NCP1011ST100T3G ON Semiconductor, NCP1011ST100T3G Datasheet - Page 12

• Manufacturer Part Number: NCP1011ST100T3G
• Description: IC CTRLR/MOSFET 100KHZ SOT223
• Manufacturer: ON Semiconductor

Specifications of NCP1011ST100T3G

• Output Isolation: Isolated
• Frequency Range: 90 ~ 110kHz
• Voltage - Input: 8.5 ~ 10 V
• Voltage - Output: 700V
• Power (watts): 19W
• Operating Temperature: -40°C ~ 125°C
• Package / Case: TO-261-4, TO-261AA, SOT-223-4
• Duty Cycle (max): 72 %
• Mounting Style: SMD/SMT
• Switching Frequency: 110 KHz
• Operating Supply Voltage: - 0.3 V to + 10 V
• Maximum Operating Temperature: + 150 C
• Synchronous Pin: No
• Topology: Flyback
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: NCP1011ST100T3G; NCP1011ST100T3GOSTR

Lowering the Standby Power with Skip- -Cycle
power by skipping unwanted cycles at light loads.
However, the recurrent frequency in skip often enters the
audible range and a high peak current obviously generates
acoustic noise in the transformer. The noise takes its origins
in the resonance of the transformer mechanical structure
Skip- -cycle offers an efficient way to reduce the standby
Figure 18. A more detailed view of the NCP101X offers better insight on how to
Permanent
Figure 19. The burst frequency becomes so low that it is difficult to keep
Latch
Vclamp = 8.7 V typ.
VCC
VCC
ON
OFF
= 8.5 V
= 7.5 V
an adequate level on the auxiliary V
+
+
properly wire an auxiliary winding.
+
--
--
+
>30 ms
--
+
http://onsemi.com
+
12
I > 7.4m
(Typ.)
Startup Source
Ground
which is excited by the skipping pulses. A possible
solution, successfully implemented in the NCP1200 series,
also authorizes skip- -cycle but only when the power
demand has dropped below a given level. At this time, the
peak current is reduced and no noise can be heard.
Figure 20 pictures the peak current evolution of the
NCP101X entering standby.
V
CC
Drain
+
CVcc
Rlimit
CC
. . .
+
Caux
D1
Laux