I'm not a electronics engineer/student, so please escuse me if my query sounds a bit naieve.
I have a Mp3+FM module (link) which I can power with a regular micro USB charger(or desktop USB). As the module cannot power a speaker I have attached a PAM8403 Class D Amp module (link) (i think it can take from 3.5 to 5.5 V).
To make this setup mobile I added a 18650 rechargable 3.7V 2200mAH battery (link) and a TP4056 1.2A 5V charging module(link). Now when I run the circuit with 5V external power attached to TP4056 it works well (thoe the volume is low and it takes few power cycles to start). But when I run it using only the battery, the module just keeps cycling the power (On/off..). (Diagram 1)
I thought as my battery is a bit underpowered and TP4056 only provides 4.2V power I can add a step-up converter. So I added MT3608 DC-DC Step Up Converter (link) and adjusted it to 5V, 7V & 8V but none of it seem to work. Can you please let me know if I had missed anything ?
Unfortunately as I don't have any electronics background, I am not aware of how do debug (sorry for the software lingo) this issue. I do have a multimeter so I would really appreciate if anyone can point me in a right direction or jolt down some steps to do more investigation.
Update: As requested these are the power specs of the various modules:
Input Supply: 5V;
Output: 550 mV;
- PAM 8403
3W Output at 10% THD with a 4Ω Load and 5V Power Supply;
Speaker With: 4~8ohms, recommended: 4ohms Speaker Power: 2~8W
- TP 4056 Battery Charger
Based on TP4056 1A Standalone Linear Li-lon Battery Charger with Thermal Regulation chip;
Preset 4.2V Charge Voltage with 1.5% Accuracy;
2.9V Trickle Charge Threshold (TP4056);
- MT3608 StepUp
Integrated 80mΩ Power MOSFET;
2V to 24V Input Voltage;
1.2MHz Fixed Switching Frequency;
Internal 4A Switch Current Limit;
Maximum Output Current: 2A;