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:
Sep. 29, 1987
Filed:
Jul. 24, 1986
Ralph W Haines, Sunnyvale, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An I/O control circuit is provided which is of the type that receives two inputs such that four sets of input conditions to the circuit are defined. A first set of input conditions establishes a low impedance path from the circuit output to the positive supply. A second set of input conditions establishes a low impedance path from the output to the negative supply, or ground. A third set of input conditions establishes a high impedance path from the output to both the positive and the negative supply. And, in accordance with the present invention, 'pull-up' means is connected to the output such that the fourth set of input conditions establishes a path to the positive supply, the path having an impedance which is intermediate that of the low impedance and the high impedance. Alternatively, 'pull-down down' means is connected to the output such that the fourth set of input conditions establishes an intermediate impedance path to the negative supply.