原标题：Powerint LinkSwitch－TN2 900 V1．44W转换器参考设计DER－737

　　Power Integrations公司的LinkSwitch™-TN2系列产品是高效率离线开关集成电路,和传统的线性和电容降压器(Capdropper)型解决方案相比,极大地提高了性能.采用高度集成的LinkSwitch-TN2集成电路进行设计,具有更多的灵活性和特性,增加了效率,几乎无所不包的系统级保护和更高的可靠性.器件支持降压,降压-升压和反激转换器拓扑结构.每个器件包括了725V功率MOSFET,振荡器,开/关控制以获得轻负载时的最高效率,用于自偏压的高压开关电流源,频率抖动(降低EMI滤波器复杂性),快速限流,滞后热关断以及输出和输入电压保护电路.工作频率66kHz,待机电流<100 μA,无负载损耗小于30mW,容易满足全球所有能源效率规范要求.主要用在仪表计量,电器,智能LED驱动器和工业控制,以及IOT,家庭和建筑物自动化.本文介绍了LinkSwitch™-TN2系列产品亮点,功能框图和应用电路,以及采用LinkSwitch-TN2 900 V的1.44W非隔离降压转换器参考设计DER-737主要特性和优势,电路图,材料清单和PCB设计图.

　　The LinkSwitch™-TN2 family of ICs for non-isolated off-line powersupplies provide dramatically improved performance compared totraditional linear or cap-dropper solutions. Designs using the highlyintegrated LinkSwitch-TN2 ICs are more flexible and feature increasedefficiency, comprehensive system level protection and higher reliability.

　　The device family supports buck, buck-boost and flyback convertertopologies. Each device incorporates a 725 V power MOSFET, oscillator,On/Off control for highest efficiency at light load, a high-voltageswitched current source for self-biasing, frequency jittering, fast(cycle-by-cycle) current limit, hysteretic thermal shutdown, and outputand input overvoltage protection circuitry onto a monolithic IC.

　　LinkSwitch-TN2 ICs consume very little current in standby resulting inpower supply designs that meet all no-load and standby specificationsworldwide. MOSFET current limit modes can be selected through theBYPASS pin capacitor value. The high current limit level providesmaximum continuous output current while the low level permits usingvery low cost and small surface mount inductors. A full suite ofprotection features enable safe and reliable power supplies protectingthe device and the system against input and output overvoltage faults,device over-temperature faults, lost regulation, and power supply outputoverload or short-circuit faults.

　　The device family is available in three different packages: PDIP-8C,SO-8C, and SMD-8C (725 V PNs only).

　　LinkSwitch™-TN2系列产品亮点:

　　Highest Performance and Design Flexibility

　　• Supports buck, buck-boost and flyback topologies

　　• Excellent load and line regulation

　　• Selectable device current limit

　　• 66 kHz operation with accurate current limit

　　• Allows the use of low-cost off-the-shelf inductors

　　• Reduces size and cost of magnetics and output capacitor

　　• Frequency jittering reduces EMI filter complexity

　　• Pin-out simplifies PCB heat sinking

　　Enhanced Safety and Reliability Features

　　• Auto-restart for short-circuit and open loop faults

　　• Output overvoltage protection (OVP)

　　• Line input overvoltage protection (OVL)

　　• Hysteretic over-temperature protection (OTP)

　　• Extended creepage between DRAIN pin and all other pins improvesfield reliability

　　• 725 V MOSFET rating for excellent surge withstand

　　• 900 V MOSFET rating series for industrial or extra safety margin

　　EcoSmart™– Extremely Energy Efficient

　　• Standby supply current <100 μA

　　• On/Off control provides constant efficiency over a wide load range

　　• Easily meets all global energy efficiency regulations

　　• No-load consumption <30 mW with external bias

　　LinkSwitch™-TN2系列应用:

　　• Appliances

　　• Metering

　　• Smart LED drivers and industrial controls

　　• IOT, home and building automation

　　图1.LinkSwitch™-TN2系列降压转换器应用电路

　　图2.LinkSwitch™-TN2系列功能框图

　　图3.LinkSwitch™-TN2系列通用输入恒压电源电路图

　　采用LinkSwitch-TN2 900 V的1.44W非隔离降压转换器参考设计DER-737

　　参考设计DER-737主要特性和优势:

　　 900 V maximum drain voltage

　　 Highly integrated solution

　　 Lowest possible component count

　　 No optocoupler required for regulation

　　 Thermal overload protection with automatic recovery

　　 <30 mW no-load consumption

　　 >73% efficiency at full load

　　 <±5% load regulation

　　This document is an engineering prototype report describing a non-isolated 12 V, 120 mA power supply utilizing a LNK3294G/P from Power Integrations. The document contains the power supply specification, schematic, bill-of-materials, printed circuit layout, and performance data.

　　图4.参考设计DER-737外形图(正面)

　　图5.参考设计DER-737外形图(背面)

　　参考设计DER-737主要指标:

　　图6.参考设计DER-737电路图

　　参考设计DER-737材料清单: