Hi Team,
Since the input is an AC wall adapter and the standard voltage is 230VAC 50Hz in Germany and 120VAC 60Hz in the USA, the maximum input voltage is definitely overshot by 428.5714% in the USA and by 821.4286% in Germany, therefore, how was the voltage stepped-down to a maximum of 28VAC? There is no step-down transformer or full bridge converter used in the design.
I have a question about the Path topology used for designing a device that can charge a battery and at the same time detect whether the battery is full so that it can power the system load automatically or use the battery to power the system automatically if the power source is not there.