TPS2663: Reverse polarity protection while using surge protection diode

Carlo Branca

Part Number: TPS2663

We are using the TPS26631 and we used the same simplified schematic in pag.1 of the datasheet. We use both the FETs for RPP and RCB and D1 for surge protection. When the serge protection diode is present, in case of reverse polarity the surge protection diode would be protecting the downstream device rather than the FETs, but it would draw high current from the upstream power supply. Is this the intended behavior in this configuration? Or am I missing something?

Thanks,

Carlo

over 1 year ago

0 Kunal Goel over 1 year ago

TI__Guru* 79181 points

Hi Carlo,

Purpose of D1 is to clamp positive and negative surges at VIN below the eFuse VIN abs max ratings. D1 breakdown should be greater than operating VIN so that it does not draw current in normal operation.

Regards

Kunal Goel

0 Carlo Branca over 1 year ago in reply to Kunal Goel

Prodigy 30 points

Hi,

We used the diode that is recommended in the excel sheet (https://www.ti.com/tool/download/SLVC765) SMCJ33CA. In normal operation if Vin is positive, everything is fine. But if Vin is reversed, let say by by operator error, then SMCJ33CA turns on and draws high current from the upstream power supply. Is the suggested diode the wrong one then? Do i need a diode that breaks outside of -60V and 67V? Even if our device is a 24V device?

0 Kunal Goel over 1 year ago in reply to Carlo Branca

TI__Guru* 79181 points

Hi Carlo,

You will need to use a bidirectional TVS diode to get protected from reverse voltage.

Regards

Kunal Goel

Power management

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TPS2663: Reverse polarity protection while using surge protection diode