Abstract: Embodiments of the present invention provide a charging and power supplying circuit, method and application device, which relate to the field of smart charging, so as to improve efficiencies of battery charging and system power supplying. The charging and power supplying circuit includes a power supplying tributary and a charging tributary. An end of the power supplying tributary is connected to a power supply, and another end is connected to a system. An end of the charging tributary is connected to the power supply, and another end is connected to a battery. A first transistor, a second transistor, a third transistor, a first amplifier, a second amplifier, a third amplifier, a fourth amplifier, a first comparator, a second comparator, a charging controller, a logical switch, an adder and a first control module are connected to the power supplying tributary and the charging tributary.

Abstract: A solderable layer has an organic buffer film (OBF) and an immersion tin coating deposited on a substrate. The OBF is first coated on the surface of the substrate to modify the surface of the substrate and having fluorocarbon-based polymers (solution type). The immersion plating solution pass through the OBF and the immersion tin coating is then coated on the substrate. A method to manufacture the solderable layer according to any one of claims 1 to 12 has following steps of (1) coating an organic buffer film (OBF) on a surface of a substrate to form a modified surface, (2) drying the modified surface, (3) applying the substrate into a solution with immersed tin compositions to allow the immersed tin to deposit on the modified surface, (4) rinsing the modified surface with water and (5) drying the substrate.