</a>LED" title="LED">LED" title="LED">LED灯电源采用LinkSwitch-PL系列的LNK457DG，具有单级PFC和精确的恒流（CC）输出以及低成本元件少与小尺寸的特点，AC输入电压90V-132V，115VAC时的效率大于90%，PF大于0.95，集成了无负载检测/短路保护，热关断自动恢复，可替代B10白炽灯。本文介绍了LinkSwitch-PL系列产品亮点，方框图，典型应用电路以及7W PFC LED驱动器指标，电路图，材料清单和PCB布局图。

The LinkSwitch-PL family enables a very small and low cost single-stage power factor corrected constant current driver for solid state lighting. Optimized for direct LED current sensing, the LinkSwitch-PL operates over a wide input voltage range delivering an output power of up to 16 W. The LinkSwitch-PL control algorithm provides flicker-free TRIAC dimming with minimal external components.

Each device incorporates a 725 V rated power MOSFET, a novel discontinuous mode variable frequency variable on-time controller, frequency jitter, cycle by cycle current limit and hysteretic thermal shutdown in a monolithic 4-pin IC, available in SO-8C, eSOP-12, and eDIP-12 packages.

LinkSwitch-PL系列产品亮点：

Dramatically Simplifies Off-line LED Drivers

• Flicker-free phase-controlled TRIAC dimming

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

• Very low component count with small non-electrolytic bulk capacitor for compact replacement lamp designs

• Compact SO8, eSOP, and eDIP packages

• Completely eliminates control loop compensation

Advanced Performance Features

• Optimized for non-isolated flyback designs

• Frequency jitter greatly reduces EMI filter size and costs

• Low dissipation direct sensing of LED current

Advanced Protection and Safety Features

• Cycle skipping regulation for abnormally low output power to clamp peak output current delivered

• 725 V integrated power MOSFET allows small bulk capacitance and maximizes power capability

• Short-circuit, overload, open feedback and output overvoltage protection

• Hysteretic thermal shutdown

• Meets high-voltage creepage between DRAIN and all other pins both on PCB and at package EcoSmart™ - Energy Efficient

• High power factor optimizes system lumen per input VA

• Control algorithm balances switching and conduction losses over line and load to maintain optimum efficiency

图1。LinkSwitch-PL系列功能方框图

图2。LinkSwitch-PL系列典型应用电路图

图3。采用LinkSwitch-PL系列的替代A19白炽灯的5W 15V LED驱动器电路图

采用LinkSwitchTM-PL系列LNK457DG的替代B10灯的7W PFC LED驱动器

This document is an engineering report describing a non-isolated LED driver (power supply) utilizing a LNK457DG from the LinkSwitch-PL family of devices.

The DER-324 provides a single 7 W constant current output.

The key design goals were high efficiency to maximize efficacy and small size. This allowed the driver to fit into B10 sized lamps and be as close to a production design as possible.

The board was optimized to operate over the low AC input voltage range (90 VAC to 132 VAC, 47 Hz to 63 Hz). LinkSwitch-PL IC based designs provide a high power factor (>0.95) meeting current international requirements.

The form factor of the board was chosen to meet the requirements for standard B10 LED replacement lamps. The output is non-isolated and requires the mechanical design of the enclosure to isolate the output of the supply and the LED load from the user.

7W PFC LED驱动器主要特性：

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

 Low cost, low component count and small PCB footprint solution

 Highly energy efficient, >90 % at 115 VAC input

 No potting is needed to operate at 75 ºC internal case ambient.

 Fast start-up time (<50 ms) – no perceptible delay

 Integrated protection and reliability features

 No-load protection / hard short-circuit protected

 Auto-recovering thermal shutdown with large hysteresis protects both components and PCB

 No damage during line brown-out or brown-in conditions

 PF >0.95 at 115 VAC

 %A THD <25% at 115 VAC

 Meets IEC 2.5 kV ring wave, 500 V differential line surge and EN55015 conducted EMI

图4。7W PFC LED驱动器PCB外形图（顶视图）

图5。安装在B10灯罩内的PCB外形图
7W PFC LED驱动器指标：


图6。230 V / 30 mA 替代灯电路图
230 V / 30 mA 替代灯材料清单：


图7。7W PFC LED驱动器PCB元件布局图（顶层）

图8。7W PFC LED驱动器PCB元件布局图（底层）
详情请见：
http://www.powerint.com/sites/default/files/PDFFiles/der324.pdf