| 摘要 |
<p>PURPOSE:To obtain the power failure compensating circuit for the memory circuit which prevents trouble of a microcomputer by supplying DC power through a transistor (Tr) except during a power failure. CONSTITUTION:The DC power is supplied to a memory circuit 20 normally from a power line 1 and if a power failure occurs, the memory circuit 20 is powered on by a storage battery 30 through a diode 31. For the purpose, a power failure detecting circuit 10 and the Tr are provided and said Tr 17 is turned off through Trs 12 and 16 when the power failure detecting circuit 10 detects a voltage drop on the DC power line 1. Consequently, if the voltage of the power line 1 drops at the time of a power failure, etc., the memory circuit 20 is not powered on from the power line 1, but powered on only by the storage battery 30, so power failure compensation is performed. Said Tr 17 normally turns on, so the memory circuit is powered on from the power source 1.</p> |
