Selecting The Correct IC For Power-Supply Applications: by William Hadden
Selecting The Correct IC For Power-Supply Applications: by William Hadden
Selecting The Correct IC For Power-Supply Applications: by William Hadden
12-V
Supply
Li+ Battery
Charger
3.5- to 4.2-V
Li+ Battery
AC-Adapter/Battery
Switchover Circuit
1.50-V, 100-mA
DC/DC Supply
2.5-V, 50-mA
DC/DC Supply
ASIC
1.25-V, 300-mA
DC/DC Supply
FPGA
1.65-V, 112-mA
DC/DC Supply
Microprocessor
3.3-V, 420-mA
DC/DC Supply
5
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1Q 2007
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Power Management
6
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Power Management
12-V
Supply
TPS5431
(5 V, 2 A)
AC
BAT
3.5- to 4.2-V
Li+ Battery
VIN
VMAIN
3.3 V
TPS62201
(1.50 V, 100 mA)
TPS65010
ASIC
25 V
LDO2
1.25 V
VCORE
FPGA
1.6 V
LDO1
Microprocessor
POUTEFFTOT = Di Pi ,
i =1
PLOSS = D PRAIL
1
RAIL
7
Analog Applications Journal
1Q 2007
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Power Management
We then sum up the power loss for all of the rails to get
the total power loss:
n
1
PLOSSTOTAL = Di Pi 1 ,
i
i =1
Conclusion
D PRAIL
PLOSSTOTAL + POUTEFFTOT
power.ti.com
www.ti.com/sc/device/partnumber
Replace partnumber with bq24010, TPS5431, TPS62201,
TPS65010, TPS71525, TPS75003, or TPS76925
POWER
RAIL
P1
P2
P3
P4
P5
LDO OR
SWITCHER?
Switcher
LDO
Switcher
LDO
Switcher
LDO OR
SWITCHER?
Switcher
LDO
Switcher
LDO
LDO
OUTPUT
VOLTAGE
(V)
1.35
2.5
1.25
1.65
3.3
OUTPUT
VOLTAGE
(V)
1.35
2.5
1.25
1.65
3.3
OUTPUT
CURRENT
(A)
0.106
0.05
0.3
0.112
0.42
POWER
(W)
0.1431
0.125
0.375
0.1848
1.386
TOTALS
2.2139
OUTPUT
CURRENT
(A)
0.106
0.05
0.3
0.112
0.42
POWER
(W)
0.1431
0.125
0.375
0.1848
1.386
TOTALS
2.2139
DUTY
CYCLE
(%)
100
100
100
100
10
EFFECTIVE
POWER
(W)
0.1431
0.125
0.375
0.1848
0.1386
0.9665
DUTY
CYCLE
(%)
100
100
100
100
10
EFFECTIVE
POWER
(W)
0.1431
0.125
0.375
0.1848
0.1386
0.9665
EFFICIENCY
(%)
90
63
90
41
90
POWER
LOSS
(W)
0.016
0.075
0.042
0.263
0.015
0.411
System Efficiency: 70.15%
EFFICIENCY
(%)
90
63
90
41
83
POWER
LOSS
(W)
0.016
0.075
0.042
0.263
0.029
0.425
System Efficiency: 69.45%
Difference: 0.71%
8
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