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. 10, 1996
Filed:
Dec. 01, 1994
Kimio Shibata, Chiba, JP;
Seiko Instruments Inc., , JP;
Abstract
A switching transistor is arranged for charging a capacitor in response to a positive going transition of a clock signal. The charging time of the capacitor is determined by controlling the charging current in accordance with an input voltage to a transistor coupled to the capacitor. The pulse width of an output signal is dependent upon the charging time of the capacitor. Using the inventive pulse width modulator, by comparing the voltage of a reference voltage source with a divided voltage obtained through feedback of the output of the pulse width modulator, a switching power source is obtained by simply adding circuitry for converting, rectifying and smoothing the output voltage. A variable range of pulse width of up to 1800 times can be obtained. When the circuit is designed using complementary MOS devices, the operating voltage can be under 1V with a consumption current of less than several .mu.A. When the circuit is integrated, the oscillator of the modulator and the oscillator of the electronic system in which the modulator is used can be easily switched, and the oscillators can be synchronized, resulting in a low noise, miniaturized switching power source.