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.

The L6564 is a current-mode PFC controller operating in transition mode (TM) and represents the compact version of L6563S as it embeds the same driver, reference and control stages in a very compact 10 pin SO package.

The highly linear multiplier, along with a special correction circuit that reduces crossover distortion of the mains current, allows wide-range-mains operation with an extremely low THD even over a large load range.

The output voltage is controlled by means of a voltage-mode error amplifier and an accurate (1% @TJ = 25 °C) internal voltage reference. The loop stability is optimized by the voltae feedforward function (1/V2 correction), which in this IC uses a proprietary technique that considerably improves line transient response as well in case of mains both drops and surges (“bidirectional”).

In addition to overvoltage protection able to control the output voltage during transient conditions, the IC also provides protection against feedback loop failures or erroneous settings. Other on-board protection functions allow brownout conditions and boost inductor saturation to be safely handled.

The totem-pole output stage, capable of 600 mA source and 800 mA sink current, is suitable for high power MOSFET or IGBT drive. This, combined with the other features and the possibility to operate with ST’s proprietary fixed-off-time control, makes the device an excellent solution for SMPS up to 400 W that require compliance with EN61000-3-2 and JEITA-MITI standards.

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):



详情请见:
http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00246620.pdf
和
http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATA_BRIEF/DM00056187.pdf
以及
http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_DIAGRAM/SCHEMATICPACK/evl6564-50wflb_schem.pdf