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:
Jul. 21, 1992
Filed:
Jun. 28, 1990
John J Price, Jr, Edina, MN (US);
VTC Bipolar Corporation, Bloomington, MN (US);
Abstract
A read/write preamplifier configured for interconnection with a magnetic head through head contacts. The preamplifier includes a write control switching circuit electrically connected between first and second supply terminals and connected to the head contacts, for controlling current flow through the magnetic head. The switching circuit includes at least one transistor. A first PNP-type transistor is connected between the first supply terminal and the at least one transistor of the write control switching circuit, for controlling current flow to the write control switching circuit so as to cause the switching circuit to be driven between selected and unselected states. A PNP-type transistor bias circuit includes a mode-controlled current sink coupled between the first and second supply terminals and to the first PNP-type transistor. The bias circuit causes the first PNP-type transistor to conduct current and drive the switching circuit to the selected state when the mode-controlled current sink is active, and causes the first PNP-type transistor to prohibit current flow and drive the switching circuit to the unselected state when the mode-controlled current sink is inactive.