Hey there,
I need a step-up converter which goes from approximately 3V to 5V. It will be used for a portable device and should charge a smartphone. I used the LT1308B. But the problem is the high power consumption when no phone is connected. It uses around 2mA. And thats too much for portable devices. Can somebody tell how to solve this problem or is there another IC which is more efficient.
I'm looking forward to your replies.
Best regards
Maurice W.
There is stuff at pollulu in the xxµA range. Keep the max current in mind, though.
You could add a switch to switch it on manually.
Both of these support an enable/disable pin:
Perhaps there is a possibility to do that kind of automatically, e.g. switch it off when device is unplugged (no current over the usb port), and restart with a pushbutton.
Is it a safe assumption that all devices will tie shield and ground together? Then one could use that a a switch. Connect shield on your side with 10kOhm to 5V. Then it will be high when nothing is plugged in, and low when a device is plugged in which ties shield to ground. Would probably have to invert that signal afterwards. No idea if that is something one would like to do or if it is a really stupid idea, though. I would not do it without further assurance.