Reliable and Flexible Switching System

[TinselKoala]

Fault Handling! Housekeeping! What a concept....

[MarkE]

Hi MarkE,

Agreed! Its going to be hard to do a single unit that will do it all!

My unit is good from about 0.04 to 7MHz for switched DC in either H-Bridge Mode or Single Switched Mode.

I think if we think broadly and then expandable after that then we can move forward with units like the Arduino Shield concept! I think there is sufficient technology out there now that this is a very achievable task and at low cost.

All the Best

  Chris

P.S: Anyone willing to do some Circuit Re-Design and throw it out there? Even if its based on the Above design!

7MHz is way beyond the regime of hard switching topologies.  You are going to have to go quasi-resonant or fully resonant in order to manage the switching losses.  Otherwise you are just going to burn your power output stage and probably the driver stage as well.

[lost_bro]

..... A few problems I had found with this circuit, supply current was not high enough from the RK-0515s at high frequency and the Fetts would not switch properly.

Chris

Hello All:


Please see the attached Isolated gate drive schematic:
This has a max Vcc of 35VDC and can source 9amps for fast switching... its a design that Cree is using in the SiC MOSFET demo boards.

This can be modified to suite the need. 
If you are not a fan of Avago optoisolators, then Silicon Labs has the LED emulator that uses proprietary technology to emulate the LED opto, but with a type of RF on chip Tx/Rx for really fast communication.
I'm a fan of GDTs, but the design of these is frequency dependent and having to wind a new one for each experiment can be tedious.

take care, peace
lost_bro

[EMJunkie]

7MHz is way beyond the regime of hard switching topologies.

Hey MarkE,

Mine works without doing any Burn Outs! I do have issues beyond 7MHz however. Heating and so on. The 47uH Inductor does a pretty good job at keeping the RF out of the isolated 15v supply.

I guess this is why we need to think outside the box!

All the Best

  Chris

[EMJunkie]

Hello All:


Please see the attached Isolated gate drive schematic:
This has a max Vcc of 35VDC and can source 9amps for fast switching... its a design that Cree is using in the SiC MOSFET demo boards.

This can be modified to suite the need. 
If you are not a fan of Avago optoisolators, then Silicon Labs has the LED emulator that uses proprietary technology to emulate the LED opto, but with a type of RF on chip Tx/Rx for really fast communication.
I'm a fan of GDTs, but the design of these is frequency dependent and having to wind a new one for each experiment can be tedious.

take care, peace
lost_bro

Thanks Lost_Bro! We will need to do some changes to go to the next step! Electronics Gurus! Anyone keen to participate?

All the Best

  Chris