In recent years, electronic fuses have attracted considerable attention and the industry’s need for solutions of this kind is continuously increasing. Conventional glass tube fuses, chip fuses and poly fuses are easily affected by ambient temperatures and other usage conditions, and the accuracy of the breaking current is low. In addition, the speed of response is slow. The impact of these issues has intensified in recent years because of the miniaturization of electronic systems and the need to improve performance of systems. Another important factor to consider is that conventional fuses must be repaired or replaced after they have blown. Moreover, fuses are now required to have more advanced functions in order to comply with IEC62368-1 - the new safety standard relating to ICT and AV equipment.
Electronic fuses are integrated circuits (ICs). Here MOSFETs are used for voltage-current detection circuits, control circuits, and current path interruptions. Because they are ICs, they integrate high-precision and high-speed functions within compact packages. These cover overcurrent, overvoltage, short-circuit, overheating, etc.. Whereas conventional fuses basically only shut down the current path, electronic fuses are able to offer many protection and control functions, thereby making it relatively straightforward to obtain IEC62368-1 certification. Electronic fuses are able to overcome the issues that are associated with conventional fuses.
Electronic fuse Toshiba eFuse IC |
Poly fuse (Poly switch / Resettable fuse) |
Chip fuse | Glass tube fuse | |
---|---|---|---|---|
Protection method |
Shut down MOSFET switch | Current limit by resistance increase |
Blown conductive part |
Blown conductive part |
Protection speed |
150ns (typ.) * | Several 100 ms to several s |
Several s | Several s |
Repeated use | Possible | Possible | Not possible | Not possible |
* Example of TCKE8xx series. Speeds may vary by product.