Abstract:
A method for erasing an electrically programmable and erasable non-volatile memory cell having a control electrode, an electrically-insulated electrode and a first electrode, provides for coupling the control electrode to a first voltage supply, coupling the first electrode to a second voltage supply, the first voltage supply and the second voltage supply being suitable to cause tunneling of electric charges between the electrically-insulated electrode and the first electrode. The method provides for a constant current to flow between the second voltage supply and the first electrode of the memory cell for at least part of an erasing time of the memory cell, the constant current having a prescribed value.
Abstract:
In a fabrication process of a nonvolatile memory device natural or low threshold transistors usable in the peripheral circuitry are economically fabricated by exploiting the MATRIX mask that is commonly used for patterning the interpoly dielectric layer for defining the channel length of the natural transistors by patterning said interpoly dielectric layer also over the channel area of the natural transistor, outside the matrix area. The so predefined interpoly dielectric is thereafter exploited as a mask of the polysilicon of first level during the patterning step of the polysilicon of second level. Electrical continuity between the polysilicon of second level and the so patterned gate of polysilicon of first level being established over the field oxide adjacent to the active area of the natural transistor.
Abstract:
The present invention is aimed at providing a method and a circuit for protecting the output stage of a power actuator against voltage transients of the surge type. In particular, it provides protection against voltage surge transients of the kind described by International Standard IEC 801-5, for a power transistor contained in the output stage of the actuator. The method of this invention provides for:
the utilization of the power transistor (PW) intrinsic diode (DP) for dumping the transient energy to one of the supply generator terminals during a positive transient; and the utilization of the power transistor (PW) restoration feature to the on state for dumping the energy thereinto during a negative transient, while simultaneously inhibiting the current limiting function.
The power transistor (PW) is turned on again, and the current limiting circuit (4) inhibited, by the following steps:
a) generating an electric signal which is substantially proportional to the voltage appearing at the output terminal (OUT) of the actuator; b) driving the control terminal (G) of the power transistor (PW) by means of said electric signal, and causing said transistor to conduct, while simultaneously disabling the current limiting circuit (4) when the output voltage exceeds a predetermined threshold; and c) allowing the transient energy to be dissipated to the power transistor (PW).
Abstract:
The present invention relates to a heat-dissipating and supporting structure (16) for a semiconductor electronic device to be encapsulated within a molded plastic package, of the type having an insulated inner heat sink. In particular, it comprises a heat-sink element (18) which has a first largest surface to be insulated by means of a plastic material layer with a first thickness, and a second largest surface, opposite from the first, to be insulated by means of a layer of plastic material with a second thickness which is thin compared to the first thickness; and a leadframe (17) consisting of a metal strip attached to the heat-sink element (18) on the same side as the first largest surface and comprising an peripheral holder structure (7) located outboard of the heat-sink element (18). Formed in a portion of a side surface (19) of the heat-sink element (18), is a relief (20) which has mouths located on the first and second largest surfaces of the heat-sink element (18), the mouth formed on the first largest surface being closed by an obstructing means (21) which extends to the heat-sink element (18) outside, toward the peripheral structure (7), such as to only leave a slit (A2) open between the obstructing means (21) and said peripheral structure (7) of the leadframe (17) next to the first largest surface of the heat-sink element and leave the mouth toward the second largest surface open wide. For the purpose of this invention, the spoiler and relief are provided at a mold gate for introducing the molten plastic material during the molding process. Thus, the relief is formed in the proximity of a side corner edge of the heat sink.
Abstract:
The invention concerns a method of avoiding disturbance during the step of programming and erasing an electrically programmable, semiconductor integrated non-volatile memory device which comprises a matrix of memory cells divided into sectors and programmable in a byte mode. An operation of verification of the contents of the byte to be programmed, to be carried out for each individual bit, is provided even before the first program pulse is applied. The invention further provides for the parallel erasing of several sectors during an erase step, and a verification of the erase step for each sector in the matrix. If the verification shows that a sector has been erased, the sector is applied no further erase pulses.
Abstract:
A monolithically integrated programmable device having elementary modules connected electrically by means of memory cells of the flash type. which cells allow the signal paths between signal lines of the elementary modules to be programmed and re-programmed. Preferably, the flash memory cells are Fowler-Nordheim Effect cells.