Tyco Electronics Announces 24V Bus - Truck Circuit Protection

Key device parameters for the family of seven devices include hold-current ratings from 0.50A to 10A with a maximum fault-current rating of 100A. The maximum operating voltage rating is 32V for all devices, the same as for vehicle electronics in Europe. The maximum operating temperature for all the devices is 125°C, permitting their use not only in the passenger compartment but also in the engine compartment. This is the first product family from Tyco Electronics to offer 32V with a high temperature rating. All the devices are housed in radial-leaded packages.

The devices are tested to the AECQ200 standard and are ROHS and ELV compliant.

Next generation wire harnesses generally have a hierarchal structure with the main power trunks dividing into smaller and smaller branches with overcurrent protection at each node. This structure results in the use of smaller wires - which save volume, weight and cost - as well as maximum system protection and fault isolation.

To gain maximum savings while achieving maximum system protection, it is difficult to route all the wires in and out of a single junction box that is accessible by the driver, said Jasmine Hu, product manager for Tyco Electronics' Raychem Circuit Protection Products. By using resettable circuit protection devices, like the AHEF family, multiple junction boxes can be used that don't need to be driver accessible.

For example, she continued, they can be placed under the seat or in door panels. And because the devices are rated to 125°C, the junction boxes can be located close to their intended electronics, whether in the passenger compartment, protecting BCUs (Body Control Units), or in the harsh environment of the engine compartment, protecting HVAC controls for example.

The resettable devices are of through-hole construction. They don't need fuse holders to be installed but can be directly installed onto PCBs with pick and place equipment, giving system designers added flexibility.