High Voltage Active Rectification

Thread Starter

jlawley1969

Joined Feb 22, 2021
16
I have been looking into active rectification options for rectifying 115VAC (and some where around 3A). The only chips I have been able to find for this purpose are only able to take in 80VAC. I read that this limit is because the gate voltages of MOSFETS are limited to about 80v max, if that is true then why are there gate drivers capable of 600V?

Aside from that does anyone have any suggestions as to low heat options for my situation? thanks
 

LowQCab

Joined Nov 6, 2012
510
~9 to ~10-Watts is not that big of a deal.
What you want can be done, but it adds a great deal of complexity to the Circuit.

Going with EXTREMELY over-rated,
Low-Forward Voltage,
individual Diodes,
can cut the above loss by around ~50%.

Using a Diode at around ~5% of its rated Current will
reduce the Forward Voltage to a limited degree.
Check the Data-Sheet Graphs for Forward-Voltage on various High-Current-Diodes.

How bad do you want virtually zero-loss-Rectification ?????
 

rcvkumar2000

Joined May 27, 2021
6
I have been looking into active rectification options for rectifying 115VAC (and some where around 3A). The only chips I have been able to find for this purpose are only able to take in 80VAC. I read that this limit is because the gate voltages of MOSFETS are limited to about 80v max, if that is true then why are there gate drivers capable of 600V?

Aside from that does anyone have any suggestions as to low heat options for my situation? thanks
Is there any possibility that you are confused between gate voltage and the drain-source voltage?
 

BobaMosfet

Joined Jul 1, 2009
1,768
I have been looking into active rectification options for rectifying 115VAC (and some where around 3A). The only chips I have been able to find for this purpose are only able to take in 80VAC. I read that this limit is because the gate voltages of MOSFETS are limited to about 80v max, if that is true then why are there gate drivers capable of 600V?

Aside from that does anyone have any suggestions as to low heat options for my situation? thanks
You use Capacitors to drop the current and voltage based on frequency. Then you rectify and filter.
 

Thread Starter

jlawley1969

Joined Feb 22, 2021
16
hopefully in a few years that chip will come down in price, but since I don't see people clamoring for it I doubt it. haha
 

BobTPH

Joined Jun 5, 2013
3,308
Active rectification is s big win for low voltages and not so much for high voltages.

This is because the voltage lost across the diode is the same in both cases.

The loss in a silicon bridge rectifier at its rated current is about 2V. When rectifying a 3V source, this is a loss of 67%. At 100V the loss is 2%.

Bob
 
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