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. 07, 1992
Filed:
Dec. 13, 1990
Toru Kido, Ibaragi, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a power monitor circuit, AC power-line voltage is converted by a DC power supply to a regulated DC voltage. The DC power supply shuts down itself in the event of a failure therein. The output of DC supply rises from zero to a specified value in slow response to power-on state and drops to zero in slow response to a significant drop in the AC voltage. A rectifier-filter converts the AC voltage to a nonregulated DC voltage. The output of the rectifier-filter rises in quick response to the power-on state and drops in quick response to the significant AC voltage drop. If the output of DC power supply drops below a specified theshold due to AC power-line failure or due to its own failure, a DC low-voltage signal is generated. If the output of rectifier-filter rises above a specified low level a first AC transitory signal is generated and if it drops below a specified high level a second AC transitory signal is generated. A latch circuit is energized with the nonregulated DC voltage to latch the DC low-voltage signal if it occurs during the interval between the first and second AC transitory signals and supplies a DC alarm signal to computer circuitry. A power controller is energized with the regulated DC voltage to supply control signals to the computer circuitry in response to the first and second AC transistory signals.