Abstract: An isolated circuit of low-voltage supply of a control circuit of a high-voltage load, in or upstream of a fullwave three-phase rectifying bridge, comprising a first low-voltage capacitor having a first electrode connected to one of the rectified output terminals of the bridge, and at least one second capacitor providing said low voltage, a first electrode of the second capacitor being connected to one of the A.C. input terminals of the bridge, the respective second electrodes of the capacitors being connected by a high-voltage diode having its cathode connected to the second capacitor.

Abstract: A circuit for detecting the zero crossing of a variable voltage across at least one switching element, including circuitry for measuring the slope of the voltage when it varies in a given direction, and for indicating a zero crossing if this slope is comprised within a range of values.

Abstract: The invention relates to an auxiliary switching circuit (10) for a chopping converter comprising a first inductive element (L0) for serial energy storage with a free-wheel diode (DL) and a switch (K), in addition to a second inductive element (L) for di/dt control when the switch is closed, the auxialiary switching circuit comprising a magnetic circuit (11) whereby a main winding thereof is formed at least partially by the first inductive element (L0), also comprising means (L1, D1, L2, D2) for discharging the second inductive element when the switch is opened or closed, and means (L2, D2) for transferring the energy corresponding to the closure vis a vis said main winding.

Abstract: A circuit for detecting an overcurrent in an element in which an A.C. supply current flows, including a first comparator, assigned to the halfwaves of a first sign of the A.C. power supply, receiving on a reference input a first reference voltage setting a first one of the thresholds, a second comparator, assigned to the halfwaves of a second sign of the A.C. power supply, receiving on a reference input a second reference voltage setting a second one of the thresholds, and an input stage providing, to respective interconnected read inputs of the comparators, a voltage proportional to the voltage across the element, the stage including at least one first resistive element introducing a voltage drop between a first one of the terminals of the element and the read inputs.

Abstract: A circuit for controlling two switches assembled in anti-parallel, comprising in series between two terminals of the anti-parallel assembly, two identical control stages respectively dedicated to each switch and between which is interposed a common impedance setting a phase angle for the turning-on of the switches, each stage comprising: a controllable current source for providing a current to a control electrode of the concerned switch; a capacitor for storing a supply voltage of at least the current source; an element of activation/deactivation of a the current source according to the voltage across the stage capacitor; and an assembly for discharging the capacitor.

Abstract: A circuit for controlling a triac, comprising: a bidirectional current-limiting active element connecting the triac gate to its opposite power electrode; and a switch connecting the gate to the other power electrode of the triac.

Abstract: A circuit for controlling a bidirectional switch referenced to a first reference voltage by a control circuit supplied by a first voltage and referenced to a second reference voltage.

Abstract: An isolated circuit of low-voltage supply of a control circuit of a high-voltage load, in or upstream of a fullwave three-phase rectifying bridge, comprising a first low-voltage capacitor having a first electrode connected to one of the rectified output terminals of the bridge, and at least one second capacitor providing said low voltage, a first electrode of the second capacitor being connected to one of the A.C. input terminals of the bridge, the respective second electrodes of the capacitors being connected by a high-voltage diode having its cathode connected to the second capacitor.

Abstract: A circuit for controlling two switches assembled in anti-parallel, comprising in series between two terminals of the anti-parallel assembly, two identical control stages respectively dedicated to each switch and between which is interposed a common impedance setting a phase angle for the turning-on of the switches, each stage comprising: a controllable current source for providing a current to a control electrode of the concerned switch; a capacitor for storing a supply voltage of at least the current source; an element of activation/deactivation of a the current source according to the voltage across the stage capacitor; and an assembly for discharging the capacitor.

Abstract: The invention relates to an auxiliary switching circuit (10) for a chopping converter comprising a first inductive element (L0) for serial energy storage with a free-wheel diode (DL) and a switch (K), in addition to a second inductive element (L) for di/dt control when the switch is closed, the auxialiary switching circuit comprising a magnetic circuit (11) whereby a main winding thereof is formed at least partially by the first inductive element (L0), also comprising means (L1, D1, L2, D2) for discharging the second inductive element when the switch is opened or closed, and means (L2, D2) for transferring the energy corresponding to the closure vis a vis said main winding.

Abstract: A method and a circuit for controlling at least one thyristor constitutive of a rectifying bridge with a filtered output, consisting of closing the thyristor when the voltage thereacross becomes greater than zero, and making the gate current of the thyristor disappear when the current therein exceeds its latching current.

Abstract: A circuit for detecting an overcurrent in an element in which an A.C. supply current flows, including a first comparator, assigned to the halfwaves of a first sign of the A.C. power supply, receiving on a reference input a first reference voltage setting a first one of the thresholds, a second comparator, assigned to the halfwaves of a second sign of the A.C. power supply, receiving on a reference input a second reference voltage setting a second one of said thresholds, and an input stage providing, to respective interconnected read inputs of the comparators, a voltage proportional to said voltage across the element, the stage including at least one first resistive element introducing a voltage drop between a first one of the terminals of the element and the read inputs.

Abstract: A converter receiving an A.C. voltage between an input terminal and a reference terminal and providing two D.C. voltages of opposite polarities across a first and a second capacitor. The converter includes a first switch connected the input terminal and a node of the circuit; a third capacitor, connected in parallel with the first capacitor, between the node and the reference terminal; circuitry including a second switch for connecting, in series, the second capacitor and the third capacitor when the second switch is closed; and a control circuit for closing the first switch only at the beginning and at the end of halfwaves of given polarity, the first switch being open when the second switch is closed.

Abstract: The present invention relates to a power dimmer of a load, powered by an a.c. voltage, of the type including a bidirectional switch associated in series with the load, the switch being normally closed and controllable to be opened upon each halfwave of the a.c. voltage.

Abstract: A converter of a high A.C. voltage into a low D.C. voltage, including a one-way switch between a first terminal of application of the A.C. voltage and a first positive output terminal, and circuitry for controlling the output voltage to a desired value, the one-way switch being controlled in linear mode.

Abstract: A device and associated method for limiting a current surge in a capacitor connected to the output of a rectifying bridge having its input connected to an a.c. voltage, the bridge being a composite bridge and being associated with means for synchronizing the turning-on of the bridge from zero crossings of the voltage of the a.c. power supply.

Abstract: The present invention relates to a switching device for selecting a voltage between an a.c. voltage and a d.c. voltage using the ground as a reference, meant to be controlled by a two-state signal, using the ground as a reference and of the same sign as the d.c. voltage, including means for adjusting the turn-on time of a switch in the selection of the d.c. voltage.

Abstract: A device and associated method for limiting a current surge in a capacitor connected to the output of a rectifying bridge having its input connected to an a.c. voltage, the bridge being a composite bridge and being associated with means for synchronizing the turning-on of the bridge from zero crossings of the voltage of the a.c. power supply.