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Power-One EPA Energy Star Presentation Mahesh Thaker & Mikhail Guz
Presented at the 2006 EPA Energy Star
Server and Data Center Conference
Reducing IBA Power Dissipation
and Consumption with
Adaptive/Intelligent Control
and Power Management 2
Discussion Points
~ 400W Power System for Server Application
Conventional Power Conversion Components
Key Characteristics
Efficiency/Power Losses
Adaptive/Intelligent Power Conversion Components
Key Characteristics
Efficiency/Power Losses Savings
Activity Based Power Management 3
Holistic Approach To System Power
INPUT POWER
POWER
DISSIPATION
APP. 25-30%
OF INPUT
POWER
POWER
CONSUMPTION
APP. 70-75% OF
INPUT POWER 4
Typical Power System Block Diagram
AC-DC
Front End
AC-DC
Front End
Intermediate
Voltage Bus
POL
POL
POL
1.2V@90A
1.8V@45A
2.5V@30A
AC
MAINS
POL
3.3V@15A
Power
Consumption
app. 313W
DC-DC conversion
(POL regulators)
40% Load
Typical 12V
AC-DC Power
Conversion
40% Load, 5
Conventional/Passive Power
System Characteristics
Redundant AC-DC Front Ends
12V intermediate bus
Operating ~ 30%-40% capacity
Efficiency optimized @ full load ( ~84%)
Typically dominated by Copper (IIR) losses
Efficiency compromised @ partial load (~82%)
Switching losses, overhead/housekeeping losses
Fixed/Passive operating parameters
Operating frequency, constant airflow, output conditions, etc
Limited/no monitoring capabilities
DC-DC Converters
Fixed/passive operating parameters
Limited/no monitoring capabilities 6
Typical Efficiencies of a
Conventional 12V Front End
77.00
78.00
79.00
80.00
81.00
82.00
83.00
84.00
85.00
86.00
87.00
0
100
200
300
400
500
600
700
POut, W
E
ff'
y
,
%
220V
110V 7
Efficiencies of a Non-Isolated
DC-DC at Vin=12V
50
55
60
65
70
75
80
85
90
95
0
1.5
3
4.5
6
7.5
9
10.5
12
13.5
15
Output Current, A
E
f
fi
ci
e
n
cy,
%
Vout=0.5V
Vout=1.2V
Vout=2.5V
Vout=3.3V
Vout=5.0V 8
Conventional Power System Losses
AC-DC
Front End
AC-DC
Front End
Intermediate
Voltage Bus
DC-DC
DC-DC
DC-DC
1.2V@90A
1.8V@45A
2.5V@30A
AC
MAINS
DC-DC
3.3V@15A
Power
Consumption
app. 313W
POL Power
Dissipation
app. 47W
82.5%
88%
90%
92%
40% Load, 82%
IBV Power
app. 360W
AC-DC Power
Dissipation
app. 79W
AC Power
app. 439W
Overall System Efficiency=71.4%
40% Load, 82% 9
Intelligent/Adaptive Power System
Redundant / Adaptive AC-DC Front Ends and DC-DC
converters
Intelligent embedded monitoring and internal controls
Digital Embedded Controls and Power Management
High level of flexibility for modifying internal operating parameters
Dynamic adjustment of internal operating parameters to match
application/operating environment
Software managed
Embedded algorithms for performance optimization
User managed software control
Optimizes efficiency/key performance over entire load range
~86%-89% from 40%-100% rated load
Adaptive drivers minimize dead time and shoot-through
Internal monitoring of critical parameters
Input/output voltages, load condition, temperature 10
Efficiency of 12V Front End
with Adaptive Controls
84.00
85.00
86.00
87.00
88.00
89.00
90.00
91.00
0.00
100.00
200.00
300.00
400.00
500.00
600.00
POut, W
Ef
f
'
y
,
%
220V
110V 11
Power Losses in Power System with
Adaptive/Intelligent Front End
AC-DC
Front End
AC-DC
Front End
Intermediate
Voltage Bus
DC-DC
DC-DC
DC-DC
1.2V@90A
1.8V@45A
2.5V@30A
AC
MAINS
DC-DC
3.3V@15A
Power
Consumption
app. 313W
POL Power
Dissipation
app. 47W
82.5%
88%
90%
92%
40% Load, 87%
IBV Power
app. 360W
AC-DC Power
Dissipation
app. 54W
AC Power
app. 414W
Overall System Efficiency=75.7%
40% Load, 87% 12
Adaptive Control for DC-DC Converters
There is an optimal operating point for a given set of
conditions
Purpose of adaptive control is to continuously modify
performance parameters of a power supply to keep its
operation as close to optimal point as possible
Example: 1.2V output
Non-optimized 12V input, 1MHz switching
frequency, standard driver. Efficiency is 80%
Optimized - 5V input, 500kHz switching frequency,
adaptive driver. Efficiency is 85.5%
Power dissipation is reduced by
1/3
by optimizing
operating point of the power supply 13
Efficiency Is A Complex Function Of
Operating Conditions
50
55
60
65
70
75
80
85
90
95
0
1.5
3
4.5
6
7.5
9
10.5
12
13.5
15
Output Current, A
E
f
f
i
ci
e
n
cy
,
%
Vout=0.5V
Vout=1.2V
Vout=2.5V
Vout=3.3V
Vout=5.0V

65
70
75
80
85
90
95
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
Output Voltage, V
E
f
fi
ci
e
n
cy
,
%
Vin=3.3V
Vin=5V
Vin=12V

