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. 20, 1990
Filed:
Mar. 03, 1989
Harufusa Kondou, Hyogo, JP;
Takeo Nakabayashi, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A first comparator compares a voltage of a pair of primary terminals of a pulse transformer with a first reference voltage, to apply an output voltage corresponding to the voltage difference therebetween to a gate of an N channel MOSFET. The N channel MOSFET is responsive to the output voltage for controlling current flowing through a primary side of a pulse transformer. Consequently, even if the impedance of a load connector to a pair of secondary terminals of the pulse transformer is fluctuated, a voltage between the pair of secondary terminals is kept constant. A second comparator compares the output voltage of the first comparator with a second reference voltage, to apply an output voltage corresponding to the voltage difference therebetween to a gate of a P channel MOSFET. When the load impedance becomes low, the P channel MOSFET performs control such that the output voltage of the second comparator does not exceed a predetermined value. Consequently, current flowing through the primary side of the pulse transformer is limited not to exceed a constant value. Thus, a voltage between output terminals does not exceed a constant value.