l6564主要特性:
■ fast “bidirectional” input voltage feedforward (1/v2 correction)
■ accurate adjustable output overvoltage protection
■ protection against feedback loop disconnection (latched shutdown)
■ inductor saturation protection
■ ac brownout detection
■ low (≤100 μa) start-up current
■ 6 ma max. operating bias current
■ 1% (@ tj = 25 ℃) internal reference voltage
■ -600/+800 ma totem pole gate driver with active pull-down during uvlo
■ ssop10 package
l6564主要应用:
■ pfc pre-regulators for:
– high-end ac-dc adapter/charger
– desktop pc, server, web server
– iec61000-3-2 or jeita-miti compliant smps
■ smps for led luminaires
图1.l6564方框图
图2.采用l6564的演示板evl6564-100w电路图
50w evl6564-50wflb评估板
the evl6564-50wflb demonstration board implements a 50 w, wide-range mains input, power factor corrected, power supply suitable for all low power applications needing a high pf, such as lighting applications, led power supplies, etc. it is possible through the use of a low-cost device like the l6564 united with a simple topology like the flyback one, providing, therefore, a very competitive solution.
the main feature of this converter is that the input current is almost in phase with the mains voltage; therefore the power factor is close to unity. this is achieved by the controller, the l6564, shaping the input current as a sinewave in phase with the mains voltage.
evl6564-50wflb评估板主要特性:
■ line voltage range: 90 to 265 vac
■ minimum line frequency (fl): 47- 63 hz
■ minimum switching frequency: 44 khz
■ reflected voltage: 140 v
■ regulated output voltage: 24 v
■ rated output power: 50 w
■ power factor (load ≥ 50%): 0.9 minimum
■ minimum efficiency at full load: 88%
■ maximum 2fl output voltage ripple: 1.1 v pk-pk (vin=230 vac, pout=50 w)
■ maximum ambient temperature: 50 ℃
■ conducted emi: in acc. with en55022 class-c
■ pcb type and size: single-side, 35 μm, cem-1, 140 x 60 mm
图3.evl6564-50wflb评估板外形图
图4.evl6564-50wflb评估板电路图
evl6564-50wflb评估板材料清单(bom):
st公司的evl6564-50wflb是采用l6564的输入电压90-265 vac的50w pfc电源,适用于需要高pf的所有低功耗应用如照明,led电源等,线路频率47-63hz,开关频率大于44khz,输出电压24v,负载大于50%时的功率系数大于0.9,满负载的效率大于88%.本文介绍了l6564主要特性,方框图,采用l6564的演示板evl6564-100w电路图以及 50w的evl6564-50wflb评估板电路图和材料清单.
