| 摘要 |
A charge termination circuit which may be disposed within the battery cell pack and used in conjunction with known battery safety circuits to protect against charging conditions which reduce the life of a battery cell. In particular, the charge termination circuit is adapted to be used in conjunction with an off the shelf battery safety circuit and one or more power FETs coupled between the battery cell and the battery charger terminals on the battery cell package. The charge termination circuit includes a microcontroller and monitors the battery cell voltage by way of an I/O part and activates a first timer anytime the charging current to the battery is below a predefine threshold, for example, indicative of a maintenance or trickle charge. When the first timer times out after a predetermined time period, for example, two hours, the charge termination current forces the one or more of the serially coupled FETs switches to interrupt battery charging of the battery cells. The charge termination circuit also monitors the battery cell voltage and closes the FETs to allow charging when the cell voltage falls below a predetermined level. As a second level of protection, each time the microcontroller is powered up, a second timer is activated. The second timer is set for a much longer period of time than the first timer, for example, six hours, and is used in the event that the charging current does not fall below the threshold discussed above. The second timer is used to terminate charging by switching the serially coupled power FETs off when the second timer times out. The charge termination circuit is adapted to work in conjunction with conventional battery safety circuit and provide and additional level of functionality with a battery cell package in order to provide protection against operating conditions which reduce battery cell life, heretofore unknown.
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