Abstract: This generator of periodic signals with exponential edges, which may be integrated at low cost, comprises a current source circuit connected to a capacitor and to a resistive element to supply them with currents having mutually correlated amplitudes, an amplifier interposed between the capacitor and the resistive element and adapted to maintain the voltage drop on the resistive element proportional to the voltage drop on the capacitor, and a switch device, connected in parallel to the capacitor and periodically switched off to allow the discharge of the capacitor.
Abstract: A voltage stabilizer with a minimal voltage drop designed to withstand high voltage transients includes a "series" type voltage regulator circuit with an NPN power transistor. The collector terminal of this transistor is connected to ground via a capacitor and to the cathode of a diode whose anode forms an input terminal of the stabilizer. The base terminal of the power transistor is connected to the collector terminals of first and second PNP transistors which have their emitter terminals respectively connected to the cathode and anode of the diode and their base terminals connected to a circuit biasing circuit.
Abstract: An improved method for the fabrication of a DMOS transistor. The method comprises forming the source region of the transistor by introducing doping from a doped, thin polycrystalline layer. A thin insulating layer is used to protect the body channel contact region from the source doping, and the thin polycrystalline layer is completely consumed and converted into an insulator by oxidation subsequent to the source doping step.
Abstract: A device for increasing the power output of a low-tension operated amplifier which is connected to a standard impedance loudspeaker and is powered at a voltage level which, in the presence of an audio signal, consists of the DC operating voltage for the set and an overlapping variable voltage which is proportional to the audio signal input to the amplifier.Thus, a high dynamic range is afforded for the output signal from the amplifer directed to the loudspeaker.
Type:
Grant
Filed:
October 8, 1986
Date of Patent:
June 21, 1988
Assignee:
SGS-Thomson Microelectronics S.p.A.
Inventors:
Edoardo Botti, Aldo Torazzina, Bruno Murari
Abstract: A broadband amplifier comprising insulated collector vertical pnp transistors, a circuit device effective to improve frequency response, and a final stage comprising a so-called complementary pair formed of an npn transistor and a pnp transistor having emitters connected to each other and to an epitaxial layer n of the insulated collector vertical pnp transistor incorporated in the gain circuit of said amplifiers. The complementary pair afford minimization of the junction parasitic capacitances of the aforesaid vertical pnp transistor.