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:
Jan. 19, 1993
Filed:
May. 17, 1991
Michael K Mayes, Sunnyvale, CA (US);
National Semiconductor Corp., Santa Clara, CA (US);
Abstract
In a sample and hold circuit comprising a plurality of serially connected comparators wherein each comparator has a feedback switch coupled between an input terminal and an output terminal of the comparator, and wherein data is held on high impedance capacitive nodes, when the series of feedback switches turn off, a capacitor is coupled across a current switching transistor which has a control terminal coupled for receiving a feedback switch control signal. When the feedback switch control signal undergoes a transition, the capacitor causes a voltage to ramp up or down. A current limiting transistor having a control terminal coupled for receiving a delay control signal is coupled in series with the current switching transistor for controlling the rate of current flow through the current switching transistor in accordance with the magnitude of the delay control signal. The voltage at the capacitor is coupled to a compare circuit having an output signal which changes state when the voltage at the capacitor passes a threshold value. This output signal functions as a delayed switching signal for delaying the turnoff of subsequent feedback switches in the series.