So how about a Tablet power supply?

[Mr RB]

Hi again, i just checked the inductor formula for henries, voltage and current and had a go at the inductor value;

"applied voltage across L1 = 7.35v
current rise = 0 to 1.19A in 31uS"

Formula is (I believe, thanks to Wiki);
L = volts/(di / dt)
L = 7.35 / (1.19A / 0.000031 secs)
L = 0.000191 H = 191 uH.

Since the commercial wound inductors always seem to skimp on turns (bean counters in management?) and have low values I would bet that was sold as a "220 uH" part.

Altronics have it listed as; 220uH, 3A, 27mm diameter and 120 milliohms
the part actually is; 191uH, 3A, 24mm diameter and 32 millioms (measured at 1A, maybe 45 milliohms at 3A).

 

[MrAl]

Hi MrRB,

Sounds good. If you like we can continue in the other thread you started so we dont have to keep jumping between the two threads.