Output Voltage Ripple Reduction for Current-ModeResonant Converter

Shogo Katayama, Noriyuki Oiwa, Yasunori Kobori, Anna Kuwana, Haruo KobayashiGunma University t15304906@gunma-u.ac.jp

1. Objective

3A-05

4. Proposed Circuit 5. Simulation 6. Conclusion

References

2. Background

1. EMI noise reduction Noise spectrum spread

LLC current-mode resonant converter

LLC resonant converter

2. Modulation ripple reduction Dual-phase configuration Reverse phase modulation

[1] M. Ochiai, Switching Power Supplies, Ohm Publishing (2015).

[2] D. Kawahara, S. Abe, S. Motomura, K. Domoto, Y. Ishizuka, T. Ninomiya, M. Shoyama, M. Kaga, “On the Parallel Operation of

LLC Current-Mode Resonant Converters in High-Voltage DC Power Distribution System” , IEICE Information and Communication Engineers,

Tech. Report (2013).

[3] K. Kawamura, T. Yamamoto, K. Hojo, “Circuit Technology of LLC Current Resonant Power Supply” , Fuji Electronic Journal, Vol.87 No.4 (2014)

EMI noise generation by current flowConventional noise reduction Analog filter Shield case

3. LLC Resonant Converter Noise spectrum spread for LLC converter

Switching frequency: 350kHzModulation signal: 500Hz Triangular

LC Resonant

Before ripple reduction

Parallel connection of power stages

Modulation ripple8mV

Steady-state ripple57mV

After ripple reductionReduce modulation ripple

Noise spectrum spreadby modulating the switchingfrequency

EMI noise reduction

Dual-phase configurationLLC resonant converterEach channel switchingfrequency modulation by reversephase

Modulation ripple reduction

Switching frequency: 350kHzModulate signal: 500Hz triangularWithout ripple reduction: 8mV rippleWith ripple reduction: 0mV rippleSwitching frequency pectrum: -13dBNoise spectrum spread equivalentto before ripple reduction

Simulate proposal circuit

Vref

C Load

VinVout

VCO

Driver

Q2

Q1

ErrorAmp

ΔVout

Ci

Ls1 Ls2

Lp

Vref

C Load

VinVout

Ci

VCO

Driver

Q2

Q1

ErrorAmp

ΔVout

Radiation noise

Conduction noise

Large scaleHigh cost

Proposed noise reduction Noise spectrum spread

Frequency

Am

plit

ud

e

Without spreading

Frequency

Am

plit

ud

e

With spreading

Feedback output voltage error to resonant frequency

05

101520253035404550

40 50 60 70 80

Ou

tpu

t V

olt

age

f1 = 52.1 kHz

Frequency area usage

Modulating switching frequency

Modulation ripple

GoalModulation ripple reduction

C Load

VinVout

Ci1

VCO

Driver

Q12

Q11

Vref

Ci2

VCO

Driver

Q22

Q21

ErrorAmp

ΔVout

PhaseRev

Reverse phase modulationeach power stage

Modulation ripple0mV

Steady-state ripple20mV to 56mV

Switching frequencyspectrum -13dB

Switching frequencyspectrum -11dB

Conditions