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:
Nov. 13, 1990
Filed:
Jul. 28, 1989
Robert B Jarrett, Tempe, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A comparator circuit with hysteresis does not require any bias current as long as the input signal applied thereto is less than a lower threshold value of the comparator. The comparator includes a current source for providing a plurality of currents when enabled, a Zener diode coupled to the current source for initially enabling the former as the input signal exceeds an upper threshold value, an output circuit which when rendered operative is placed in parallel to the Zener and disables the same while maintaining the current source enabled and providing an output signal from the comparator, and an amplifier responsive to the current source which renders the output circuit operative as the magnitude of current sourced thereto exceeds a predetermined value. A feature of the comparator circuit is that the currents flowing in the output circuit and amplifier have complementary temperature coefficients whereby the composite temperature coefficient of the upper and lower threshold values of the comparator can be adjusted to have a substantially zero temperature coefficient.