The charge input voltage is from a micro USB connector, going through a diode, to the 1A linear lithium ion battery charger IC, TC4056A by China Fu Man Electronics Group. The charging current is about 0.6A (the current programming resistor at Pin 2 is 2000Ω, I = 1V/2000Ω*1200). Taiwan Fortune Semiconductor's DW01-G battery protection IC and China Hottech Semiconductor's 8205A dual n-channel MOSFETs (drain pins tied) provide over-voltage (4.25V), over-discharge (2.4V) and over-current protection, which is set to about 3A (with Rdson of the two FETs 50 milli-Ohms total). We can get an estimate of the charge current by measuring GND and the negative battery terminal; the gain is 20A/V.
A step-up regulator FP6298 by Feeling Technology generates 5V. Given that the battery discharge limit to 3A, the 5V output cannot reach the specified 4A. The actual measured current limit is about 2.6A and 5V output tops out at about 1.5A.
The 3.3V output is generated by 3 parallel Torex XC6206P linear regulators with input from the battery. The 3.3V output does not seem stable; it is noticed that there is no output capacitor. Each regulator has rated maximum output current of 200mA. The current limit is 450mA before foldback. The dropout voltage is 500mV at 200mA. The outputs of the 3 regulators are tied together directly. If the outputs are not exactly the same, the regulator with the highest output voltage will dominate and causes the other two to shutoff. So the output current is sourced from only one regulator until it starts current limiting. Surprisingly, the actual measurements show that the output current can reach 1A. The dropout from the battery voltage is likely to be limiting factor for the output voltage to be in regulation.
A slide switch switches power to the USB A connector, but it does not turn off the regulators. The idle current is 0.3mA.
The battery holder is backwards, reversed from the polarity marking as a result of layout footprint error. The marking on the PCB is correct.
You did solve the problen on the 3,3V Voltage line right? With the blue soldered caps like in the foto?
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