I really like the Qlite driver (8x7135 Rev. A) but would like a version with lower current. Could this be achieved by simply de-populating one or more of the 7135’s?
If so, are there any downsides? Any termination concerns?
Thanks very much.
Yep, it’s as simple as that. Remove the 7135 chips to the output voltage that suits you. No downsides, most boards that come factory with lower output simply have an unpopulated area or two where these chips were designed to fit but not utilized.
Perfect. Thanks very much!
Yep a permanent solution would be to remove a few of the 7135 chips, they are all wired in parallel so you can just remove as many as you need.
A reversible but trickier solution would be to reprogram or flash custom firmware on the MCU and simply change the maximum output duty cycle (pwm) so that high is really a throttled back mode.
The only downsides to removing chips is some fiddly soldering and a chance of messing up the traces if you’re not careful. But it should be doable if you have a decent soldering iron and a small tip.
Good luck
Would it be possible to just use a heatgun? I haven’t done that with a 7135, but I did remove some surface mount resistors like that… just heat the board, then wait for the solder to turn shiny, and pull them off with tweezers.
Hint: they slide off more easily than lift off.
Another option is to de-solder the “OUT” pin and lift it up.
You can use hot air, but the little 7135s come off pretty easy with just an iron. Hold the chip with tweezers and lift a little while holding the iron onto the tab. As soon as the solder melts the chip will lift free. Applying enough heat to melt solder under the much bigger center pad will spread out enough to also melt the two outer pins without having to touch them.
How about just snipping a leg on the chip
Because they are not raised up off the PCB like a SOIC chip, they lay flat and the solder extends all the way under the chip package.