Soft as a Feather Pillow (SFP) SSR Soft Start Circuit GB

[1883]

Thank you, you make it look easy, Is my understanding of the XH connections correct?

 

[Gthibodeaux]

Get a normally open switch - coffeemaker thermostat. I typically choose 85C trip point. Mount it on the heatsink, and if it ever closes, the SFPP shuts down and requires a power cycle to reset. If you have more than one, wire them in parallel. Any one will set it off as a logical OR function. You can test the functionality by shorting or closing the contacts of the JST connector pins.

Like this:
View attachment 1451383

I just ordered a couple of these. Where on the heatsink, in relation to the position of the mosfet's (AN39) would you install these?

 

[Gthibodeaux]

Looks pretty good. Make sure you have D4 aligned correctly or it won’t work if backwards. If you plan to use external LEDs on the indicators where the JST jacks are, you need to remove the onboard LEDs D1 and D2, as you can’t drive both simultaneously.

For testing, connect at 2kohm 10w power resistor to the output as a dummy load. Or connect primaries from a power trafo.

You need the momentary pushbutton switch to activate it.

Like this:
View attachment 1451313

Good luck!

Thought I'd also note that I checked the spec sheet on that LED, and it shows a triangle on the back for polarity. I pointed the apex away from R12, which I believe is correct.

 

[slaikan]

Building a v2.3 EZ with the updated U2

For the switch, the schematic says momentary SPDT. Trying my luck, can I use a latching SPDT switch or does the switch have to be momentary press?

Thanks

 

[xrk971]

It has to be momentary. To prove it works just touch two wires together for enable and other one for disable. A screwdriver blade touching 1 pin and middle ground on one side and other side and ground would work.

It is also called “self resetting”. Like this one should work. They are only $1.65 from China but you would have to wait 10 days.

https://a.co/d/cDmCm3G

https://a.aliexpress.com/_mPvoQAP

 

[slaikan]

Thanks for that info, ordered one off Amazon, should arrive tomorrow. Will try the shorting of pins as a test later tonight

 

[xrk971]

Hi Folks,
As Slaikan was kind enough to be the Beta tester for this board SFPP 2.3EZ, he found that you need to be careful about the specific comparator AP331 variant. Make sure you don’t get the AP331AWRG, but get the AP331AWG. The R literally means reversed logic. Slaikan tested it out by doing a dead bug wire swap to make sure it was the wrong part and it all works well now.