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US 2009/0058523 A1Published application
Amplifying circuit
AssigneesSanyo Electric Co., Ltd., Sanyo Semiconductor Co., Ltd.
InventorTakashige OGATA
Life of this patent
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Abstract
An amplifying circuit comprising an output stage circuit composed of a first and a second output transistor and operating as a class AB push-pull circuit reduces electricity consumed by an idle current. A pre-stage circuit outputs a first and a second control signal, and controls a channel current of the first and the second output transistor. In a period in which one control signal causes the corresponding output transistor to operate in class AB mode, the other control signal places the corresponding output transistor in a cutoff state.
Claims3
An amplifying circuit, comprising:
- an output stage circuit provided with a first output transistor for controlling a conducting current based on a first control signal and a second output transistor for controlling a conducting current based on a second control signal, the transistors causing the output stage circuit to operate as a class AB push-pull circuit;
- and
- a pre-stage circuit, in which the first control signal and the second control signal are generated in accordance with an input signal;
- wherein,
- the first control signal causes the first output transistor to operate in class AB mode in a first ON period set in accordance with a positive signal period in which the input signal is positive, and places the first output transistor in a cutoff state in a first OFF period set in accordance with a negative signal period in which the input signal is negative;
- and
- the second control signal causes the second output transistor to operate in class AB mode in a second ON period set in accordance with the negative signal period, and places the second output transistor into a cutoff state in a second OFF period set in accordance with the positive signal period.
4 more elements
Dependencies are inferred from the claim text.