CLASS D AMPLIFIER

• US 20050225384A1
• Filed: 06/07/2005
• Published: 10/13/2005
• Est. Priority Date: 10/03/2002
• Status: Active Grant

• Current Assignee: Kenichi Taura, Masayuki Ishida, Masayuki Tsuji, Tsuyoshi Nakada
• Original Assignee: Kenichi Taura, Masayuki Ishida, Masayuki Tsuji, Tsuyoshi Nakada
• Inventors: Taura, Kenichi, Nakada, Tsuyoshi, Tsuji, Masayuki, Ishida, Masayuki
• Granted Patent: US 6,989,714 B2
• Time in Patent Office: Days
• US Class Current: 330/10
• CPC Class Codes: H03F 2200/331 Sigma delta modulation being used in an amplifying circuit
• CPC Class Codes: H03F 3/217 Class D power amplifiers; Switching amplifiers

Abstract

A pulse modulated signal (ei) output from a pulse modulator (1) and a feedback signal (ef) containing distortion caused by a power switch (3) are integrated in a first integrator (21) and a second integrator (24), respectively, and are input to input terminals of a comparator (25 or 29), respectively, so that a correction signal (Vc) is generated.

Claims

1. A class D amplifier comprising:

a pulse modulator for generating a pulse modulated signal;

a correction circuit for correcting a feedback signal input thereto by feedback in reference to said pulse modulated signal; and

a power switch for generating a voltage signal on the basis of a correction signal output from said correction circuit, wherein

said feedback signal is generated on the basis of said voltage signal, and

said correction circuit includes;

a first integrator for performing integration on the basis of said pulse modulated signal;

a second integrator for performing integration on the basis of said feedback signal; and

a comparator for comparing a first integrated signal output from said first integrator and a second integrated signal output from said second integrator, thereby generating said correction signal in correspondence with the result of comparison.

2. The class D amplifier according to claim 1, wherein

said correction circuit further includes:

a gain controller for controlling gain of said first integrated signal;

a first subtracter for obtaining a difference between an output signal from said gain controller and said pulse modulated signal, thereby generating a first differential signal to be input to said first integrator; and

a second subtracter for obtaining a difference between said output signal from said gain controller and said feedback signal, thereby generating a second differential signal to be input to said second integrator.

3. The class D amplifier according to claim 1, further comprising

a feedback circuit for attenuating an amplitude of said voltage signal generated in said power switch and outputting said feedback signal to be input to said correction circuit.

4. The class D amplifier according to claim 1, wherein

a constant for gain of said first integrator and a constant for gain of said second integrator are equal to each other.