DN94 Datasheet | Diodes Incorporated

A Product Line of Diodes Incorporated High performance rectifiers significantly improve server power supply efficiency Dr Yong Ang, Diodes Incorporated Introduction Alternative appr oaches ca n improve the existing me thods of using Schottky diod es in h igh reliability, h igh ava ilability and low downt ime se rver sta ndby power su pplies. T wo dif ferent secondary circuit approaches, including syn chronous rectification a nd Su per Barrier Rectifie r (SBR™) were used to find the highest practica l efficiency in a +5VSB power supply capable of delivering 27W p eak p ower. Ef ficiency improvements were mea sured i n a n experimental converter, at 3.5% for synchronous rectification and 0.5% for SBR over the Schottky solution. This design note discusses the details. Server standby power supplies Desktop derived servers are de signed to ope rate in high re liability a nd availability a pplication environments whe re it must b e working continuously wit h ext remely low unsch eduled downtime. T ypically t he architecture of t he power supply fo llows a t wo st age conve rsion approach as show n in F igure 1. The front en d stage is a Continu ous Co nduction Mode active power factor correcting Boost converter and delivering a constant 400V DC rail to a downstream forward DC-DC converter processing the tightly regulated +/-12V, +5V and +3.3V rails required by the system. AC input EM I filter an d re ctif ie r Ac tive pow er facto r co rrecti o n +400 V Iso lated DC- D C co n ver ter Cb ulk +12V, +5V, +3.3V, -12V 4-ch an n el seco n d ar y moni to rin g IC A u xiliary po wer sup p ly T1 C1 1n F 1k V O ption #2 : A2 Super B arri er B 2 R ectifie r L1 2.4μ H C4 470μ F C5 470 μ F +5VSB, 5A R1 100kΩ D1 S1M O ption #1: A1 Sync hr onous R ectifie r B1 RTN U4 +12VC C_P , 100m A R2 D2 Aux D3 Z SR1200 Voltage r egulator C6 47μ F SO T 223 C7 1 μF C2 22μ F R3 U1 Vcc HV D GN D FB US 1J SM A RTN +5VSB R4 200 Ω R5 U2 10kΩ C3 R6 5. 1kΩ C Y1 R7 4.7kΩ 1n...