EVBUM2822/D
10
Figure 14. NCP1680 Skip Mode Operation (Ch1 = Bulk Voltage, Ch2 = PFCOK, Ch4 = SKIP)
Control Loop Measurement
The NCP1680 controller is embedded with an internal
compensator circuit which provides the necessary loop
bandwidth to ensure good power factor performance, and
also provides sufficient phase & gain margin at the loop
crossover frequency to ensure stable and robust operation of
the application. Verification of the control loop
characteristics is a good practice for any power supply
design. The NCP1680 motherboard provides a 1 k
W
injection resistor and test points (TP14, TP7) around the
injection resistor enabling the use of a network analyzer with
an isolated injection transformer to measure the loop
response of the EVB. Figure 15 shows the loop response of
the NCP1680 EVB with 300 W load, measured at 115 V
AC
and 230 V
AC
. The loop bandwidth measures from ~ 8–11 Hz
with about 70
°
of phase margin and > 14 dB of gain margin.
Summary of Contents for NCP1680
Page 12: ...EVBUM2822 D www onsemi com 12 MOTHERBOARD PCB ARTWORK Figure 17 Motherboard PCB Part 1 3...
Page 15: ...EVBUM2822 D www onsemi com 15 DAUGHTERBOARD PCB ARTWORK Figure 20 Daughterboard PCB Part 1 2...
Page 17: ...EVBUM2822 D www onsemi com 17 TRANSFORMER DATA SHEET Figure 22 Transformer Data Sheet...
Page 19: ...EVBUM2822 D www onsemi com 19 Daughter Card Figure 25 Daughter Card...
