ST公司的EVL6564-50WFLB是采用L6564的輸入電壓90-265 VAC的50W PFC電源,適用于需要高PF的所有低功耗應用如照明,LED電源等,線路頻率47-63Hz,開關頻率大于44kHz,輸出電壓24V,負載大于50%時的功率系數大于0.9,滿負載的效率大于88%.本文介紹了L6564主要特性,方框圖,采用L6564的演示板EVL6564-100W電路圖以及 50W的EVL6564-50WFLB評估板電路圖和材料清單.

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主要應用:

■ 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

圖1.L6564方框圖

圖2.采用L6564的演示板EVL6564-100W電路圖

50W EVL6564-50WFLB評估板

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評估板主要特性:

■ 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


圖3.EVL6564-50WFLB評估板外形圖


圖4.EVL6564-50WFLB評估板電路圖
EVL6564-50WFLB評估板材料清單(BOM):



詳情請見:
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