The invention discloses a light portable computer charging circuit. The light portable computer charging circuit includes a control system and a modulation circuit forming a USB interface in the control system, wherein the control system includes a quick charging power supply, the modulation circuit of the USB interface and electric equipment of different specifications. Larger mobile devices suchas notebook computers can be charged by adding the modulation circuit to a mobile phone quick charging device which is portable and mature and has high compatibility with mains supply, the portability and compatibility of a quick charger are used, a usual bulky laptop charger is replaced, the convenience of charging mobile devices such as notebook computers is improved, the improvement of the portability and endurance of the mobile devices is facilitated, power supply in different voltage areas, on-board, mobile power blank and other ways can be achieved, the voltage is transformed through aswitching circuit and a high-frequency transformer, and the portable and multi-compatibility charging method in which the current after voltage transformation is supplied to the electrical equipment by the modulation circuit is achieved.