Lilliput +12v PSU...how can it work?

MikeH · 01-08-2004, 04:55 PM

OK gearheads....
After pulling apart the Lilliput 12V DC-DC supply, we find that it uses an LM2596-12 switching regulator inside. However, if you look at the graph of the dropout voltage (below), it shows approx .9v required from input to output. This (to me) means that the input must be at least 12.9v for the output to be at 12v. Has anyone with a weak battery experienced the Lilliput going blank when the engine is off? Am I reading this wrong?

shchua · 01-09-2004, 12:30 AM

I bench tested the Lilliput cigarette lighter adapter and found out that the dropout voltage is more like 1.7V (12.5V in, 10.8V out). The Lilliput works fine at 10.8V - only thing is the brightness of the backlight is visibly reduced.

MikeH · 01-09-2004, 09:31 AM

Schua...did you measure the current draw?