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:
Aug. 12, 1986
Filed:
Sep. 28, 1983
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention relates to a digital control circuit which controls the drive of a load by the use of a clock pulse. More particularly, it relates to an integrated circuit device for combustion control which controls the combustion of a burner in a water heater, an air heater or the like. A combustion control circuit performs an ignition operation for a predetermined time, and stops the supply of fuel in case of misfire. When the reception of the time-keeping clock pulses has stopped within the predetermined time, such predetermined time will become infinite, and in the case of misfire, the fuel supply will continue dangerously. According to the present invention, a capacitor is charged by the output clock pulse of a circuit for shaping the waveform of the received clock pulse, an buffer circuit prevents the discharge of the capacitor toward the pulse shaping circuit when the clock pulse is at its low level, a discharge circuit for discharging the capacitor at this time is connected in parallel with the capacitor, and a voltage detecting circuit detects the voltage of the capacitor so that, when the capacitor voltage is unequal to a preset voltage, the combustion operation may be stopped by the output of the voltage detecting circuit. The constituents other than the capacitor are disposed within the integrated circuit device.