The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1977
Filed:
Oct. 17, 1975
Richard H Heeren, Palatine, IL (US);
Teletype Corporation, Skokie, IL (US);
Abstract
A read-only memory and sense amplifier system for sensing whether a selected memory cell of a memory bank includes a high-impedance memory device, or a low-impedance device, and for generating a binary output signal representing stored data in response to the sensed difference. The cells are programmed with a pattern of high and low-impedance devices, such as inoperative and operative field-effect transistors in accordance with stored data. The memory bank, including the impedance of the selected cell, is connected to a first input node of the amplifier, and has either: (A) a first or 'ON' bank impedance between the first node and a reference node, such as circuit ground, if the selected cell is in the low-impedance state: or (B) a second or 'OFF' bank impedance if the selected cell is in the high-impedance state. A reference impedance is connected between the other amplifier node and the reference node, and has a value between the ON bank impedance and the OFF bank impedance. The amplifier includes circuitry for sensing a difference in impedance connected to the two nodes, and for generating the binary output signal in response to the sensed difference, representing the data stored in the selected memory cell.