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:
Nov. 03, 1992
Filed:
Aug. 29, 1991
Masanori Fujisawa, Kumagaya, JP;
Kenichi Kokubo, Tatebayashi, JP;
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
The present invention provides a B class push-pull amplifying circuit suitable for use in a headphone type tape recorder and the like. The amplifying circuit utilizes a current mirror circuit system in its output transistors to provide an idling current for compensating for crossover distortion by using the mirror ratio. The current mirror circuit system includes a pair of output current mirror circuits complimentarily coupled with each other. One branch of these output current mirror circuits includes a diode-connected transistor, the emitter current path of which is ON-OFF controlled by a drive transistor in the other branch. Thus, when no signal is input, the respective one of the current mirror output circuits complimentarily coupled with each other functions as a current mirror circuit such that the small idling current determined by the mirror ratio will pass therethrough. On the other hand, the inputting of a signal causes the output of the opposite side drive transistor to make the current mirror circuit inoperative. The output transistor functions as a normal amplifying circuit. An amplification factor h.sub.FE provided at this time can reliably assure a sufficiently large amplification degree.