| 摘要 |
PROBLEM TO BE SOLVED: To enable full DC coupling and facilitate one-chip integration, using a minimum number of components by controlling the offset and input impedance of a differential output amplifying circuit according to differential outputs. SOLUTION: The in-phase output and opposite-phase output of a differential amplifier 2 are branched and inputted to peak detecting circuits 5 and 6, which detect and hold the peak values of in-phase output pulses and opposite-phase output pulses. The difference voltage between the held peak values of the in- phase output and opposite-phase output is amplified by an operational amplifier 7 and led to the base of a transistor 4. The offset is controlled according to this difference voltage. Further, a means value detecting circuit 8, consisting of a resistance voltage-dividing circuit, obtains the mean value of the in-phase output and opposite-phase output of the differential output amplifier 2. This mean value is compared by an operational amplifier 10 with a low-voltage source 9 and then amplifier and led to the base of a transistor 3. The input impedance is controlled according to this comparison result. |
