| 摘要 |
PROBLEM TO BE SOLVED: To suppress deterioration in output waveform quality when an output amplitude is reduced. SOLUTION: A driver circuit includes a variable amplitude amplifier VA capable of adjusting the amplitude of an output signal, and an amplifying circuit comprising at least one amplifier DIFFa. The variable amplitude amplifier VA comprises an amplification portion including a transistor for amplification to which input signals DINP, DINN are input, an amplitude adjustment portion including a transistor for amplitude adjustment cascade-connected to the transistor for amplification and adjusting the amplitude of the output signal of the transistor for amplification in accordance with an amplitude adjustment signal input to the transistor for amplitude adjustment, and a current source supplying a constant current to the amplification portion and amplitude adjustment portion. The amplifier DIFFa comprises an output portion including a transistor for amplification receiving the output signal of the variable amplitude amplifier VA, and a current source supplying a constant current to the output portion. COPYRIGHT: (C)2011,JPO&INPIT
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