Energy Efficiency Energy Star 33 External Power Adaptors

Energy Efficiency Energy Star 33

External Power Adaptors u Crucial to the operation of virtually all small electronic devices u Most do not have an On/Off switch and consume in a noload situation u 1. 5 billion in use in the US today (Approximately 5 for every person) v 300 billion k. Wh/year v US$ 25 billion/year v 6% of the national electric bill; or approximately 30% of the typical home electric bill by 2010 if left unchecked Energy Star 4

Energy Star 2. 0 In addition to the Active Mode efficiency requirements found above, power supplies with greater than or equal to 100 watts input power must have a true power factor of 0. 9 or greater at 100% of rated load when tested at 115 volts @ 60 Hz. Effective date is November 1, 2008 Energy Star 5

Energy Star 2. 0 In addition to the Active Mode efficiency requirements found above, power supplies with greater than or equal to 100 watts input power must have a true power factor of 0. 9 or greater at 100% of rated load when tested at 115 volts @ 60 Hz. Energy Star 6

Energy Star 2. 0 Energy Star 7

Efficiency Criteria for EPS (Adaptor) Energy Star 8

What is “ 80 Plus”? u Developed by Ecos Consulting and California Electric Commission u Specifically for computer power supplies u Requirements are 80% efficiency at 20%, 50% and 100% load, plus PF of 0. 9 at 100% load Energy Star 9

“ 80 Plus” for Computer Power Supplies Energy Star 10

“ 80 Plus” for Computer Power Supplies Energy Star 11

Designing the “Perfect” Supply Lower Cost Higher Efficiency Optimized Design u u Smaller Size Energy Star u No single solution Trade-offs in every decision Every benefit has a cost 12

Major Design Issues 1. Meeting standby mode requirements • �� 0. 3~0. 5 W for external supplies and notebooks • �� 2. 0 W for desktop computers and workstations 2. Meeting active mode requirements • �� Don’t over design the power supply • �� PFC will eventually be required 3. Biggest design challenge • �� Achieving 80% efficiency at 20% rated power 4. Possible solutions • �� Multi-mode / Variable frequency operation • �� Careful component selection • �� Consider efficiency at every step Energy Star 13

Switching Power Supply Technologies Energy Star 14

Topology Tree Energy Star 15

Basic Converters 降壓型轉換器 Step-Down (Buck) Converter 升壓型轉換器 Step-Up (Boost) Converter 降升壓型轉換器 Step-Down/Up (Buck-Boost) Converter Energy Star 16

Derived Converters Forward Half-Bridge Energy Star Flyback Push-Pull Full-Bridge 17

Possible Topologies for High-Efficiency Energy Star v Multi-mode-controlled Quasi-Resonant Flyback (Valley Switching) Converter v Active-clamp Forward Converter v Asymmetrical Half-Bridge Converter v Serial-resonant Half-bridge LLC Converter v Synchronous Rectification 18

Where are the Losses Occurring ? Standby Power Active Power 1. 2. 3. 4. 5. Energy Star Capacitive losses : Biasing network Controller current Gate charge : Start-up network Rectifier conduction Transformer loss FET conduction loss Resistor dissipative loss Snubber losses 19

Conventional Flyback Converter Fixed-frequency Control CCM/DCM Operation Hard-Switching Transition-mode Control Variable-frequency Operation Hard-Switching High-frequency Operation @ highline / light-load Hard to meet EPS new requirements, especially Light Load. Energy Star 20

Quasi-Resonant Flyback Converter Same flyback converter configuration u Switching-on at valley points u Switching-off by peak current PWM control u Energy Star 21

Multi-mode Control of Flyback Converter Energy Star 22

Multi-mode Control of Flyback Converter Energy Star 23

Multi-mode Control of Flyback Converter Advantages : • Quasi-Resonant Mode For Reduced EMI And Low Switching Losses (Valley Switching). • DCM Operation Eliminates Reverse Recovery on Secondary Diode. • DCM and FFM can Reduce Switching Losses, especially at Light Loads. • Burst Mode can Reduce Power Consumption at very Light Load and No Load Conditions. Suitable to meet EPS Requirements for Small_Medium Power Applications. Energy Star 24

Forward Converter --- Various Reset Approaches Energy Star 25

Conventional 2 -Switch Forward Converter • PWM fixed-frequency operation. • Hard-switching on both MOSFETs and Diodes. • Easy to implement SR. • Low magnetizing current. • No reset winding needed. Energy Star 26

