| 摘要 |
PROBLEM TO BE SOLVED: To provide a driver circuit for driving a driver amplifier at low power voltage of 3V system. SOLUTION: A driver amplifier 100 is an amplifier of a current outputting type in which a buffer circuit 10, which amplifies the voltage of an input signal vi by a gain 1 to obtain a current im according to the voltage, is provided as an inputting stage and a current amplifier circuit 12, which amplifies the current im by an amplification factor (m) to output, is provided as an outputting stage. A feedback resistor R2 for negatively feeding back current is connected between its output terminal 18 and a second terminal 16 on the output side of the circuit 10, and an output resistance is set to be the same value as a load RL by setting the resistance R2 and the current amplification factor (m) to be prescribed values. Thus, serial resistance to be matched with a load is removed to directly supply output from the amplifier 100 to the load, thereby its dynamic range can nearly be halved and a power voltage can be dropped.
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