Overcurrent protection
Protection against disturbances - Protective components: use

The overcurrents we deal with here are not those related to the overvoltages presented in paragraphs 1 to 4. These are slower overcurrents (rise time > 1 ms), due to variations in circuit impedance or supply voltage.

This field of application is, of course, that of thermistors.

• An interesting application for this type of protection is securing the operation of MOSFET transistors.

  These components fault (short-circuit or drain current drift) when subjected to overcurrents or overvoltages outside the Safe Operation Area (SOA) (figure 18).

  From this curve, we can deduce the values of the maximum overcurrent before degradation as a function of its duration t _d, which enables us to choose a suitable protection component: in this case, a polymer...