Any Interest - Soft Start PCBs

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Ray P
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#1 Any Interest - Soft Start PCBs

Post by Ray P »

These look like quite useful units to have available;

https://www.diyaudio.com/forums/power-s ... 9kpxg.html

and I wondered if there's any interest in a group buy? I had a look at JLCPCB and 20 PCBs with 2oz copper and gold enig finish would cost about $5 per board delivered to UK. Local distribution would be on top but at cost. The unknown is whether customs charges will be applied so maybe budget for about £7.50 a board and hope it comes in less.

Anyone interested?
Sorry, I couldn't resist!
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Nick
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#2 Re: Any Interest - Soft Start PCBs

Post by Nick »

He has made that very complex just to avoid using a £2 AVR (IMHO). Not sure why bother using a thermistor instead of some resistors as they will be out of circuit after half a second. But at least that’s the way I do it.

This doc has a simple power on mute that does the same sort of thing, but doesn't give you the button control

http://www.ti.com/lit/an/snaa057c/snaa0 ... 0517405713
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Wolfgang
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#3 Re: Any Interest - Soft Start PCBs

Post by Wolfgang »

He has made that very complex just to avoid using a £2 AVR (IMHO). Not sure why bother using a thermistor instead of some resistors as they will be out of circuit after half a second. But at least that’s the way I do it.
It's really too complex! Not necessary IMO.

Using a thermistor instead of resistor is probably a safety measure in case the bypassing stops working.
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Ray P
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#4 Re: Any Interest - Soft Start PCBs

Post by Ray P »

Well, that's rendered that proposition dead in the water!

Mixing metaphors, I'll plough my own furrow.
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Nick
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#5 Re: Any Interest - Soft Start PCBs

Post by Nick »

Well, there is nothing stopping you from making something that works for you as well and seeing if others want to use that. I tend to build the soft start into whatever other control function is required. So for example the power amps have that sort of soft start, but they also have temp reading from sensors on the heatsink that will shut the thing down if needed, likewise the speaker protection goes through the same system (via opto isolators from, the error detect circuit) so a error will also shut the amp power supply down. The fact you are using soft start means its likely to be an amp, and if its a amp then all the control is simpler in one place. Also allows you to flash the power switch to signal a error.

Using a 8 bit AVR to control it all is just so simple, free tools to program it are available and it just needs a bit of C and a programmer interface which can be got for £10 upwards.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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