Reverse Power Feed (RPF): Benefits and Constraints

Power Matters
Reverse Powering
Its Benefits and Constraints
Daniel Feldman – VP Business Development,
Microsemi
Agenda
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Why Fiber to the Distribution Point?
MDU ONT Reverse Power Fed
Benefits of Reverse Power Feeding (RPF)
Force Power vs ETSI RPF
Typical RPF Circuit
RPF Constraints
How much power can be delivered?
How fair is this to the end user?
Summary
© 2014 Microsemi Corporation.
Power Matters
2
Why Fiber to the Distribution Point (DP)?
 Cable competition can support over 1Gbit/s
•
•
•
•
DOCSIS 3.0: 912Mbit/s in the US, 1.2Gbit/s in Europe
DOCSIS 3.1: 10Gbit/s
Real deployments already up to 250Mbit/s
Works on standard hybrid coaxial/fiber already in place
 Fiber to the Home is expensive
• Last 250 meters cost ~$1000 (source: http://arstechnica.com/techpolicy/2010/03/fiber-its-not-all-created-equal/)
 Last 250m need to compete with cable in terms of
• Speed: G.FAST bringing up to 500Mbit/s (1Gbit/s w/vectoring)
• Cost: Reverse Power Feeding (RPF) MDU/DSLAM from home
eliminates added drilling and power metering
© 2014 Microsemi Corporation.
Power Matters
3
Multiple Dweller Unit ONT Reverse Power Fed
Power fed to remote node over
same copper pair as XDSL signal
POTSA/POTSD
CO
cabinet
DP
NTE
POTSD
SG
Central Office
Fibre-fed Remote Node
(cabinet or DP located)
Derived Voice
Local Power Feed
Definitions
RPF: Reverse Power Feeding
PSE: Power Sourcing Equipment
PD: Powered Device
© 2014 Microsemi Corporation.
Home network
Power Matters
4
Benefits of Reverse Power Feeding
 Flexibility
• No need for AC source proximity, or location safe for AC
• No need to wait for the electrical company to install
 Cost per user lower than $31.25
• 8 users can be covered by a single MDU ONT+DSLAM
• Average Smart Meter installation cost (for local power) is $250 (source:
http://www.emeter.com/smart-grid-watch/2010/how-much-do-smartmeters-cost/
• RPF benefits increase with smaller MDU ONT+DSLAM
– $250/8=$31.25
– $250/4=$62.50
– $250/2=$125.00
 Standardized by ETSI
• Interoperability
• Safety
© 2014 Microsemi Corporation.
Power Matters
5
Force Power (non-ETSI) vs ETSI RPF
Force Power (non-ETSI)
ETSI RPF Power Up protocol
 Lower cost – doesn’t
 Additional component cost
 Power enabled through
require extra components
for startup protocol
 Power always exist on the
line
• Safety
• End equipment exposed to
constant high power – fire
hazard
 Doesn’t Interoperate with
foreign power (I.E. POTSDC) and ETSI standard
successful handshaking
• Active handshake
– Requires both ends to be
powered (battery/charge circuit)
– Handshaking Protocol over data
• Passive handshake
– Resistive signature based
detection doesn’t require power
on DP side
 Interoperability with foreign
power on the line and ETSI
Standard
© 2014 Microsemi Corporation.
Power Matters
6
Typical RPF circuit for CPE and 8-port MDU
 CPE RPF components
HPF
xDSL IAD/Modem
RJ11
Connector
1500Vrms Isolation
• Power injection circuitry
• Isolated boost
• Larger AC/DC power supply
802.11
SoC
Packetized
Voice
DSL AFE
LPF
RF Front
End
RJ11
Connector
RPF PSE
Isolated
12Và 55V
Boost
N-port
Ethernet
Switch
xDSL SoC
Ethernet
PHY xN
Nx RJ45
Connector
12VDC
VAC
Connector
 CPE RPF Injector
Primary
AC/DC
12VDC
Non-Isolated
DC/DC
Internal AC/DC Power supply
• Works with non-RPF modem
• Pay for RPF only once
Smart Power
Sharing
12V
RPF DP FE + Isolated
DC/DC #1
12V
Non-Isolated
DC/DC
 DPU RPF components
3.3V, 1.8V, 1.1V, 0.9V,...
