U.S. Philips Corporation

Cornelis D Hartgring

Roger Cuppens

Tiemen Poorter

Roelof H Salters

Cormac M O'Connell

Joannes J Koomen

Jan Dikken

Frans J List

The invention relates to an integrated circuit having a programmable cell, more particularly for use in an electronic card. The cell is provided with a programmable element (P) having two conductive layers (51, 52), which are separated from each other by a dielectric layer (53). The element can be programmed by applying between the layers 51, 52 a programming voltage such that an electric breakdown is produced in the dielectric layer (53), as a result of which the element passes permanently from an electrically non-conducting state to an electrically conducting state. According to the invention, the programmable cell comprises an asymmetric bistable trigger circuit (I,II). The trigger circuit (I,II) is loaded with the element (P) in such a manner that during operation it is in a first state if the element is electrically non-conducting and is in a second state if the element is electrically conducting.

Integrated circuit comprising a programmable cell

A memory cell is read by first charging a pair of bit lines to given positive potentials and then raising the potential of a cell access line to render access transistors conductive. The cell supply voltage is sufficient to cause substantial hot-electron stress in the n-channel transistors of the cell if it were applied directly across their source-drain paths while they were conductive. However, a limit is imposed on the maximum positive potentials which are applied to the bit lines from the exterior, and on the minimum ratio of the sizes of the cell n-channel amplifier transistors to the sizes of the access transistors, taking into account the threshold voltages of the amplifier transistors, and as a result substantial hot-electron stress does not occur. Substantial hot-electron stress is also prevented during a write operation by arranging that this is effectively preceded by a read operation.

Static RAM having a precharge operation which exhibits reduced hot

A digital circuit with a 5 V power supply voltage in which NMOS transistors constructed in sub-micron technology are protected against excessive field strengths by means of additional transistors in order to prevent so-called 'hot carrier stress' for this purpose the additional transistors have a greater channel length and/or a higher threshold voltage.

Output buffer having reduced electric field degradation

A C-MOS semiconductor memory circuit includes a read amplifier and a tristate bus driver. The read amplifier is a two stage amplifier. The bit lines in the memory are connected via P-MOS pull-up transistors to the supply voltage. The logic low level is 1 Volt below the supply voltage. In order to bring the input signals for the difference amplifier at a most sensitive and fast level, a d.c.-shifting amplifier of the 'emitter follower' type is connected between each input thereof and the associated bit line. The difference amplifier and the two follower amplifiers are activated only for a short period of time by means of a selection signal which gives a strong restriction in the power dissipation. The tristate driver comprises a push-pull output stage and an inverting AND gate which is controlled by the output of a difference amplifier and by an equalization signal which is also applied to the difference amplifier and therefore is of a simple design and gives only a low signal delay.

Semiconductor memory circuit having a fast read amplifier tristate bus

An integrated logic circuit includes an output circuit for generating an output current which increases linearly in time. In integrated logic circuits the problem presents itself that the rapid variation of the (dis) charging of a data output causes a reverse voltage pulse VL across the inductance formed by the connection wires. The reverse voltage is limited by causing the charge or discharge current (for the load capacities present) to increase linearly to a maximum permissible value. This is done by driving the output field effect transistor with a control voltage VC which varies in time in the form of a square root.

Integrated logic circuit having a control circuit for generating a

The invention relates to a (static) memory which is divided into a number of memory blocks, memory cells being arranged in rows and columns in each memory block. A row in a memory block is activated via a selection gate whereto there are applied an inverted row selection signal (which is applied to all memory blocks) and a non-inverted and an inverted block selection signal (which is applied to all section gates in a memory block). The selection gate comprises a P-MOS transistor and two parallel-connected N-MOS transistors. The junction between the P-MOS and the N-MOS transistors constitutes the gate output (for activating a row of cells). The row selection signal is applied to the gate electrode of the PMOS transistor and of a first N-MOS transistor. The inverted block selection signal is applied to the gate electrode of the other N-MOS transistor and the block selection signal is applied to the main electrode of the P-MOS transistor.

Integrated memory circuit having an improved logic row selection gate

A memory and a non-volatile, programmable, static memory cell in which a programmable transistor and a capacitance are added to a known static memory cell. The cross-wise couplings between the transistors of the static cell form a first and a second junction. The gate and a main electrode (drain) of the programmable transistor are connected to the first junction. The second junction is connected to an injection location opposite the floating gate of the programmable transistor whose channel is connected in series with the capacitance the other side of which is connected to the sources of the two transistors of the static cell.

Non-volatile, programmable, static memory cell

In order to prevent an excessively fast rise of the programming voltage for an (E)EPROM, a stage is inserted which on the one hand prevents voltage losses and which on the other hand realizes the required large time constant of the voltage rise in spite of the use of small capacitances.

Circuit for controlling rise time of EPROM programming voltage

Field effect transistors having a short channel length are desirable for carrying out logic operations at a high speed. However, they are then not capable of withstanding the comparatively high programming and erasing voltage at which an (E)EPROM has to be operated. During the programming cycle the field effect transistors are kept in the current-nonconducting state, while recording the logic information obtained by the logic operations, the 'fast' transistors are nevertheless capable of withstanding the comparatively high voltage.

Integrated circuit with improved programmable read-only memory

The invention relates to an EPROM or an EEPROM in which the information is stored in the form of electrical charge above the channel region of a MOST, as a result of which the threshold voltage of the MOST is determined by the stored information. Writing/erasing of the memory generally requires high voltages to cause charge current to flow through an insulating layer to and from the charge storage region. In order to avoid having the parasitic MOSTs becoming conductive, means are provided by which during operation a small reverse bias is applied to the sources of these parasitic transistors, as a result of which due to the high k factor the threshold voltage of the parasitic transistors increases considerably. This does not require additional logic because use can be made of the generator in the reading circuit, which generates a suitable small voltage.

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Eindhoven, Netherlands

Cornelis D Hartgring