| 摘要 |
PROBLEM TO BE SOLVED: To operate the writing and reading operation of a flash memory 36 by obtaining a power from a data input edge RXD and a data request input edge CTS of a serial interface RS232C, and driving a processing circuit. SOLUTION: An input signal having waveform changing across +10 V corresponding to a logic '1' and -10 V corresponding to a logic '0' is applied to signal input lines 8 and 9, and first and second capacitors C1 and C2 are changed through diodes D1, D2: D3, D4. The charge of the second capacitor C2 is polarity inverted by a polarity converting circuit 24, and stored in a third capacitor C3. The output voltages of the first and third capacitors C1 and C3 are voltage converted by a step-down type chopper system switching regulator, and applied to a processing circuit 31. Thus, the writing and reading operation of a flash memory 36 is controlled. Therefore, an outside power source can be unnecessitated. |
