Monolithic Switched-Capacitor Power Converters: Present Trends and Future Predictions. N. Butzen, A. Sarafianos and M. Steyaert

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1 Monolithic Switched-Capacitor Power Converters: Present Trends and Future Predictions N. Butzen, A. Sarafianos and M. Steyaert

2 Overview Introduction Switched-Cap: Trends Switched-Cap: Present Focus Conclusions 2

3 INTRODUCTION 3

4 Why Monolithic? Footprint Profile Space Number of pins Bill of Materials IR Ldi/dt Power Regulation Cost High volume Silicon Technologies 4

5 Why Switched-Capacitor? Both Switches and Capacitors are used in Digital Circuits Readily available Scale well to advanced nodes 5

6 Switched-Capacitor Survey Select publication titles (TPEL, JSSC, ISSC, APEC, ) A total of 63 publications From M. Steyaert, N. Butzen, H. Meyvaert, A. Sarafianos, P. Callemeyn, T. Van Breussegem and M. Wens, "DCDC performance Survey", [Online]. Available: 6

7 SWITCHED-CAP: TRENDS 7

8 Switched-Capacitors are Hot 70 Total publications Year 8

9 Switched-Capacitors are Hot 70 Total publications J. F. Dickson Year 9

10 Switched-Capacitors are Hot log 2 [Total publications] Year 10

Switched-Capacitors are Hot log 2 [Total publications] 7 6

11 Switched-Capacitors are Hot log 2 [Total publications] Year x2 / 7years 11

12 Switched-Capacitors are Hot log 2 [Total publications] Year x2 / 4years 12

Switched-Capacitors are Hot log 2 [Total publications] 7 6 5 4 3 2 1 0 1970

13 Switched-Capacitors are Hot log 2 [Total publications] Year x2 / 4years Intel cancels Pentium 4 successor 13

14 For what application? Charge-pumps Memory (EEPROM) High VCR / Low Efficiency Memory Battery connected device Scavengers Processor/SoC's General Other 15

15 For what application? Portable devices Efficiency becomes important Memory Battery connected device Scavengers Processor/SoC's General Other 16

16 For what application? Systems on Chip Energy Harvesting General papers Allround designs Memory Battery connected device Scavengers Processor/SoC's General Other 17

17 For what application? Processors (DVS/DVFS) Automotive/MEMS/ Actuators High Power, Voltage Range Memory Battery connected device Scavengers Processor/SoC's General Other 18

18 For what application? Processors (DVS/DVFS) Automotive/MEMS/ Actuators Increasingly diverse set of applications High Power, Voltage Range Memory Battery connected device Scavengers Processor/SoC's General Other 19

19 What about technology? SC s are on the bleeding edge Node [nm] Year Max Mean Min Lowest available 20

20 What about technology? But don t need to be Node [nm] Year Max Mean Min Lowest available 21

21 SWITCHED-CAP: PRESENT FOCUS 22

22 A Selection Wide efficient Voltage Range Efficiency/Power Density Limits 23

23 Wide efficient Voltage Range Efficiency limited by Conversion Ratio Use a lot of VCR s [Jung2016] 24

24 Wide efficient Voltage Range Efficiency limited by Conversion Ratio Use a lot of VCR s But what at high power density? [Jung2016] 25

25 Efficiency/Power Density Limits Peak Efficiency [%] Bulk 45 SOI/TriGate 40 DT/FerroElectric 35 1E-7 1E-6 1E-5 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1 Power Density at Peak Efficiency [W/mm 2 ] 26

26 Efficiency/Power Density Limits Peak Efficiency [%] Bulk 45 SOI/TriGate 40 DT/FerroElectric 35 1E-7 1E-6 1E-5 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1 Power Density at Peak Efficiency [W/mm 2 ] 27

Efficiency/Power Density Limits Peak Efficiency [%] 100 95 90 85 80 75 70 65 60 55 50 45 40 Charge Sharing losses (SSL) are part of

27 Efficiency/Power Density Limits Peak Efficiency [%] Charge Sharing losses (SSL) are part of both 35 1E-7 1E-6 1E-5 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1 Bulk SOI/TriGate DT/FerroElectric Power Density at Peak Efficiency [W/mm 2 ] 28

28 Pushing The Limits Three Strategies: Hybridization Rethink power delivery Advanced Multiphasing 29

29 Hybridization Adding Inductor makes Caps Better Resonant Converters Soft-switching [Kesarwani2015] [Lei2013] Better Efficiency / Output Power Requires External component (potentially PowerSiP) 30

30 Rethink power delivery Change how load gets power (or in which form) Voltage Domain Stacking Flying Domain CMOS Allow large Ripple [Rajanpandian2005] [Salem2016] [Zimmer2015] Better Efficiency / Output Power Requires changes in load design 31

31 Advanced Multiphasing Make use of CMOS strengths Low Complexity Cost High Frequency ceiling Low Fragmentation cost Whole is bigger than sum of its parts

Advanced Multiphasing Peak Efficiency [%] 100 95 90 85 80 75 70 65 60 55 50 45 40 [Butzen2016] 94.

32 Advanced Multiphasing Peak Efficiency [%] [Butzen2016] 2:1 Bulk SOI/TriGate DT/FerroElectric 35 1E-7 1E-6 1E-5 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1 Power Density at Peak Efficiency [W/mm 2 ] 33

33 Advanced Multiphasing Scalable Parasitic Charge Redistribution Confidential 34

34 Advanced Multiphasing Scalable Parasitic Charge Redistribution Confidential 35

35 CONCLUSIONS 36

36 Conclusions Switched Capacitors are (still) on the rise, being continuously used in new Applications part of very diverse research area Many Promising research directions Still a lot of research to be done! 37

37 Thank you for your attention! QUESTIONS? 38

Fully Integrated SC DC-DC: Bulk CMOS Oriented Design

Fully Integrated SC DC-DC: Bulk CMOS Oriented Design Hans Meyvaert Prof. Michiel Steyaert 17 Nov 2012 Outline Towards monolithic integration CMOS as technology vehicle Techniques for CMOS DC-DC Conclusions