| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a supply power control method capable of continuing to supply electric power to an electric load by maintaining near full charge state without causing a secondary battery to be over-charged, in the case where the secondary battery, charged with a surplus electric power at the time when the electric power from outside is supplied to the electric load, is fully charged, and to provide a power-supply unit using the supply power control method. <P>SOLUTION: The duty ratio of PWM control that is given to a control terminal 21 is controlled so that, before a secondary battery 4 is fully charged, the secondary battery 4 is charged with a part of or the entire surplus electric power which is a residue available by subtracting the electric power that should be supplied to an electric load 8 from the electric power supplied from an external power source 1. After the secondary battery 4 is fully charged, if there is a surplus electric power that is a residue available by subtracting the electric power that should be supplied to the electric load 8 from the electric power which is generated by a switching power supply 2 by PWM-controlling the electric power supplied from the external power source 1, the duty ratio is controlled so that the charging/discharging current of the secondary battery 4 comes to be a charging current or discharging current that is smaller than the current of refilling charge. <P>COPYRIGHT: (C)2012,JPO&INPIT |
