| 摘要 |
PURPOSE:To stabilize a collector-base voltage of a 1st transistor(TR) by forming a differential amplifier by 3rd and 4th TRs of the same polarity as that of the 1st TR and a 2nd TR, a current mirror circuit and a current source and giving its differential output to a common base of the 1st and 2nd TRs. CONSTITUTION:The differential amplifier is formed by NPN TRs Q3, Q4, a current mirror circuit 11 and a resistor R3, and its differential output is fed to the common base of the TRs Q1, Q2 to realize the beta compensation and the stability of the collector-base voltage of the TR Q1. Thus, the current amplification factor (betaN) dependancy of TRs is decreased to reduce the current error between the input and output currents and to suppress the fluctuation of the base-collector voltage of the current input TR.
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