| 摘要 |
PURPOSE:To prevent the waste of the current capacity limited for a battery, etc., by counting the time during which the power supply voltage drops between two points to stop the device when the counting time is shorter than a certain time, then stopping the device at the value less than the minimum voltage level with which the working is assured for the device when the counting time is longer than a certain time. CONSTITUTION:The power supply voltage voltage drops as shown by a curve A in a reproduction mode. In this case, a timer is started at a time point when the voltage drop is less than the voltage value V1. Then the time during which the drop becomes less than the voltage value V2 is counted within a control circuit 2, and therefore the time T1 is calculated. With this dropping speed, the control is impossible if the operation is stopped with the remaining current capacity at a level less than the minimum voltage value V3 which can assure the operation. Therefore the operation is stopped before the voltage drops down to the value V3. With a curve B, the value V1 is changed to a level less than the voltage V2 during the time T2. The remaining current capacity has a margin although the operation is stopped at the level less than the V3. Thus the control is always possible. |
