High-Side High Voltage IGBT-MOSFET Power Switches

[@jost459]

Nice to see that you show multiple solutions.

[@LewisLoflin]

I'm trying a new format and it seems to work. Thanks.

[@PEGuyMadison]

Thanks for the video! I have a winter project to design a new autopilot for my boat. The current one uses large BJT's for the H-Bridge, its from the early 90's so thats what was available. I wanted to replace these with MOSFETs to reduce the power loss in the circuit.

[@nicksauer6749]

Can you do a video on smoothing PWM power to a large DC motor? How to size and whether to use a capacitor or choke? Thanks

[@LewisLoflin]

Voltage and current have to be known. I'll try to cover that in an upcoming video.

[@usmanumer9871]

always great explanation. Thanks

[@LewisLoflin]

My pleasure!

[@Theunspokentruth77]

Is there a way to stop the higher voltage flow(24-72v) to the load supplying a transistor (5-10v to gate), while continuous flow of electricity to the load when 5-10v to the transistor gate is not supplied?

[@LewisLoflin]

Not sure what the question is. Voltage does not "flow" current does. Do you switch voltage ON-OFF or switch to a different voltage?

[@Theunspokentruth77]

@@LewisLoflin thanks! I meant to say when there is no current given to the transistor's gate/base, the higher current flows through the drain-source. But when low current given to the transistor, the current does not flow at all to drain-source. Just like the normally closed relays. Switching ON-OFF, not switching different voltages.

[@usmanumer9871]

when we use N channel mosfet as High side. we don't need bootstrap capacitor ?

[@dand8282]

no, the pv driver generates a voltage on the gate that is higher than the source.

[@LewisLoflin]

No. The generated PV opto is the on voltage.

[@LewisLoflin]

In an n-channel the gate is positive with respect to source. In p-channel the opposite. It is not a matter of "higher" it is the voltage difference.

[@sc0or]

VOM1271 has a very bad temperature-Vco curve sir. When it 0, Vco is about 10V, which is enough to open a MOSFET up to a Rdson from specs, but when it becomes really hot, Vco can be as low as 5V. But nobody stops us from using it in series with a zenner (cause when it's below 0, Vco can be more than 10V), but this must be calculated yet because of a small output current. I prefer to use some high voltage PWM IC and PCB coils for a floating voltage source(s), and some simple traditional optocoupler

[@LewisLoflin]

OK, thanks. I will address this in the next video with an alternative part. It is also slow frequency, which I'll also address.

[@sc0or]

@@LewisLoflin Great! Thank you sir. The slowness could not be a problem in case of a permanent on/off switch. In my case for instance, I needed 16 switches for an active cell balancer, and the cheapest solution with good specs were exactly 16 floating voltage sources. Just 50c PWM IC with 50c supplemental discretes, $1 ferrite core, x16 10c diodes, x16 20c capacitors, x16 5c resistors, and x16 17c optocouplers.

[@dan_chay]

Thank you!

[@LewisLoflin]

You're welcome!

[@colleenpierce9626]

thank you

[@LewisLoflin]

You're welcome