![]() With a two wire transformer connected to an H-bridge means the associated winding is allowed to go through the push pull oscillations in a reverse forward manner. The results become even better when four N-channel mosfets are involved. We all know that among the different inverter typologies, the H-bridge is the most efficient one, since it does not necessitate the use of center tap transformers, and allows the use of transformers with two wires. How the Inverter Circuit is Configured Stage-wise.Using 4 N-Channel Mosfets for the Inverter.And unlike what others have said, if you're planning to drive the gates with just a microcontroller, you'll barely turn the high-side FETs on anyway. Long story short, what you've got here is not how you do an all-N-channel H-bridge that's more complicated. Since you're probably talking about 5 V or 3.3 V control signals, you'll need something to level-shift, but that can be done with a pair of NPN transistors. ![]() As long as your supply voltage for the H-bridge is lower than your Vgs max from the FET datasheet (usually about 20 V), your gate drive circuitry will be fairly simple. If your supply voltage is low, and you want to avoid the expense and complexity of a system like this, I recommend you go with a P-channel/N-channel H-bridge. When Q2 is off and Q1 is on, the source of Q1 is ideally close to the "Up to 200 V" supply, and the diode is reverse-biased. This supply that is referenced to the center of the half bridge powers the gate drive circuitry for Q1. This forward-biases Dboot and charges Cboot up to ~14.4 V (15 V - 0.6 V diode drop). When the low-side FET (Q2) is on, the output of the half-bridge is near 0 V, ideally. It does this by using a diode (Dboot) to charge a capacitor (Cboot) referenced to the source of the high-side FET (Q1). ![]() See the second page of the datasheet for the schematic. It generates a supply that sits on top of the source of the high-side FET. It is for half of an H-bridge, or a half-bridge, so you'd need two for a full H-bridge. If you want to use all N-channel MOSFETs in an H-bridge, you can't drive the high-side FETs efficiently without floating (bootstrapped or otherwise) supplies. ![]()
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