| 摘要 |
<p>PURPOSE:To inform automatically the drop, etc. of a battery power supply to the main body side of a computer after reducing the consumption of a battery due to forgetting to turn off a power supply, by providing a means which detects the level of the signal supplied from the computer main body incorporating the battery power supply. CONSTITUTION:A detecting circuit detects the level of the signal supplied from a computer main body incorporating a battery power supply. For instance, a power supply VCC is supplied to a power supply control block 21 of an interface circuit 20 from the computer main body. Thus a transistor TR2 is turned on, and then a TR1 is turned on by the detection output of the TR2. Then the voltage VDD given from a battery 24 is supplied to a signal conversion block 22. The voltage level of the battery 24 is detected by a signal converting circuit consisting of transistors TR3 and TR29 and 29' of the block 22. Then the state of the signal supplied from the outside is delivered to a data bus by a transmission/control circuit block 23 via an I/O port 27 and on the basis of the result of detection of the voltage level of the battery 24.</p> |
