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, 2001
Filed:
May. 03, 2000
Stuart B. Shacter, Tucson, AZ (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A comparator circuit having a first state and a second state, a threshold potential for transition from the first state to the second state, another threshold potential for transition from the second state to the first state, and hysteresis characteristics that are independent of process, temperature, and supply voltage variations. Preferably, the threshold potentials and hysteresis characteristics depend only on a reference potential and on ratios of resistances of pairs of resistors. In some embodiments, the circuit asserts an output signal in response to an input potential and a reference potential, and includes a comparator (having an output which asserts a binary output signal and two comparator inputs) and additional circuitry coupled to the comparator inputs and coupled to receive the input potential, the additional circuitry including a set of resistors and a current source, the current source is coupled to the output and configured to draw a first current when the output signal has its first value and a second current when the output signal has its second value, the current source includes a second set of resistors and is coupled to receive the reference potential, and the current source is implemented so that each of the first current and the second current is independent of all parameters other than the reference potential and a resistance of each resistor of the second set of resistors.