Archive for January 9th, 2018
A high energy collision / accident / mishap in front of Adams Fairacre Farms (a.k.a., the grocery store) demolished 20 feet of their dry laid stone wall along Rt 44, flattened several bushes, gouged trenches in the grass, and scattered plastic debris into the parking lot. The remains of a headlight eyebrow running light emerged from a snow pile:
From the back:
Contrary to what I expected, it has one white LED at each end of the chromed reflecting channel, topped with a shaped plastic lens collecting the light:
The LED PCBs are in series, which produced a backwards wire color code on one end:
The other end looked more reasonable:
The white SMD LEDs draw 300+ mA at 3.6 V, so they’re obviously depending on external current limiting provided by the regulator PCB, sporting a TLE4242 linear current regulator and a handful of passives:
AFAICT, they didn’t use the chip’s PWM control input or its LED failure status output.
Extracting the various PCBs from the wreckage and reconnecting the wires produced a satisfactory result:
The regulator limits the LED current to 120 mA at any input from a bit over 7 V to well past 12 V, with each LED dropping 3.0 V.
Dunno what I’ll use this junk for, but at least I know a bit more about eyebrow lights. The chip date codes suggest 2010 and 2012; perhaps linear regulators have become passe by now.