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. 11, 1985
Filed:
Jan. 17, 1983
Kenzi Toudo, Yanai, JP;
Motoshi Miyanaka, Yanai, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a digital control circuit, a clock pulse is counted so that when a predetermined timing is reached the driving of a load is controlled. The digital control circuit may preferably be an integrated circuit for controlling the combustion of a burner for a combustion apparatus such as a water heater or an air heater. The combustion control circuit performs the igniting operation for a predetermined period of time and the supply of fuel is stopped if the ignition can not be attained within the predetermined period. In the digital control circuit, a clock pulse having a predetermined bias voltage is counted by a time measuring circuit and whether the clock pulse has the predetermined bias voltage or not is judged by a detecting circuit so that the igniting operation is stopped when the clock pulse has the predetermined bias voltage, thereby avoiding a risk that, if the input of the clock pulse is interrupted within the predetermined period, the predetermined period may be prolonged indefinitely and the supply of fuel may be continued even though ignition has not been attained.