Stmicroelectronics S.r.l.

Sgs-thomson Microelectronics S.r.l.

Consorzio Per La Ricerca Sulla Microelettronica Nel Mezzogiorno

Atanasio La Barbera

Natale Aiello

Giovanni Luca Torrisi

Stefano Sueri

Vincenzo Randazzo

Vito Graziano

Sergio Palara

Sergio Spampinato

An electronic thermal protection circuit is for high currents which can occur in the start-up phase in lighting converters. The circuit is associated with a power device having an output terminal connected to an electric load and at least one control terminal receiving a predetermined driving current value by a driving circuit portion. Advantageously, an integrated temperature sensor is provided to detect the temperature of the power device, and an output stage is connected downstream of the sensor to switch off the driving circuit portion when a predetermined operation temperature is exceeded.

Protection circuit against high currents in lighting converters

An electronic circuit is for the gradual start-up of electric loads, particularly halogen lamps. The circuit may include a power device having an output terminal connected to the electric load and having at least one control terminal receiving a predetermined driving current value. The circuit may further include a comparator having a first input terminal coupled to the power device output and a second input terminal kept at a reference potential. The comparator output may be connected to a controlled switch inserted upstream of the control terminal to control the opening of the switch and adjust the start-up phase of the power device according to the value of the reference potential.

Electronic circuit for the gradual start-up of electric loads, particularly halogen lamps

Herein described is a driver circuit of a fluorescent lamp having a first and a second electrode and igniting when the voltage between the first and second Electrode exceeds a given threshold voltage. The driver circuit comprises an inductance coupled to a supply voltage and to a terminal of the first electrode a first condenser coupled to the other terminal of the first electrode and to a terminal of the second electrode, a control device comprising a first and a second system of switches capable of guaranteeing oscillations of a voltage signal on the inductance and on the first condenser up to the ignition of the lamp. The driver circuit comprises a device associated to the control device and capable of acting on the first system of switches so as to regulate the frequency of the oscillations from a frequency greater than the resonance frequency of the inductance and of the first condenser to the same resonance frequency so as to guarantee a preheating of the first and second electrodes. The device is sensitive to the depletion of gas of the lamp and is capable of sending a turn-off signal to the control device.

Fluorescent lamp driver circuit

An electronic circuit is for optimizing or reducing switching losses in current-driven power devices and includes a switching power device connected to an electric load. The power devices has at least one control terminal arranged to receive a predetermined drive current value produced by a first current generator. The control terminal also receives an additional drive current portion produced by a second independent current generator. Advantageously, the electronic circuit includes a control circuit for controlling a switch connected between the second current generator and the control terminal of the switching power device during the turn-on and turn-off phases of the power device.

Electronic circuit for optimizing switching losses in current-driven power devices

A voltage converter circuit with a self-oscillating half-bridge configuration has a first and a second input terminal, and a first and a second output terminal, and including: a first power switch coupled between the first input terminal and the first output terminal, a second power switch coupled between the first output terminal and the second input terminal, a first voltage sensor having a first and a second sensing terminals coupled between the first input terminal and a control terminal of the first power switch, and a second voltage sensor having a first and a second sensing terminals coupled between the first output terminal and a control terminal of the second power switch. Each voltage sensor detects a voltage variation supplied on its respective first sensing terminal and generates on the respective second sensing terminal an activation potential for the respective power switch.

Voltage converter circuit having a self-oscillating half-bridge structure

A circuit controls switching of a load between two supply terminals by a device in an emitter-switching configuration formed by a high-voltage bipolar power transistor and a low-voltage switch element. The bipolar power transistor has a collector connected to the load. The switch element has a first terminal connected to the emitter of the bipolar power transistor, a second terminal connected to ground, and a control terminal connected to a control terminal of the circuit. The circuit has a biasing circuit connected to a base terminal of the bipolar power transistor. To ensure that the bipolar power transistor operates in the saturation region throughout the period of conduction, even with a sinusoidal driving voltage, the biasing circuit includes a capacitive device and a charging circuit for charging the capacitive device to bias the base of the bipolar power transistor.

