NCP1380 ON Semiconductor, NCP1380 Datasheet - Page 15

• Manufacturer Part Number: NCP1380
• Description: Quasi-Resonant Current Mode Controller
• Manufacturer: ON Semiconductor

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valleys are incremented from the first to the fourth. When
the fourth valley is reached, if FB voltage further decreases
below 0.8 V, the controller enters VCO mode.
decrease until it reaches 17.5% of the maximum peak
current: the switching frequency expands to deliver the
As the output load decreases (FB voltage decreases), the
During VCO operation, the peak current continues to
Figure 28. Output Load is Decreased from 2.8 A Down to 100 mA at 120 Vdc Input Voltage
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necessary output power. This allows achieving very low
standby power consumption.
current of a 19 V, 60 W adapter decreases from 2.8 A to
0.1 A. No instability is seen during the valley transitions
(Figures 29, 30, 31 and 32)
The Figure 28 shows a simulation case where the output