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Automatic Current Balancing Circuit for Multi-Phase ...
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Automatic Current Balancing Circuit for Multi-Phase Constant On-Time Hysteresis Control Converter Shogo Katayama, Jing Li, Yifei Sun, Tran Minh Tri, Yasunori Kobori, Anna Kuwana, Haruo Kobayashi (Gunma University) [email protected] 1. Objective 1B-07 4. Simulation 5. Conclusion References 2. Background 1. For large load current Multi-Phase configuration COT hysteresis control converter Correcting the on-time of the COT pluse by the error amplifier feedback control Error amplifier feedback the inductor current difference to on-time reference Automatic current imbalance correction COT hysteresis control converter for large load current 2. Automatic current imbalance correction Feedback the current difference COT: Constant On-Time [1] H. Kobayashi, T. Nabeshima (Editors), Handbook of Power Management Circuits, Pan Stanford Publisher (2016) [2] Y. Xiong, K. Asaishi, N. Miki, N. Tsukiji, Y. Kobori, H. Kobayashi, “Constant On-Time Controlled Four-Phase Buck Converter via Two Ways of Saw-tooth-wave Circuit and PLL Circuit” , IEEE International Symposium on Intelligent Signal Processing and Communication Systems, Xiamen, China (2017). [3] J. Li, Y. Xiong, Y. Sun, T. M. Tri, Y. Kobori, H. Kobayashi, “ Fourphase Ripple Controlled Switching Converter with EMI Noise Reduction Circuit” , International Conference on Mechanical, Electrical and Medical Intelligent System, Kiryu (2018). [4] K. Asaishi, N. Tsukiji, Y. Kobori, Y. Sunaga, N. Takai, H. Kobayashi, “ Hysteresis Control Power Supply with Switching Frequency Insensitive to Input/Output Voltage Ratio ” , IEEE 13th International Conference on Solid-State and Integrated Circuit Technology, Hangzhou, China (2016). 0.6 1.0 1.4 1.8 2.2 2.6 3.0 2.500m 2.502m 2.504m 2.506m 2.508m 2.510m Inductor Current [A] Time [s] Current imbalance from L, C element variation Causes overcurrent Increase voltage ripple Current imbalance Goal Automatic current balancing 3. Proposed Circuit Dual Phase COT Converter In Quad-Phase For large load current Parallel connection of power stages Error Amp R 1 R 1 I L2 I L1 I L3 R 2 R 2 Error Amp R 1 R 1 R 2 R 2 Error Amp R 1 R 1 R 2 R 2 LPF LPF LPF LPF V cot V dd C t COMP Phase 2 COT Pulse Phase 3 COT Pulse Phase 4 COT Pulse Phase 2 COT Timer SAW tooth I Phase 3 COT Timer Phase 4 COT Timer I L4 R f C L 1 S Load V in V out C f L 2 S V r I L2 I L1 Ripple Comp COMP V ref COMP Phase 1 COT Pulse Phase 2 Power Stage Phase 1 Power Stage Phase 1 COT Timer Phase Divider Phase 2 COT Timer Correction Circuit Phase 2 COT Pulse SAW tooth COMP V cot SAW tooth COMP V cot Peak Hold SAW Gen SAW Gen Error Amp LPF LPF Proposal 1 Element variation: C t2 increase by 10% Conditions Proposal 2 Current imbalance correction Feedback the current difference to On-Time Feedback the current difference to each sub-converter C element variation L element variation Before imbalance correction Compensate on-time reference Inductor current difference 41% 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 Output Current [A] 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 0.0 1.0m 2.0m 3.0m 4.0m 5.0m 6.0m 7.0m Average Current [A] Time [s] I o I o = 4A 5A 6A I L2 I L1 , I L3 , I L4 7A 8A 9A 10A 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.500m 2.502m 2.504m 2.506m 2.508m 2.510m 2.512m 2.514m 2.516m 2.518m 2.520m Inductor Current [A] Time [s] I L1 I L2 I L3 I L4 0.6 1.0 1.4 1.8 2.2 2.6 3.0 2.500m 2.502m 2.504m 2.506m 2.508m 2.510m 2.512m 2.514m 2.516m 2.518m 2.520m Inductor Current [A] Time [s] I L1 I L2 I L3 I L4 After imbalance correction Inductor current difference 1% Reduce current imbalance Increase load current 4A to 10A I o =10A: Inductor current difference 2% Proposal correction circuit in large load current: Stable Increase 10% COT timer capacitor C t2 Without correction circuit: Inductor current difference 41% Within correction circuit: Inductor current difference 1% Current balance improves significantly Simulate proposal corection circuit
Transcript of Automatic Current Balancing Circuit for Multi-Phase ...
