Sgs-Thomson Microelectronics S.a.

Bernard Majoux

Serge Pontarollo

Philippe Sirito-Olivier

Jean-Claude Kaire

Colette Laot

The invention relates to a control circuit for setting a .DELTA.Vbe/R bias source at stand-by from a stand-by control signal including circuitry for virtually modifying, as a function of the state of the stand-by control signal, the emitter surface area of at least one of the matching-pair current mirror bipolar transistors in the bias source.

Control circuit for setting a bias source at partial stand-by

An amplifier is provided in an integrated circuit in MOS technology. To ensure current limitation of a push-pull type stage when the internal resistance of the output transistors is not sufficient to ensure the limitation, there is provided a circuit including a resistor for detecting whether the current value is exceeded; a limiting transistor connected across the resistor for detecting the overcurrent; a transistor for duplicating current in the limiting transistor and a resistor biasing this transistor; a connection between the duplicating transistor and the amplifier input; and an isolation transistor between the duplicating transistor and the amplifier input.

Amplifier with an output current limiter

A device for compensating the offset of an input stage having two current output legs, the first of which is connected to the input of a real stage pushing into this first leg a parasitic current; the device including a fake stage pushing a compensation current having a value equal to the value of the parasitic current divided by a predetermined factor greater than 1, this compensation current being amplified by an amplifier having a gain equal to said predetermined factor, before being pushed into the second output leg of the input stage.

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Meylan, France

Bernard Majoux