TND308

TND308 Graphical Data Test Circuits for the NCP1651 Prepared by Alan Ball ON Semiconductor Applications Engineering The following circuits are the test configurations that were used to obtain the data for the graphical section of the NCP1651/D data sheet. Each graph has a schematic associated with it and in some cases a description of the procedure. http://onsemi.com APPLICATION NOTE NCP1651 NCP1651 1.5 V 13 16 VCC Startup 11 AC Comp 8 FB/SD 10 Ref Fltr 9 AC Input 12 0.1 mF Vref Output 1 IS+ 5 Iavg 7 6 Iavg fltr 14 V 1 mF + 0–1 V 0.5 nF Ramp GND 2 CT Comp 34 4.7 k 470 pF 47 k Figure 1. Current Sense Amplifier Gain Re: NCP1651/D data sheet, Figure 4 Energize all three power sources, beginning with the 14 volt supply. Cycle the 14 volt supply down to 8 volts and back to 14 to start unit operating. Adjust power supply on pin 5 and read voltages on pins 6 and 7. 13 12 0.1 mF 16 VCC Startup 8 FB/SD 11 AC Comp R8 10 Ref Fltr 9 AC Input Vref Output IS+ 1 5 Iavg 7 6 Iavg fltr Ramp GND CT Comp 2 34 470 pF 47 k 14 V 1 mF 1 nF Figure 2. FB/SD V–I Characteristics Re: NCP1651/D data sheet, Figure 5 Using a decade resistance box for R8, set it to 1 MW. Turn on the 14 volt source. Cycle it down to 8 volts and back up to 14 to turn the unit on. Read the voltage and pin 8 and note the resistance. Reduce R8 until the unit shuts down. Calculate the current for each reading. © Semiconductor Components Industries, LLC, 2002 May, 2002 – Rev.0 1 Publication...