DRSSTC thoughts
Experimentonomen, Sat Aug 11 2007, 08:32PMHow high current igbt´s are needed for a tiny drsstc, ones that max do 120A pulse won´t work, eh ?
I got alittle tempted to mame a small drsstc outta a small secondary i wound that is around 1-5MHz.
Would this schemo work ? I sampled some UCC´s so i´ve changed the schemo.
mod edit-oversized images and double posting
Re: DRSSTC thoughts
CT2, Sun Aug 12 2007, 05:52PM
1-5MHz is really high for a DRSSTC, but someone on this forum made a really small one so maybe you can look at his to get some ideas. Link If it is really that small then I bet those IGBT's could be made to work with that current rating, getting them to work at the MHz range will be a tough though. Good luck!
CT2, Sun Aug 12 2007, 05:52PM
1-5MHz is really high for a DRSSTC, but someone on this forum made a really small one so maybe you can look at his to get some ideas. Link If it is really that small then I bet those IGBT's could be made to work with that current rating, getting them to work at the MHz range will be a tough though. Good luck!
Re: DRSSTC thoughts
Experimentonomen, Sun Aug 12 2007, 05:59PM
These are mosfets, NOT igbt´s! I have two secondaries i could use, either that small MHz one, or a larger one that swings at around 700KHz.
Anyway would the topology in the schemo work ? I borrowed Jim´s schemo and modded it abit, would my way of faking a enable pin work ?
Experimentonomen, Sun Aug 12 2007, 05:59PM
These are mosfets, NOT igbt´s! I have two secondaries i could use, either that small MHz one, or a larger one that swings at around 700KHz.
Anyway would the topology in the schemo work ? I borrowed Jim´s schemo and modded it abit, would my way of faking a enable pin work ?
Re: DRSSTC thoughts
Steve Conner, Mon Aug 13 2007, 09:18AM
No, IGBTs will very probably not work in the MHz range, for fundamental semiconductor physics reasons.
Steve Conner, Mon Aug 13 2007, 09:18AM
No, IGBTs will very probably not work in the MHz range, for fundamental semiconductor physics reasons.
Re: DRSSTC thoughts
Reaching, Mon Aug 13 2007, 09:56AM
meh.
i dont know if switching supply voltage to driver ics with a few hundred hz is common. there are many other ways to interrupt the signal without switching the driver ics on and off. they have a turn on time or a power on time.
why not use a nand gate like a 7400?
you can use on input of a nand for your hf signal, the other input of the nand for your inerrupter, ant voila, the output of the nand is your interruptet hf signal. put a second nand behind that to reinvert the signal for active low.
i build many drsstcs that uses the same principle and they all work without problems. at the moment im on a discrete brick driver and the control electronics are just the same
Reaching, Mon Aug 13 2007, 09:56AM
meh.
i dont know if switching supply voltage to driver ics with a few hundred hz is common. there are many other ways to interrupt the signal without switching the driver ics on and off. they have a turn on time or a power on time.
why not use a nand gate like a 7400?
you can use on input of a nand for your hf signal, the other input of the nand for your inerrupter, ant voila, the output of the nand is your interruptet hf signal. put a second nand behind that to reinvert the signal for active low.
i build many drsstcs that uses the same principle and they all work without problems. at the moment im on a discrete brick driver and the control electronics are just the same
Re: DRSSTC thoughts
Experimentonomen, Mon Aug 13 2007, 10:58AM
As i said in an earlier post, i fixed some UCC´s instead, i will probobly also skip using the small secondary and go with the one i used in the vttc.
The main question however was if my alterations to jim´s circuit would work. Will it or will it not ?
Experimentonomen, Mon Aug 13 2007, 10:58AM
As i said in an earlier post, i fixed some UCC´s instead, i will probobly also skip using the small secondary and go with the one i used in the vttc.
The main question however was if my alterations to jim´s circuit would work. Will it or will it not ?
