Power amplifier
AssigneeNippon Gakki Seizo Kabushiki Kaisha
InventorKenji Yokoyama
Life of this patent
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Abstract
In a power amplifier arranged so that a load is driven by a first amplifying circuit having a low distortion factor, the power supply voltage of said first amplifying circuit is varied in accordance with an input signal by a second amplifying circuit having a good power efficiency, to supply always a voltage of a minimum level to said first amplifying circuit whereby to enhance the power efficiency of said first amplifying circuit, wherein arrangement is provided so that the first amplifying circuit is free from the effect of the second amplifying circuit represented by the distortion factor which increases especially in the high frequency range, so that the power amplifier is operated with low distortion factor and high power efficiency even for the high frequency range.
Claims12
A power amplifier, comprising:
- a first amplifying circuit having amplifying elements for amplifying an input signal in either class-A, class-B or class-AB mode, to drive a load;
- a second amplifying circuit using, as an input, a signal corresponding to said input signal for supplying to said amplifying elements an output voltage as a first power supply voltage;
- fixed power supplies supplying a second power supply voltage to said second amplifying circuit;
- and
- switching circuits for switching between said first power supply voltage and said second power supply voltage to be delivered to said amplifying elements in accordance with a potential difference between an output voltage of said first amplifying circuit and the output voltage of said second amplifying circuit.
A power amplifier comprising:
- a first amplifying circuit for amplifying an input signal to drive a load;
- first supply means for supplying a first power supply voltage to the first amplifying circuit;
- second supply means for supplying a second power supply voltage to the amplifying circuit;
- and
- switching means for switching between the first power supply voltage and the second power supply voltage as a function of the frequency of the input signal.
A power amplifier comprising:
- a first amplifying circuit for amplifying an input signal to drive a load;
- a second amplifying circuit receiving the input signal as an input and providing an output voltage as a first power supply voltage to the first amplifying circuit;
- fixed power supplies for supplying a second power supply voltage to the second amplifying circuit;
- and
- switching circuits for switching between the first power supply voltage and the second power supply voltage to be delivered to the first amplifying circuit, wherein the switching is done as a function of the difference between the output voltage of the first amplifying circuit and the output voltage of the second amplifying circuit.
Dependencies are inferred from the claim text.