| 摘要 |
PURPOSE: An automatic gain controller is provided, which obtains an equal voltage even though a capacity of an internal capacitor is reduced, and has a noise immunity by preventing an error operation as to noise. CONSTITUTION: A capacitor provides a voltage to control a gain of a control gain amplifier by performing a charging according to a provided charging current and performing a discharge of a precharged voltage as much as a provided discharge current amount. A current providing part(10) provides the charging current and the discharging current variably, depending on a difference between an output signal of the control gain amplifier and a fixed DC signal. A current reduction part(20) reduces the charging current and the discharging current from the current providing part and then provides the reduced charging current and the reduced discharging current to the capacitor. The reduced charging current corresponds to the reduced discharging current. The current reduction part comprises a charging current reduction part and a discharging current reduction part.
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