ncp1080 ON Semiconductor, ncp1080 Datasheet - Page 4

• Manufacturer Part Number: ncp1080
• Description: Integrated Poe-pd & Dc-dc Converter Controller
• Manufacturer: ON Semiconductor

transformer to provide power to the NCP1080 DC−DC controller via its VDDH pin. This topology shuts off the current flowing
from VPORTP to VDDH and therefore reduces the internal power dissipation of the PD, resulting in higher overall power
efficiency.
Spare
Pairs
Pairs
Data
Figure 4 shows the same non−isolated fly−back configuration as Figure 3, but adds a 12 V auxiliary bias winding on the
Figure 5 shows the NCP1080 used in a non−isolated forward topology.
Spare
Pairs
Pairs
Data
RJ− 45
RJ− 45
DB1
DB2
DB1
DB2
Figure 4. Non−Isolated Fly−back with Extra Winding
Figure 5. Non−Isolated Forward Converter
Simplified Application Diagrams
R1
R2
R2
R1
Rclass
Rinrush
http://onsemi.com
Rilim1
Rclass
Rinrush
Rilim1
INRUSH
TEST2
TEST1
VPORTP
VPORTN1
CLASS
ILIM1
UVLO
VPORTN2
4
INRUSH
TEST2
TEST1
VPORTP
VPORTN1
CLASS
ILIM1
UVLO
VPORTN2
Css Rosc
NCP1080
Css Rosc
NCP1080
VDDH
GATE
ARTN
VDDL
RTN
CS
FB
C1comp
VDDH
GATE
ARTN
VDDL
RTN
CS
FB
C2comp
C1comp
Cvddh
Cvddl
Cpd
Rslope
Rcomp
C2comp
Cvddh
Cvddl
R5
Rcomp
Rslope
LD1
Rd1
Cpd
D3
LD1
Rd1
M1
Rcs
D2
T1
M1
Rcs
T1
D1
D2
R3
D1
R4
L1
R3
R4
Voutput
Cload
Voutput
Cload