| 摘要 |
<p>PURPOSE:To prevent an internal battery from being suddenly exhausted and to prevent internal data from volatizing owing to frequent use in an IC card and erroneous starting due to external noise. CONSTITUTION:Registers 4a and 4b formed in RAM 4 count the number of the starting times of the card 1 and the number of the continuous erroneous starting times of the card 1. When the values reach a set point, a reception circuit 11 is switched to a reception circuit 12 which has a high threshold and which does not require bias current or a suppression circuit makes the threshold of the reception circuit high. Thus, the internal consumed power of the card is suppressed and influence owing to external noise is prevented. When the values of the registers reach the set point, an external device informs a user of it by sound or display.</p> |
