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:
Feb. 27, 2001
Filed:
Mar. 13, 1998
Christopher Kimsal, Chanhassen, MN (US);
Jan B. Wilstrup, Moundsview, MN (US);
Wavecrest Corporation, Edina, MN (US);
Abstract
A linear ramp generating and control circuit finding particular applicability in a time interval measurement system. The linear ramp circuit includes a hold capacitor which may be linearly discharged during one operating mode of the circuit by coupling a constant current source to the capacitor. The voltage on the hold capacitor is linearly discharged away from a baseline voltage level to a data voltage level which is subsequently passed to an analog-to-digital converter of the time interval measurement system for further processing. The hold capacitor voltage is returned to the baseline voltage level during a recovery mode of circuit operation by a recovery or recharge network. The recharge network may include an active-feedback circuit which implements an approximately second-order voltage response to the hold capacitor during the recovery mode of operation. The circuit may also include a composite amplifier for buffering the hold capacitor voltage level to a circuit output during a hold mode of circuit operation. The effect of this invention is that the errors such as drift, signal noise, and baseline voltage instability can be minimized.