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:
Feb. 02, 1993
Filed:
Oct. 15, 1991
Philip N King, Ft. Collins, CO (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A driver circuit for use in a circuit board tester performs both functional and in-circuit tests on a given device under test (DUT). The tester provides a control signal representative of a command for the driver circuit to provide test signals to the DUT. The driver circuit incorporates two stages: a pre-driver stage and a driver stage. The pre-driver stage consists of an amplifier connected to fast switching transistors with the ability to move in and out of saturation rapidly. The amplifier receives control signals and the switching transistors provide actuation signals to the driver stage. The driver stage comprises two emitter follower transistors that operate exclusively in an unsaturated state. The driver stage provides test signals to the DUT in response to the actuation signals from the two switching transistors of the pre-driver stage. Additionally, the driver circuit may be programmed to change the output voltage amplitudes of the test signals.