Patent ID: 8139330

Claim:
A semiconductor integrated circuit comprising: a first power supply domain circuit having a first power supply terminal and a first ground terminal; a second power supply domain circuit having a second power supply terminal and a second ground terminal; an internal signal propagation line propagating a signal from a circuit which belongs to the first power supply domain circuit to a circuit which belongs to the second power supply domain circuit; a voltage detector detecting a surge voltage input to the first power supply terminal and a surge voltage input to the second power supply terminal and outputting a control signal from a control signal node in accordance with the detection, the voltage detector determining a potential of the control signal node in accordance with a capacitive coupling by a first capacitor between the first power supply terminal and the control signal node, a second capacitor between the second power supply terminal and the control signal node, and a load capacitance at an output side of the control signal node; and a voltage limiting circuit connected to the internal signal propagation line, controlled by the control signal, and limiting a voltage of a signal on the internal signal propagation line.