Circuit for controlling the switching of a load by means of an emitter-switching device

An integrated device in an emitter-switching configuration comprises a first bipolar transistor having a base region, an emitter region, and a collector region, a second transistor having a charge-collection terminal connected to an emitter terminal of the first transistor, and a quenching element having a terminal connected to a base terminal of the first transistor. The quenching element is formed within the base region or the emitter region of the first transistor.

Integrated device in an emitter-switching configuration

A device in an emitter-switching configuration comprises a high-voltage transistor having a first terminal connected directly to a first power terminal of the device, a control terminal connected to a control terminal of the device, and a second terminal. The device also includes a low-voltage transistor having a first terminal connected directly to the second terminal of the high-voltage transistor and a second terminal and a control terminal which are connected directly to a second power terminal and to the control terminal of the device, respectively. A circuit portion is provided for recovering an electrical charge discharged from the control terminal of the high-voltage transistor to the second terminal of the low-voltage transistor during the turning-off of the device.

Device in an emitter-switching configuration with means for recovering

An integrated device comprises a high-voltage transistor and a low-voltage transistor in an emitter-switching configuration integrated in a chip (400) of semiconductor material comprising a buried P-type region (120) and a corresponding P-type contact region (405) which delimit a portion of semiconductor material within which the low-voltage transistor is formed. The contact region (405) has a network structure such as to divide this portion of semiconductor material into a plurality of cells (410) within each of which there is an elemental P-type base region (425) and an elemental N-type emitter region (430) of the low-voltage transistor. The elemental regions (425) and (430) of the various cells (410) are electrically connected to one another by means of surface metal contacts.

Integrated device in an emitter switching configuration and with a

An integrated structure comprises a protective Zener diode connected between a first and a second terminal of the structure, and is formed in a chip of semiconductor material within an insulating region. The structure includes first and second biasing Zener diodes connected back-to-back between the first and the second terminals of the structure. The first and the second biasing diodes are disposed respectively in the opposite direction to and in the same direction as the protective diode, and having a common terminal connected to the insulating region. The protective diode has a reverse threshold voltage lower than a reverse threshold voltage of the second biasing diode.

Protective integrated structure with biasing devices having a

A monolithically integrated power device for driving electrical loads includes a power stage having a high-voltage bipolar transistor and a low-voltage auxiliary transistor cascade-connected and inserted between a first power supply terminal and a second power supply terminal of the device. The power device also includes a driver circuit for the power stage having an input connected to an input terminal of the device. In accordance with the present invention the device includes a circuit for protection thereof against an excessive temperature rise and controlling power down of the power stage. It includes specifically a temperature sensing circuit which generates a signal dependent on the temperature present in the device, a comparator circuit which receives this signal and compares it with a reference voltage and at least a first switch circuit generating an interdiction signal when the temperature in the device exceeds a preset maximum value and which is interlocked with an output of the comparator circuit and connected functionally through its output to the power stage. The device is advantageously usable in a fluorescent lamp driving circuit, that is to say in the so-called 'lamp ballast'.

Bipolar power device having an integrated thermal protection for driving

The present invention relates to an integrated circuit adapted to perform the function of a diode of the DIAC type, the circuit having an input terminal and an output terminal. The circuit includes a first input transistor having a first terminal connected to a fixed voltage reference, a second terminal, and a control terminal coupled to the input terminal of the circuit. The circuit further includes second and third transistors in a current mirror configuration, each having a first terminal for coupling to the input terminal of the circuit, and a second terminal, and associated control terminals connected together and coupled to the second terminal of the first input transistor, the second terminal of the second transistor being connected to the control terminal of the first transistor. Finally, the circuit includes a fourth output transistor connected, with first and second terminals, between the output terminal and the input terminal of the circuit, the fourth output transistor also having a control terminal connected to the second terminal of the third transistor.

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Mascalucia, Italy

Atanasio La Barbera