With this tiny thing you can almost charge all the devices which are charged via the USB, like iPod or cellphones, with only two Aa-Cells!
Thus why I should build this?
The reason is completely simple: I am bored empty batteries (IPod, cellphone) while I 'am on the outward journey. And the solution with the linear regulator as 7805 is in fact very
simple, but very unefficient, because: firstly you need a provisioning which provides approximately 3 volts more than you need for the usb and secondly the majority of the cases the difference enters the tension of entry and the tension of output are lost in heat.
The solution to the problem comes from linear technology. Compenent most important of the cicuit presented in the next stages is LT1301 . It is a small stage
to the top of the converter for establishing the mode of commutation actuate the supplys with only some external components.
Skema Rangkaian Charge HP Menggunakan battery AARangkaian Charge Spesifikasi:
- Input: 1,5 to 3 volts
- Output: 5 Volts @ 200mA max. (really enough to charge an iPod mini or a mobile phone, trust me ;-) )
- Watts and efficiency:
- In: 0,95W at 2,5 V
- Out: 0,875W at 5 V
- loss: 0,075W
- 8 percent loss
- 92% efficiency
The input capacitator should be as close as possible to pin 6 (Vin) of the LT1301!
Keep all cicuit traces short! Directly tie Pin1(GND) Pin8 (PGND) and Pin3 (Shutdown) togheter and connect it to ground. Avoid long soldering times for to prevent destruction of components by overheating... For the detailed placement of the components on the circuit board you can use your own creativity...
So much now its fact, but before connecting it to any device usb, is sure that functions correctly! (the tension should be 5 volts, the LED only would owe rougeoyer, etc) when all ischecked and you are sure that all works you can (if you like it) start to put the hot cast iron around it as a a little protection. If you would put 't as the hot cast iron you can put device in a box of matches or very which you want. left wing of the image you see an older version of the right-sided than you see the smaller and increased version newer