| 摘要 |
PURPOSE:To ensure the extremely high accuracy with a clamping action by providing a charging circuit and a discharging circuit to a clamping capacitor and a differential amplifier which controls the working states of both charging and discharging circuits in response to the difference between a reference potential and the capacitor potential. CONSTITUTION:In a clamping mode a clamp pulse input terminal [base of a transistor (TR) 9] is set at a low level and the TR9 is cut off. A collector current flows to a TR8. The TRs 8 and 7 whose bases and emitters are short- circuited respectively form a so-called current mirror. The collector current equal to that of the TR8 flows to the TR7. The TR7 drives with a constant current the common emitter of differential amplifiers TRs 5 and 6 by the constant current characteristics of said collector current. The base potential V0 of the TR5 is set equal to the potential (reference potential to be clamped) at a base point A of the TR6. |