• Power sharing circuit
• 8xPower extraction circuit
• Power conversion circuit
Optical
Connector
CPU +
MDU
ONT/
Xceiver +
xDSL
DSP
+xDSL
AFE
125MHz, 70.656MHz,
25Mhz, ...
RPF DP FE + Isolated
DC/DC #2
RPF DP FE + Isolated
DC/DC #3
RPF DP FE + Isolated
DC/DC #4
RPF DP FE + Isolated
DC/DC #5
RPF DP FE + Isolated
DC/DC #6
Clock
Management
RPF DP FE + Isolated
DC/DC #7
Crystal or
Oscillator
© 2014 Microsemi Corporation.
RPF DP FE + Isolated
DC/DC #8
VDC
Connector
MELT #1
37V to 57V
Line Driver #1
LPF
HPF
MELT #2
LPF
Line Driver #2
HPF
MELT #3
LPF
Line Driver #3
HPF
MELT #4
LPF
Line Driver #4
HPF
MELT #5
LPF
Line Driver #5
HPF
MELT #6
LPF
Line Driver #6
HPF
MELT #7
LPF
Line Driver #7
HPF
MELT #8
LPF
Line Driver #8
HPF
RJ11 to
CPE #1
RJ11 to
CPE #2
RJ11 to
CPE #3
RJ11 to
CPE #4
RJ11 to
CPE #5
RJ11 to
CPE #6
RJ11 to
CPE #7
RJ11 to
CPE #8
Power Matters
7
Reverse Power Feeding Constraints
 Primary Constraints
• Local safety standards: If user can be exposed, voltage must be <60V
• Wires may have 0.4mm diameter: 26.78Ω at 100m
• CPE devices at various ranges from DP: from 10m* to 250m**
 ….so….
• CPE Current limiting losses  source output voltage is closer to 55V
• Different power losses on every cable
• Different input voltage on every port  Need to define minimum
 …. so…..
• Power available to power DP depends on distance and wire type
• Load from every home is different  fair power sharing needed
 Additional ETSI standard constraints
• 21W, 15W and 10W maximum power output classes
• POTS interoperability
© 2014 Microsemi Corporation.
Power Matters
8
Available Power for 21W class, 0.4mm cable
Cable Length
10
50
100
150
200
250
0.35
0.35
0.35
0.35
0.35
0.35
55
55
55
55
55
55
19.25
19.25
19.25
19.25
19.25
19.25
Cable Resistance/length (0.4mm cable, AWG26)
0.13
0.13
0.13
0.13
0.13
0.13
Cable Loop Resistance (2 wires)
Power loss on cable
PD Voltage at the PD port
Power available to DPU input RJ11 connector
2.68
13.39
26.78
40.17
53.56
66.95
0.33
1.64
3.28
4.92
6.56
8.20
54.06
50.31
45.63
40.94
36.25
31.57
18.92
17.61
15.97
14.33
12.69
11.05
Per pair Current (Plug)
PSE Voltage at the port
PSE Output Power
Output power at 12V (simple current sharing)
1.40
1.40
1.40
1.40
1.40
1.40
0.49
0.49
0.49
0.49
0.49
0.49
0.07
0.07
0.07
0.07
0.07
0.07
18.36 17.05 15.41 13.77 12.13 10.49
90%
90%
90%
90%
90%
90%
16.52 15.34 13.87 12.39 10.91
9.44
Output regulated power (w/Short protection)
15.97
Diode Bridge Vfwd
Diode losses
PD Isolating Switch losses (0.6ohm)
Input power to Isolated Converter
Isolated Converter PoE to 12V Efficiency
14.83
13.40
11.98
10.55
9.12
Assumptions:
a) Input voltage range on PD should be 36V to 60V
b) VDSL2 application can work with 11.5W
c) Minimum desirable range is 100m
© 2014 Microsemi Corporation.
