Stmicroelectronics S.a.

Sgs-Thomson Microelectronics S.a.

Stmicroelectronics N.v.

François Van Zanten

Marc Sabut

Michel Mouret

Jean Ravatin

Raymond Ribas

Hugo Gicquel

Marc Gens

Fabien Reaute

Florence Giry-Cassan

A switched capacitor amplifier having an amplification unit adapted to amplify a differential signal; a first switched capacitor block including a first plurality of capacitors operable to sample a first differential input signal during a first sampling phase and to drive the amplification unit during a first drive phase; and a second switched capacitor block including a second plurality of capacitors operable to sample a second differential input signal during a second sampling phase and to drive the amplification unit during a second drive phase.

Switched capacitor amplifier

An embodiment of an amplifier circuit comprising a succession of amplification stages having at least a first amplification stage receiving a first signal and a second amplification stage downstream of the first amplification stage; a stage of unity gain capable of receiving the first signal and of providing a second signal corresponding to the low-impedance copy of the first signal; and a third amplification stage having its input connected to the output of the stage of unity gain by a capacitor and having its output connected to the output of the second amplification stage.

Compensation of an amplifier comprising at least two gain stages

A method and device are disclosed for receiving digital television signals by a frequency tuner. The power of the signal is measured after an analog/digital conversion in the frequency tuner, and the gain thereof is controlled on the basis of this power measurement according to a predetermined control law. The power of the analog signal, tapped between an input amplifier stage and a first frequency transposition stage, or immediately after the first frequency transposition stage, is also measured. The measured power is compared with a predetermined power threshold so as to obtain first binary information, and the gain control law is set on the basis of the value of the first binary information.

Process for controlling the gain of a frequency tuner, and corresponding tuner, in particular for the reception of terrestrial digital television signals

An amplifier circuit comprising an amplification chain having a differential output stage; a common mode correction block acting on the input of the output stage as a function of a common mode voltage at the output of said stage and introducing a phase shift between its input and its output for frequencies close to the cut-off frequency of the circuit; and, in parallel with the correction block, a means introducing no phase shift between its input and its output and having at frequencies greater than or equal to the circuit cut-off frequency an output impedance much smaller than the output impedance of the correction block.

Differential amplifier with a common mode voltage loop

A circuit for correcting the offset of an amplification and filtering chain having a predetermined gain and cut-off frequency depending on the value of at least one capacitor, comprising: a correction means for subtracting from the chain input a correction signal depending on the value of a programmable digital word; a digital automaton for, in a setting phase, searching, then memorizing one of two consecutive values of the digital word between which the output signal of the chain switches sign, the input signal being canceled during a setting phase; and comprising a means for, during the setting phase, reducing the value of said at least one capacitor with respect to its normal operating value.

Method and circuit for correcting the offset of an amplification chain

An input stage for a video receiver includes a variable gain amplifier, an analog-to-digital converter for sampling a video signal and a digital processing unit for processing digital samples of the video signal. An analog regulating circuit sets an input potential at an input of the variable gain amplifier. A differential architecture is used for the variable gain amplifier and the digital analog converter. A conversion circuit between an input coupling capacitor and the variable gain amplifier allows generating the video signal on two channels in antiphase, which are centered on the common mode voltage. Such differential architecture allows reducing the amplitude of analog signals, which is particularly advantageous in the case of a low voltage supply delivering a few volts. In addition, linearity of the video signal processing is enhanced.

Calibration device for a video input stage

A variable-gain amplifier with a differential input and differential output, including an attenuator block, receiving an input voltage and providing, on several outputs, voltages, each of which is equal to the attenuated input voltage; differential transconductor elements, each having a first input connected to a respective output of the attenuator block, and generating first and second positive currents and first and second negative currents; a current source assembly adapted to controlling the transconductance of each differential transconductor element according to an analog control signal; and an output block converting first and second input currents into a differential output voltage and providing a second input of each differential transconductor element with a feedback voltage depending on the output voltage.

Variable-gain differential input and output amplifier

The method includes an adjustment phase in which a filtering device is operated as an oscillator, the frequency of oscillation of the filtering device is determined, and the characteristics of the filtering device are corrected with respect to the determined oscillation frequency and to a pre-established relation between the frequency of oscillation and the theoretical cutoff frequency, in such a way as to confer upon the filtering device a cutoff frequency equal to the theoretical cutoff frequency to within a tolerance. After the adjustment phase, a working phase takes place in which the filtering device carries out its filtering function.

Method of adjusting the cutoff frequency of an electronic filtering system, and corresponding system

A mirroring circuit operating at high frequencies is provided. The mirroring circuit includes a first branch having a first transistor in series with a first resistor, a second branch having a second transistor in series with a second resistor, and a servo circuit for controlling current flowing in the first branch and the second branch. The servo circuit includes a third transistor configured as a diode, a source of the third transistor coupled to a source of the first transistor, a fourth transistor configured as a shift lever, a source of the fourth transistor coupled to ground via a third resistor, a fifth transistor configured as a diode, a source of the fifth transistor coupled to a source of the second transistor, and a sixth transistor configured as a shift lever, a source of the sixth transistor coupled to ground via the third resistor.

Mirroring circuit for operation at high frequencies

The present invention relates to a voltage regulator, including at least two input terminals for receiving, each, an independent supply voltage, and including a means for automatically selecting the highest supply voltage from among the voltages present at the input terminals, and a means for insulating the supply terminal associated with the lowest voltage from the rest of the circuit, these means introducing a very low voltage drop between the input terminal at the highest voltage and an output terminal of the regulator.

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Meylan, France

François Van Zanten