Can the diode STPS2H100 used for freewheeling of inductive load ?

[vineeth_1511]

The datasheet suggest its suitable for SMPS / lighting power supplies. Not clear if they can be used for the inductive load at the output of the hotswap controller.

[Peter BENSCH]

Welcome @vineeth_1511, to the community!

The STPS2H100 is extremely fast when switching due to the Schottky operating principle, so that you can use it for freewheeling a coil under certain conditions:

• the switch-off peak of the coil must not be higher than the maximum reverse voltage of the diode (100V)
• Schottky diodes have a significantly higher reverse current than e.g. Ultrafast Rectifiers, which can lead to significantly higher power dissipation, especially at rising temperatures, and can therefore also amplify itself with positive feedback

Hope it helps?

Regards
/Peter

[vineeth_1511]

The thing is we are using the DIODE as freewheeling for DC fan powered at 54V which consumes around 340W. Is it better to use this Diode or a TVS diode in the scenario? or Do we need to have a diode with higher rated current?

more over the Hotswap IC is rated 80V max so is it okay to use a diode with 100V or should we go for lower value?

[Peter BENSCH · Accepted solution]

The DC fan then draws approx. 6A, so that the freewheeling diode must also be able to withstand at least this current, which is why a diode with higher current is recommended, e.g. the STPS10H100C.

Theoretically, you can also use a TVS, but with a 340W motor it is a challenge to find a suitable one. However, TVS in a suitable power class are typically significantly more expensive than a freewheeling diode as mentioned above.

It is also a question of the desired behaviour: with a freewheeling diode, the motor continues to run at falling speed, while the TVS limits the voltage and thus slows the motor down more.

Regards
/Peter