AN3203 Datasheet, PDF (1/49 Pages) STMicroelectronics – This application note describes the characteristics and performance

AN3203
Application note
EVL250W-ATX80PL: 250W ATX SMPS
demonstration board
Introduction
This application note describes the characteristics and performance of a 250 W wide range
input and power factor corrected power supply designed to be used in an ATX application.
Good electrical performance allows meeting the most demanding efficiency targets.
The converter consists of four main blocks:
■ A PFC front-end stage using the L6563S PFC controller which generates the +400 V bus
voltage.
■ An AHB (Asymmetrical half bridge) stage using the L6591 ZVS half bridge controller
which performs the conversion from the high voltage bus to the +12 V output providing
insulation.
■ Two DC-DC post-regulator stages using the L6727 which obtain the +5 V and +3.3 V
outputs from the +12 V bus.
■ An auxiliary power supply (STANDBY) stage using the VIPer27H in isolated flyback
configuration which provides the +5 V_SB output with 10 W power capability.
Figure 1. 250 W ATX SMPS demonstration board
January 2011
Doc ID 17402 Rev 2
1/49
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