Attaching the power schematic for EC200U. It includes 74LVC1G00GV NAND IC which acts as flipflop to enable short press ON and Long press On of the main Power IC.
LN2220 is a step up IC which boost the battery 3.7V to 5V. It gets merged with USB supply through schkttky diode. LN5059SOT converts it to 4V, required to drive 4G module and LN6215 converts to 3.3V for other peripheral ICs.
Attaching the datasheet of each ICs(Most ICs datasheet are in Chinese, can’t help here)
Kindly review and suggest if the power circuit is good enough to drive 4G module both in terms of stability and current sourcing.
LN5059_C.pdf (640.3 KB)
LN6215_C.pdf (1018.0 KB)
LN2220_C(1).pdf (456.8 KB)