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.

Date of Patent:
Dec. 17, 2019

Filed:

Oct. 09, 2013
Applicant:

Hitachi Automotive Systems, Ltd., Hitachinaka-shi, Ibaraki, JP;

Inventors:

Masahiro Matsumoto, Tokyo, JP;

Hiroshi Nakano, Tokyo, JP;

Keiji Hanzawa, Hitachinaka, JP;

Satoshi Asano, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01F 1/696 (2006.01); G01F 25/00 (2006.01); G01R 31/02 (2006.01);
U.S. Cl.
CPC ...
G01F 1/696 (2013.01); G01F 25/0007 (2013.01); G01R 31/025 (2013.01);
Abstract

In configurations in which a circuit element is connected in parallel with a resistor, it is difficult to detect a break in the two wires. A thermal flow meter includes a heating element and a temperature controlling bridge circuit that is formed of a plurality of resistors and controls the temperature of the heating element. The thermal flow meter includes: a circuit element connected in parallel with at least one resistor configuring the temperature controlling bridge circuit through two wires drawn from both ends of the resistor; a voltage detection circuit that detects that the magnitude of voltage produced between the two wires has become smaller than a first predetermined value; and a fault signal output circuit that, when it is detected at the voltage detection circuit that the. magnitude of the voltage has become smaller than the first predetermined value, outputs a signal indicating a fault.


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