摘要：  本文主要介绍了参考设计DER285主要特性， 驱动器电源指标和参考设计电路图，材料清单和PCB布局图.

关键字：  LED驱动，  器件，  PCB

Powerint公司的高效非隔离的25W离线LED驱动参考设计是采用LinkSwitch-PH系列的LNK409EG器件，能以350mA驱动72V LED串，输入电压范围从180 VAC到265 VAC，功率因素大于0.9，效率大于90%，在230VAC时的THD小于20%，和IEC61000-3-2兼容.本文主要介绍了参考设计DER285主要特性， 驱动器$电源指标和参考设计电路图，材料清单和PCB布局图.

25 W Non-Isolated， Buck-Boost Topology， Power Factor Corrected， LED Driver Using LinkSwitchTM-PH LNK409EG

The document describes a non-isolated， power factor corrected， low THD， high-efficiency LED driver designed to drive a 72 V LED string at 350 mA from an input voltage range of 180 VAC to 265 VAC.

The LinkSwitch-PH has been developed to cost effectively design a highly efficient single-stage power factor corrected LED driver with primary-side constant current control.

The LinkSwitch-PH controller was optimized for LED driver applications with minimal external parts count and control of the output current through the LED load without the use of an optocoupler.

The LinkSwitch-PH monolithically integrates the 725 V power MOSFET and controller.

The controller consists of an oscillator， PWM， 6 V regulator， BYPASS (BP) pin programming functions， over-temperature protection， frequency jittering， cycle-by-cycle current limit， leading edge blanking， and charge controller for output CC (constant current) control.

The LinkSwitch-PH also provides a sophisticated range of protection features including auto-restart for control loop open/short faults and output short-circuit conditions. Accurate hysteretic thermal shutdown ensures safe average PCB temperatures under all conditions.

The non-isolated power factor corrected buck-boost presented in this report shows how LinkSwitch-PH dramatically simplifies off-line， high-efficiency， power factor corrected LED driver design with very low parts count.

LED驱动参考设计主要特性:

Dramatically simplifies off-line， power factor corrected， LED driver design

Single-stage， power factor corrected， non-isolated LED driver

Compact with extremely low component count

High PF >0.9 across line and load

High efficiency >90%

Low THD， <20% at 230 VAC

IEC61000-3-2 compliant

Eliminates all control loop compensation

No output current sensing required

Advanced performance features

Compensates for inductance tolerance

Compensates for input voltage variations

Compensates for output voltage variations

Frequency jittering greatly reduces EMI filter costs

Advanced protection and safety features

Auto-restart protection for short-circuit

Hysteretic thermal shutdown

图2.LED驱动参考设计和PQ2620电感器外形图

LED驱动器电源指标:

图3.LED驱动参考设计电路图:T1占位适合EFD30， PQ2620和RM8骨架

图4.电感器电路图

电感器电指标:

LED驱动参考设计材料清单:

图5.LED驱动参考设计PCB布局图