Abstract: A circuit for generating a reference current, including, between two terminals of application of a supply voltage: at least a first branch formed of at least a first and of at least a second transistors in series; at least a second branch formed of at least a third and of at least a fourth transistors in series with a switched-capacitance circuit.

Abstract: A circuit of generation of a reference voltage by a first MOS transistor of a first type connected to a first terminal of application of a supply voltage. The first transistor is connected with a second MOS transistor of the same type controlled by an input stage of a transconductance amplifier and their junction point defines an output terminal providing the reference voltage. A first current source of fixed value connects the first supply terminal to the gate of the first transistor, a second current source of fixed value connecting the second transistor to a second terminal of application of the supply voltage.

Abstract: 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.

Abstract: A differential amplifier having a first and second output terminals and receiving an input signal at an input terminal. The amplifier comprises a first amplifier having a first input connected to the input terminal, a second input and a first output connected together to the first output terminal, and a second output connected to the second output terminal, the first amplifier reproducing the input signal on the first output. The amplifier comprises a second amplifier having a first input receiving a reference signal and a second input connected to the output terminals by resistive elements and controlling the provision by the first amplifier on the second output of a signal such that the signals received at the first and second inputs of the second amplifier are equal.

Abstract: 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.

Abstract: A device for controlling a voltage-controlled switch from a digital signal, comprising: a first means for providing the digital signal to the output terminal of the switch; a second means for biasing the switch control terminal to a level greater than the threshold voltage of the switch and smaller than the sum of said threshold voltage and of the maximum voltage of the digital signal; and a third means for adding or subtracting to said level said maximum voltage of the digital signal respectively at the rising and falling edges of the logic inverse of the digital signal.

Abstract: A controllable assembly of current sources includes several first output terminals, with a first transistor associated with each first output terminal, the current on each first output terminal depending on the current flowing through the first transistor, and a circuit configured, in response to a predetermined variation of a control voltage, to successively progressively turn on, then progressively turn off, each first transistor. The first transistors are MOS transistors, and each first output terminal is associated with a current mirror formed of MOS transistors, the current mirror providing to the first output terminal a current depending on the current flowing through the first transistor.

Abstract: 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.

Abstract: 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.

Abstract: A controllable assembly of current sources including several first output terminals, a first transistor associated with each first output terminal, the current on each first output terminal depending on the current flowing through the first transistor, and a control means provided for, as a response to a predetermined variation of a control voltage, successively progressively turning on, then progressively turning off, each first transistor, in which the first transistors are MOS transistors, and in which each first output terminal is associated with a current mirror formed of MOS transistors, the current mirror providing to the first output terminal a current depending on the current flowing through the first transistor.

Abstract: 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.

Abstract: 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.