Infineon Technologies Ag

Carl Stephelbauer

Manfred Haberl

Markus Zannoth

Günter Haider

Gerhard Habring

Andreas Scheiber

Hans-Peter Fuchs

A controllable amplifier is disclosed. The amplifier includes two current paths which couple an input to an output of the controllable amplifier. Each current path has a respective transistor which is connected as source follower. One of the two current paths is designed to be controllable. It is thus possible to adjust the attenuation and hence the overall gain of the source/follower circuit as a function of a set value for the overall gain (CTRL). The circuit can be used as a variable gain amplifier (VGA), or as a programmable gain amplifier (PGA), in radio-frequency transmitters.

Controllable amplifier and its use

A high frequency amplifier arrangement comprises a first stage with a modulator receiving a baseband signal, and a controllable current shunting device coupled with the modulator; a second stage coupled with the first stage comprising a gain controllable emitter follower; a third stage comprising a gain controllable amplifier coupled with the second stage; and a gain control unit for providing control signals for the first, second and third stage.

Variable gain amplifier

Method for controlling an output signal (A) of a voltage-current converting device, to which a reference voltage (U) is fed and in which a voltage signal (I, IX) applied on the input side is converted into a current signal, a reference voltage (U) setting the output quiescent current (I). The provision of a setting device, which is connected to the reference input and is used to determine an envelope of an amplitude-modulated signal at the input is furthermore expedient.

Voltage-current converter with adjustable quiescent current

An amplifier arrangement includes a variable-gain signal amplifier. A control block is used to process a control signal in order to set the gain. A trimming unit acts on the control block such that signals which are produced by the control block can be trimmed relative to one another in order to set the gain of the signal amplifier.

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Ennsdorf, Austria

Carl Stephelbauer