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:
Dec. 13, 1983
Filed:
Aug. 25, 1981
Hisao Nishino, Sendai, JP;
Tohoku Metal Industries, Ltd., Sendai, JP;
Abstract
A control circuit for a main switching transistor in a switching regulator, wherein PWM pulses are produced by varying a DC bias of triangular-wave pulses in response to a detected error signal, and which pulses are provided as a control signal for switching on and off the main switching transistor. In order to reduce power dissipation due to carrier storage at each turn-off operation of the switching transistor, a negative voltage potential is produced by a diode and a capacitor from square-wave pulses of a constant repetition frequency from which pulses the triangular-wave pulses are formed, and is applied to an emitter of an NPN transistor which operates as a variable impedance circuit for varying the DC bias of the triangular-wave pulses in response to the error signal, so that the triangular-wave pulses are biased to a negative voltage potential. Therefore, the base of the switching transistor rapidly drops down to a negative voltage potential at the time of each turn-off operation of the switching transistor, so that the stored carrier is rapidly drawn out of the base of the switching transistor.