Crowbar Module

Nice!

Clone of your crowbar ;) Though on my quest for perfection I found a IC to more acuratly control tripping of the crowbar. I'm sure it's all hysteria and lots of over-perfection talking, but I read all over the net that this basic circuit is kinda hard to control at very low voltages... But I'm sure it works fine :) hehe. But just for the fun of it I'm exploring IC based design for this as we speak... lets see how it turns out.... datasheet for the IC: http://www.onsemi.com/pub_link/Collateral/MC34161-D.PDF

Now, ain't that a nice-looking little PCB. Level-up with red SMT LEDs for broken fuse indication. I found such a board at work today and one of these day's I'll clone that.

But, this is far easier to service. Kudos!

Nice find technobreath! I was looking for an up-to-date replacement for the MC3423.

The above circuit will do. But the problem with zeners is they only come in certain values.

So for example a 12.6V zener kicks in if the voltage exceeds 5%.

However the 5.6V zener kicks in after 12%. Which could already be fatal.

I'm drawing up some schems for this IC based solution now. This IC seems very promising the more I look into it. However, I have certain issues trying to wrap my head around how it really works. I'm soon there though ;). This chip, however is particulary interesting since it can do voltage window comparing. The undervoltage condition detection is a really interesing bonus. I'll try and come up with a design that trigger the SCR at precise over voltage conditions, and also a autoshutdown of all rails at under-voltage condition. I have done an experimental PSU schem some months ago to learn about how to achieve these functions using basic components. The huge drawback to this was that the design had much more discrete components, and many comparator ICs. It also provided seperate vref from a seperate ciruit. This IC seems to have all of this built in, and I only need 3 resistors for each of the ICs to set the window for it to operate in normal state. This IC also makes it easier to incorporate these status LEDs jojjelito asks for, though I'm not sure how interesting such leds really would be. A single LED that is green when all rails are operational and that is red if a fuse is gone would probably be enough for me. Those 5x20mm glass fuses is easy enough to visually confirm broken or not. I try to keep the design as simple as possible... In the final design I will pobably use panel mount fuse holders, to make it way easier to change them if they blow. Any ideas to this IC based design is very welcome.