Active-clamp Forward Converter • PWM fixed-frequency operation. • Soft-switching on MOSFETs is possible. • Very easy to implement SR. • Low magnetizing current. Energy Star 27

Conventional Half-Bridge Converter • PWM fixed-frequency operation. • Hard-switching on both MOSFETs and Diodes. • Easy to implement SR. • Low magnetizing current Energy Star 28

Asymmetrical Half-Bridge Converter ZVS • PWM fixed-frequency control. • D and (1 -D) duty operation with dead time control. • Less hold-up time. • Higher secondary diode voltage stress. • DC bias on transformer. • Easy to implement SR. Energy Star 29

Resonant Half-Bridge Converter SRC SPRC LLC PRC Variable-Frequency Operation Energy Star 30

Series Resonant Half-Bridge Converter LLC Energy Star 31

Regulation Equation of LLC-SRC f<fr f>fr f=fr Energy Star 32

Basic Resonant Cell Diode on Diode off Energy Star 33

Half-Bridge LLC Converter Energy Star 34

Half-Bridge LLC Converter FHA Energy Star 35

Features of LLC Converter • • • Variable Frequency Operation. 50% Duty on each Transistor. Zero-Voltage-Switching Naturally. No DC Bias on Transformer. Less Voltage Stress on Secondary Diodes (2 Vo). Higher Current Stress but Zero-Current-Switching on Secondary Diodes. • Complicated to Implement SR. • Longer Hold-up Time. • Higher Magnitizing Current, Lower Efficiency at Light Load. Suitable for High-Efficiency Applications Energy Star 36

Synchronous Rectification VIN=12 V, VO=5 V, IO=20 A, L=2. 5 u. H, 15 mΩ, C=2200 u. F, 12 mΩ Rdson=10 mΩ, Diode=MBR 3020 CT f. S=120 k. Hz, PSpice Energy Star IQH RMS (A) IQL RMS (IDL AVG) (A) PQH (W) PQL (W) Con. Buck 13. 89 10. 56 1. 929 5. 344 SR Buck 13. 70 15. 00 1. 877 2. 246 37

LLC-SRC HB with Synchronous Rectifiers Efficiency Improvement 1. 5 ~ 2% for 12 V 2 ~ 2. 5% for 19 V Energy Star 38

Hardware Implementation Bridge Rectifier PFC Choke Energy Star LLC Tank Bulk Cap SR Module 39

Average Efficiency Measurement (Cable-end) LLC 120 W 0. 94 0. 93 Efficiency 0. 92 0. 91 0. 9 100 V 0. 89 115 V 230 V 0. 88 0. 87 25% VacLoad　 Energy Star 50% % of Full-Load 75% 100% 25% 50% 75% 100% Average 100 V 0. 8798 0. 9173 0. 9198 0. 9144 0. 9078 115 V 0. 8870 0. 9197 0. 9236 0. 9263 0. 9142 230 V 0. 9113 0. 9186 0. 9281 0. 9292 0. 9218 40

Performance Comparison Efficiency Load Company A Company B Bestec 115 V 230 V 100% 89. 10 90. 25 86. 89 87. 83 92. 63 92. 92 75% 90. 32 90. 30 87. 59 87. 86 92. 37 92. 81 50% 90. 64 88. 81 87. 15 86. 54 91. 97 91. 86 25% 91. 09 90. 33 88. 47 87. 02 88. 70 91. 13 AVG 90. 29 89. 92 87. 52 87. 31 91. 42 92. 18 Power Factor Load Company A Company B Bestec 115 V 230 V 100% 0. 990 0. 933 0. 990 0. 939 0. 996 0. 969 75% 0. 980 0. 908 0. 982 0. 917 0. 991 0. 953 50% 0. 959 0. 865 0. 967 0. 883 0. 988 0. 911 25% 0. 617 0. 404 0. 496 0. 421 0. 957 0. 816 Energy Star 41

EMI Test Results Conducted Emission 110 Vac Energy Star 220 Vac 42

Thermal Test Results (90 V/60 Hz, 120 W) Energy Star 43

No (Light) Load Power Consumption Ø Burst –mode operation to decrease average switching frequency. Ø Synchronous Burst –mode operation to APFC circuit. Energy Star 44

No Load and Light Load Power Dissipation Input Voltage Energy Star 100 Vac 115 Vac 230 Vac No load 0. 27 W 0. 33 W Po=0. 5 W 0. 97 W 0. 94 W Po=1 W 1. 64 W 1. 60 W 1. 55 W Po=1. 5 W 2. 31 W 2. 24 W 2. 14 W 45

多謝 Energy Star 47