Amplifier circuit with offset compensation, in particular for digital modulation devices
AssigneeInfineon Technologies AG
InventorsMartin Isken, Josef Schmal, Bernd Memmler, Günther Tränkle
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Abstract
An offset voltage at an output of a differential amplifier is compensated for by a control circuit having a digital setting device. The control circuit has a control device which is controlled by an offset voltage of the differential amplifier and which feeds an offset compensation signal into the differential amplifier. Compared with analog compensation with an external storage capacitor, temporal drift effects do not distort the offset compensation on the differential amplifier. The described principle can be applied, for example, in radio frequency receiver circuits.
Claims9
An amplifier circuit with offset compensation, comprising:
- a differential amplifier having a differential output including two output terminals outputting an offset voltage;
- and
- a control circuit having a digital setting device connected to said differential amplifier, said control circuit receiving and processing the offset voltage of said differential amplifier and feeding an offset compensation signal back to said differential amplifier, said control circuit having a comparator with an output outputting a sign of the offset voltage, and said comparator having an input including two input terminals each connected to a respective one of said output terminals of said differential amplifier.
A digital modulation device, comprising:
- an amplifier circuit with offset compensation, said amplifier containing:
- a differential amplifier having a differential output including two output terminals outputting an offset voltage;
- and
- a control circuit having a digital setting device connected to said differential amplifier, said control circuit receiving and processing the offset voltage of said differential amplifier, said control circuit feeding an offset compensation signal back to said differential amplifier, said control circuit having a comparator with an output outputting a sign of the offset voltage, and said comparator having an input including two input terminals each connected to a respective one of said output terminals of said differential amplifier.
Dependencies are inferred from the claim text.