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, 1998
Filed:
Jul. 26, 1995
Shigefumi Odaohara, Yamato, JP;
International Business Machines, Armonk, NY (US);
Abstract
Two batteries can be selectively coupled to a computer, each through a separate pair of serially coupled transistors. Each of the four transistors is shunted by a diode, and each transistor can be individually controlled by a control circuit. To couple one of the batteries to the computer, the control circuit activates one pair of transistors, such that the battery current flows through the transistors and not through the diodes, thereby avoiding any power loss that would occur in the diodes. When switching from one battery to the other, the control circuit enters an intermediate mode in which one transistor in each of the two pairs of transistors is switched OFF, such that both batteries are momentarily 'OR' coupled to the computer through two of the diodes, thereby preventing a momentary loss of power during the switching operation. A door covers both batteries such that neither battery can be removed except when the door is open. A door switch sends a signal to the control circuit that indicates door position. When the door is open, the control circuit 'OR' couples both batteries to the computer through two of the diodes, thereby permitting either battery to be removed without interrupting power to the computer.