cupoftea
Advanced Member level 5
Supposing I have a 28V bus system which can suffer surges of up to 175VDC for 100ms.
I also need to add in reverse polarity connection protection.
I will use low side NFETs to do the reverse polarity protection.
When the described surge is not there, for the reverse polarity protection, I can get away with 50V low side NFETs at the front end….but supposing someone connects up with reverse polarity, then just leaves it connected in reverse….then when the 175V transient comes along, it will blow up the 50V NFETs.
Would this make you want to use 200V reverse polarity NFETs instead?
Is it cheating to use 50V NFETs in this case?
I also need to add in reverse polarity connection protection.
I will use low side NFETs to do the reverse polarity protection.
When the described surge is not there, for the reverse polarity protection, I can get away with 50V low side NFETs at the front end….but supposing someone connects up with reverse polarity, then just leaves it connected in reverse….then when the 175V transient comes along, it will blow up the 50V NFETs.
Would this make you want to use 200V reverse polarity NFETs instead?
Is it cheating to use 50V NFETs in this case?