Battery monitor:

Some time ago, Philips introduced a new Battery Management IC: the SM 1501T. This IC was developed specifically for application in intelligent battery packs, increasingly popular add-ons for laptops, camcorders, electrical tools, and others. These packs consist of a traditional NiCd or NiMH battery and a rnicroelectronic circuit to indicate the state of the battery and, if required, to control a fast charging process. Thus, the IC forms the brain, as it were, of an intelligent battery.