Power Matters
9
Available Power for 21W class, 0.5mm cable
Cable Length
10
50
100
150
200
250
0.35
0.35
0.35
0.35
0.35
0.35
55
55
55
55
55
55
19.25
19.25
19.25
19.25
19.25
19.25
Cable Resistance/length (0.5mm cable, AWG24)
0.08
0.08
0.08
0.08
0.08
0.08
Cable Loop Resistance (2 wires)
Power loss on cable
PD Voltage at the PD port
Power available to DPU input RJ11 connector
1.68
8.40
16.80
25.20
33.60
42.00
0.21
1.03
2.06
3.09
4.12
5.15
54.41
52.06
49.12
46.18
43.24
40.30
19.04
18.22
17.19
16.16
15.13
14.11
Per pair Current (Plug)
PSE Voltage at the port
PSE Output Power
Output power at 12V (simple current sharing)
1.40
1.40
1.40
1.40
1.40
1.40
0.49
0.49
0.49
0.49
0.49
0.49
0.07
0.07
0.07
0.07
0.07
0.07
18.48 17.66 16.63 15.60 14.57 13.54
90%
90%
90%
90%
90%
90%
16.63 15.89 14.97 14.04 13.11 12.19
Output regulated power (w/Short protection)
16.08
Diode Bridge Vfwd
Diode losses
PD Isolating Switch losses (0.6ohm)
Input power to Isolated Converter
Isolated Converter PoE to 12V Efficiency
15.36
14.47
13.57
12.68
11.78
Assumptions:
a) Input voltage range on PD should be 36V to 60V
b) VDSL2 application can work with 11.5W
c) Minimum desirable range is 100m
© 2014 Microsemi Corporation.
Power Matters
10
Available Power for 30W class, 0.4mm cable
Cable Length
10
50
100
150
200
250
0.50
0.50
0.50
0.50
0.50
0.50
55
55
55
55
55
55
27.50
27.50
27.50
27.50
27.50
27.50
Cable Resistance/length (0.4mm cable, AWG26)
0.13
0.13
0.13
0.13
0.13
0.13
Cable Loop Resistance (2 wires)
Power loss on cable
PD Voltage at the PD port
Power available to DPU input RJ11 connector
2.68
13.39
26.78
40.17
53.56
66.95
0.67
3.35
6.70
10.04
13.39
16.74
53.66
48.31
41.61
34.92
28.22
21.53
26.83
24.15
20.81
17.46
14.11
10.76
Output power at 12V (simple current sharing)
1.40
1.40
1.40
1.40
1.40
0.70
0.70
0.70
0.70
0.70
0.15
0.15
0.15
0.15
0.15
25.98 23.30 19.96 16.61 13.26
90%
90%
90%
90%
90%
23.38 20.97 17.96 14.95 11.93
1.40
0.70
0.15
9.91
90%
8.92
Output regulated power (w/Short protection)
22.60
8.62
Per pair Current (Plug)
PSE Voltage at the port
PSE Output Power
Diode Bridge Vfwd
Diode losses
PD Isolating Switch losses (0.6ohm)
Input power to Isolated Converter
Isolated Converter PoE to 12V Efficiency
20.27
17.36
14.45
11.54
Assumptions:
a) Input voltage range on PD should be 36V to 60V
b) G.FAST application can work with 17.5W
c) Minimum desirable range is 100m
© 2014 Microsemi Corporation.
Power Matters
11
Available Power for 30W class, 0.5mm cable
Cable Length
10
50
100
150
200
250
0.50
0.50
0.50
0.50
0.50
0.50
55
55
55
55
55
55
27.50
27.50
27.50
27.50
27.50
27.50
Cable Resistance/length (0.5mm cable, AWG24)
0.08
0.08
0.08
0.08
0.08
0.08
Cable Loop Resistance (2 wires)
Power loss on cable
PD Voltage at the PD port
Power available to DPU input RJ11 connector
1.68
8.40
16.80
25.20
33.60
42.00
0.42
2.10
4.20
6.30
8.40
10.50
54.16
50.80
46.60
42.40
38.20
34.00
27.08
25.40
23.30
21.20
19.10
17.00
Per pair Current (Plug)
PSE Voltage at the port
PSE Output Power
Output power at 12V (simple current sharing)
1.40
1.40
1.40
1.40
1.40
1.40
0.70
0.70
0.70
0.70
0.70
0.70
0.15
0.15
0.15
0.15
0.15
0.15
26.23 24.55 22.45 20.35 18.25 16.15
90%
90%
90%
90%
90%
90%
23.61 22.10 20.21 18.32 16.43 14.54
Output regulated power (w/Short protection)
22.82
Diode Bridge Vfwd
Diode losses
PD Isolating Switch losses (0.6ohm)
Input power to Isolated Converter
Isolated Converter PoE to 12V Efficiency
21.36
19.53
17.70
15.88
14.05
Assumptions:
a) Input voltage range on PD should be 36V to 60V
b) G.FAST application can work with 17.5W
c) Minimum desirable range is 100m
© 2014 Microsemi Corporation.
