Ptc Resettable Fuse Application Notes

0805l150sl and 1206l150sl are ideal for overcurrent protection in vbus of usb 3 0 usb 2 0 ports.

Ptc resettable fuse application notes. Both devices function by reacting to the heat generated by the excessive current fl ow in the circuit. There is an important area of applications where the use of resettable fuses ptcs has become a requirement. Positive temperature coefficient devices provide overcurrent protection for applications where ultra low. Use of low resistivity surface mount pptc in li ion polymer battery packs control ic battery.

A secondary method of battery protection application note. The graph below shows the response of the ptc device to temperature. Choosing between a ptc and a fuse overcurrent circuit protection can be accomplished with the use of either a traditional fuse or the more recently developed resettable ptc. This application note addresses the various requirements for protecting the universal.

A typical battery management unit bmu design figure 3. Basically ptc can protect the circuit system from overcurrent by increasing ptc resistance exponentially. This ptc operation is similar function as a fuse. Resettable ptc thermistors for industrial pdf 233 15 kb warning lights pdf 163 42 kb polymeric positive temperature coefficients pptcs for current limit control in power supplies to reduce power and cost application note pdf 536 55 kb.

A resettable fuse or polymeric positive temperature coefficient device pptc is a passive electronic component used to protect against overcurrent faults in electronic circuits the device is also known as a multifuse or polyfuse or polyswitch they are similar in function to ptc thermistors in certain situations but operate on mechanical changes instead of charge carrier effects in semiconductors. Figure 2 2 is shown operation of ptc device as resettable fuse. Poly fuse resettable ptcs specifications are subject to change without notice. The fuse element melts open interrupting the current fl ow while the ptc changes from low resistance to high resistance to limit current fl ow.

Polymeric positive temperature coef cient resettable fuse thermal fuse or a controllable battery protector see figure 3. Littelfuse polyswitch and poly fuse devices are polymeric positive temperature coefficient pptc devices which offer a resettable overcurrent protection alternative thereby reducing warranty service and repair costs. Polyswitch resettable ptc fuses. Verify the performance in their application.

A traditional fuse is always the choice of the designer or technician but in some cases ptc s offer a convenient form of circuit protection to improve the reliability of an application. Surface mount low rho series. Both devices function by reacting to the heat generated by the excessive current flow in the circuit.