May 2010Doc ID 15333 Rev 11 32 AN2929 Application note Wide range 90 V 265 V input 5 V 12 W output VIPER27LN demonstration board with improved standby performance Introduction In consumer applications such as LCD or plasma TVs some models of DVD recorders set top boxes with hard disk as well as desktop computers the power supply often includes two modules the main power supply that provides most of the power and is off when the application is in standby mode and the auxiliary power supply that provides energy for specific peripherals such as USB ports remote receivers and modems The auxiliary power supply is also on when the application is in standby mode and it is often required that its input power be as low as possible The demonstration board presented in this application note meets the specification of a wide range of auxiliary power supplies for these applications and is optimized for very low standby consumption helping to meet the most stringent energy saving requirements Figure 1 VIPER27LN demonstration board ContentsAN2929 2 32 Doc ID 15333 Rev 1 Contents 1Board description 5 1 1Electrical specifications 5 1 2Schematic and bill of material 5 1 3Transformer 7 2Testing the board 9 2 1Typical board waveforms 9 2 2Precision of the regulation and output voltage ripple 10 2 3Efficiency 13 2 4Light load performance 17 2 5Overload protection 21 2 6Secondary winding short circuit protection 22 2 7Output overvoltage protection 24 2 8Brownout protection 26 2 9EMI measurements 29 3Conclusion 30 4References 30 5Revision history 31 AN2929List of figures Doc ID 15333 Rev 13 32 List of figures Figure 1 VIPER27LN demonstration board 1 Figure 2 Schematic 5 Figure 3 Transformer size 8 Figure 4 Transformer size and pin diagram inches mm 8 Figure 5 Drain current and voltage at full load 115 VAC 9 Figure 6 Drain current and voltage at full load 230 VAC 9 Figure 7 Drain current and voltage at full load 90 VAC 9 Figure 8 Drain current and voltage at full load 265 VAC 9 Figure 9 Output voltage ripple 115 VINAC full load 11 Figure 10 Output voltage ripple 230 VINAC full load 11 Figure 11 Output voltage ripple 115 VINAC at no load burst mode 12 Figure 12 Output voltage ripple 230 VINAC 50 mA at no load burst mode 12 Figure 13 Efficiency vs VIN 14 Figure 14 Efficiency vs load 14 Figure 15 Active mode efficiency vs VIN 15 Figure 16 Input voltage averaged efficiency vs load 16 Figure 17 ENERGY STAR efficiency criteria 17 Figure 18 Input power vs input voltage for different loads 19 Figure 19 Average switching frequency vs input voltage 19 Figure 20 Output power vs input voltage with input power of 1 W 20 Figure 21 Output short circuit 21 Figure 22 Operation with output shorted 22 Figure 23 2nd OCP tripping 23 Figure 24 Operating with secondary winding shorted restart mode 23 Figure 25 OVP circuit 24 Figure 26 OVP 25 Figure 27 Jumper J7 setting brownout disabled 26 Figure 28 Jumper J7 setting brownout enabled 26 Figure 29 Brownout protection 26 Figure 30 Input AC voltage steps from 90 VAC to 75 VAC 28 Figure 31 Input voltage steps from 90 VAC to 0 28 Figure 32 115 VAC 29 Figure 33 230 VAC 29 List of tablesAN2929 4 32 Doc ID 15333 Rev 1 List of tables Table 1 Electrical specifications 5 Table 2 Bill of material 6 Table 3 Transformer characteristics 7 Table 4 Output voltage and VDD line load regulation 10 Table 5 Output voltage ripple 10 Table 6 Burst mode related output voltage ripple 13 Table 7 Efficiency 13 Table 8 Active mode efficiencies 15 Table 9 Line voltage averaged efficiency vs load 15 Table 10 Energy efficiency criteria for standard models 16 Table 11 Energy efficiency criteria for low voltage models 16 Table 12 No load input power no brownout 17 Table 13 Energy consumption criteria for no load 17 Table 14 Low load performance POUT 25 mW 18 Table 15 Low load performance POUT 50 mW 18 Table 16 Output power when the input power is 1 W 20 Table 17 Input and output load 25 Table 18 Document revision history 31 Board description Doc ID 15333 Rev 15 32 1 Board description 1 1 Electrical specifications The electrical specifications of the VIPER27LN demonstration board are listed in Table 1 1 2 Schematic and bill of material The schematic of the board is shown in Figure 2 Table 2 gives the list of components bill of material Table 1 Electrical specifications SymbolParameterValueUnit VINInput voltage range 90VRMS 265VRMS V VOUTOutput voltage5 V IOUTMax output current2 4A VOUT LFPrecision of output regulation 5 VOUT HFHigh frequency output voltage ripple50mV TAMax ambient operating temperature60 C Schematic 6 32 Doc ID 15333 Rev 1 ReferencePartDescriptionManufacturer BR1DF06M600 V 1 A diodes bridge Fairchild General Semiconductor C1 C1322 nF X2 capacitorEvox Rifa C3450 V 33 F electrolytic capacitor C435 V 22 F electrolytic capacitor C5Not mountedNot mounted C625 V ceramic capacitor C725 V ceramic capacitor C8Y1 2 2 nF capacitor C9 C1416 V ZL 1000 F 10X201000 F 16 V electrolytic capacitorRubycon C1016 V 100 F YK100 F 16 V YK rub