Atmel Germany Gmbh

Atmel Corporation

Atmel Automotive Gmbh

Juergen Schnabel

Thorsten Fahlbusch

Juergen Eckert

Marco Schwarzmueller

Hans-Peter Waible

Wolfgang Roeper

Horst Haefner

Reinhard Reimann

Burkhard Gehring

Leo Friesen

Friedemann Schmidt

Gerald Krimmer

Hermann Hammel

Michael Amann

Andreas Leistner

Michael Hecker

Wolfgang Schneider

Michael Vogt

Hans-Werner Groh

An integrated circuit for use in remote keyless entry (RKE) applications is disclosed that integrates two drivers with a shared dual mode antenna. The drivers may be integrated on a single integrated circuit chip using high voltage (HV) complementary metal-oxide-semiconductor (CMOS) processes. In immobilizer mode of operation, an immobilizer driver coupled to the dual mode antenna is configured to drive the dual mode antenna, while an LF mode driver coupled to the dual mode antenna is configured to be idle. In LF mode of operation, the LF mode driver is configured to drive the dual mode antenna, while the immobilizer driver is configured to be idle. In some implementations, the drivers are coupled to a common node coupled to the dual mode antenna and are selectively biased with different supply voltages based on the current mode of operation to prevent current leakage and component damage.

Integrated circuit for remote keyless entry system

A compensating circuit for a mixer stage is provided, wherein the mixer stage has an input stage to which an input signal for mixing can be applied and has, following the input stage, a switching stage for mixing a differential input signal&#x2014;obtained from the input stage as a function of the input signal&#x2014;with an oscillator signal, wherein the input of the compensating circuit can be connected to an input signal terminal of the input stage and the output of the compensating circuit can be connected to an input signal terminal of the switching circuit at which the differential input signal obtained by means of the input stage is present, and wherein a compensating signal obtained by means of a compensating stage of the compensating circuit, in particular for compensating intermodulation products, can be produced by the compensating circuit at its output. The compensating circuit has a compensating input stage with means for influencing an amplitude and/or phase of the input signal, by which means the compensating stage can be supplied with a modified input signal.

Compensating circuit for a mixer stage

A d.c. signal controlled oscillator includes a frequency-determining network having a control input and a modulation input. A phase regulating loop includes the oscillator and components that provide a control signal to the control input. A circuit apparatus for driving the oscillator includes a modulation generator that provides a modulation signal to the modulation input, and a circuit arrangement that autonomously generates a signal depending on and representing a slope of the modulation and provides this slope signal to the modulation generator, which generates the modulation signal dependent on the slope signal. A method of operating the oscillator involves switching a frequency divider successively to two different frequencies, respectively sampling and holding the two different arising control voltages, forming a difference between the two control voltages, and activating the modulation generator so that a modulation swing of the modulation signal is determined by this difference between the control voltages.

Method and apparatus for driving a direct current or voltage controlled oscillator with modulation slope feedback

A control unit and two negative feedback branches limit the amplitudes of the output signal of an inverting differential amplifier. Each feedback branch includes a threshold value switch including a transistor as well as an adjustable current source and a resistor forming a voltage divider between a supply voltage and the amplifier output. The voltage divider output is connected to the transistor's base. The transistor selectively connects or disconnects the input of the amplifier with either the supply voltage or the amplifier output. The control unit controls the two current sources based on external programming commands, to establish two adjustable threshold values within which the negative and positive amplitudes of the output signal are limited, symmetrically or independently, in a hard or soft clipping manner. Even with small supply voltages, the limited output will not overdrive subsequent amplifier input stages and will not superimpose harmonics on the useful signal.

Amplitude limiting method for a differential amplifier

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Leingarten, Germany

Juergen Schnabel