Automatic Current Balancing Circuit for Multi-PhaseConstant On-Time Hysteresis Control Converter
Shogo Katayama, Jing Li, Yifei Sun, Tran Minh Tri, Yasunori Kobori, Anna Kuwana, Haruo Kobayashi (Gunma University) [email protected]
1. Objective
1B-07
4. Simulation 5. Conclusion
References
2. Background
1. For large load current Multi-Phase configuration
COT hysteresis control converter
Correcting the on-time of the COT pluseby the error amplifier feedback controlError amplifier feedback the inductor current difference to on-time reference
Automatic current imbalance correction
COT hysteresis control converterfor large load current
2. Automatic current imbalance correction Feedback the current difference
COT: Constant On-Time
[1] H. Kobayashi, T. Nabeshima (Editors), Handbook of Power Management Circuits, Pan Stanford Publisher (2016)
[2] Y. Xiong, K. Asaishi, N. Miki, N. Tsukiji, Y. Kobori, H. Kobayashi, “Constant On-Time Controlled Four-Phase Buck Converter via Two Ways of Saw-tooth-wave Circuit
and PLL Circuit” , IEEE International Symposium on Intelligent Signal Processing and Communication Systems, Xiamen, China (2017).
[3] J. Li, Y. Xiong, Y. Sun, T. M. Tri, Y. Kobori, H. Kobayashi, “ Fourphase Ripple Controlled Switching Converter with EMI Noise Reduction Circuit” , International
Conference on Mechanical, Electrical and Medical Intelligent System, Kiryu (2018).
[4] K. Asaishi, N. Tsukiji, Y. Kobori, Y. Sunaga, N. Takai, H. Kobayashi, “ Hysteresis Control Power Supply with Switching Frequency Insensitive to Input/Output Voltage
Ratio ” , IEEE 13th International Conference on Solid-State and Integrated Circuit Technology, Hangzhou, China (2016).
0.6
1.0
1.4
1.8
2.2
2.6
3.0
2.500m 2.502m 2.504m 2.506m 2.508m 2.510m
Indu
ctor
Cur
ren
t [A
]
Time [s]
Current imbalance from L, C element variationCauses overcurrentIncrease voltage ripple
Current imbalance
GoalAutomatic current balancing
3. Proposed CircuitDual Phase COT Converter
In Quad-Phase
For large load currentParallel connection of power stages
Error AmpR1
R1
IL2
IL1
IL3
R2
R2
Error AmpR1
R1
R2
R2
Error AmpR1
R1
R2
R2
LPF
LPF
LPF
LPF
Vcot
Vdd
CtCOMP
Phase 2COT Pulse
Phase 3COT Pulse
Phase 4COT Pulse
Phase 2 COT Timer
SAWtooth
I
Phase 3 COT Timer
Phase 4 COT Timer
IL4
Rf
CL1
S
Load
Vin
Vout
Cf
L2
S
Vr
IL2
IL1
RippleComp
COMP
Vref
COMP
Phase 1COT PulsePhase 2 Power Stage
Phase 1Power Stage
Phase 1COT Timer
Phase Divider
Phase 2COT Timer
Correction Circuit
Phase 2COT Pulse
SAWtooth
COMP
Vcot
SAWtooth
COMP
Vcot
PeakHold
SAWGen
SAWGen
Error AmpLPF
LPF
Proposal 1
Element variation: Ct2 increase by 10%
Conditions
Proposal 2
Current imbalance correctionFeedback the current difference to On-Time Feedback the current difference
to each sub-converter
C element variationL element variation
Before imbalance correction
Compensateon-time reference
Inductor currentdifference 41%
3.04.05.06.07.08.09.0
10.011.0
Out
put
Cur
ren
t [A
]
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
0.0 1.0m 2.0m 3.0m 4.0m 5.0m 6.0m 7.0m
Ave
rage
Cur
ren
t [A
]
Time [s]
Io
Io = 4A 5A 6A
IL2
IL1, IL3, IL4
7A 8A 9A 10A
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.500m 2.502m 2.504m 2.506m 2.508m 2.510m 2.512m 2.514m 2.516m 2.518m 2.520m
Indu
ctor
Cur
ren
t [A
]
Time [s]
IL1 IL2 IL3 IL4
0.6
1.0
1.4
1.8
2.2
2.6
3.0
2.500m 2.502m 2.504m 2.506m 2.508m 2.510m 2.512m 2.514m 2.516m 2.518m 2.520m
Indu
ctor
Cur
ren
t [A
]
Time [s]
IL1 IL2 IL3 IL4
After imbalance correction Inductor currentdifference 1%
Reduce current imbalance
Increase load current 4A to 10A
Io=10A: Inductor current difference 2%
Proposal correction circuit in large load current: Stable
Increase 10% COT timer capacitor Ct2
Without correction circuit: Inductor current difference 41% Within correction circuit: Inductor current difference 1%Current balance improves significantly
Simulate proposal corection circuit
