简介：

The followingdesign note features the latest techniques for minimizing the  standby power consumption of a 65 W notebook adapter.
 
主要特点：

NCP1246是一个新的固定频率电流模式控制器具有动态自供电。此功能极大地简化了设计辅助电源和VCC电容通过激活供货期间控制器的内部启动电流源启动，瞬变，锁存器，待机等设备中含有一种特殊高压检测器，其检测应用程序从AC输入拔除线和触发的X2的放电电流。 HV结构允许在掉电检测以及。它具有一个基于计时器的故障检测，确保检测过载和一个可调的补偿，以帮助保持最大功率的输入电压无关。由于频率折返，控制器具有优良的在轻负载条件下的效率，同时还实现了非常低待机功耗。内部频率抖动，斜坡补偿和一个多功能闩锁输入该控制器出色的候选人，强劲的电源设计。一个专门的关闭模式，可以达到非常低的空载通过“沉睡”了整个装置的输入功耗，从而控制电路的功率消耗最小化。

•固定频率电流模式操作（65 kHz和100 kHz频率选项）                                 

•频率折返，然后跳跃模式，最大化性能轻载和待机状态下

•定时器过载保护锁存（选项A）自动恢复功能（选项B）操作                        

•高电压电流源，掉电检测和动态自供电，VCC电路的简化设计

•调频软化EMI签名                                                                                         

•可调节过载保护家属的散装电压

•闭锁开关量输入相结合的压制保护感应输入                                                 

•高达28 V的VCC操作，具有过压检测

•500/800 mA源出/吸入驱动器峰值电流能力                                                  

 •10 ms软启动

•内部热关断                                                                                                  

•空载待机功耗<30 mW的

•X2电容EMI过滤器排气功能                                                                           

•这些器件是无铅和无卤/ BFR免费

2.

The NCP4353 and NCP4354 are secondary side SMPS controllers designed for use in applications which require extremely low no load power consumption. The device is capable of detecting ’no load’ conditions and entering the power supply into a low consumption OFF mode. During OFF mode, the primary side controller is turned off and energy is provided by the output capacitors thus eliminating the power consumption required to maintain regulation. During OFF mode, the output voltage relaxes and is allowed to decrease to an adjustable level. Once more energy is required, the NCP4353 or NCP4354 automatically restarts the primary side controller.

During normal power supply operation, the devices provide integrated voltage feedback regulation, replacing the need for a shunt regulator. The A versions include a current regulation loop in addition to voltage regulation. Feedback control as well as ONOFF signal can be provided with only one optocoupler.

The NCP4354 includes a LED driver pin implemented with an open drain MOSFET driven by a 1 kHz square wave with a 12.5% duty cycle for indication purpose. The NCP4354 is available in SOIC-8 package and the NCP4353 is available in TSOP-6.

方案特点：

When focusing on the no load power consumption of an adapter design, the key losses need to be identified. Switching losses and circuit biasing must be minimized or

eliminated completely. The latest technique for minimizing losses during no load is to turn off the Ac-Dc controller and allow the output voltage to drop. Because the adapter is not supplying power, a drop in output voltage is viewed as acceptable. The following design utilizes the NCP1246 flyback controller and the NCP4354A  secondary side controller to realize this technique. Both controllers have built-in features focused on minimizing no load input power consumption.

Constant Voltage Constant Current Regulation (CCCV)

Very Low Input Power at Light and No Load

High Efficiency Across the Entire Load Range

Overpower Protection

Universal Mains Operation

方案参考原理图：


图1 参考原理图

参考PCB图：

              

               图2： 参考PCB图

详情请见： http://www.onsemi.cn/pub_link/Collateral/EVBUM2138-D.PDF