The universal serial bus (USB) has become really universal in recent years, with power delivery and all kinds of data protocols connected through a single Type-C port. In particular, the USB Type-C Power Delivery (PD) standards allow the cable to deliver 100W of power or more. However, the thermal issue becomes the limiting factor for fast charging an extremely compact portable device. How to move the heat out of the device, meanwhile keeping the device small and thin, becomes a question of great concern. An integrated charger involves a switching power converter, in which the power inductor is one of the main sources of power loss, besides occupying the largest area. To address this problem, an attractive solution is to relocate the power inductor in a DC-DC converter from the high-current output side to the low-current input side [1-3]. Such inductor-first topologies considerably reduce the average current on the inductor, and thus allowing the use of a smaller one. Furthermore, moving the inductor to the input side also allow the replacement of the discrete inductor by the parasitic inductor of the USB cable [1], eliminating the need for any magnetics on-board, and reducing the on-board power dissipation. Thus far, prior solutions still put the power converter chip inside the portable devices, which means the generated heat is still inside the device. In addition, using this structure means that the power converter design should also take the cable type, length, and electrical characteristics into consideration for a closed-loop regulation.