Test Procedure for the NCP1250 40-W Demonstrator 1 Christophe Basso – December 2010 Board Electrical Schematic R26 47 R15 510k R7 330k R27 510k R3 330k R2 option 220k R25 47 R11 R13 47k 47k Vbulk + - R20 510k D1 1N964 1N4148 C12 82uF 400 V 10 R21 22 L1 D6 C11 470n X2 C8 1nF F1 2AT C10 R5 22pF 1.8k 250 V 85-265 V rms Ac input voltage 2 Christophe Basso – December 2010 D3 1N4937 1 6 2 5 3 4 C15 220p . 2 L2 2.2uH C7 12 220uF Ns 5-6 V / 3.3 A C5b C5a 680uF 680uF R8 1k Naux 12 R12 18k D7 1N4937 C17 100uF R10 20k 22 C4 100pF 1N4148 R16 C3 4.7uF 8-7 . Q1 2N2907 C18 22pF . D4 1N4937 R24 220 NCP1250 2 x 10mH Wurth 744822120 11 Np 1 R22 470k IN R17 510k 3 C9 330pF D10 IC4 KBU4K Bridge C2 10n R14 NTC D5 NTST30100SG T1 1 kV C6 10nF R18 22k R19 1k C5 10nF R23 1k IC2 TL431 R6a R6b R6c 1.3 1.3 1.3 R9 10k C13 2.2nF Type = Y1 Dc output voltage Board Picture Live parts, lethal voltages Input voltage from 85 V rms to 265 V rms. Nominal range 100-240 V rms 3 Christophe Basso – December 2010 Isolated output Output voltage is 12 V, nominal current is 3.3 A Needed Equipment The needed equipments are the following: an ac source, delivering 80 V ac to 265 V ac, needed power is below 100 W. An electronic source or a simple variac can do. an input ac watt-meter, up to 100 W a dc load absorbing up to 100 W, Vin,max < 20 V, Iout,max < 5 A either the above load can display dc V and dc A or separated V and A-meters are necessary If the load does not use local Kelvin sensors, then the output voltage must be measured at the board level, not at the cable ends. 4 Christophe Basso – December 2010 Board Test Fixture W-meter Pin Test n°1: -Apply 90 V rms -No output current -Read output voltage: 11.5 < Vout < 12.5 -Apply 230 V rms Ac-source 85 V to 265 V -Repeat the above -Let the board warm up for 10 mn -Read input power 70 mW < Pin < 100 mW 5 Christophe Basso – December 2010 Electronic load No-load standby Board Test Fixture W-meter Pin Test n°2: -Apply 90 V rms -Load with 3.3 A -Read output voltage and Pin: 11.5 < Vout < 12.5 Ac-source 85 V to 265 V 38 W < Pin < 47 W -Apply 265 V rms -Load with 3.3A Electronic load -Repeat the above Nominal Power 6 Christophe Basso – December 2010 Board Test Fixture W-meter Pin Test n°3: -Apply 90 V rms -Increase Iout while reading output voltage -At a certain point, Iout,max, Vout collapses, the converter hiccups (typical is 4.2 A) 3.6 A < Iout,max < 5 A Ac-source 85 V to 265 V -Apply 265 V rms -Repeat the above steps -The Iout,max points slightly increases Electronic load Maximum Power 7 Christophe Basso – December 2010 Board Test Fixture W-meter Pin Test n°4: -Apply 90 V rms -Apply a short-circuit at the output, usually via the dc load Ac-source 85 V to 265 V -Vout must collapse, the converter tries to re-start (hiccup mode). Read the input power (watt-meter in average mode) 5 W < Pin < 15 W -Apply 265 V rms Electronic load -Repeat the above steps Short-Circuit 8 Christophe Basso – December 2010