TPS61086: External over voltage protection circuit

Takahiro Saito

Expert 5315 points

Part Number: TPS61086

Hi team,

Fig. 22 in the datasheet shows the over voltage protection circuit by a zener diode and Rlimit.

Could you explain me how to choose the breakown voltage of the zener diode and Rlimit value?

Regards,

Saito

over 5 years ago

0 Jing Ji over 5 years ago

TI__Intellectual 2645 points

Hi Saito,
Zener diode is according to your OVP voltage, For Fig22, Vout=15V we choose a 18V Zener to guarantee Vout is not higher than 18V.
Rlimit is 100ohm is OK. When R2 is short, Rlimit could prevent Zener current is not too high.

0 Takahiro Saito over 5 years ago in reply to Jing Ji

TI__Expert 5315 points

Hi Jing,

Thanks. I understand Rlimit limits the current through the zener diode when the over voltage is caused by R2 is short.

Regards,

Saito

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TPS61086: External over voltage protection circuit