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:
May. 21, 1991
Filed:
Jun. 06, 1990
Richard W Hull, Laguna Hills, CA (US);
Timothy G O'Shaughnessy, Norco, CA (US);
Western Digital Corporation, Irvine, CA (US);
Abstract
A DAC embodied in a CMOS integrated circuit converts a multi-bit digital signal to an analog-current signal. A higher-order portion of the digital signal, e.g., the most significant 5 bits of a byte, are decoded separately from the lower-order portion, e.g., the 3 least significant bits. The DAC includes circuitry for producing a first bias voltage, a first set of current sources each biased by the first bias voltage to produce a switchable current having a unit magnitude, and switching circuitry controlled by the decoded lower-order portion to cause a selected number of the unit-magnitude currents to contribute to the analog-current signal. The DAC further includes circuitry for producing a second bias voltage, a second set of current sources each biased by the second bias voltage to produce a switchable current having a multi-unit magnitude, and switching circuitry controlled by the decoded higher-order portion to cause a selected number of the multi-unit-magnitude currents to contribute to the analog-current signal.