| 摘要 |
PURPOSE: To provide an input protection network that prevents electrostatic discharge damage, satisfactorily maintains the waveform of an input signal, and can prevent electrostatic discharge damage in input resistance. CONSTITUTION: In the input protection network, an inverting amplifier circuit 10 performs conversion so that the input signal V1 exceeding an input range that is the range of potential of a signal that can be inputted to an IC internal circuit 11 is contained within the input range. Additionally, a protection diode D1 is connected to a virtual grounding node N1 and a positive power supply T2 between an input resistor R1 and an operational amplifier OP, and allows the input signal V1 that excessively exceeds the input range to the side of the positive power supply T2 to flow to the side of the positive power supply T2. A protection diode D2 is connected to an arbitrary point between an input terminal T1 and the input resistor R1, and a negative power supply T3, and allows the input current of the input signal V1 excessively exceeding the input range to the side of the negative power supply T3 to flow to the input terminal T1 from the negative power supply T3 to protect the IC internal circuit 11.
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