NCP1351 ON Semiconductor, NCP1351 Datasheet - Page 17

• Manufacturer Part Number: NCP1351
• Description: Variable Off Time Controller Featuring Short-circuit Protection
• Manufacturer: ON Semiconductor

error flag assertion will correspond to either 50% of the
maximum power (full load DCM design) or a value above
this number if the converter operates in CCM at full load and
remains in CCM at half the switching frequency.
Depending on the design conditions (DCM or CCM), the
Figure 21. The B Version Enters an Auto-Recovery Burst Mode in Presence of a Fault
DRV
DRV
DRV
V
V
V
timer
timer
timer
V
V
V
I
I
I
FB
FB
FB
cc
cc
cc
FB reacts
FB reacts
FB reacts
FB reacts
startup
startup
startup
startup
Figure 20. The A Version Latches-off in Presence of a Fault
ICC1
ICC1
ICC1
ICC1
fault
fault
fault
fault
ok
ok
ok
ok
Latched
Latched
state
state
A version, latched
B version, auto-recovery
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Pulses
Pulses
stopped
stopped
NCP1351
17
User
User
reset
reset
ICC4
ICC4
controller options.
Pulldown
Pulldown
SCR action
SCR action
The figures below details circuits operation for the various
ICC < 20 μA
ICC < 20 μA
Auto- recovery
Auto- recovery
Fault
Fault
still present
still present
ICC1
ICC1
ICC1
ICC1
ok
ok
Vcc
Vcc
Vcc
Vcc
V
V
Vcc
Vcc
V
V
V
V
40 μA
40 μA
40 μA
zener
timer
zener
zener
timer
timer
ON
stop
ON
ON
stop
stop