Stmicroelectronics S.a.

Sgs-thomson Microelectronics S.a.

Stmicroelectronics S.r.l.

Michel Barou

Marius Reffay

Danika Chaussy

Jean-Pierre Blanc

Gerard Le Roux

Eric Cirot

Ashraf Kessaissia

An amplifier including an input stage having two inputs, each input being connected to the control terminals of first and second transistors, a current output of the first transistor being connected to a first terminal of a resistor and to a reference supply rail via a variable current source having a value capable of automatically varying according to the voltage applied between said amplifier inputs up to a limiting value, and a current output of the second transistor being connected to the reference supply rail via a fixed current source and to the second terminal of the resistor.

Fast transconductance amplifier

A device for producing a video image sharpness improvement signal (DOC-DOC), with black level clipping of an associated video signal, comprises a differential transconductance stage processing the video signal and whose bias currents (Imax) are directly proportional to the active component (&#x394;V) of the video signal so as to bring about a black level sharpness improvement signal clipping.

Device for generating a video image sharpness improvement signal

A class AB amplifier circuit includes a complementary output stage and a biasing circuit for biasing the output stage. The complementary output stage includes a P-type MOS transistor and an N-type MOS transistor, and the biasing circuit includes a bipolar transistor. The emitter and collector of the bipolar transistor are respectively connected to the gates of the P-type and N-type MOS transistors. The bipolar transistor is biased for controlling a bias voltage between the respective gates of the P-type and N-type MOS transistors.

Class AB amplifier circuit

A circuit for providing a reference voltage, including a first transistor of bipolar type, the emitter of which provides the reference voltage and the collector of which is connected to a first supply pole, a second MOS-type transistor, the drain of which is connected to the base of the first transistor and the source of which is connected to a second supply pole, a control block, an output of which is connected to the gate of the second transistor and an input of which is connected to the emitter of the first transistor, a capacitor connected to the output of the control block and coupled to the first supply pole via a first impedance, and a second impedance connected on the one hand to the second transistor and on the other hand to the connection point between the capacitor and the first impedance.

Circuit for providing a reference voltage

A preamplifier including an input stage adapted to receiving an analog signal via a connection capacitor, and a differential output stage adapted to providing the signal referenced with respect to a predetermined level, and circuitry for enabling the input stage to accept a signal referenced to the differential stage ground, the signal provided by the output stage being referenced to this ground.

Video preamplifier

A preamplifier includes an output stage having a bandwidth which is adjustable by a control signal. The output stage includes an amplifier with an adjustable bandwidth. The amplifier includes a main input for receiving an input current, a main output for providing an output voltage, a resistor connected between the main input and output. A current amplifier with an adjustable gain is connected for receiving the input current. A capacitor is connected between an output of the current amplifier and the main output. An inverting transconductance circuit is connected between the output of the current amplifier and the main output.

Preamplifier with an adjustable bandwidth

An integrated circuit includes a high-voltage output stage. The high-voltage output stage, in turn, comprises a first MOS transistor, a second MOS transistor, a current source and a diode. This high-voltage output stage can be improved by the addition of a third MOS transistor, a first bipolar transistor and, possibly, a second bipolar transistor.

Circuit with high-voltage output stage

The present invention relates to a current amplifier including a first MOS transistor with a drain defining a first terminal for controlling the amplifier with a current and a source connected to a first supply line. It also includes a second MOS transistor with a drain forming a terminal of current output of the amplifier and a source connected to the first supply line, and at least one first bipolar transistor having a base connected to the first control terminal, an emitter connected to a gate of the first MOS transistor and is, via a first biasing resistor, connected to the first supply line and having a collector of the first bipolar transistor being connected to a second supply line.

Frequency compensation of a current amplifier in MOS technology

A voltage/current converter includes a first differential pair including a first and second NPN transistor, a second differential pair including a third and fourth NPN transistor, a first resistor disposed between the emitters of the transistors of the first differential pair, a second resistor disposed between the emitters of the transistors of the second differential pair, third and fourth resistors disposed between the bases of the first and third transistors and of the second and fourth transistors, respectively, and a voltage negative feedback means disposed between the terminals of the second resistor and the bases of the transistors of the first differential pair in order to fix the voltage across the second resistor to a predetermined input voltage.

Voltage to current converter with negative feedback

In a circuit comprising a power MOS transistor (MP) connected to an inductive load (L), the gate (GP) of the power MOS transistor is connected, on the one hand, to a voltage booster circuit (3) and, on the other hand, to the drain (DL) of a logic MOS transistor (ML). A control circuit (56) fed by the supply source has an output (63) connected to the gate (GL) of the logic MOS transistor. Means are provided for limiting the source voltage of the logic MOS transistor to a voltage lower than the supply voltage (VCC) minus a predetermined threshold voltage when the power MOS transistor is conductive. The control circuit is then capable of controlling the switching of the logic MOS transistor with the supply voltage available at the supply source.

Circuit for controlling a power MOS transistor on an inductive load

In a device for detecting the flow of a current lower than a given threshold current in a load (L) in series with a power MOS transistor (M1), the free terminal of the MOS transistor is connected to a first terminal (1) of a supply source, the second terminal (2) of which is connected to the free terminal of the load (L), the gate (G1) of the MOS transistor being connected to a control source (3). A means (11) for detecting the voltage drop is connected across the terminals of the MOS transistor and a control loop (12) imposes an appropriate gate voltage to the MOS transistor as soon as the voltage drop across its terminals tends to decrease below a determined level.

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Voreppe, France

Michel Barou