| 摘要 |
PURPOSE: To provide the circuit for preventing saturated bipolar transistors(TRs), without stealing a base current of the bipolar TRs. CONSTITUTION: Different input pairs shape part of collector current of a TR9' in a saturation-preventing circuit 30, having two different inputs for preventing the TR9' from being in operation in a saturated mode in order to detect a state just before the TR9' to be protected reaches the saturation mode, together with monitoring of a collector-base voltage of the TR9'. The reduction in the collector current increases the collector voltage to keep a collector-base junction to be reverse bias, thereby preventing the TR9' from being in operation in the saturation mode. Since the saturation preventing circuit 30 does not steal any base current from the TR9', an input impedance of the TR9' is not offected. Thus, this saturation prevention circuit is useful for a high-performance nonlinear circuit and a high-performance linear circuit. |
