;;;;; powerint 公司的der-227 是采用linkswitch-xt 系列lnk362的3w通用低功耗适配器设计案例,输入电压从85v到265ac,3w单输出(5v/0.6a),230vac时无负载功耗小于10mw,工作模式的效率大于70%, 超过energy star v2, ec coc v4 和eup tier 2的规范要求,满足en55022b/cispr22b的emi要求,主要用于手机,pda,数码相机,mp3/手提音频播放器等充电器/适配器,以及家用电器,工业系统和计量表电源.本文介绍了linkswitch-xt 系列主要特性,方框图,典型应用电路以及采用lnk362的2 w 通用输入的cv适配器电路图, 3w通用低功耗适配器详细电路图和材料清单(bom).

linkswitch-xt incorporates a 700 v power mosfet, oscillator, simple on/off control scheme, a high-voltage switched current source, frequency jittering, cycle-by-cycle current limit and thermal shutdown circuitry onto a monolithic ic. the startup and operating power are derived directly from the drain pin, eliminating the need for a bias winding and associated circuitry.

product highlights

optimized for lowest system cost

• proprietary ic trimming and transformer construction techniques enable clampless™ designs with lnk362 for lower system cost, component count and higher efficiency

• fully integrated auto-restart for short circuit and open loop protection

• self-biased supply – saves transformer auxiliary winding and associated bias supply components

• frequency jittering greatly reduces emi

• meets hv creepage requirements between drain and all other pins both on the pcb and at the package

• lowest component count switcher solution

features superior to linear/rcc

• accurate hysteretic thermal shutdown protection –automatic recovery improves field reliability

• universal input range allows worldwide operation

• simple on/off control, no loop compensation needed

• eliminates bias winding – simpler, lower cost transformer

• very low component count – higher reliability and single side printed circuit board

• auto-restart reduces delivered power by 95% during short circuit and open loop fault conditions

• high bandwidth provides fast turn-on with no overshoot and excellent transient load response ecosmart®– extremely energy-effi cient

• easily meets all global energy efficiency regulations with no added components

• no-load consumption 300 mw without bias winding at 265 vac input (50 mw with bias winding)

• on/off control provides constant efficiency to very light loads – ideal for mandatory cec regulations

applications

• chargers/adapters for cell/cordless phones, pdas, digital cameras, mp3/portable audio players, and shavers

• supplies for appliances, industrial systems, and metering



图1.linkswitch-xt功能方框图


图2.linkswitch-xt典型应用电路



图3.采用lnk362的2 w 通用输入的cv适配器电路图

3w通用适配器

general purpose adapter: 3 w single output, <10 mw no-load consumption, isolated adapter using linkswitch-xt

3w通用适配器主要特性:

universal input: 85 to 265 vac

ecosmart® – easily meets all current international energy efficiency standards

- china (cecp) / cec / energy star 2 / eu coc

extremely low no-load input power consumption: <10 mw at 230 vac

ec ipp rating of 5 out of 5 stars

high active mode efficiency: >70 %

exceeds 64% energy star v2, ec coc v4 and eup tier 2 requirements

meets en55022b/cispr22b conducted emi limits without a y-capacitor across the isolation barrier

this document is an engineering report describing a 5 v, 0.6 a power supply utilizing the lnk363dn (so8 package) from the linkswitch-xt family. it contains the power supply specification, schematic, bill of materials, transformer documentation, printed circuit layout, and performance data.

this design highlights the ultra low no-load input power consumption that is possible when using a linkswitch-xt device.



图4.3w通用适配器外形图

图5.3w通用适配器电路图

3w通用适配器材料清单(bom):




图6.3w通用适配器pcb布局图