TE Circuit Protection, a business unit of TE Connectivity, has unveiled the MHP-TA series of ultra-low-profile (L: 5.8mm x W: 3.75mm x H: 1.15mm) resettable thermal cut-off (TCO) devices for lithium battery protection. The MHP-TA series features a 9VDC rating, two product categories with different levels of current-carrying capacity, and multiple cut-off temperature ratings.
The launch of the series comes in response to designers who are increasingly turning to high-capacity, envelope-like LiP (Lithium Polymer) cells to optimise space in media tablets, ultra-thin PCs, electronic readers and other small, slim consumer electronics. At the same time, battery manufacturers are under pressure to find ultra-compact over-temperature protection devices that can meet the higher currents typically found in these applications.
The MHP-TA series is an extension of TE Circuit Protection’s MHP (Metal Hybrid PPTC) technology which connects a bimetal protector in parallel with a PPTC (polymeric positive temperature coefficient) device. The initial MHP product offerings, the MHP30-36 and MHP-SA series, target higher-current (above 30Vdc, 30A) Li-ion battery pack applications used in portable power tools and energy storage systems.
The new MHP-TA series is intended for applications with lower voltage and current ratings. As a result, TE Circuit Protection was able to downsize the MHP product to offer an ultra-compact device that meets the space requirements of the growing LiP market. In battery cell designs, the MHP-TA series helps provide resettable overtemperature protection, while utilizing the PPTC to act as a heater and to keep the bimetal latched until the fault is removed.
“To keep pace with the on-going trend toward miniaturization in consumer electronics, battery designers are increasingly using LiP cells in the thinnest products hitting the market,” said Ty Bowman, Strategic Marketing Manager for TE Circuit protection. “But at the same time, these designers have been faced with limited options for providing over-temperature protection in high-capacity lithium polymer cell designs. With the introduction of the MHP-TA series they now have an ultra-compact, resettable, and high-performance alternative.”
The MHP-TA series comprises nine devices with two levels of current carrying capacity: low-current MHP-TA6-9 products with an approximately 6A hold current @25°C, and high-current MHP-TA15-9 products providing a hold current of approximately 15A. The low-current MHP-TA6-9 devices are available in four different current ratings (72°C, 77°C, 82°C, 85°C) and the high-current MHP-TA15 devices in five ratings (72°C, 77°C, 82°C, 85°C, 90°C).