| 摘要 |
PURPOSE:To premit quick charging and prevent overcharging with a simple conconstruction of merely providing a constant voltage circuit on the rectified output side. CONSTITUTION:A diode 32 is connected between an input terminal 23, to which a secondary battery 21 is connected, and an output terminal 33, a zener diode 37 and a diode 35 are connected between an input terminal 28, to which a rectified output 25 is coupled, and an input terminal 28, and a resistor 29 is connected between the terminals 23 and 28. Usually, the rectified output 25 is higher than the voltage of the secondary battery 25, and the battery 21 is charged through a resistor 29 while at the same time the rectified voltage is coupled through the diode 35 to the load. When the voltage of the secondary battery 23 exceeds the output voltage of the zener diode, the diode 32 is rendered conductive, so that the charging current to the battery 21 ceases. When the rectified voltage 25 is reduced to zero, the diode 35 is cut off, and current is supplied from the secondary battery 21 through the other diode 32 to the load. In this way, the application of voltage to the load and charging of the secondary battery from the rectified voltage side on one hand and prevention of overcharing of the battery and supply of current from the secondary battery to the load on the other hand are automatically switched over to one another depending upon the relations of voltages on various parts. |
