Stmicroelectronics S.r.l.

Sgs-thomson Microelectronics S.r.l.

Rosario Scollo

Simone Buonomo

Massimo Nania

Giovanni Vitale

Giuseppe Consentino

Giuseppe Catalisano

Antonino Gaito

Santina Leo

Marc Laudani

A driving device for a lamp, in particular an HID lamp, the device including a first circuit to convert a network input voltage into a output direct voltage, a second circuit that receives the direct voltage as an input and converts the direct voltage into an alternating signal for supplying the lamp. The first circuit includes a transformer provided with a secondary winding elements a center tap. The driving device further includes at least two capacitive elements connected to the center tap of the secondary winding of the transformer and coupled with the ends of the secondary winding and with the input of the second circuit.

Electronic driving device for lamps, in particular HID lamps

A method and system controls the power factor associated with a power supply line. The system includes a control circuit having a power factor control cell connected to the power supply line. The power factor control is performed by modulating the conduction time of a bipolar transistor in the control cell using the storage time of the bipolar transistor, and by regulating the modulation of the conduction time by feedback-driving a control terminal of the bipolar transistor.

Method and cell for controlling the power factor of a power supply line

An embodiment of the invention relates to a driving circuit for an emitter-switching configuration of transistors having at least one first and one second control terminal connected to the driving circuit to form a controlled emitter-switching device having in turn respective collector, source and gate terminals. Advantageously the driving circuit comprises at least one IGBT device inserted between the collector terminal and a first end of a capacitor, whose second end is connected to the first control terminal, the IGBT device having in turn a third control terminal connected, through a first resistive element, to the gate terminal, as well as a second resistive element inserted between the gate terminal and the second control terminal. Advantageously, the driving circuit further comprises an additional supply inserted between the first and second ends of the capacitor to ensure its correct biasing.

Driving circuit for an emitter-switching configuration

A driving circuit for an emitter-switching configuration of transistors having first and second control terminals connected to the driving circuit, forms a controlled emitter-switching device having in turn respective collector, source and gate terminals. The driving circuit comprises a driving block coupled between the collector terminal and the source terminal of the controlled emitter-switching device and connected to the first control terminal of the emitter-switching configuration. Further advantageously, the driving block comprises at least one IGBT driving device coupled between the collector terminal and the first control terminal of the emitter-switching configuration and having, in turn, a third control terminal, as well as a driving bipolar transistor, coupled between the collector terminal and the first control terminal of the emitter-switching configuration for controlling a saturation condition of said bipolar transistor of said emitter-switching configuration maintaining a base-collector junction thereof at a voltage next to zero and having, in turn, a fourth control terminal.

Driving circuit for an emitter-switching configuration of transistors

A drive circuit for an emitter switching configuration of transistors having a cascode connection of a power bipolar transistor and of a power MOS transistor control the saturation level of the configuration in applications which provide highly variable collector currents. The drive circuit includes a circuit operable to apply a varying voltage value to the control terminal of the bipolar transistor. A current/voltage converter senses a collector current flowing in the power bipolar transistor and controls conduction of a first transistor responsive thereto, the conduction of the first transistor controlling the conduction of a second transistor so as to vary the control terminal voltage in proportion to the sensed collector current of the power bipolar transistor.

Driven circuit of an emitter switching configuration to control the saturation level of a power transistor when used with highly variable collector currents

A push-pull converter has a transformer provided with a primary winding and a secondary winding. A capacitive element is connected between the input terminals of the primary winding, and two switch elements are arranged between a respective input terminal of the primary winding through an inductor and a supply input of the converter. The current-input terminals of the switch elements are connected to one another, and the current-output terminals of the switch elements are each connected to the respective input terminals of the primary winding. The switch elements are made up of NPN bipolar transistors connected in common-collector configuration. The push-pull converter is particularly suited for driving a cold-cathode fluorescent lamp.

