| 摘要 |
A battery charging circuit includes a first voltage divider means connected across a source of DC potential. An impedance element connects the first voltage divider to an input terminal of an first operational amplifier. Another input terminal of the first operational amplifier is connected to a second voltage divider which is connected across a series combination of a resistor and a battery to be charged. The output terminal of the first operational amplifier is connected to a current regulating device for controlling the magnitude of a charging current flowing from the DC source to a battery. When the terminal voltage of the battery is below a predetermined value, the first operational amplifier effects the flowing of the charging current of a first magnitude, sufficient to rapidly charge the battery through the current regulating device. A second operational amplifier has one input terminal connected to the point between the resistor and the battery, and its other input terminal connected to a third voltage divider. The third voltage divider is connected in parallel with the second voltage divider. The output of the second operational amplifier controls a transistor which is connected to the impedance element. When the battery charging current falls below a predetermined value, the second operational amplifier effects conduction in the transistor which, in turn, effects a change in the signal applied to the first operational amplifier from the impedance element. That change, in turn, causes the magnitude of the charging current to be reduced to a value sufficient only to substantially maintain the battery in its acquired state of charge. Thereafter, when the battery terminal voltage decreases below a predetermined value, the second operational amplifier provides an output signal which is effective to return the transistor to its initial nonconducting state whereby the first operational amplifier again effects the flow of the charging current of the first magnitude through the current regulating device, and the battery is again rapidly charged, but not overcharged.
|
