Kapanadze Cousin - DALLY FREE ENERGY

[lost_bro]

lost_bro


verpies posted this http://overunity.com/12736/kapanadze-cousin-dally-free-energy/msg494989/#msg494989
It is essential and important to make it as fast as possible without complicated isolated gate drivers.
Is it possible to modify this circuit and use transistors and ultra-fast diodes to obtain the same result ?

Diag 3 on verpies post

Good Day forest

Diagram #3 on Verpies post is a common Drain configuration and gains it functionality from the two pairs of Isolated dc-dc Power supplies.  If you modify/remove the isolated  power supplies you will be effectively starting over from scratch with the design.
I agree with Verpies, you cannot beat the new generation isolated drivers w/ isolated power supplies for speed and reliability.
When I have time, I will post a White Paper from TI regarding *old* school isolated gate drivers- with  miller clamping, etc.

take care, peace
lost_bro

[verpies]

How this active miller clamp can be extended for two fets connected together to make bi-directional switch, which can work also wit AC signal ?

It cannot be.  Miller clamp will only help to turn off a MOSFET faster, but it will not turn it on

Fast bidirectional switch can be made with 2 antiparallel MOSFETs and isolated gate drivers.  Isolated either by DC-DC converters or gate pulse transformers (no slow optos!)
You can do it with a stack of photodiodes in PV mode instead of the DC-DC converters, but then the MOSFETs will switch sloooooowwwwlllyy.

Why is everyone so afraid of these DC-DC converters.  Nobody sells them in your part of the world ?

can you post examples of those anty-miller gate drivers ?

I already did here.

[lost_bro]

Good day,
Figure I'd go ahead and show one of my pcbs;

It is an isolated synchronous buck converter /complementary push-pull driver. I designed it originally as part of the control circuit for a QCWDRSSTC utilizing a Synchronous buck converter capable of over 3 kiloWatts.

Capable of accepting a single-sided (not complementary) signal, like the type generated by the output of a CD4046 or Arduino for example.

The signal is processed by a TI UC3715D complementary switch which enables *independent* DeadTime control of both the Leading and Falling edges of the signal and generates a *complementary pair* of signals on the output.

This pair of signals are fed  to a pair of ACPL-K33T-060E AVAGO High  Speed optos which incorporate LVLO.

The end result is a *pair* of complementary signals which are galvanically isolated from the small signal logic input.

The design incorporates 4 isolated adjustable dc-dc power supplies, so it floats a Negative voltage on each the gate drive signals (as mentioned by Verpies) to accelerate FET/IGBT turn-off/combate Miller effect.

I have tested it up to over 1Mhz without problems. The Isolated power supplies are rated to over 5KV.

I  will use this to power my Push Pull on this replication as soon as my bench has the extra space and I have extra time to do so.

take care, peace
lost_bro

EDIT, on my next design I will use the Silicon Labs Isolation ICs as mentioned by Verpies, as I do believe they are a superior product to the Avago optos.........

[GeoFusion]

Good day GeoFusion
OK, between 2nd and 3rd layer of Grenade......  is that where the winding direction changes from CCW to CW?

take care, peace
lost_bro

Hi Good Day to you to Lost-bro,
Yes that is where the winding directions change from CCW to CW ( which I have on bench)
It can be done CW to CCW too.

Tc,
  Cheerz~

[forest]

verpies


Any of Analog Devices Adum drivers are suitable ?


The only source for me at that stage  are old samples :-(