Title:
電力増幅回路
Document Type and Number:
Japanese Patent JP4434557
Kind Code:
B2
Abstract:
A pulse-width modulation circuit comprises a comparator having hysteresis characteristics of positive feedback, and an integrator, whose integrated output is compared with an input signal to produce a pulse-width modulation (PWM) signal having an advanced phase characteristic due to differentiation of the input signal. A switching circuit amplifies the pulse-width modulation signal based on the positive and negative source voltages (VPX, VMX). The amplified pulse-width modulation signal is supplied to a speaker via an LC filter, and it is also negatively fed back to the pulse-width modulation circuit. Since the pulse-width modulation signal whose phase is advanced is transmitted through the LC filter, it is possible to reduce phase revolution in the output of the power amplifier circuit. Thus, it is possible to effect negative feedback on the pulse-width modulation signal in a stable manner.
Inventors:
Nobuaki Tsuji
Masao Noro
Masao Noro
Application Number:
JP2002182823A
Publication Date:
March 17, 2010
Filing Date:
June 24, 2002
Export Citation:
Assignee:
Yamaha Corporation
International Classes:
H03F3/217; H03K7/08; H03F3/45
Domestic Patent References:
| JP57121308A | ||||
| JP60103724A | ||||
| JP2000295049A | ||||
| JP4281606A | ||||
| JP10150329A | ||||
| JP715304A | ||||
| JP1129607A | ||||
| JP5967719A |
Attorney, Agent or Firm:
Masatake Shiga
Takashi Watanabe
Takashi Watanabe