| 摘要 |
<p>PURPOSE:To produce a sequence signal for input of a battery back-up mode regardless of the voltage of a battery back-up system and to facilitate the use of a general-purpose power supply which does not output a power cut-off previous announcement signal. CONSTITUTION:A battery back-up system is provided with a DC/DC converter 3 which produces a working power supply of an SRAM 6 from the power voltage Vcc of the system. A voltage detecting circuit 1 is provided with a means (reset IC, etc.) which produces the timing signals (PD1, PD2) for battery back-up based on the power voltage level of the system.</p> |
