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:
Sep. 01, 1998
Filed:
Feb. 28, 1996
Seiko Instruments Inc., , JP;
Abstract
A pulse frequency modulation type DC-DC converter has first and second voltage level comparators for controlling the frequency of a control signal used to drive an output coil. The first voltage comparator detects a first voltage level and the second voltage comparator detects a second voltage level. A reference voltage circuit produces reference voltages corresponding to the first and second voltage levels and provides the reference voltages to the first and second voltage comparators, respectively. An oscillating circuit generates the control signal under control of the first and second comparators. The control signal has one of a first pulse width and a second pulse width depending upon outputs of the first and second voltage comparators for controlling a switching device used for driving an output coil. The switching device is turned on to drive the output coil during a first pulse width when the first voltage comparator detects that the output voltage coincides with the first voltage level. The switching device is turned on to drive the output coil during a second pulse width when the second voltage comparator detects that the output voltage coincides with the second voltage level. Thus, outputs from the first and second voltage comparators determine the frequency of the control signal by controlling the pulse width of respective pulses of the control signal.