Sgs-thomson Microelectronics S.a.

Stmicroelectronics S.a.

Bendix Electronics S.a.

Serge Ramet

Fran&ccedil;ois Van Zanten

Francedillaois Van Zanten

Francois Vernieres

The present invention relates to a circuit including at least one analog processing cell having a time constant determined by a capacitor and a resistor. A calibration circuit comprises a bridge formed of a switched-capacitance resistor and of a resistor adjustable by means of a digital control signal; and a feedback loop to adjust the digital control signal so that the voltage at the midpoint of the bridge is equal to a predetermined fraction of the voltage applied across the bridge. The resistor of the processing cell is also adjustable by the digital control signal.

Time constant calibration device

An analog switch formed from a MOS transistor switch includes means for applying to the bulk terminal of the transistor switch the voltage of either one of the two main terminals of the transistor switch as a function of the relation between the voltages of said main terminals.

Low-voltage analog switch having selective bulk biasing circuitry

An amplifier includes in series, between high and low supply voltages, first, second, and third transistors. The first transistor is an input transistor of a first current mirror, and the second transistor is an output transistor of a second current mirror. The control electrode of the third transistor forms an inverting input of the amplifier. The amplifier further includes, in series between the high and low supply voltages, fourth, fifth, and sixth transistors. The fourth transistor is an output transistor of the first current mirror, and the fifth transistor is an input transistor of the second current mirror. The control electrode of the sixth transistor forms a non-inverting input of the amplifier. The output current of the amplifier is provided by a seventh transistor. The amplifier is applied to form a band-gap voltage generator having a small number of circuit branches.

Amplifier architecture and application thereof to a band-gap voltage

An adjustable current source comprising a bipolar transistor (BT), the base of which receives a signal adapted to approximately set the current which flows therethrough, and a MOS transistor (MT), in series with the bipolar transistor, the gate (G) of which receives an adjustment signal stored by a capacitor (C) connected between its gate and its drain. This current source can be used for forming the upper stages of an auto-calibration digital converter.

Adjustable current source and digital/analog converter with

A device for comparing currents comprises a first resistor (R1) connected between a high voltage source (VCC) and a connection node (N), first and second current source (I1, I2) connected between a low voltage source (VEE) and the connection node by first and second switches (S1, S2) closed during the first and second phases, a first differential amplifier (A1), a first input (-) of which is connected with the connection node by a first capacitor (C1), a second input (+) of which is connected with an intermediate voltage source, and the output of which is connected with the input (-) by a third switch (S3) closed during the first phase, a second resistor (R2) having a high value with respect to the first resistor connected between the connection node and the intermediate voltage source, and servo-control means operating during a phase preliminary to the first and second phases for urging the voltage on the connection node to be equal to the intermediate voltage, when the first switch is closed.

Sequential operation differential current amplifier

Low-pass filter for integrated circuit

This device comprises, at a first end (1) of the line, at least one controlled voltage source (SV2) and a current receiver (RI2) capable of detecting the current (I) flowing in the line (L) and, at the second end (3) of the line, at least one controlled current source (SI2) and a voltage receiver (RV2) capable of detecting the voltage (V) present on the line, the controlled current source (SI2) being adapted to impose the flowing in the line (L) of a programmable current (I) that is independent of the voltage receiver (RV2), of the voltage source SV2) and of the current receiver (RI2), while the controlled voltage source (SV2) is adapted to impose on the line (L) a programmable voltage (V) that is independent of the current source (SI2), of the current receiver (RI2) and of the voltage receiver (RV2). Application to electronic ignition systems for internal combustion engines.

Growing community of inventors

Grenoble, France

Serge Ramet