[原创] OnSemi NPC1337 60W适配器参考设计方案

OnSemi公司的NCP1337是一款结合电流模式调节器和退磁检测器的芯片，以充分确保边界线/临界传导模式在任何负载/传输线条件连同最低漏电压开关（准-谐振操作）。因为Soxyless概念，变压器铁心重置检测在内部完成，没有使用任何外部信号。根据CISPR-22 EMI限制标准，内部频率被限制于130kHz，防止控制器操作达到150kHz。该芯片具有过载保护重启功能，一旦过载，设备会自动重启恢复。本文主要介绍NCP1337芯片、芯片特性、应用方向及内部结构图。本文还介绍了采用NCP1337芯片作为主芯片的60W参考设计方案，给出该方案的介绍、方案原理图、PCB制板图及元器件清单列表。

The NCP1337 combines a true current mode modulator and a demagnetization detector which ensures full Borderline/Critical Conduction Mode in any load/line conditions together with minimum drain voltage switching (Quasi−Resonant operation). The transformer core reset detection is done internally, without using any external signal, due to the Soxyless concept. The frequency is internally limited to 130 kHz, preventing the controller to operate above the 150 kHz CISPR−22 EMI starting limit.

By monitoring the feedback pin activity, the controller enters skip mode as soon as the power demand falls below a predetermined level. As each restart is softened by an internal Soft−Skip_, and as the frequency cannot go below 25 kHz, no audible noise can be heard.
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