| 摘要 |
PURPOSE:To prevent the consumption of a built-in battery by providing a means to inhibit the resetting action of a resetting means when connection to an external power supply is not detected. CONSTITUTION:When the connection between an electronic equipment and a battery is cut off, the voltage drops at the output side of a stabilized power circuit 7. This voltage drop is detected by a B/U detection circuit 2 and a B/U terminal 10 of a microcomputer 1 is set at an L level. Thus the microcomputer 1 is set in a last memory holding state and the operation of the microcomputer 1 is stopped. When the output side of the circuit 7 is set at 3V or less, the power of about 3V is supplied to the microcomputer 1 from a built-in battery 5 via an R3 and D2. Thus the microcomputer 1 is kept in a memory holding state. As a result, the resetting action of a controller resetting means is inhibited by an inhibiting means when the connection to an external power supply is not detected by a means which detects said connection. Therefore, a controller is never reset as long as no connection is secured to the external power supply, and a built-in battery is never consumed. |
