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. 04, 1998
Filed:
Mar. 26, 1997
Koichi Yamasaki, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
This circuit improves power efficiency and reduces number of parts required in a voltage step-up circuit. This circuit includes a switching control circuit and a voltage transformer circuit. The control circuit is a push-pull circuit comprising a constant-current-on type transistor Tr1 and a differential-pulse-on type transistor Tr2. The transformer circuit comprises an NPN type switching transistor Tr3, a coil L1, a diode D1, and a electrolytic capacitor C2. With Tn being the duration of the ON state of Tr3, and Tf the duration of the OFF state, the output voltage is Vcc(Tn+Tf)/Tf. Since the constant-current-on type transistor Tr1 is laid closer to the power source than the differential-pulse-on type transistor Tr2, the switching transistor Tr3 can be driven directly and no PNP type transistor is necessary.