| 摘要 |
PURPOSE:To reduce fluctuation based on the Early's effect of a constant current flowing to a load by supplying a correction current corresponding to the fluctuation of a operating potential point to a current path of a constant current transistor (TR). CONSTITUTION:A bias voltage VB1 having no AC component by a P-channel depletion MOS-FETQ11 and a diode Q4 is impressed to a base of a Q1. Thus, a constant current Iout flows to a +VCC power supply, a load RL and a collector and emitter of the Q1. If the +VCC power supply is fluctuated, the collector- emiter voltage VCEQ1 of the Q1 is increased and a current Iout tends to be increased by the early effect. An emitter-collector current IC1 of the Q2, however, is increased and the current IC1 is injected to the collector of the Q1. Thus, the current flowing to the load RL is reduced corresponding to the current IC1, kept to nearly constant current and the fluctuation of the current Iout by the Early's effect is cancelled by the cancellation with the current IC1. |