Power Matters
12
Power Limits Results
 Maximum DP port consumption with existing ETSI standard
• Worst case condition: single CPE powering multi-port DPU
• At 250m: 9.12W  is this enough?
• At 100m: 13.40W  should be enough for VDSL2 DPU
 This may not be enough for G.FAST
• For 17.5W DPU, need a 30W class at ETSI
© 2014 Microsemi Corporation.
Power Matters
13
End User cost allocation: is this fair?
20W load 10-150m
0.4mm cable
0.5mm cable
Cable Length
Per pair Current (Plug)
PSE Voltage at the port
PSE Output Power
16W load 10-250m
0.4mm cable
0.5mm cable
10
150
10
150
10
250
10
250
0.22
0.27
0.22
0.24
0.17
0.25
0.17
0.20
55
55
55
55
55
55
55
55
11.95
14.84
11.90
13.35
9.54
13.80
9.51
11.27
Cable Resistance/length
0.13
0.13
0.08
0.08
0.13
0.13
0.08
0.08
Cable Loop Resistance (2 wires)
Power loss on cable
PD Voltage at the PD port
Power available to DPU input RJ11 connector
2.68
40.17
1.68
25.20
2.68
66.95
1.68
42.00
0.13
2.92
0.08
1.49
0.08
4.21
0.05
1.76
54.42
44.16
54.64
48.88
54.54
38.20
54.71
46.39
11.83
11.92
11.83
11.87
9.46
9.58
9.46
9.51
Output power at 12V (simple current sharing)
1.40
0.30
0.03
11.49
90%
10.34
1.40
0.38
0.04
11.49
90%
10.34
1.40
0.30
0.03
11.49
90%
10.34
1.40
0.34
0.04
11.49
90%
10.34
1.40
0.24
0.02
9.20
90%
8.28
1.40
0.35
0.04
9.20
90%
8.28
1.40
0.24
0.02
9.20
90%
8.28
1.40
0.29
0.03
9.20
90%
8.28
Output regulated power (w/Short protection)
10.00
10.00
10.00
10.00
8.00
8.00
8.00
8.00
Diode Bridge Vfwd
Diode losses
PD Isolating Switch losses (0.6ohm)
Input power to Isolated Converter
Isolated Converter PoE to 12V Efficiency
PSE AC/DC efficiency
AC power consumption
Yearly power consumption
Electricity cost
Yearly electricity cost
Yearly end user cost difference
75%
15.94
139.62
$ 0.20 $
$ 27.92 $
$
75%
75%
19.79
15.87
173.33
139.04
0.20 $ 0.20 $
34.67 $ 27.81 $
75%
75%
17.81
12.72
155.98
111.39
0.20 $ 0.20 $
31.20 $ 22.28 $
75%
75%
18.40
12.67
161.16
111.02
0.20 $ 0.20 $
32.23 $ 22.20 $
75%
15.03
131.65
0.20
26.33
6.74
3.39
9.95
4.13
$
$
$
Assumptions:
a) G.FAST application consumes 20W with 2 loads
b) VDSL2 application consumes 16W with 2 loads
c) Simple current sharing used, with 100% accuracy
© 2014 Microsemi Corporation.
Power Matters
14
Fair Power Sharing
 Definition: load each DP ports based on CPE consumption
including cable losses, so loads are identical
 Option 1: communicate CPE power consumption
• CPE host reads PSE power  expensive isolation on every CPE
• DPU reads power consumed from each CPE  does it interoperate?
• Precludes RPF Injector  pay for RPF every CPE refresh
 Option 2: determine power consumption on DPU
•
•
•
•
DPU FairPower™ infers cable length from input voltage
DPU FairPower™ measures no load CPE output voltage
Works with ANY CPE, with embedded RPF or RPF injector
FairPower™ circuit cost spread over multiple ports
© 2014 Microsemi Corporation.
Power Matters
15
Summary
 Reverse Power Feeding is an important G.FAST enabler
 Work to be done at ETSI to fully support G.FAST
• 30W class support
 FairPower™ sharing can simplify the acceptance of RPF
© 2014 Microsemi Corporation.
Power Matters
16