| 摘要 |
PURPOSE:To supply a constant current even if the current/voltage characteristics of a transistor(TR) are changed by providing the titled circuit with a reference current source circuit for detecting the current amplification factors of a starting circuit and the TR, and correcting the dispersion of the current/voltage characteristics of the TR. CONSTITUTION:When the current amplification factor (hFE) of the TR Q4 is finite, the emitter voltage VE4 of the TR Q4 becomes VE4=V'BE0-1/3.I0/hFE.R04 (where, V'BEO is the voltage between the base and emitter of the Q4, I0 is current in a balanced state and R04 is the resistance value of a resistor R4). The value hFE of the TR Q4 is almost determined by base width and base density similarly to the IE-VBE characteristics of the TR Q4, and when the value hFE is increased, the voltage VBE is dropped if the current IE is constant, so that when a change DELTAVBE at the time of a constant IE is selected so as to be DELTAVBE=1/3.I0/hFE.R04, a constant current value can be obtained from the voltage VBe even if the IE-VBE characteristics of the TR Q4 is changed.
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