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UCC3958 -1/-2/-3/-4

UNITRODE CORPORATION

7 CONTINENTAL BLVD. • MERRIMACK, NH 03054

TEL. (603) 424-2410 • FAX (603) 424-3460

When the chip senses an under-voltage condition, it dis-

connects the load from the battery pack and shuts itself

down to minimize current drain from the battery. Several

circuits remain powered and will detect placement of the

battery pack into a charger. Once the charger presence

is detected, the linear loop is activated and the chip al-

lows charging current into the battery. This linear control

mode of operation is in effect until the battery voltage

reaches a level 300mV above the under-voltage thresh-

old, at which time normal operation is resumed.

APPLICATION INFORMATION (continued)