Push-pull converter, in particular for driving cold-cathode fluorescent lamps

A method for controlling the power factor of a power supply line is described, the method using a power factor control cell connected to the power supply line. Advantageously according to the invention, the power factor control is performed by adjusting the turn-on and turn-off time of a bipolar transistor comprised in the power factor control cell. A cell for controlling the power factor of a power supply line is also described, of the type comprising a first and a second input terminals, a first and a second output terminals, the first input terminal being connected to the first output terminal by means of the series of an inductor and a diode, connected to each other in correspondence with an internal circuit node and the second input terminal and the second output terminal being connected to each other. Advantageously according to the invention, the control cell comprises a bipolar transistor inserted between the internal circuit node and the second input terminal and having a control terminal receiving a control signal derived from a signal having an elementary alternated trend.

A driving network for an emitter-switching circuit comprises a pair of cascode-configured transistors, the one of the bipolar type and the other of the MOS type, and the driving network is of the type comprising a driving block for respective conduction terminals and of said pair of transistors. The driving network () further comprises sensor means in the driving block suitable for measuring a voltage to be compared with a reference value in a first comparator block. A negative feedback network between the output of the comparator and the driving block to provides a voltage value to said driving block to bias the conduction terminal of the bipolar transistor of the emitter-switching circuit in order to regulate the storage time thereof.

Emitter switching driving network to control the storage time

A driving circuit is provided for a control terminal of a bipolar transistor in an emitter-switching configuration. The emitter-switching configuration is between first and second voltage references. The driving circuit includes at least one first resistive element connected to the control terminal of the bipolar transistor and a first capacitor connected to the resistive element with respect to a first circuit node and to the second voltage reference. The driving circuit further includes a Zener diode connected between the first circuit node and a second circuit node, and a second capacitor between the second circuit node and the second voltage reference.

Driving circuit for a control terminal of a bipolar transistor in an emitter-switching configuration and corresponding method for reducing the VCESAT dynamic phenomenon

A driving circuit is provided for a control terminal of a bipolar transistor in an emitter-switching configuration. The emitter-switching configuration is between a resonant load and a voltage reference. The driving circuit includes at least one capacitor between the control terminal of the bipolar transistor and the voltage reference. The driving circuit further includes an additional resonance capacitor between a collector terminal of the bipolar transistor and a circuit node, a first diode between the circuit node and the control terminal, and a second diode between the circuit node and the voltage reference.

Driving circuit for a control terminal of a bipolar transistor in an emitter-switching configuration having a resonant load

A resonant driving system for a fluorescent lamp having one end connected to a primary winding of a transformer. The driving system includes an inductor inserted between an input section of the resonant driving system and an internal circuit node that is connected to another end of the fluorescent lamp a converter inserted between the internal node and a voltage reference and comprising a first transistor and a second transistor of the complementary type, inserted, in series to each other, between the internal node and the voltage reference, and a control circuit connected to a secondary winding of the transformer and to the converter as well as to the control terminals of the first and second transistors of the converter, wherein the control circuit comprises an inductor connected to a resistor that is connected to the control terminals of the first and second transistors through a first and a second capacitor respectively.

Resonant driving system for a fluorescent lamp

A method and circuit for emulating a contact breaker in trumpets having an inductor coil powered from a battery through a power driver device. The method includes obtaining the derivative of the current value flowing through the inductor of the trumpet coil, sensing a change in the slope of this derivative, and turning off a circuit portion of the driver device upon a negative slope being sensed. The circuit portion is turned back on with a transient of predetermined duration.

Method and circuit for emulating a trumpet contact breaker

A self-protected, low emission electronic device for driving a warning horn includes a coil powered from a battery through a control push-button adapted for operation by a user and included in an electric connection between a terminal of the coil and the battery. The device includes a protective circuit portion connected between the battery and the warning horn. The protective circuit portion includes a bridge structure of power components. At least a pair of the power components are MOS power transistors of which one is driven by a charge pump.

Growing community of inventors

Misterbianco, Italy

Rosario Scollo