My goal is to power a 5V circuit using a rechargeable battery with an optional USB power source. I have a TP4056 battery charger (with battery protection circuit) to charge my 3.7V 900mAh LiPo battery such as this one here:
The default value of the current RPROG resistor on the TP4056 board is 1.2K. Do I have to change the resistor for my 3.7V 900mAh battery or is this fine?
The circuit I'm going to power, however requires 5V supply. So I'm using a DC-DC step up converter (B6286, similar to MT3608), like the one shown below, to step up the 3.7V from LiPo to 5V output. The question here is, will this 5V output be regulated?
Or do I need an additional 7805 regulator for this? For using the 7805, I understand that the input voltage for the 7805 IC now has to be stepped up from 3.7V to at least 7v. My load just consists of a XBee Module which draws around 40mA and a Joystick Module which works at 5V.
The DC-DC step up board also comes with a USB port, so I have the option of using both USB power source as well as battery as the source. So, is the a good method to supply power or is there an alternate better method? The goal is to keep the components and battery as small as possible.