ncp1239f ON Semiconductor, ncp1239f Datasheet - Page 18

• Manufacturer Part Number: ncp1239f
• Description: Lowstandby High Performance Pwm Controller
• Manufacturer: ON Semiconductor

Figure 37 depicts the V
Vcc
Timer
FB
Error
Flag
VccON
VccOFF
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*This time is programmed by the Pin 6 capacitor. C
More generally, the times approximately depend on C
− Soft−Start Time (T
− Jittering Period (T
− Fault Detection Delay (T
− T
− T
− T
7.5ms*
ss
jittering
delay
CC
Full power
SS
= 7.5 ms * C
=100 ms * C
evolution during a proper startup sequence, showing the state of the error flag:
=10 ms * C
Ip max
pin6
jittering
ss
pin6
pin6
):7.5 ms
/ 390 nF
/ 390 nF
/ 390 nF
): 10 ms
delay
Feedback loop
reacts...
): 100 ms
regulation
Skip level
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No error has
been confirmed
Latch−off phase level
Logic reset level
Figure 37.
NCP1239
18
pin6
pin6
= 390 nF nearly sets the following intervals:
as follows: