Patent ID: 8488360

Claim:
A semiconductor integrated circuit comprising: a logic circuit module; and a plurality of first photodetectors arranged in the logic circuit module, the plurality of first photodetectors each including a first conduction type MOS transistor and a photo-detecting second conduction type MOS transistor arranged in series on a current path, wherein the first conduction type MOS transistor is placed in a state of conduction by an enable signal inputted to a gate terminal thereof from an output of a source external to an inverter for outputting a detection signal, and the photo-detecting second conduction type MOS transistor is in a state of non-conduction based on short-circuiting of a gate terminal and a source terminal of the photo-detecting second conduction type MOS transistor when the logic circuit module is operable, wherein a potential of a connection point between the first conduction type MOS transistor in the state of conduction and the photo-detecting second conduction type MOS transistor in the state of non-conduction varies based on a ratio of (i) a current driving force varying when the photo-detecting second conduction type MOS transistor in the state of non-conduction is irradiated with light and (ii) the current driving force of the first conduction type MOS transistor in the state of conduction, wherein the connection point between the first conduction type MOS transistor and the photo-detecting second conduction type MOS transistor is connected to an input of the inverter for outputting the detection signal, and wherein the detection signal is used for stopping operation of the logic circuit module.