65
70
75
80
85
90
95
3
4
5
6
7
8
9
10
11
12
Input Voltage, V
E
f
f
i
ci
e
n
cy, %
Vout=0.5V
Vout=1.2V
Vout=2.5V
Vout=3.3V

80
82
84
86
88
90
92
94
500
750
1000
Switching Frequency, kHz
E
f
f
i
ci
e
n
cy
3.3Vin/2.5Vout
5Vin/1.2Vout
12Vin/5Vout
OUTPUT
LOAD
OUTPUT
VOLTAGE
INPUT
VOLTAGE
SWITCHING
FREQUENCY 14
Adaptive/Intelligent Front End &
DC-DC POLs Reduce Power Losses
AC/DC
Front End
AC/DC
Front End
Intermediate
Voltage Bus
DC-DC
DC-DC
DC-DC
1.2V@90A
1.8V@45A
2.5V@30A
AC
MAINS
DC-DC
3.3V@15A
Power
Consumption
app. 313W
POL Power
Dissipation
app. 38W
85%
90%
92%
93%
40% Load, 87%
IBV Power
app. 352W
AC-DC Power
Dissipation
app. 53W
AC Power
app. 404W
Overall System Efficiency=77.5%
40% Load, 87% 15
Further Power Reduction With
Activity Based Power Management
Enabled by digital power technology
Managing System reduction in both power
dissipation and power consumption
Modify performance parameters of entire system
as a function of system load, supply voltages,
and temperature
Managing Loads reduction in power consumption
Change clock frequency and supply voltage as a
function of processor load (DVS)
Intelligent control of cooling fans 16
Activity Based Power Management
SYSTEM PROCESSOR:
1. CALCULATES LOAD
2. SELECTS OPTIMAL IBV
SETTING FOR THE LOAD,
TEMP, AND MAINS
3. SETS OUTPUT OF AC/DC
TO MAXIMIZE SYSTEM
EFFICIENCY
Z-ONE
TM
DIGITAL
POINT OF LOAD
REGULATORS
Efficiency=f(IBV, LOAD,
VOUT, TEMP)
Vo2
Vo3
Vo1
Von
AC/DC
FRONT END POWER
SUPPLY
Efficiency=f(MAINS,
LOAD, IBV, TEMP)
INTERMEDIATE VOLTAGE BUS
INDUSTRY STANDARD I2C COMMUNICATION BUS
CONTINUOUS LOAD
MONITORING
REPORTING:
VOLTAGE, CURRENT, AND
TEMPERATURE
FOR EACH OUTPUT
CONTINUOUS MONITORING
AND ADJUSTMENT
REPORTING:
VOLTAGE (IBV AND MAINS),
AND TEMPERATURE
ADJUSTMENT:
INTERMEDIATE BUS VOLTAGE
AC MAINS 17
Typical Processor Utilization Curve
Source: EPRI/Ecos field measurements
Supply voltage clock scalable CPUs allow reducing power
consumption by varying clock frequency and supply voltage
as a function of utilization 18
Activity Based Power Management With DVS
SYSTEM PROCESSOR RUNS ACTIVITY-BASED OPTIMIZATION ALGORITHMS
POWER DISSIPATION REDUCTION
POWER CONSUMPTION REDUCTION
1. CALCULATES LOAD
1. DETERMINES CPU UTILIZATION
2. SELECTS OPTIMAL IBV SETTING
2. SELECTS OPTIMAL CPU CLOCK
FOR THE LOAD, TEMP, AND MAINS
FREQUENCY
3. SETS OUTPUT OF AC/DC
3. SETS CPU CLOCK FREQUENCY
TO MAXIMIZE SYSTEM EFFICIENCY
4. DETERMINES AND SETS NEW CPU
SUPPLY VOLTAGE
Z-ONE
TM
DIGITAL
POINT OF LOAD
REGULATORS
Efficiency=f(IBV, LOAD,
VOUT, TEMP)
Vo2
Vo3
Vo1
Von
AC/DC
FRONT END POWER
SUPPLY
Efficiency=f(MAINS,
LOAD, IBV, TEMP)
INTERMEDIATE
VOLTAGE BUS
INDUSTRY STANDARD
I2C COMMUNICATION BUS
CONTINUOUS
MONITORING
AND ADJUSTMENT
REPORTING:
VOLTAGE, CURRENT,
AND TEMPERATURE
ADJUSTMENT:
OUTPUT VOLTAGE
CONTINUOUS MONITORING
AND ADJUSTMENT
REPORTING:
VOLTAGE (IBV AND MAINS),
AND TEMPERATURE
ADJUSTMENT:
INTERMEDIATE BUS
VOLTAGE
AC
MAINS
DATA
PROCESSING
LOADS
CONTINUOUS
MONITORING
AND ADJUSTMENT
REPORTING:
UTILIZATION, CLOCK
FREQUENCY
TEMPERATURE
ADJUSTMENT:
CLOCK FREQUENCY 19
Power Savings Summary Per System
$25K
77.5%
91
313
PS with Adaptive
AC FE & POLs
$29K
78.5%
86
313
PS with Activity
Based Power
Management
$47K
78.1%
82
292
PS with Activity
Based PM and DVS
$18K
75.7%
100
313
PS with Adaptive
AC Front End
$0K
71.4%
126
313
Conventional Power
System
Annual
Savings
Overall
System
Efficiency
Power
Losses
(Watts)
Power
Consumption
(Watts)
Assumes 75% equipment utiliza