| 摘要 |
<p>PURPOSE:To output a minute current accurately by providing a current mirror circuit generating a constant current being a multiple of A of a constant current IE and a current mirror circuit generating a constant current being a multiple of B of the constant current IE and outputting a constant current of a multiple of (A-B) of the value IE. CONSTITUTION:A current output comparator consists of NPN transistors (TRs) Q12-14, PNP TRs Q15, Q16, resistors R7-10, and a collector current IC 12 of the TR Q12, the TR Q5 acts like a current mirror of the TR Q3, the TR Q12 acts like a current mirror of the TR Q13, and the TR Q16 acts like a current mirror of the TR Q4 respectively. Through the constitution above, when the TR Q2 is cut off, the TRs Q4-Q7 and the TR Q16 are cut off to cause a current to flow to the TRs Q3, 8, 15, 13, 14, 12 and the current is IC8-IC12. In such a case, the resistance of resistors R1, R4, R8, R9 is selected properly to regulate the current IC8 to have relations of (IC8)=A(Ir) (Ir is a collector current) and (IC12)=B(Ir). When the TR Q1 is cut off, the current flow is reversed.</p> |
