Power amplifier apparatus

• US 20030020539A1
• Filed: 07/18/2002
• Published: 01/30/2003
• Est. Priority Date: 07/27/2001
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sawashi, Tokihiko
• Granted Patent: US 6,653,897 B2
• Time in Patent Office: Days
• US Class Current: 330/10
• CPC Class Codes: H03F 3/217 Class D power amplifiers; Switching amplifiers
• CPC Class Codes: H03F 3/26 Push-pull amplifiers; Phase-splitters therefor duplicated single-ended push-pull arrangements or phase-splitters therefor H03F3/30

Abstract

A power amplifier apparatus includes a pair of power amplifiers for performing switching-type power amplification, a transformer, and a capacitor. The transformer is formed of a pair of coils which are connected in series between the corresponding output terminals of the pair of power amplifiers and the corresponding ends of a speaker. The capacitor is connected in parallel with the output terminals of the pair of coils. With this configuration, a mutual inductance and a leakage inductance are generated in the coils. As a result, 180°-out-of-phase and in-phase noise components contained in an output of the power amplifier apparatus can be eliminated.

Claims

1. A power amplifier apparatus comprising:

a pair of power amplifiers, which form a balanced-transformerless-type amplifier, for performing switching-type power amplification;

a transformer including a pair of coils connected in series between output terminals of said pair of power amplifiers and corresponding ends of a speaker; and

a capacitor connected in parallel with output terminals of said pair of coils,

wherein said pair of coils include a mutual inductance and a leakage inductance.

2. A power amplifier apparatus according to claim 1, further comprising a drive amplifier for supplying pulse modulation signals to said pair of power amplifiers, the pulse modulation signals being out of phase with each other by 180 degrees, an integrated value of the pulse modulation signals corresponding to a level of an original analog audio signal.

3. A power amplifier apparatus according to claim 1, wherein said transformer comprises a separated-type transformer in which said pair of coils are wound around corresponding independent cores.