Micronas Gmbh

Trident Microsystems (far East) Ltd.

Entropic Communications, Inc.

Norbert Greitschus

Miodrag Temerinac

José Manuel Garcia González

Stefan Noe

Josè Manuel Garcia Gonzáles

An amplifier (V) for an integrated circuit amplifier circuit (IC) having a switched capacitor circuit (C, C) includes a capacitor for frequency compensation (CC) that is connected in parallel to an amplifier stage (V). This amplifier is advantageous because at least one second capacitor for frequency compensation (CC) is selectively connected in parallel to the first capacitor for frequency compensation (CC) via a switch controlled by a capacitor switching signal (clk).

Amplifier and switched capacitor amplifier circuit

The invention relates to a compensation circuit () to compensate nonlinear distortions of an A/D converter comprising a signal input and a compensation system. In order to avoid the high costs related to the complex analog design of the A/D converter and/or the high energy consumption in this converter and compensation system, it is proposed that a compensation circuit be used that is composed of digital circuit elements that are connected following the A/D converter and which has a nonlinearly distorted output signal of the A/D converter supplied to it to compensate the nonlinear distortion. Adaptive coefficients are preferably employed here for the compensation.

Compensation circuit and compensation method to compensate nonlinear distortions of an A/D converter

An at least second-order active filter circuit includes an operational amplifier (Op) whose frequency response, in conjunction with an RC network (R , R , C , C ), serves to set a predetermined low-pass characteristic. The frequency response of the operational amplifier (Op) forms an integral part of this low-pass characteristic.

Active filter circuit with operational amplifier

A pulse-width-modulated DC-DC converter provides an output signal that is feedback to an error amplifier. The converter includes a comparator for comparing the output voltage of the error amplifier with the output voltage of a compensated ramp generator and having its output coupled to a switching transistor. The compensated ramp generator is designed so that the signal proportional to the current (I ) through an inductor is superimposed on the ramp voltage so as to generate an output voltage having a sawtooth waveform with a concave rise.

Pulse-width-modulated DC-DC converter with a ramp generator

An amplifier has a first amplifier stage with a first input terminal to which an input signal is applied and with an output terminal that is connected to an input terminal of a second amplifier stage located downstream. The second amplifier stage provides an output signal that is fed back to a second input terminal of the first amplifier stage through a feedback path, which preferably contains a passive network. The amplification of this combination of the first and second amplifier stages with feedback depends essentially on the parameters of the network in the feedback path. The amplifier according to the invention also has a noise source that is connected in parallel with the first amplifier stage, and is also connected to the input terminal of the second amplifier stage. The level of a signal component at the output of the second amplifier stage depends on the parameters of the network in the feedback branch and the amplification of the first amplifier stage. These values are variable and can be adjusted such that the level of the signal component provided by the noise source is independent of the amplification of the amplifier. One embodiment of the passive network comprises a voltage divider, with one tap of the voltage divider connected to the second input terminal of the first amplifier stage. A k-fold multiple of the output signal at the second amplifier stage is applied to the second input terminal of the first amplifier stage, with the feedback factor k depending on the voltage divider ratio. The amplification of the first amplifier stage may also be adjustable as a function of the feedback factor k. In one embodiment, the first amplifier stage contains a plurality of amplifiers connected in parallel that can be switched as a function of the feedback factor k. The amplifiers of the first amplifier stage are therefore preferably designed as differential amplifiers.

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Endingen, Germany

Norbert Greitschus