2

Application information

2.1

Overvoltage crowbar protection

An application featuring the strong current robustness of TN5015H-6I is the overvoltage crowbar protection,

implemented in AC/DC switch mode power supply. An application global schematic is shown Figure 12. Global

schematic of a crowbar overvoltage protection application.

In case of overvoltage on line power terminals (example: lightning event), the voltage is rising quickly across the

DC/DC module and can reach voltages limitations of devices, leading to possible application failure. The

overvoltage crowbar protection answers to this issue by placing the SCR in parallel of the rectifier bridge output,

and limiting the induced surge current during electrical over-stress.

The protection principle is to trig the TN5015H-6I when the overvoltage reaches the maximum authorized voltage.

At TN5015H-6I turn-on, the electrical overvoltage stress becomes an overcurrent stress, flowing through the

TN5015H-6I. No more voltage stress is applied across the down stream converter and the TN5015H-6I absorbs

the overcurrent, making the application safe.

Additionally, the AC/DC SMPS efficiency and stand-by losses are not impacted by the protection thanks to the

very low leakage current of the TN5015H-6I.

TN5015H-6I

Application information

DS12178 - Rev 3

page 7/13