One of benefits of stocking open source hardware kits @ the Maker store is you can always improve upon the design or just do something slightly different – so here’s a modification to the MintyBoost kit using a new boost converter chip to squeeze out even more juice. Ziemaginations writes –
…the most apparent change is instead of using the MAX756 boost converter chip, mine uses the newer MAX1675 boost converter. The biggest difference is in size, with the MAX1675 being many many times smaller. Also, this new chip does not require the use of an external diode to protect against reverse current (or whatever it did on the original Mintyboost, I did not look into it very much), increasing efficency by eliminating a major source of a voltage drop. All this adds up to a theoretical increase in efficency of up to 10%. The Mintyboost was rated at about 82%-84%, depending on the parts used. This chip is capable of up to 94%, but I lack the materials to verify that for myself. Also, my board design is single sided, allowing for easier fabrication at home. The single sided design, while easier, also removes the ability to add low battery LEDs…
Minty Boost Kit
Everything you need to make your own small & simple, but very powerful USB charger for your mp3 player, camera, cell phone, and any other gadget you can plug into a USB port to charge! Uses 2 AA batteries (not included), more than doubles your iPod 4G/5G battery life! – Link & get it at the Maker store.