Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
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 (20, 30) 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.
Abstract:
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.
Abstract:
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.
Abstract:
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.