| 摘要 |
An integrated current amplifier circuit (10) combining bipolar and MOS technologies provides accurate current gain over a wide voltage supply range. The amplifier circuit includes a current source (12, 14, 20, 22) for providing first (I1) and second (I2) currents and first (24, 26) and second (30) resistive circuits coupled to the current source for sinking the respective currents supplied therefrom. A feedback transistor (36) connected between the current source and an output of the amplifier circuit provides current feedback to the first resistive circuit to establish the current gain of the amplifier circuit which becomes a ratio of two resistors times an input current supplied to the second resistive circuit. The ratio of the two resistors can be accurately controlled thereby controlling the current gain of the amplifier circuit. Additionally, an active turn-off circuit (40, 42, 44) requiring no standby bias current is provided to ensure that the feedback transistor is non-conducting when the amplifier is in an off state. |
