Abstract: A device for differential-mode processing of an incident voltage relative to a reference voltage includes a differential circuit including a voltage/current conversion block having a differential input, designed to receive the incident voltage at a first input and the reference voltage at a second input. A current amplification block includes a gain module and a current subtraction module. A current/voltage conversion block includes an operational amplifier with differential transimpedance supplied with a common-mode voltage, receiving the two currents output from the amplification block at its input, and delivering two calibrated opposing voltages at its output that are centered around the common-mode voltage.

Abstract: A low-pass filter with a variable gain comprising a transconductance differential amplifier stage comprising a differential input and a differential output, the latter receiving a passive circuit, such as a first-order RC filter, in order to realize low-pass filtering of the amplifier stage. The filter is chosen so that the cut-off frequency is below the frequency range to be treated. The filter further comprises a control element controlling the differential amplifier stage's bias point to allow control of the gain associated to filtering. Thus, low-pass filtering associated to a variable gain can be realized in a very simple way. The circuit is perfectly adapted for incorporation into a semiconductor product.

Abstract: A calibration device for a video circuit input stage comprises an analog-to-digital converter and an input capacitor constantly discharged by a power source and recharged by a charging circuit by means of a first and a second charging current. The charging circuit is controlled by a central processing unit receiving an estimate of the variation between the converter's output code and a clamp value.

Abstract: A device for differential-mode processing of an incident voltage relative to a reference voltage includes a differential circuit including a voltage/current conversion block having a differential input, designed to receive the incident voltage at a first input and the reference voltage at a second input. A current amplification block includes a gain module and a current subtraction module. A current/voltage conversion block includes an operational amplifier with differential transimpedance supplied with a common-mode voltage, receiving the two currents output from the amplification block at its input, and delivering two calibrated opposing voltages at its output that are centered around the common-mode voltage.

Abstract: A sinusoidal frequency generator comprising an oscillation circuit controlled by a control voltage, characterized in that the oscillating circuit is a gyrator made up of two transconductance amplifiers whose bias points are fixed by the control voltage in order to regulate oscillation frequency. The gyrator is easy to integrated in a phase control loop in order to realize a square-to-sinusoidal frequency converter.

Abstract: A low-pass filter with a variable gain comprising a transconductance differential amplifier stage comprising a differential input and a differential output, the latter receiving a passive circuit, such as a first-order RC filter, in order to realize low-pass filtering of the amplifier stage. The filter is chosen so that the cut-off frequency is below the frequency range to be treated. The filter further comprises a control element controlling the differential amplifier stage's bias point to allow control of the gain associated to filtering. Thus, low-pass filtering associated to a variable gain can be realized in a very simple way. The circuit is perfectly adapted for incorporation into a semiconductor product.

Abstract: A sinusoidal frequency generator comprising an oscillation circuit controlled by a control voltage, characterized in that the oscillating circuit is a gyrator made up of two transconductance amplifiers whose bias points are fixed by the control voltage in order to regulate oscillation frequency. The gyrator is easy to integrated in a phase control loop in order to realize a square-to-sinusoidal frequency converter.

Abstract: A calibration device for a video circuit input stage comprises an analog-to-digital converter and an input capacitor constantly discharged by a power source and recharged by a charging circuit by means of a first and a second charging current. The charging circuit is controlled by a central processing unit receiving an estimate of the variation between the converter's output code and a clamp value.