| 摘要 |
PURPOSE: A non-inversion gain control amplifier having a DC voltage level shift function and a low frequency filtering function is provided, which reduces a layout area and power consumption and improves an offset voltage characteristics. CONSTITUTION: The non-inversion gain control amplifier comprises an operational amplifier, a feedback capacitor(C21) and a feedback variable resistor(R25) having a low frequency filtering function, and input resistors(R21,R23) and variable resistors(R22,R24) for a voltage gain and DC voltage level shift function. The feedback capacitor and the feedback variable resistor determine a frequency characteristics of a low frequency filter, and its amplitude is R25/R21 and its phase is inverted. The resistor(R21,R23) and the variable resistors(R22,R24,R25) determine a DC voltage gain value. The variable resistor(R24) and the variable resistor(R25) are connected with an external input signal(Vofst) to perform the DC voltage level shift function.
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