65W laptop power adapter circuit design 65W laptop power adapter circuit design ON Semiconductor has designed a 19 V/65 W demonstration circuit board based on the NCP1250 controller. In this design, the rated output current is 3.2 A, and it provides over-power protection (3.8 A@100 Vac, 4.1 A@265 Vac), over-temperature protection, and over-voltage protection on the Vcc pin.

65 W power adapter demo circuit board The specific design of this 65 W demo circuit board, including component selection and related calculations. In addition to this 65 W demo board, ON Semiconductor also provides a 40 W demo board with 12 V/3.3 A output, which also provides over-power protection, over-temperature protection, and over-voltage protection on the VCC pin. Energy efficiency test results 65 W demonstration circuit board (including 1.2 m long cable) shows high energy efficiency under common load conditions such as 25%, 50%, 75%, and 100% (see Table 1), such as 230 Vrms The average energy efficiency under these conditions is as high as 88.67%. In addition, the energy efficiency performance of this demonstration circuit board at no load is also excellent, consuming only 40 mW of power. And because of the frequency anti-walking technology and the use of skip cycle mode, the light load energy efficiency is also very good. For example, under the condition of 230 Vrms, the input power when outputting 0.5 W, 0.6 W and 0.7 W power is only 0.74 W, 0.86 W and 0.86 W respectively. 0.98 W.
Based on NCP1250's 65W laptop power adapter demonstration board energy efficiency test results. The average energy efficiency of the 40 W demo board measured at 115 Vrms and 230 Vrms is 87.8% and 87.2%, respectively (for the case where the load is applied to the circuit board connector), and the no-load input power is at 100 Vrms and 230 Vrms. They are 33 mW and 75 mW respectively, which also provide high energy efficiency and low energy consumption.