I recently purchased this GSM/GPS module.
I would like to power this module via a USB cable but can see that it has varying input voltages.
So bearing in mind that USB is 5V and that I'm an electronics newbie (I've only worked with evaluation boards that regulate the voltage for me), I'm not sure how to proceed.
On the site it recommends the following voltages:
- GSM: 3,2 ~ 4,8 V
- GPS: 2.8 ~ 4.3 V
- VCHG: 5 V
I assume 'VCHG' has something to do with charging. I can't see any battery in the schematic below so I'm not sure what that's used for but I can also see that 'TEMP BATT' is pin 2. It also has an ON/OFF switch on pin 1, is this a red herring?
If VCHG won't help (I had hoped that would be some form of input that would regulate the voltage for me but I'm not sure), what's the easiest way to reduce the voltage down to the recommended amount? Should I aim for half way between the varying voltage values? Also, if I was to use GSM and GPS, do I only need to power pin 17 (GPS) as it appears that they connect after the R13 resistor.
The datasheet for the SIM928A can be found here.