Replacing diode + MOSFET with BJT on High side mains

Thread Starter

tomerbr

Joined Oct 16, 2017
46
Are you using both diodes in the package? If so are you using any series resistance for current balancing?
I am using both, I do not use anything to balance the current as each one is sufficient for my requirements.
The main reason for choosing that diode was its low Vf and the package which is very good at dissipating power and also has a matching heatsink.
 

Irving

Joined Jan 30, 2016
4,001
I am using both, I do not use anything to balance the current as each one is sufficient for my requirements.
The main reason for choosing that diode was its low Vf and the package which is very good at dissipating power and also has a matching heatsink.
Agreed, its not a bad diode, but I think there are more cost effective devices that meet the requirement, e.g. V30D45CHM3_A/I which is a near identical part priced at $0.509 @ 2000off v currently $1.690 @ 1600off (Mouser)

Between that and MOSFET change that could be a cost saving of $1.84 per unit @ 2000off quantity
 

Thread Starter

tomerbr

Joined Oct 16, 2017
46
Agreed, its not a bad diode, but I think there are more cost effective devices that meet the requirement, e.g. V30D45CHM3_A/I which is a near identical part priced at $0.509 @ 2000off v currently $1.690 @ 1600off (Mouser)

Between that and MOSFET change that could be a cost saving of $1.84 per unit @ 2000off quantity
I can see that.
That is most helpful. thank you very much Irving
 

Irving

Joined Jan 30, 2016
4,001
You're welcome :)

Incidentally, another thought would be to put the switch off MOSFET in the -ve side,, and use a N-channel MOSFET which gives many more options for low-cost devices. Of course the trade off is complications around the ground reference but these can usually be resolved.
 

Thread Starter

tomerbr

Joined Oct 16, 2017
46
You're welcome :)

Incidentally, another thought would be to put the switch off MOSFET in the -ve side,, and use a N-channel MOSFET which gives many more options for low-cost devices. Of course the trade off is complications around the ground reference but these can usually be resolved.
That is true ( I actualy have that solution in another part of the board), but I usually prefer to keep the return path as smooth as possible.
 
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