Atmel Corporation

Daniel Payrard

Michel Cuenca

Frederic Demolli

Eric Brunet

Thierry Soude

Jimmy Fort

Renaud Dura

Didier Davino

Thierry Soudé

Bilal Farhat

A dual mode, single ended to fully differential converter structure is incorporated into a fully differential sample and hold structure which can be coupled with an ADC as a front end for mixed mode applications. The structure incorporates additional switches which allow negative and positive charges to be sampled on both negative and positive sides of the structure. By inverting the sampled charge on one side, single ended to fully differential conversion is obtained. The structure can be implemented in a compact, generic block which performs single ended to fully differential conversions as well as sample and hold functions, without compromising speed and accuracy in either mode.

Dual mode, single ended to fully differential converter structure

A dual differential sawtooth signal generator includes a first sawtooth voltage generator that has a first capacitor and a second capacitor that are alternately charged with a feedback control source current from a low voltage reference voltage level. A second sawtooth voltage generator has a first discharge capacitor and a second discharge capacitor that are alternately discharged with a feedback control sink current from a high voltage reference voltage level. The output signals of the two sawtooth voltage generators are compared to control a phase frequency comparator that provides signals to control a dual charge pump that provides the feedback control source current and that provides the feedback control sink current.

Differential amplitude controlled sawtooth generator

Aspects of the present invention include a method, apparatus and device for generating a power on reset (POR) signal in relation to the crossing point of two currents wherein at least one current is a quadratic function and the other is a logarithmic function, where each has a mathematical correlation to a function of the power supply voltage.

Method for providing a power on reset signal with a logarithmic current compared with a quadratic current

Aspects of the present invention include a method, apparatus and device for generating a power on reset (POR) signal in relation to the crossing point of two currents wherein at least one current is a quadratic function and the other is an exponential function, where each has a mathematical correlation to a function of a predetermined power supply voltage.

Method for providing a power on reset signal with a quadratic current compared to an exponential current

A sawtooth voltage generator has a first capacitor that is charged with a variable feedback control current to provide a sawtooth output signal with a controlled amplitude. A feedback loop includes a comparator that compares a version of the sawtooth output signal with a fixed voltage reference to provide a comparator output signal to a phase frequency comparator, the output of which controls a source of the variable feedback control current. A method includes controlling the amplitude of a sawtooth output signal by charging a capacitor in a sawtooth voltage generator with a variable feedback control current; comparing a version of the sawtooth output signal with a fixed reference voltage to provide a comparator output signal; processing the comparator output signal in a phase frequency comparator to provide up/down control signals; and controlling the variable feedback control current with the up/down control signals from the phase frequency comparator.

Amplitude controlled sawtooth generator

An oscillator circuit for use in integrated circuits. The oscillator circuit includes a delay generation circuit having a current mirror with at least a first current mirror branch and a second current mirror branch, a current source coupled to the first current mirror branch, a capacitive element coupled to the first current mirror branch; and a resistive element coupled to the second current mirror branch. The oscillator circuit further includes a plurality of inverting elements coupled in series with one another and a transconducting element coupled to an output of the plurality of inverting elements. The transconducting element is configured to discharge the capacitive element. A latching element is coupled to latch to an output signal of the plurality of inverting elements.

Low cost and low variation oscillator

A current compensation circuit and an optimized current compensation circuit are disclosed for a Parallel Resistors Architecture (PRA) digital-to-analog converter (DAC). The circuits are used to balance code dependent current consumption of the PRA-DAC.

Growing community of inventors

St. Maximin, France

Daniel Payrard