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12 议程 Agenda ? 简介 Introduction: ? 交错式PFC基础知识 Basics of interleaving ? 主要优势 Main benefits ? NCP1631:新颖的交错式PFC控制器 NCP1631: a novel controller for interleaved PFC ? 异相管理 Out-of-phase management ? NCP1631支持使用较小电感 The NCP1631 allows the use of smaller inductors ? 主要功能 Main functions ? 实验结果及性能 Experimental results and performance ? 一般波形 General waveforms ? 能效 Efficiency ? 总结 Summary

13 NCP1631概览 NCP1631 Overview ? 交错式2相PFC控制器 Interleaved, 2-phase PFC controller ? 频率钳位临界导电模式(FCCrM)优化完整负载范围内的能效 Frequency Clamped Critical conduction Mode (FCCrM) to optimize the efficiency over the load range. ? 包括启动、过流保护(OCP)或瞬态序列在内的所有条件下提供 稳固的异相工作 Substantial out-of-phase operation in all conditions including start-up, OCP or transient sequences. ? 具备前馈,改善环路补偿 Feedforward for improved loop compensation ? 简化下行转换器设计 Eased design of the downstream converter: ? 提供 pfcOK 信号,含动态响应增强器及待机管理功能 pfcOK, dynamic response enhancer, standby management ? 高保护等级 High protection level: ? 输入欠压保护,精确的1引脚限流,浪涌电流检测,单独引脚用于(可编 程)过压保护(OVP)等Brown-out protection, accurate 1-pin current limitation, in-rush currents detection, separate pin for (programmable) OVP…

14 NCP1631概览 NCP1631 Overview ? 交错式2相PFC控制器 Interleaved, 2-phase PFC controller 零电压检测(第2支路) Zero voltage detection (branch1) ? 固定最大导通时间 Fixes the max. on-time ? 前馈 Feed-forward 一个CS引脚感测总输入电流,用 于过流保护及浪涌检测 One CS pin to sense the total input current for Over- Current Protection and Inrush detection 闩锁输入:若闩锁电压高于2.5 V,控制器关闭 Latch input: if VLatch >

2.5 V, the controller shutdowns 固定最大开关频率 Fixes the max. switching frequency 调节稳压环路带宽 Adjusts the regulation loop bandwidth 调节频率反走特性 Adjusts the Frequency Foldback characteristic 输入欠压检测,带50 ms沿隐延 迟,符合维持时间要求 Brown-out detection with a 50-ms blanking delay to meet hold-up time requirements 过压及欠压保护(OVP, UVP) Over and Under voltage protection (OVP, UVP) PFC就绪时(稳态)高电平(5 V) High (5 V) when PFC is ready (steady state) 零电压检测(第2支路) Zero voltage detection (branch2)

15 NCP1631典型应用 NCP1631 Typical Application 完全内部实现相位同步 Synchronization of phases is completely internal EMI Filter Ac line Vin LOAD D R Vout Cin C I

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10 11 Vcc pfcOK Rocp R zcd1 Rzcd2

2 bulk L2 L1 M1 M2 D1 coil2 I coil1 I in Cosc Cp Rz Cz Rt RFF Rout2 Rout1 Vout Rbo1 Rbo2 Cbo2 OVPin OVPin sense Vaux2 Vaux2 FB Rout3 BO 单个电流感测电阻

1 current sense resistor 提示下行转换器PFC已经就绪 Indicates the downstream converter that the PFC is ready

16 交错式PFC:主/从方案 Interleaving: Master / Slave Approach… ? 主支路自由工作 The master branch operates freely ? 从支路以180°相移跟随主支路工作 The slave follows with a 180° phase shift ? 主要挑战:维持CrM工作(无CCM,无死区时间) Main challenge: maintaining the CrM operation (no CCM, no dead-time)

2 sw T

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2 sw T 电流模式:电感不平衡 Current mode: inductor unbalance 电压模式:导通时间转换 Voltage mode: on-time shift