| 摘要 |
PURPOSE:To obtain a differential amplifier fitted to an integrated circuit by changing the current value of a variable current source and altering the cutoff frequency of an input/output frequency characteristic. CONSTITUTION:Transistors 3 and 4, resistors 7 and 8, a voltage source 13 and the variable current source 11 constitute an inverter amplifier. When a voltage amplification facter is set to be AO, the capacitance value of a capacitor 9 to be CO, the resistance value of resistors 5 and 6 to be RO, the cutoff frequency of the input/output frequency characteristic is approximated to 1/(2XCO.AO.RO) by a mirror effect. The voltage amplification facter AO can be altered by changing the current value of the variable current source 11. Thus, the cutoff frequency of the input/output characteristic in the differential amplifier can be changed by changing the current value of the variable current source 11. Thus, the amplifier is fitted to be made into the integrated circuit. |
