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:
May. 14, 1996
Filed:
Nov. 07, 1994
Ravi Vig, Bow, NH (US);
Jacob K Higgs, Concord, NH (US);
Allegro Microsystems, Inc., Worcester, MA (US);
Abstract
There is added to a conventional magnetic-field detector, which includes a magnetic-field-to-voltage transducer such as a Hall element connected to a Schmitt trigger circuit, a DC voltage monitor circuit to produce a high binary monitor signal only when the DC supply voltage is within a predetermined normal band, and a logic circuit having one input connected to the output of the monitor circuit and a second input connected to the output of the Schmitt trigger circuit. During periods when the binary-Schmitt-output voltage remains high, corresponding for example to a high ambient magnetic field, noise spikes on the DC line can cause an anomalous change in the binary-Schmitt-output voltage of a magnetic-field detector from a high level to a low level. The logic circuit is such that during an enabling period in which the output signal from the DC supply voltage monitor is continuously of the one type, the logic output produces a binary logic output-signal transition from a first binary level to the second binary level only following a transition in the Schmitt output signal from the high level to the low level, so that in the presence of noise spikes of either polarity that momentarily cause the DC supply voltage to exit the predetermined normal DC supply voltage band, the binary logic output signal essentially mirrors the Schmitt output signal with noise removed.