摘要：  本文介绍了LinkSwitch-PH系列(LNK403-409EG/413-419EG)主要特性，功能方框图，7W和14W LED驱动电路图以及采用LNK403EG的TRIAC调光 8W LED驱动器参考设计电路图，材料清单以及变压器相关资料。

关键字：  控制器，  开关，  LED驱动器，  调光

Powerint公司的LinkSwitch-PH系列集成了725V功率MOSFET，连续模式PWM控制器，用于自偏压的高压开关电流源，频率抖动，逐个周期的限流和带滞后的热关断电路，从而简化了功率因素大于0.9，TRIAC调光和高效率LED驱车器的设计。主要用于离线LED驱动器。本文介绍了LinkSwitch-PH系列(LNK403-409EG/413-419EG)主要特性，功能方框图，7W和14W LED驱动电路图以及采用LNK403EG的TRIAC调光 8W LED驱动器参考设计电路图，材料清单以及变压器相关资料。

TRIAC Dimmable 8 W LED Driver Using LinkSwitchTM-PH LNK403EG Compatible with High Power Dimmers

LNK403-409EG/413-419EG LinkSwitch-PH Family

The LinkSwitch-PH dramatically simplifies implementation of LED drivers requiring PF >0.9， TRIAC dimmer capability (LNK403-409) and high efficiency. The single-stage PF and constant current controller eliminates passive circuitry required for power factor correction and electrolytic bulk capacitor. The advanced primary-side control techniques used by the LinkSwitch-PH device provide accurate constant current control while eliminating the need for an optocoupler and secondary-side current control circuitry.

LinkSwitch-PH incorporates a 725 V power MOSFET， a continuous-mode PWM controller， a high voltage switched current source for self biasing， frequency jittering， cycle-by-cycle current limit and hysteretic thermal shutdown circuitry， all in a monolithic IC.

LNK403EG产品亮点：

　　Dramatically Simplifies Off-line LED Drivers

　　 LNK403-409 family is optimized for flicker-free operation in TRIAC dimming applications

　　 Single stage power factor corrected and accurate constant current (CC) output

　　 Eliminates optocoupler and all secondary current control circuitry

　　 Eliminates all control loop compensation circuitry

　　 Simple primary-side PWM dimming interface

　　 Universal input voltage range

　　 Enables designs that are electrolytic-free

　　Accurate and Consistent Performance

　　 Compensates for transformer inductance tolerances

　　 Compensates for line input voltage variations

　　 Frequency jittering greatly reduces EMI filter size and costs

　　Advanced Protection and Safety Features

　　 Auto-restart for short-circuit protection

　　 Open circuit fault detection mode

　　 Automatic thermal shutdown restart with hysteresis

　　 Meets high voltage creepage requirement between DRAIN and all other signal pins both on PCB and at package

　　EcoSmart – Energy Efficient

　　 Low standby power remote ON/OFF feature (<50 mW at 230 VAC)

　　 No current sense resistors – maximizes efficiency

　　 High efficiency operation， >85% achievable

　　Green Package

　　 Halogen free and ROHS compliant package

　　LNK403EG应用：

　　 Off-line LED driver

　　图1。LNK403EG功能方框图

　　图2。LNK403EG典型应用电路图

　　图3。LNK403EG通用输入高功率因素绝缘TRIAC调光14W LED驱动器

　　图4。LNK403EG通用输入高功率因素绝缘7W LED驱动

　　采用LinkSwitchTM-PH LNK403EG的TRIAC调光 8W LED驱动器参考设计

　　The document describes a high power-factor corrected dimmable LED driver designed to drive a 22 V nominal LED string at 380 mA from an input voltage range of 198 VAC to 265 VAC. The LED driver utilizes the LNK403EG from Power Integrations.

　　LinkSwitch-PH ICs allow the implementation of cost effective and low component count LED drivers which both meet power factor and harmonics limits but also offer enhanced end user experience. This includes ultra-wide dimming range， flicker free operation (even with low cost with AC line TRIAC dimmers) and fast， clean turn on.

　　The topology used is an isolated flyback operating in continuous conduction mode. Output current regulation is sensed entirely from the primary side eliminating the need for secondary side feedback components. No external current sensing is required on the primary side either as this is performed inside the IC further reducing components and losses. The internal controller adjusts the MOSFET duty cycle to maintain a sinusoidal input current and therefore high power factor and low harmonic currents.

　　The LNK403EG also provides a sophisticated range of protection features including autorestart for open control loop and output short-circuit conditions. Line overvoltage provides extended line fault and surge withstand， output overvoltage protects the supply should the load be disconnect and accurate hysteretic thermal shutdown ensures safe average PCB temperatures under all conditions.

　　In any LED luminaire the driver determines many of the performance attributes experienced by the end customer (user) including startup time， dimming， flicker and unit to unit consistency. For this design a focus was given to compatibility with as wider range of dimmers trading off dimmer compatibility against efficiency. Efficiency data for a nondimming configuration is shown in section 11 for reference.

　　This document contains the LED driver specification， schematic， PCB diagram， bill of materials， transformer documentation and typical performance characteristics.

　　图5。TRIAC调光 8W LED驱动器参考设计外形图

　　TRIAC调光 8W LED驱动器参考设计主要特性：

　　Superior performance and end user experience

　　TRIAC dimmer compatible (including low cost leading edge type and high power rating)

　　No output flicker

　　>1000:1 dimming range (dependant on dimmer model)

　　Clean monotonic start-up – no output blinking

　　Fast start-up (<100 ms) – no perceptible delay

　　Consistent dimming performance unit to unit

　　Highly energy efficient

　　≥78% at 230 VAC (≥83% non-dimming configuration)

　　Low cost， low component count and single sided small printed circuit board footprint solution

　　No current sensing required

　　Frequency jitter for smaller， lower cost EMI filter components

　　Integrated protection and reliability features

　　Output open circuit / output short-circuit protected with auto-recovery

　　Line input overvoltage shutdown extends voltage withstand during line faults.

　　Auto-recovering thermal shutdown with large hysteresis protects both components and printed circuit board

　　No damage during brown-out or brown-in conditions

　　IEC 61000-4-5 ring wave， IEC 61000-3-2 Class C and EN55015 B conducted EMI compliant

　　TRIAC调光 8W LED驱动器参考设计指标：

　　图6。TRIAC调光 8W LED驱动器参考设计电路图

　　TRIAC调光 8W LED驱动器参考设计材料清单(BOM)：

　　图7。参考设计变压器电框图

　　变压器主要指标：