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:
Aug. 01, 1978
Filed:
Mar. 21, 1977
Thomas M Frederiksen, San Jose, CA (US);
Robert S Sleeth, San Jose, CA (US);
William M Howard, Campbell, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An improved comparator circuit is employed to respond to the charge on a capacitor which represents the integrated value of an input current. When the charge exceeds the comparator trip point, an output is generated. The output is delayed in time from the onset of the input current by an amount that is almost exactly linearly proportional to the current magnitude. The improvement comprises a circuit that senses the onset of comparator conduction and supplies the current necessary to operate the comparator. At very low input current values a condition can be reached where the current drawn by the comparator input equals or exceeds the applied current. For this condition an ordinary comparator will never trip. The improved circuit prevents this and, since the current added is only to compensate, the timing function is not seriously perturbed.