[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: IR - SSTC Half-Bridge Driver



Original poster: "Jan Wagner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jwagner-at-cc.hut.fi>


 > While searching the outer reaches of the Internet "Empire"
 > for information on series resonant half-bridge converters for
 > possible service for SSTC, I think I found a hidden diamond
 > in the rock pile.  The driver control chip is an International
 > Rectifier IR2153D

Looks like an elegant solution! :)

 > , and it is predominantly used for SS
 > flourescent lamp ballasts.  The advantages to the experimenter
 > are:
 > 1.  Readily available at Digikey for less then $3.00 ea. (US)
 > 2.  Is functionally a combination of a 555 oscillator + T flip-flop
 >       and high and low side half bridge HV FET driver (600V
 >       level shift no less)!!!   :^)  Useful frequency from 10's of kHz
 >       to ~300kHz (or more).

Well, rather like 10-100kHz limited because the output dead time is,
according to specs, 1.2us typical and 0.75us minimum.

 > 3.  Chip will operate from ~10V to 600V input (with proper
 >       Vcc 5mA current limiting resistor or 5mA constant current
 >       source)

I wonder what the peak output current of those gate drivers might be...
The specs don't say it. Around 250mA maybe? (but it seems to be "enough"
for IRF820 in the PFC/ballast circuit, anyway :)

 > 4.  Integral soft start and shut down (external gating) by pulling
 >       Ct pin low.  This will facilitate modulation efforts or hard
 >       shutdown with an overcurrent or fault condition.  Also
 >       may facilitate a highly desirable VCO function with only
 >       a few additional passive components.
 > 5.  Frequency adjustable by adjusting Rt value, in flourescent
 >       lamp reference below (see first reference application
 >       circuit).
 > 6.  Minimal parts count to build a SSTC from 50W to 1kW or
 >       more.

If I read the functional block diagram correctly, you could just put some
feedback signal from the TC secondary directly into the C_t pin, with
DC level shifted up to 5V. And leave out R_t, and C_t.
As long as the internal prop delay of this chip isn't too much, this'd be
the ultimate single-chip-two-IGBT SSTC solution! 8-)
Thanks for sharing the info about this IC! :)

cheers,

  - Jan

--
*************************************************
  high voltage at http://www.hut.fi/~jwagner/tesla
  Jan OH2GHR