SOB thermal protection questions

[mfrey]

Wayne,

I apologize if the below have been asked and answered elsewhere. Here goes:

How does the thermal protection on the SOB board work? Does it shut down current to the emitter altogether upon reaching a certain temperature or does it reduce current as the temperature rises above that threshold?

What is the temperature threshold at which the thermal protection activates?

I ask the above with concern for certain hand soldering operations that tend to heat saturate the board namely the reflow soldering of a brass button on the Vin pad and the reflow soldering of the Ground ring to the can.

I worry about scrambling the thermal protection and causing it to permanently reduce the current to the emitter. Is this possible? Is it safe to assume that if the board successfully powers the emitter when the assembly is complete and cool that an SOB 1000, for instance, is running 1A to the emitter?

(I know...I wish I had that multimeter to check).

Thank you,
Matt

 

[dat2zip]

You are talking to different numbers. The board is safe to solder to higher temperatures non powered. The powered state thermal protection the IC has built in is only relavant when the board is powered up.

I don't think you should have any concerns soldering the board into place. I bake the boards at 225C to reflow them into the light engines.

I use a 700F degree soldering iron to solder on parts onto the board including the IC.

The IC stops operating when the die reaches 150C and resumes normal operation when it drops 15C.

Wayne

 

[mfrey]

Thanks, Wayne.:thumbsup: