ncp1081 ON Semiconductor, ncp1081 Datasheet - Page 3

• Manufacturer Part Number: ncp1081
• Description: Integrated High Power Poe-pd Interface & Dc-dc Converter Controller
• Manufacturer: ON Semiconductor

output voltage regulation is accomplished with an external opto−coupler and a shunt regulator (Z1).
compensation network is inserted between the FB and the COMP pin for overall stability of the feedback loop.
Spare
Spare
Pairs
Pairs
Pairs
Pairs
Data
Data
Figure 2 shows the integrated PoE−PD switch and DC−DC controller configured to work in a fully isolated application. The
Figure 3 shows the integrated PoE−PD and DC−DC controller configured in a non−isolated fly−back configuration. A
RJ− 45
RJ− 45
DB1
DB2
DB1
DB2
R1
R2
Figure 3. Non−Isolated Fly−back Converter
Figure 2. Isolated Fly−back Converter
R2
R1
Simplified Application Diagrams
Rinrush
Rilim1
Rclass
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Rinrush
Rclass
Rilim1
INRUSH
UVLO
TEST2
TEST1
VPORTN1
VPORTN2
VPORTP
ILIM1
CLASS
Css
INRUSH
TEST2
TEST1
VPORTN1
VPORTP
CLASS
ILIM1
UVLO
VPORTN2
NCP1081
3
Rosc
nCLASS_AT
Css Rosc
NCP1081
VDDH
GATE
VDDL
ARTN
RTN
CS
FB
nCLASS_AT
Cvddh
Cvddl
VDDH
GATE
ARTN
VDDL
Rslope
RTN
CS
FB
C1comp
Cpd
LD1
Rd1
C2comp
Cvddh
Cvddl
Rcomp
Rslope
M1
Rcs
T1
C2
Cpd
LD1
Rd1
M1
Rcs
Optocoupler
T1
OC1
Z1
D1
C1
R5
R3
R4
R3
R4
Voutput
Voutput
Cload
Cload