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:
Jun. 22, 1999
Filed:
Oct. 10, 1996
Craig H Becker-Irvin, Redondo Beach, CA (US);
Other;
Abstract
A circuit and method are presented for making differential voltage measurements when one or both measurement points are at voltages that exceed those allowed by a typical differential amplifier, and is particular useful for monitoring the individual cell voltages of a number of series-connected cells that make up a rechargeable battery in which some cell voltages must be measured in the presence of a high common mode voltage. Each measurement point is connected to an input of a respective voltage divider, with all the divider outputs connected to a multiplexer having two outputs. The two multiplexer outputs are connected to a differential amplifier. When the voltage dividers are 'closely matched,' the output of the differential amplifier is directly proportional to the differential voltage between the pair of points to which the dividers are connected, and the differential voltage between those two points is accurately determined. The voltage dividers divide down the voltage of each measurement point so that each is low enough to be input to a conventional differential amplifier. By selecting the 'ratio' of each voltage divider, the circuit can be used to measure differential voltages in the presence of almost any common mode voltage. The invention requires a single differential amplifier powered by a conventional dual power supply.