COMMON BIAS CIRCUIT

摘要

PURPOSE: To omit an AC signal coupling capacitor and a bias by-pass capacitor by DC-coupling each bias circuit of individual ICs together and operating individual integrated circuits with a common bias source. CONSTITUTION: The connecting point 28 of an IC 22 is connected to a bias circuit 12 similarly to the bias pin of an IC 10. AC signal coupling capacitors 32 and 34 are not required any more and a filter capacitor 30 is omitted as an unnecessary capacitor. Resistors 36 and 38 work instead of a resistor 40 and couple a bias voltage with the IC 10 from a bias generating circuit 12 without causing much voltage drop and, at the same time, performs alternating insulation for preventing the ground fault of AC signals through a capacitor 18. Thus, the shown IC operates at the same bias voltage when the bias/filter points of all individual ICs are coupled together. Thereby, each stage is DC- coupled and each bias by-pass capacitor can be omitted.