high speed gate drive for mosfets

[exxos]

Hi all,

Has anyone got any idea for high speed switching for power mosfets ? a
typical mosfet has like 3,000pf gate capacitance and my driver can just
about cope with 1mhz, but 2mhz my drive wave appears like a sawtooth wave,
so the mosfets never really hit fully on or so, so they heat up like hell...
Theres some small info on using a class C and class E design though I dont
have any experiance in these, I think the class c design is for ham radio
users driving up into the 10mhz range...

If anyone can suggest something to look into then this would help me out...

thanks,
chris

 

[John Fields]

On Thu, 28 Oct 2004 22:47:41 +0100, "exxos" <exxos@home.co.uk> wrote:

Hi all,

Has anyone got any idea for high speed switching for power mosfets ? a
typical mosfet has like 3,000pf gate capacitance and my driver can just
about cope with 1mhz, but 2mhz my drive wave appears like a sawtooth wave,
so the mosfets never really hit fully on or so, so they heat up like hell...
Theres some small info on using a class C and class E design though I dont
have any experiance in these, I think the class c design is for ham radio
users driving up into the 10mhz range...

If anyone can suggest something to look into then this would help me out...

---
http://www.micrel.com/_PDF/mic4451.pdf


--
John Fields

 

[exxos]

"John Fields" <jfields@austininstruments.com> wrote in message
news:v913o09j21508bndqckb25mtu32v6vjmin@4ax.com...

On Thu, 28 Oct 2004 22:47:41 +0100, "exxos" <exxos@home.co.uk> wrote:

Hi all,

Has anyone got any idea for high speed switching for power mosfets ? a
typical mosfet has like 3,000pf gate capacitance and my driver can just
about cope with 1mhz, but 2mhz my drive wave appears like a sawtooth wave,
so the mosfets never really hit fully on or so, so they heat up like
hell...
Theres some small info on using a class C and class E design though I dont
have any experiance in these, I think the class c design is for ham radio
users driving up into the 10mhz range...

If anyone can suggest something to look into then this would help me
out...

---
http://www.micrel.com/_PDF/mic4451.pdf

wow, thats one sexy bit of kit! thanks,
Chris

--
John Fields