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, 1999
Filed:
Dec. 21, 1995
Richard Pye, Waltham, MA (US);
Moses Khazam, Lexington, MA (US);
Genrad, Inc., Westford, MA (US);
Abstract
A hybrid scanner for switching internal analog buses to system pin channels. Semiconductor switches switch most scanner buses to system pin channels, but mechanical relays perform switching for at least one bus used for high-current test signals. To perform low-impedance guarding and/or high-current backdriving, the low impedance, high current bus is typically connectable to one or more overdriver circuits and a guard voltage potential through mechanical relays. The scanner is capable of supporting in-circuit tests covering the most significant regions of the fault spectrum can be made more reliable and much smaller and less costly than the scanners conventionally used in traditional broad spectrum testers. It turns out that this test-supporting capability can be achieved by adding only a few mechanical relays to an otherwise semiconductor-switch-based scanner. Only those necessary to support low-impedance and high-current test operations.