Sgs-thomson Microelectronics S.a.

Alain Bailly

Luc Wuidart

Jean Nicolai

Jean-Michel Ravon

The present invention relates to a supply circuit with a storage capacitor and a method of control of this circuit including, across a rectifying bridge, a storage capacitor associated with a charge path and with a discharge path, in which the duration of charge periods of the storage capacitor is set, at least at steady state, to a predetermined duration.

Device of adjustment of the charge current of a storage capacitor

A device for providing a high d.c. voltage supply and a low d.c. voltage supply. The device includes, in parallel, a first diode connected in series with a capacitor, a rectifier having a polarity opposite to that of the first diode, and a breakover voltage limiter. The terminals of the low d.c. voltage source correspond to the terminals of the capacitor.

High and low d.c. voltage power supply

The present invention relates to a device for starting and supplying a fluorescent tube, including a resonant system connected to the tube and to a rectified supply circuit with a switch in series. A first detector controls the switch to turn off when the current provided by the supply exceeds a determined threshold; and a second detector controls the switch to turn on for each transition through zero of the voltage on a node of the resonant system and for each transition through a minimum of this voltage.

Device for starting and supplying a fluorescent tube

A circuit and method for controlling the speed of a universal motor driven by an AC source is disclosed. The method includes the steps of measuring a value of a temporal property of a current through the motor and determining a speed of rotation of the universal motor using the temporal property. The method for controlling the speed of the universal motor further includes comparing the determined speed of rotation with a desired speed of rotation and adjusting the current through the motor so that the speed of the motor approaches the desired speed of rotation.

Sensorless universal motor speed controller

The present invention relates to a device for limiting transient variations of a voltage for supplying a load from a dc/dc converter, including an input terminal, that receives the voltage provided by the converter, and connected to an output terminal of the device connected to the load; a first power transistor connected between a supply voltage of the converter and the output terminal; a second power transistor connected between the output terminal and the ground; and means for linearly and individually controlling each power transistor in case of an abrupt variation of the load.

Device for limiting transient variations of a supply voltage

The present invention relates to a device for improving the harmonic ratio sent back onto the mains in a rectified power supply including a rectifying bridge and at least one capacitor connected to a first output terminal of the rectifying bridge. Between the second terminal of the capacitor and a second output terminal, a first charge path including a resistor is provided, as well as a second switchable discharge path, associated with means for switching on the discharge path only after the supply voltage has transmitted through a maximum.

Power factor of a rectified power supply

Disclosed is a switching supply device having a power factor close to unity. The device is characterized by its limited number of components, namely only one power switch, only one control circuit and basic components. Application to power supplies for fluorescent lamps (lighting).

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Simiane, France

Alain Bailly