Research And Design Of A 90w Adapter For Laptop Computers

With the development of laptop computer, more and more electrical equipments on the adapter for laptop computer,such as higher Power factor,higher power density,lower standby loss and higher overall efficiency.At the same time, manufacturers have introduced better performence control chips ,so the industry is launching a study-wave to investigate adapter for laptop computer.A 90 W,wide-range mains,power-factor-corrected AC-DC adapter prototype is described in this paper. Its electrical specification is tailored on a typical hi-end portable computer power adapter. The peculiarities of this design are the very low no-load input consumption (<0.4 W) and the very high global efficiency.The architecture is based on a two-stage approach: a front-end PFC pre-regulator based on the L6563 CRM PFC controller and a downstream multi-resonant half-bridge converter that makes use of the new L6599 resonant controller. The Standby function of the L6599,pushing the DC/DC converter upon recognition of a light load to work in burst mode and the logic dedicated to stop the PFC stage allows meeting the severe no-load consumption requirement. So the overall efficiency of the circuit is higher.Firstly, this paper introduce the operation principle of the front-end CRM PFC. Then introduce the downstream LLC half-bridge converter ,and the operation principle and working process in different frequency ranges are expatiated in detail. Based on this, the mathematical model of the converter is built by the method of first harmonic approximation and the influences of the main parameters to the performance of the converter are analyzed .Secondly,according the principle of the two stage,chose the power devices of front-end and design the peripheral circuit of the control IC L6563;then chose resonant inductor and capacitor is introduced concretely and the design process of the converter is analyzed in detail, chose the power devices of downstream and design the peripheral circuit of the control IC L6599.Last,a prototype is made to validate the correctness of theory analysis. The experiment and analysis of the prototype are presented, including soft switching experiment in different operation conditions, the dynamic response experiment in condition of input voltage or load changes and the soft start experiment of the converter.