Re: DRSSTC thoughts
Reaching, Mon Aug 13 2007, 11:40AM
i doubt that it would work. cause the driver ics need say 100µS to fully turn on when enabled with supply voltage, the hf signal within this time is low current an d low voltage, causing the gdt to go mad, and the bridge too. you wont have fun with this circuit, even if it seems to work
Reaching, Mon Aug 13 2007, 11:40AM
i doubt that it would work. cause the driver ics need say 100µS to fully turn on when enabled with supply voltage, the hf signal within this time is low current an d low voltage, causing the gdt to go mad, and the bridge too. you wont have fun with this circuit, even if it seems to work
Re: DRSSTC thoughts
Experimentonomen, Mon Aug 13 2007, 01:32PM
I said im gonna use a coil below 1MHz!!!! without topload the secondary is around 700-900MHz, which with a topload should be 400-500KHz, i even bought a large secondary on ebay that resonates @ 275KHz (bought mostly for performande comparison between my diy ones and a factory made one.)
Btw the original circuit is for a tiny drsstc that runs on several MHz, check Jim´s drsstc build featured on the 4hv main page, then tell me my coil that´ll be 3 times larger wont work.
Seriously i am beginning to question the seriousness of this forum, others make stuff that works nicely, but when i take their schem and just move some components around or convert from fullbridge to halfbridge, i get told the components cannot handle the freq and wont work.
And for the CT, i am going to put a burden on it and bias the schmitt trigger just before it turns on to reduce trigger voltage.
Experimentonomen, Mon Aug 13 2007, 01:32PM
I said im gonna use a coil below 1MHz!!!! without topload the secondary is around 700-900MHz, which with a topload should be 400-500KHz, i even bought a large secondary on ebay that resonates @ 275KHz (bought mostly for performande comparison between my diy ones and a factory made one.)
Btw the original circuit is for a tiny drsstc that runs on several MHz, check Jim´s drsstc build featured on the 4hv main page, then tell me my coil that´ll be 3 times larger wont work.
Seriously i am beginning to question the seriousness of this forum, others make stuff that works nicely, but when i take their schem and just move some components around or convert from fullbridge to halfbridge, i get told the components cannot handle the freq and wont work.
And for the CT, i am going to put a burden on it and bias the schmitt trigger just before it turns on to reduce trigger voltage.
Re: DRSSTC thoughts
Reaching, Mon Aug 13 2007, 02:42PM
i didnt said that a coil at those frequencys wont work. i said i doubt that your interrupter circuit will work, cause the tc4422 have no enable pin, you want to enable them with the supply voltage of the ics.
i said nothing about your halfbridge or feedback circuit or so, only about the parts you added in the shematic.
look at others shematics and compare to yourself. your idea would definatly not work.
yeah, and blow your parts away cause i think you missunderstand some of the members good meanings. so learn by yourself and not from others, try it out...
the first question i tell myself when a member says that my circuit wont work is; why? so i answered yours.
Reaching, Mon Aug 13 2007, 02:42PM
i didnt said that a coil at those frequencys wont work. i said i doubt that your interrupter circuit will work, cause the tc4422 have no enable pin, you want to enable them with the supply voltage of the ics.
i said nothing about your halfbridge or feedback circuit or so, only about the parts you added in the shematic.
look at others shematics and compare to yourself. your idea would definatly not work.
yeah, and blow your parts away cause i think you missunderstand some of the members good meanings. so learn by yourself and not from others, try it out...
the first question i tell myself when a member says that my circuit wont work is; why? so i answered yours.
Re: DRSSTC thoughts
Experimentonomen, Mon Aug 13 2007, 02:56PM
also i said that i have SAMPLED SOME UCC´S WHICH HAVE AN ENABLE PIN as i scrapped my idea of using transistors to chop the Vss of the TC´s. but since everyone is complaining that the circuit wont work, then heres another cidcuit:
link
Experimentonomen, Mon Aug 13 2007, 02:56PM
also i said that i have SAMPLED SOME UCC´S WHICH HAVE AN ENABLE PIN as i scrapped my idea of using transistors to chop the Vss of the TC´s. but since everyone is complaining that the circuit wont work, then heres another cidcuit:
link
Re: DRSSTC thoughts
Dr. Drone, Mon Aug 13 2007, 04:03PM
Dr. Drone, Mon Aug 13 2007, 04:03PM
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