Re: SCR based coil

• To: tesla-at-pupman-dot-com
• Subject: Re: SCR based coil
• From: Eddie Burwell <eburwell-at-HIWAAY-dot-net> (by way of Terry Fritz <twf-at-verinet-dot-com>)
• Date: Sun, 31 Jan 1999 20:59:33 -0700
• Approved: twf-at-verinet-dot-com

Device physics seems to be a factor as to why SCRs can have higher current
and voltage ratings than conventional bipolars. Acording to _Power
Transistors:Device Design and Applications_ (IEEE Press) "A good rule of
thumb that can be used for device design is that the saturated on resistance
of the power bipolar transistor will increase as the square of the blocking
voltage capability."  and for GTOs: (I imagine it will be the same for SCRs
since the silicon between the cathode and anode is the same with some
differences to the gate structure) "This conductivity modulation makes the
development of high voltage GTOs feasible because the current density in
these devices decreases at a milder square root dependence upon the blocking
voltage capability."
  The first statement is fairly self explanitory but I'm not sure about the
second. I'm assuming it means the maximum allowable current density. My best
interpretation of this is that for a given chunk of silicon and a given
blocking voltage(like 1KV) a SCR will have a higher current capacity.


Eddie Burwell

• Prev: Re: cap value
• Next: Re: SCR based coil
• Index(es):
  • Main
  • Thread