| 摘要 |
PURPOSE:To perform input clamping with simple constitution without adding a separate circuit element and to prevent the malfunction of a signal processing circuit at a rear stage from occurring by using a parasitic diode formed at an integrated circuit. CONSTITUTION:An inputted signal from a signal source Vin is inputted to the base of a transistor Q2 of emitter-follower for impedance conversion, and is supplied from the emitter to the signal processing circuit 6 at the rear stage. The parasitic diode D3 is turned on(ON) when a base voltage exceeds a prescribed voltage(V3+VF) by a voltage from an appropriate power source V3 which clamps the collector of the transistor Q2, and a base current flows to the collector, thereby, input clamping can be performed. |
