| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption and to extend communication distance by adjusting a degree of modulation, even if the voltage of an internal power supply is decreased. SOLUTION: When a contactless IC card requires a long communication range with a main body device, even though an internal power supply voltage by a power supply control circuit 11 is decreased, a REG signal controls a regulator circuit 10 to provide many power transmission waves to the power supply control circuit 11 so as to maintain the internal power supply voltage as its control, and operates N-channel transistors(TRs) 33, 34 of a modulation circuit 15 in a nonconductive direction so as to decrease the degree of modulation by the modulation circuit 15 and to reduce the power consumption, thereby enabling communication even if the extended communication range becomes large. |
