Method and apparatus for charging batteries
View Patent ↗A charge system is disclosed. A charge system includes a switching device and a controller. The switching device performs switching of a DC input voltage at a predetermined switching frequency to generate an output voltage, and the output voltage being utilized for charging said battery. The controller allows the switching device to operate at a first switching frequency immediately after starting of charge and at a second switching frequency when a frequency changing condition holds. The second switching frequency is higher than that of first switching frequency.
1. A charge system comprising:
a switching device that performs switching of a DC input voltage at a predetermined switching frequency to generate an output voltage, the output voltage being for charging a battery; and
a controller for allowing said switching device to operate at a first switching frequency immediately after starting of charge and to operate at a second switching frequency when a frequency changing condition holds, wherein said second switching frequency is higher than said first switching frequency, wherein said controller controls said battery in a constant current/constant voltage control manner, wherein said controller allows said switching device to operate at said first switching frequency during most of said constant current charge duration, and at said second switching frequency during a part of said constant current charge duration and during the entire portion of said constant voltage charge duration.
2. The charge system of claim 1 , wherein said frequency changing condition is set within a range where a protection circuit does not operate with a ripple voltage included in said output voltage, wherein said protection circuit being configured to protect said battery, and at timing when a charge electricity amount becomes the highest.
3. The charge system of claim 1 , wherein said switching device includes a first switching device and a second switching device operating in a synchronous rectification manner.
4. The charge system of claim 1 , wherein said controller determines that said frequency changing condition holds when an average value of said output voltage reaches a predetermined value during said constant current charge duration.
5. The charge system of claim 1 , wherein said controller determines that said frequency changing condition holds when a remaining electricity amount of said battery reaches a predetermined value during said constant current charge duration.
6. The charge system of claim 1 , wherein said controller determines that said frequency changing condition holds when a duty ratio of said switching device reaches a predetermined value during said constant current charge duration.
7. The charge system of claim 1 , wherein said controller determines that said frequency changing condition holds when a peak value of said output voltage, including a ripple voltage reaches a predetermined value during said constant current charge duration.
8. The charge system of claim 1 , wherein said battery is a lithium battery.
9. The charge system of claim 8 , wherein said battery is of a quick-charge type capable of being charged with a charge current exceeding 1 C.