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. 12, 1999
Filed:
Jul. 25, 1997
Victor Paul Schrader, Oakland, CA (US);
James Lee Brubaker, Santa Cruz, CA (US);
Linear Technology Corporation, Milpitas, CA (US);
Abstract
A voltage interpolation circuit for a digital-to-analog converter comprises a differential amplifier with composite input devices, each of which is composed of multiple active subtransistors. Interpolation is effected between a first voltage and a second voltage by selectively connecting the gates of the active subtransistors in one of the composite devices to either the first voltage or the second voltage. Each active subtransistor operates in conjunction with a voltage-controlled degeneration subtransistor to form a functional subtransistor pair. Using the nonlinear conductance characteristic of MOS devices operated in the triode region, the transconductance of each functional subtransistor pair is modulated in such a way as to be made relatively insensitive to changes in effective gate-to-source voltage V.sub.GS ', so that the interpolation circuit produces equally sized interpolated voltage steps at an analog output.