| 摘要 |
PROBLEM TO BE SOLVED: To easily construct a voltage amplifier of a wide band by driving an output stage driving circuit which drives an output stage circuit and also a current supply circuit which supplies a current to the output stage driving circuit based on a drive signal. SOLUTION: The emitter of a transistor TR 75 is connected to the base of a TR 31 which drives an output stage circuit, and a TR 71 is cascaded to the TR 75. Thus, both TR 31 and TR 75 are driven in response to the differential voltage between an input signal Vin and the base of a TR 13. At the same time, the TR 71 is driven by the TR 75 with no deterioration of the high band characteristic since the TR 75 has a base grounded operation. Thereby the emitter current of the TR 71 is reduced when the collector current of the TR 31 is increased. As a result, the base current of a TR 61 is increased compared with a conventional voltage amplifier.
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