Main > Everything Else

IC diagrams

<< < (4/4)

Ed_McCarron:
If I'm switching a solenoid or a motor via the output on a PIC, I like the FET as a low side switch.  Simple, low loss, works like a charm.

For power work, I still like the venerable 2N3055.

Guess that means I'm older. :)

lilshawn:

--- Quote from: Ed_McCarron on January 06, 2011, 07:52:22 am ---For power work, I still like the venerable 2N3055.

--- End quote ---

what not a fan of the 2N2222?? i suppose you loath the 555 too!  :lol

Ed_McCarron:

--- Quote from: lilshawn on January 06, 2011, 10:03:21 am ---
--- Quote from: Ed_McCarron on January 06, 2011, 07:52:22 am ---For power work, I still like the venerable 2N3055.

--- End quote ---

what not a fan of the 2N2222?? i suppose you loath the 555 too!  :lol

--- End quote ---

It's all about power.  2N2222's pop when you pass 10A thru them.  I still miss the LM3909 LED flasher chip that got many a kid following Forrest Mims' guides into electronics.

MonMotha:
I did an off-line flyback SMPS design that used a Fairchild FCPF16N60 as the switch.  This is a true monster of a MOSFET for its size (TO-220 package): 16A w/ a rated blocking voltage of 600V.  Honestly, it was more than the design needed on those fronts, but the very low Rds(on) of less than a quarter ohm combined with the low gate capacitance (55nC) made it a good choice.  The supply operated from either 22-180VDC or 22-120VAC and delivered a regulated 24V DC at about half an amp.  The humongous input voltage range was a challenge, but the sucker worked.

I had a small heatsink on the FET, but it probably wasn't strictly necessary.  I put it on there as a precaution since Rds(on) increases with junction temperature, and without an easy way to measure the FET's temperature and perform a thermal shutdown, it would have been possible for the device to run away thermally.  I was able to use the isolated TO-220F rather than the metal tab version, at least, so there was no electrically hot heatsink.

Interestingly, MOSFETs do NOT suffer from thermal runaway in a typical class AB push-pull linear amplifier design, unlike bipolar devices.  This may be one reason why were popular in automotive applications.


I've been cooking up a three-phase inverter design for a while, now.  My goal is 60A out at 240V (yes, you read that right: 60 AMPS at 240V).  Probably going to be using some International Rectifier IGBTs (I forget the exact part number), not MOSFETs, though.  The MOSFETs just don't seem to be quite there at that power level, though they'd have lower on-state losses.  I bet that'll change over the next 5-10 years as small, low cost power electronics are driven by demand for the electric vehicle market.  And yes, the power electronics are going to be tested inside an explosion proof housing!

Navigation

[0] Message Index

[*] Previous page

Go to full version