JP2001237659A - Power amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power amplifier preventing generation of beat noises in a simple configuration. SOLUTION: Concerning the power amplifier provided with power amplifier circuits for five channels, the power amplifier circuit equal to or more than one cannel is constituted in a D class power amplifier circuit 5 and power amplifier circuits for remaining plural channels are constituted in AB class power amplifier circuits 1-4. Then, only when amplifying the output of an AM tuner, the D class power amplifying circuit 5 is turned into operation stop.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power amplifying device, and more particularly to a power amplifying device for amplifying a plurality of channels of audio signals.

[0002]

2. Description of the Related Art A conventional power amplifying apparatus having a plurality of channels for amplifying power of an audio signal has a D-class amplifier for amplifying all of the plurality of channels for high efficiency.

[0003]

However, in the case where the output from, for example, an AM tuner is amplified by a conventional power amplifier having a plurality of channels for amplifying the audio signal, the output from the class D power amplifier circuit is increased. There is a problem in that a beat sound is generated by radiation or a change in sensitivity suppression occurs.

[0004] It is an object of the present invention to provide a power amplifying device which has a simple configuration and prevents generation of a beat sound.

[0005]

A power amplifying apparatus according to the present invention is a power amplifying apparatus having a plurality of channels of power amplifying circuits.
A class power amplifier circuit, wherein the class D power amplifier circuit is in an operation stop state only when amplifying the output of the tuner.

According to the power amplifying device of the present invention, when a tuner, for example, an AM tuner is selected, only the D-class power amplifying circuit is in an operation stop state. The influence of the class D power amplifier circuit and the radiation from the class D power amplifier circuit do not generate a beat sound or change the sensitivity suppression.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a power amplifying device according to the present invention will be described with reference to an embodiment.

FIG. 1 is a block diagram showing a configuration of a power amplifying device 15 according to one embodiment of the present invention.

The power amplifying device 15 is composed of class AB power amplifying circuits 1, 2, 3, and 4 and class D power amplifying circuit 5,
One of the sound sources in the sound source device 6 including the AM tuner, the FM tuner, the cassette deck, and the CD playback device is selected, and an audio signal output from one of the sound sources selected from the sound source device 6 is amplified to class AB. Power amplifier circuit 1,
The amplified output signals from 2, 3, and 4 are separately output to the left front speaker 7, the right front speaker 8, the left rear speaker 9, and the right rear speaker 10 to drive the respective speakers, and the D-class power amplifier circuit 5 And outputs the amplified output signal to the subwoofer 11 to drive the subwoofer 11.

In the tone generator 6, a signal indicating that the AM tuner is selected is supplied to the D-class amplifier circuit 5 to stop only the operation of the D-class amplifier circuit 5. Therefore,
Only when the AM tuner is selected, an operation stop signal is output to the class D power amplifier circuit 5 and the subwoofer 1
Only 1 is not driven. However, the class AB power amplifier circuits 1, 2, 3, and 4 are operating, and the class AB power amplifier circuits 1, 2, and 3 that have amplified the output signal from the AM tuner.
In response to the amplified output signals from the speakers 3 and 4, the left front speaker 7, the right front speaker 8, the left rear speaker 9, and the right rear speaker 10 are driven to output a reproduced sound based on the reproduced audio signal.

Therefore, when the AM tuner is selected, the reproduced sound is not interrupted and only the D-class power amplifier circuit 5 is stopped. There is no influence of noise emission such as beat sound. When a device other than the AM tuner is selected in the sound source device 6, the class D power amplifier circuit 5 is in the operating state and the subwoofer 11
Is driven as in the conventional case.

In the above description, the number of class AB power amplifier circuits is not limited to four, and the number of class D power amplifier circuits is not limited to one. The power amplifying device is provided with six AB class power amplifying circuits and two class D power amplifying circuits.
The left and right super tweeters, the left and right front speakers, and the left and right rear speakers are individually driven by the output signals of the class B power amplifier circuits, and the left and right super woofers are output by the output signals of the class D power amplifier circuits. It is also possible to drive the speakers individually, and to stop the operation of all the class D power amplifier circuits when the AM tuner is selected. Also in this case, the same effect as in the case of the power amplifying device 15 can be obtained.

As described above, according to the power amplifying device 15, when the AM tuner is selected, only the class D power amplifying circuit is in an operation stop state.
The influence of the class D power amplifier circuit when the M tuner is selected, the generation of a beat sound by the radiation from the class D power amplifier circuit, and the change of the sensitivity suppression do not occur.

In the power amplifying device 15, the case where the power amplifying circuit other than the class D power amplifying circuit is a class AB power amplifying circuit is exemplified. However, another power amplifying circuit, for example, a class B power amplifying circuit is used. Alternatively, a class A power amplifier circuit and an AB class power amplifier circuit may be mixed, and the power amplifier circuit may be constituted by a power amplifier circuit other than the class D power amplifier circuit.

In the power amplifying device 15, the case of the output of the AM tuner has been described, but the same applies to the output of a tuner that receives a broadcast of another modulation method instead of the output of the AM tuner.

[0016]

As described above, according to the power amplifying apparatus of the present invention, when the tuner is selected, only the D-class power amplifying circuit is in an operation stop state. The influence of the class D power amplifier circuit and the radiation from the class D power amplifier circuit do not generate a beat sound or change the sensitivity suppression.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a power amplification device according to an embodiment of the present invention.

[Explanation of symbols]

1-4 AB class power amplifier circuit 5 D class power amplifier circuit 6 Sound source device 7-10 Left and right front speakers and left and right rear speakers 11 Subwoofer 15 Power amplifying device

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 5J069 AA01 AA41 AA53 AA54 AA66 CA00 CA41 FA18 KA62 SA05 TA01 5J091 AA01 AA41 AA63 AA64 AA66 CA00 CA41 FA18 KA62 SA05 TA01 5J092 AA01 AA41 AA63 CA08 KA06

Claims (2)

[Claims] In a power amplifying apparatus provided with a power amplifying circuit of a plurality of channels, a power amplifying circuit of one or more channels is a class D power amplifying circuit, and the class D power amplifying circuit operates only when amplifying a tuner output. A power amplifying device which is brought into a stop state. 2. The power amplifier according to claim 1, wherein an output of the tuner is an output of an AM tuner.