US Patent 10122201 Charging system and charging method, and power adapter

The present disclosure discloses a charging system, a charging method and a power adapter. The system includes a battery, a first rectifier, a switch unit, a transformer, a compositing unit, a sampling unit, and a control unit. The control unit outputs a control signal to the switch unit, and adjusts a duty ratio of the control signal according to a voltage sampling value and/or a current sampling value obtained by primary sampling of the sampling unit, such that a second alternating current outputted by the compositing unit meets a charging requirement. The second alternating current is applied to the battery.