ncp1927 ON Semiconductor, ncp1927 Datasheet - Page 3

• Manufacturer Part Number: ncp1927
• Description: Combination Power Factor Correction Controller And Flyback Controller For Flat Panel Tvs
• Manufacturer: ON Semiconductor

PControl
POVUV
PSKIP
PZCD
GTS
PCS
PFB
PCT
R GTS
Flyback_OVLD
I PSKIP
I PCT(charge)
PFC_OK
I UVP
V DD
V disable
V REF
0.955*V REF
PFC_OK
V standby
30 ms
Filter
I PCS > I OCP
PFAULT
V ZCD(rising)
V ZCD(falling)
30 ms
Filter
PDRV
V DD
V OVP
Detect
0 mA
V UVP
V DD
PFAULT
OVP_int
GTS Timer
GOS Timer
PDRV
OVP_int
I PControl(boost)
S
R
9*R
R
Figure 2. Internal Block Diagram
Q
PDRV
Frequency Clamp
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FFAULT
PFAULT
30 ms
Filter
START_DELAY
DRV
ZCD
TSD
SS_enable
CLK
CS_STOP
SS_end
FFAULT
Shutdown
Latch
R
S
30 ms
Filter
3
R
R
S
Q
PDRV
START_DELAY
Saw
Q
FFAULT
FFB
Shutdown
FFAULT
Jittering
Saw In
Skip Out
CS_STOP
Reset
Latch
WDT
Frequency
Foldback
Soft−Skip
Timer
FFAULT
t ON(MAX)
Reset
Timer
Timer
Reset
V CC(reset)
V CC(off)
V CC(on)
PFM
FM
V SHDN
10 ms
Filter
Soft−Start
START_DELAY
Timer
OSC
SQUARE
V CS(stop)
S AW
S
R
30 ms
Filter
Flyback_OVLD
5V Reg
Q
V ILIM
SS_enable
V FSKIP
SS_end
Saw
R
PFC_OK
Saw
S
R
V DD
V DD Reg
V FFB(open)
Q
V DD
V ILIM
R ramp
B5
I Shutdown
LEB
LEB
Clamp
R FFB
Clamp
V CC
V CC
Shutdown
V CC
IENABLE
FFB
FCS
FDRV
PDRV
GND