Product Releases  PPTC Devices Protect Circuits and Maximize
Battery Pack Run Time  Fri, 06/01/2001 - 5:04am  Low resistance
PPTC devices provide both overcurrent and over-temperature
protection  By Frank Owen, Tyco Electronics Corporation/ Raychem
Circuit Protection Division  Wireless communication is
transforming the way we live and work, and consumer demand for
smaller portable equipment that provides longer run time is
driving the development of smaller, lighter cells with higher
energy density. Advances in digital wireless phones, cameras,
and camcorders, which require a pulsed current supply, have made
the cell's charge rate and internal impedance a critical issue.
These new cell chemistries have also increased the complexity of
battery circuit protection designs.  PPTC devices used in a wide
variety of portable electronics applications  Battery cells and
packs are sensitive to overcurrent/overtemperature conditions
caused by accidental shorting and abusive or runaway charging.
These conditions can rais