| 摘要 |
<p>PURPOSE:To provide a memory card improved so that the electric power of an external power cannot be wastefully consumed. CONSTITUTION:In a memory card 11 having a battery 15 for back-up to impress the voltage to semiconductor memories 12 and 13, switching means 34 and 35 to impress an external power voltage to the semiconductor memories 12 and 13 in place of the output voltage of the battery 15 for back-up while the external power voltage impressed to a power terminal 20 is higher than the output voltage of the battery 15 for back-up and a detecting means 16 driven by the external power voltage impressed to the power terminal 20 and to detect the output voltage of the battery 15 for back-up, preventing means 36, 37 and 38 to prevent that the external power voltage is impressed to the detecting means 16 in accordance with the size of the external power voltage impressed to the power terminal 20 are equipped.</p> |
