《90W单级笔记本适配器设计技巧》.pdfVIP

Prepared by: Terry Allinder ON Semiconductor Sr. Applications Engineer APPLICATION NOTE General Description Detailed Circuit Description The 90 W demo board demonstrates the wide range of The detailed operational description and design equations features found in the NCP1651. It provides an 18.5 V, 4.86 A are contained in the NCP1651 data sheet and in application isolated output, foldback current limit which is ideal for note AND8124/D. This application note relates to this low−cost battery charger and notebook adaptor applications. 18.5 Vdc 90 W adaptor design. This unit will provide an isolated 18.5 V output from an The 18.5 Vdc 90 W adaptor was designed using the input source with a frequency range from 47 Hz to 63 Hz, Excel Design Spreadsheet which can be downloaded from and a voltage range of 90 Vrms to 265 Vrms. It is fully the ON Semiconductor website (). The self−contained and includes an internal high voltage startup design steps for the adaptor are listed below. The schematic circuit, and bias supply that operates off of the Flyback for the 90 W demo board, Figure 7, is located at the end of transformer auxiliary winding. the technical write up. In addition to excellent power factor, this chip offers fixed Design Steps frequency operation in continuous and discontinuous modes 1. Specifications, refer to Table 1 (90−265 V, of operat