One-time-programmable EEPROM cell
First Claim
1. A one-time electrically programmable read-only memory comprising:
- a floating gate MOS transistor serving as a physical memory element and having a source connection, a drain connection, a bulk connection and a control gate connection, with said control gate and said bulk connections being connected to a common line for a programming voltage (VPP), and circuit means for supplying the drain connection of said floating gate transistor with a supply voltage during programming, with said circuit means comprising a series circuit of a first and a second MOS transistor connected between said drain connection and a supply voltage terminal and having respective control gates for receiving respective control signals.
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Accused Products
Abstract
The invention relates to a one-time-programmable read-only memory cell, abbreviated as PROM. According to the prior art, PROM cells are programmed by the deliberate destruction of a component. Since the information is burnt into the memory cell in this way, a PROM cell can only be programmed once. If read-only memory cells are to be electrically programmed and cleared several times, floating gate transistors in particular are used. With the floating gate transistor, the information is stored as a charge on a completely insulated gate electrode. If PROM and EEPROM memory cells are now integrated on a common chip, this requires additional circuitry due to the different voltage requirements of the two different memory cells. In accordance with the invention, a repeatedly electrically programmable read-only memory is connected such that it can only be electrically programmed once.
44 Citations
12 Claims
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1. A one-time electrically programmable read-only memory comprising:
a floating gate MOS transistor serving as a physical memory element and having a source connection, a drain connection, a bulk connection and a control gate connection, with said control gate and said bulk connections being connected to a common line for a programming voltage (VPP), and circuit means for supplying the drain connection of said floating gate transistor with a supply voltage during programming, with said circuit means comprising a series circuit of a first and a second MOS transistor connected between said drain connection and a supply voltage terminal and having respective control gates for receiving respective control signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
Specification