| 摘要 |
PURPOSE:To reduce distortion factors, by negatively feeding back an output signal of a transistor (TR) pair connected to the collector and the base of TRs constituting a differential pair. CONSTITUTION:A signal inputted at a terminal 4 is amplified at an operational amplifier 14 and becomes a signal V1. A collector current of TRs 1a, 1b is converted in terms of current-voltage at operational amplifiers 3 and 17, added via resistors 16 and 19 and negatively fed back to the operational amplifier 14. The sum of the emitter currents of the TRs 1a and 1b and that of TRs 2a and 2b are changed according to the signal V1. Thus, a negative feedback signal proportional to the difference between the collector current of the TRs 1a and 1b, and the TRs 2a and 2b is produced. Since distortion included in the output signal V1 of the operational amplifier 14 is fed back in opposite phase, the distortion can be reduced. |
