220V AC Cooling Fan power module circuit design and analysis

In the "220V AC Cooling Fan" system SPCE061A the need to use 3.3V power supply, AMS1117 chip production. AMS1117 is a positive LDO, AMS1117, there are two: one for fixed output voltage, the voltage value "220V AC Cooling Fan" has the power module output: 1.5V, 1.8V, 2.5V, 2.85V, 3.0 V, 3.3V; the other is to regulate the output voltage. AMS1117 internal integrated thermal protection circuit and overcurrent protection circuit. In order to protect the stability of the AMS1117, the "220V AC Cooling Fan" power module to be connected to an output of at least 22UF tantalum capacitor voltage generated by the AMS1117 3.3V constituted