| 摘要 |
PURPOSE:To prevent the breakage of a built-in semiconductor IC (integrated circuit) due to the external high voltage noise by always keeping an MOS transistor connecting a contact terminal with a conductor having reference potential under a conduction mode excepting the data writing and reading modes. CONSTITUTION:A protection circuit 3 for IC card consists of an MOS transistor TR7, and its drain D is connected to each connection conductor 6, and the source S is connected to the conductor 6 serving as the reference potential of a semiconductor IC2, respectively. A gate G of the TR7 is connected to a minus electrode of a solar battery 5. While the plus electrode of the battery 5 is connected to the conductor 6 serving as the reference potential of the IC2 like the source S. In a conduction mode of the TR7, the input signal sent from a contact terminal 4 is not transmitted to the IC2, and bypassed to a reference potential level. |
