Infineon Technologies Ag

Henning Hohmann

Bernd Pflaum

Lothar Johannes Musiol

An electronic component has at least a first diode and a second diode that are capacitance diodes. The characteristic curve of the second diode has a fixed, known relationship to that of the first diode. For example, the first diode and the second diode can have an identical variation ratio, being the quotient of the maximum and minimum adjustable capacitances. These components are suitable for use in television tuners, for example in three-band tuners, where diodes having the same characteristic curve and coming from different components are arranged and connected in each sub-receiving unit. The integration of a plurality of diodes reduces the number of components required, and also the time and cost involved in grouping together diodes with good synchronization properties.

Electronic component containing capacitance diodes, having different capacitance ranges, and circuit configuration containing the component

Conventional circuit configurations for range changeover between different bands (UHF, VHF) in television receivers utilize MOS tetrodes whose operating point adjustment is unproblematic. The MOS tetrodes of the inventive circuit configuration comprise a constant potential at their source electrode regardless of the band that is selected. Besides the savings in terms of components, the invention simplifies the dimensioning of the circuit configuration. The invention can be used in all high-frequency receivers having a plurality of frequency ranges between which a changeover is performed.

Circuit configuration for band changeover in high-frequency receivers

A circuit configuration is configured such that selectively a first amplifier or a second amplifier amplifies signals. The second amplifier is operated depending on the conditions established at the input terminal of the first amplifier. A switching element has a controlled path connected to an input terminal of the second amplifier. The switching state of the switching element can be controlled by the input terminal of the first amplifier. As a result, it is possible to effect the changeover between the amplifiers with minimal outlay and without disturbing the amplifiers.

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Munich, Germany

Henning Hohmann