I have been reading stackexchange for last 5 days but could not see any proper / answered circuit / discussion about Lipo battery charging and backup and thus asking the question here.
I am doing a circuit (GSM Modem Based) which eats around 50mA current for normal operation and a peak current of 1.6A (While GSM bursts).
I need a backup solution for the device. The circuit runs on 4V (Actually the GSM Modem can work within a voltage range of 3.6V to 4.4V. I am thinking to put a 700mAh Lipo as the power backup.
Now for the main power regulator of my circuit I have chosen LM2596 and for Lipo Charger I have made my mind to use TP4056 (for its damn low price). I know that there are specially designed power path management ICs from Texas Instruments, Microchips and other vendors, but they are costly. This circuit is a LOW COST challenge.
Can anyone guide me for a circuit for battery charging and power source switching?