ncp1083 ON Semiconductor, ncp1083 Datasheet - Page 4

• Manufacturer Part Number: ncp1083
• Description: Integrated High Power Poe-pd Interface & Dc-dc Converter Controller With 9v Auxiliary Supply Support
• Manufacturer: ON Semiconductor

transformer to provide power to the NCP1083 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.
High Power Considerations
configurations of high−power PoE systems including those
based on the developing IEEE 802.3at
operation can be enabled by a Dual Event Layer 1
classification or a Single Event Layer 1 classification
Spare
Spare
Pairs
Pairs
Pairs
Pairs
Data
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 NCP1083 used in a non−isolated forward topology.
The NCP1083 is designed to implement various
RJ−45
RJ−45
Figure 4. Non−Isolated Fly−back with Extra Winding and Rear Auxiliary Supply
DB1
DB1
DB2
DB2
Raux2
Raux2
VAUX(−)
VAUX(−)
VAUX(+)
VAUX(+)
Figure 5. Non−Isolated Forward Converter with Rear Auxiliary Supply
D3
D4
Raux3
Raux3
Raux1
Raux1
D4
D5
Z_line
Z_line
standard. High power
Simplified Application Diagrams
Cline
Cline
R2
R2
R1
R1
http://onsemi.com
Rinrush
Rinrush
Rclass
Rclass
Rilim1
Rilim1
Css
Css
INRUSH
TEST
VPORTN1
VPORTN2
INRUSH
TEST
VPORTN1
VPORTN2
4
UVLO
AUX
UVLO
AUX
VPORTP
CLASS
ILIM1
VPORTP
CLASS
ILIM1
SS
SS
combined with a Layer 2 high power classification. The
NCP1083 also supports proprietary designs capable of
delivering 25 W to 40 W to the load in two−pair
configurations. A separate application note describes these
implementations (“NCP1081 High Power PoE Applications”).
NCP1083
NCP1083
Rosc
Rosc
nCLASS_AT
nCLASS_AT
OSC
OSC
VDDH
VDDH
ARTN
ARTN
VDDL
GATE
VDDL
GATE
COMP
COMP
RTN
RTN
CS
CS
FB
FB
Cvddl
Cvddl
Cvddh
R5
C1comp
C1comp
Cpd
Cvddh
Cpd
Rcomp
Rcomp
Rslope
Rslope
Rd1
Rd1
C2comp
C2comp
LD1
LD1
D3
D2
M1
Rcs
M1
Rcs
T1
T1
D1
D1
R4
R3
D2
L1
R3
R4
Voutput
Voutput
Cload
Cload