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:
Sep. 27, 2011
Filed:
Jul. 18, 2008
Manabu Ito, Sayama, JP;
Takeshi Uchida, Sayama, JP;
Manabu Ito, Sayama, JP;
Takeshi Uchida, Sayama, JP;
Nihon Dempa Kogyo Co., Ltd., Tokyo, JP;
Abstract
Provided is a control circuit for a thermostatic oven in an oven controlled crystal oscillator, which is capable of further improving stability of an oscillation frequency. A control circuit in which a thermistor whose resistance value changes according to a temperature outputs a signal according to the ambient temperature of the thermostatic oven inside the oscillator, an operational amplifier outputs a signal according to a difference between the output of the thermistor and a reference signal, a power transistor amplifies the output of the operational amplifier, and a heater generates heat based on a collector voltage of the power transistor, is provided with a temperature sensor circuit having a transistor with a base to which the output of the operational amplifier is input. The control circuit outputs a collector voltage of the transistor as an internal temperature signal which changes according to a temperature inside the oscillator.