PPTC Offers New Option for Circuit Protection

摘要

Advances in material science have made possible the development of polymeric positive temperature coefficient (PPTC) devices that are rated for line voltages of 120 Vac and 240 Vac, providing cost-effective alternative to fuses and CPTC devices. You can use several circuit protection schemes in power supplies to help guard against fault conditions and the resultant overtemperature damage, including thermal fuses, current fuses, and circuit breakers. One solution is to use a thermal fuse on the primary side and an overcurrent fuse on the secondary side. This method can protect against overtemperature and overcurrent conditions. However, this approach requires two components, which can increase cost. Also, since fuses are single-shot devices, a fault may permanently disable the charger.