ncp1239f ON Semiconductor, ncp1239f Datasheet - Page 15

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

(SS/timer)
Vpin6
Drv
FB
4.3V
3.0V
1.8V
Stby_detect latch is armed
Stby_detect latch is reset
FB−skip (Vpin7)
*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
ss
jittering
delay
= 7.5 ms * C
=100 ms * C
=10 ms * C
100ms*
PFC running
pin6
jittering
ss
pin6
pin6
Fb is ok
):7.5 ms
/ 390 nF
/ 390 nF
/ 390 nF
): 10 ms
Standby is not confirmed
delay
Figure 34. Standby Detection
): 100 ms
Standby Detection
Bunches of pulses
http://onsemi.com
NCP1239
Standby is entered
15
FB−stby−out (1.7*Vpin7)
pin6
100ms*
delay
pin6
= 390 nF nearly sets the following intervals:
Skip activity
as follows:
PFC is down
Standby is confirmed,
Standby is left
Jittering 10ms*
No delay