series connection with the output node, an output of the differential amplifier is connected to a control node of the at least one transistor, a first input of the amplifier is responsive to an input signal, and a second input of the amplifier is responsive to a voltage across the variable resistance. Such a circuit may overcome noise problems in transconductance circuits which operate over a wide range of input signals with a fixed resistor in series with the at least one transistor.

Transconductance circuit and a current digital to analog converter using such transconductance circuits

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Adare, Ireland

Sean B Brennan