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. 30, 1999
Filed:
Apr. 28, 1998
Nozomi Toki, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
Disclosed is a PWM driver in which, when no signal is input, a PWM pulse wave is not output so as to thereby reduce a power to be consumed and a high output level can be obtained even by the use of a single-polarity power source. Also, provided is a PWM driver capable of changing an output amplitude by a simple circuit. For this purpose, a PWM driving apparatus for supplying a power proportional to an input signal to a load by outputting a PWM pulse wave whose duty cycle is changed in proportion to the input signal, comprises: a PWM modulator for outputting a first PWM pulse having a pulse width proportional to an absolute value of the input signal in a predetermined cycle; an inverting amplifier for outputting a second PWM pulse having a polarity opposite to the polarity of the first PWM pulse; switch means for outputting the first PWM pulse or the second PWM pulse in response to the polarity of the input signal; and an amplifier for outputting the PWM pulse wave in response to an output pulse of the switch means.