Analog Devices,inc.

Analog Devices Global

Alan Gillespie

Roderick McLachlan

Dennis A Dempsey

Eoin Edward English

Mark Murphy

Donal P Geraghty

Avinash Gutta

Teng-Hee Lee

A data converter can include a resistor network, a switch network connected to the resistor network and having a plurality of switch circuits, each with an NMOS and a PMOS switch transistor, and a voltage generator to generate a drive voltage for driving a gate of at least one of the NMOS or PMOS switch transistors of at least one of the switch circuits. The voltage generator can include first and second pairs of transistors, each pair having connected control terminals and being connected to a second NMOS or PMOS transistor, a first or second resistor, and the other pair of transistors. The first and second resistors can have substantially equal resistance values. A ratio of width-to-length ratios of the second NMOS to PMOS transistors can be substantially equal to such a ratio of the switch circuit NMOS to PMOS transistors.

Voltage generator, switch and data converter circuits

A device and method are provided to drive piezoelectric elements in haptic applications. In one embodiment, a pattern generator provides user programmable PWM waveforms to a driver. The load of the driver is an inductor in series with the piezoelectric element. The filtration of the inductor in series with the capacitance of the piezoelectric element suppresses the high-frequency components of the PWM pulse train, and recovers a value commensurate with the duty cycle of the PWM pulse train. The resulting waveform across the piezoelectric element is converted to physical motion, thereby creating a haptic effect on a user interface. Advantageously, there is reduced power loss, reduced switching induced noise, and a more haptic rich environment.

Reactive networks to reduce acoustic noise and ensure maximum efficiencies in driving piezoelectric elements in haptic applications

A digital to analog converter comprising: a digital to analog conversion core adapted to receive at least one reference voltage and a digital word to be converted, and to output an analog voltage as a function of the digital word and the at least one reference voltage; a sensing circuit for sensing a difference between a first ground voltage associated with an output of the digital to analog converter and a ground reference voltage occurring at the digital to analog converter; and a compensation circuit for applying a compensation voltage to the at least one reference voltage used by the conversion core of the digital to analog converter.

Digital to analog converter and a ground offset compensation circuit

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East Lothian, United Kingdom

Alan Gillespie