Ronald C Potter

US Patent:

45874778, May 6, 1986

Filed:

May 18, 1984

Appl. No.:

6/611803

Inventors:

Thomas Hornak - Portola Valley CA
Gary L. Baldwin - Palo Alto CA
Ronald W. Potter - Saratoga CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

G05F 316

US Classification:

323312

Abstract:

A binary scaled current source in which a set of binary switches M. sub. 1,. . . , M. sub. n controllably switch a current I to a selected one of a set of n outputs. Each switch M. sub. k is controlled by an associated control signal B. sub. k having a duty cycle of 2. sup. k-n-1. At any given time one and only one of the control signals is high so that the current I is diverted to the kth output a fraction 2. sup. k-n-1 of the time. In two particular schemes referred to as the weighted pulse width (WPW) and the weighted repetition rate (WRR) schemes, all of the control signals are periodic with a group pattern repetition period T. In the WPW scheme, B. sub. k has in each period T a single pulse of duration 2. sup. k-n-1 *T. In the WRR scheme, B. sub. k has in each period T2. sup.