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:
Oct. 18, 2005
Filed:
Feb. 26, 2004
Toshio Maejima, Iwata, JP;
Toshio Maejima, Iwata, JP;
Yamaha Corporation, Santa Clara, CA (US);
Abstract
A pulse width modulation (PWM) amplifier which is capable of reducing unwanted radiation from a PWM output thereof, which can cause EMI, while reducing manufacturing costs thereof. A triangular wave-generating circuit () of the PWM amplifier outputs a triangular wave. The triangular wave has a waveform steep or gentle in pulse rising and falling slopes dependent on a value of current flowing through an FET () or an FET (). The value of current is changed by a current flowing through a FET (). A switching element () changes voltage applied to the gate of an FET (), for control of increase and decrease in the current flowing through the FET (). This enables the triangular wave to be generated such that it is formed by pulses having different periods. An input signal is subjected to PWM amplification based on the triangular wave generated.