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:
May. 04, 1999
Filed:
Nov. 14, 1996
Abstract
According to one embodiment of a switching power supply, a superimposition circuit including a resistor is connected in parallel to the primary coil of a transformer. A superimposition current is supplied to a current sensing circuit during a switching-on period of a switching element. The current sensing circuit detects the current flowing through the primary coil during the switch-on period. According to the detected current, a switch control circuit controls switching on and off of the switching element so as to stabilize the output voltage. When the current becomes low in a case in which the circuit has a light load or receives a high input voltage, noise generally causes substantial adverse effects. However, since the detected current in the current sensing circuit is biased to become larger by superimposing the superimposition current of the superimposition circuit on the current flowing through the primary coil, the output voltage is stabilized without receiving adverse effects of noise even if the current passing through the primary coil becomes low.