Re: 556 sstc idea

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Fucian-at-aol-dot-com>

In a message dated 2/10/02 3:43:42 PM Eastern Standard Time, tesla-at-pupman-dot-com 
writes:

<< Hi Matt and All, it's very possible, they are used in this way all
 over the place. Not exactly for MOSFET half-bridges, but, for time
 delay. Where one output goes low, then after a preset time, the other
 output goes high and vice versa. Where the two outputs are never both
 hi at the same time.
 
 It is this the so-called "break before make" operation that you want
 in MOSFET bridge circuits, where the one (in a half-bridge) or two
 (full-bridge) MOSFET's don't conduct at the same time. When they are
 all on at the same time, the situation is referred to as
 "shoot-through" or "cross-conduction", and usually results in gooey
 MOSFET splattered all over the inside of a project box ; )
 
 Just for the record, I will say that there's nothing you can do with
 a 556 that can't be done with two 555's. Other than save board space.
 The 556 is nothing more than two 555's, with their Vcc and GND pins
 internally connected. Everything else is totally separate.
 
 I can't remember the schematic offhand, but I think it results in a
 time delay that is way too long for our SSTC use (introduction of
 dead-time where no FET's are on).
 
 I think it's better suited for photography and other stuff that runs
 in the millisecond range, but I imagine a variation would get down
 into our required microseconds.
 
 Take care,
 
 Justin Hays
 KC5PNP
 Email: justin-at-hvguy-dot-com
 Website: www.hvguy-dot-com
  >>
Alright, it was just an idea:-)

Matt