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:
Oct. 20, 1992
Filed:
Dec. 05, 1989
Koji Tanimoto, Hyogo, JP;
Mikio Bessho, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A thermal flow sensor of a switching control type for measuring the flow rate of intake air of an internal combustion engine comprises a bridge circuit including temperature sensing resistors, a differential amplification circuit, a pulse generating circuit, a power supply control circuit and a resonance preventing circuit. The amplification circuit amplifying the output from the bridge circuit. The pulse generating circuit receives the output from the amplification circuit and generates a pulse train which has a time ratio corresponding to the output level of the amplification circuit. The power supply control means comprises a switching transistor which is turned on and off by the pulse train from the pulse generating circuit and a smoothing circuit which makes the output from the transistor continuous and supplies the continuous voltage to the bridge circuit. The resonance preventing circuit comprises a phase lag compensation circuit including a resistor and a capacitor connected in series between a differential amplifier of the amplification circuit, or a variable DC unbalanced voltage generator including a V/I converter which converts the voltage received from the bridge circuit to a current corresponding to the level of the received voltage and a resistor which converts the current output from the V/I converter to a voltage and outputs a variable DC unbalanced voltage thereacross, whereby the resonance phenomenon in the full range of the flow rate is prevented.