Hi guys, finally got around to building an LTC3539 boost converter, the chip has been sitting on the bench for months
. Boost a chemical battery, I don't know, let's go for it, give it a shot, nice idea, build it and then "to measure is to know". Classic science.
So I built an LTC3539 boost converter, same as Jay_Diddy_B's design, 1MHz, burst mode with 2x10uF on input and output, it works well, nice one Linear Tech
. Not trying to build it small I used a relatively huge inductor, best I could do for a prototype.
Inductor is 8 turns 0.5mm diameter copper onto a Ferroxcube TN14/9/5 4C65, Al is 50nH to 55nH per turn squared (deliberately wrote squared there). Overkill and probably 3u3, peak flux density using volt time product is B = V*t/N*Ae, units are B=Tesla, V=Volts, t = us, Ae = mm
2 and N = number of turns. V = 1.5 (V), t = 0.5 (us) (assuming 50% duty cycle), N = 8 (Should have been 7 to get 2u2), Ae = 12.3 (mm
2) and then B = 7.6 mT or not very much at all. At least I can justify my inductor choice. That's going to be linear BH loop and almost lossless. Next thing is switching losses...
Nice to see independant engineers choose the same chip, I chose startup voltage, peak current and operating frequency as my parameters. Just thinking out loud.
Going to test two Energizer Max Alkaline batteries with and with out boost converter at 150mA load, seems a good place to start.