High-Efficiency Full-Bridgeless PFC Power Supply Circuit

Noriyuki Oiwa, Shogo Katayama,Yasunori Kobori, Anna Kuwana, Haruo Kobayash

(Gunma University)

1.Objective

[1] Y. Kobori, L. Xing, G. Hong, T. Shishime, M. Ohshima, H. Kobayashi, N. Takai, K. Niitsu, “Novel AC-DC Direct Converter

Design with PFC”, International Conference on Power Electronics and Power Engineering, Phuket, Thailand (Dec. 2011).

t181d011@gunma-u.ac.jp

Reference

6.Conclusion

3.Proposed Circuit

4.Simulation Result

5.Relation Vlim

AC-DC converter improvement

➾ Efficiency

Decreasing Conduction loss

Diode brede → MOSFETs

2.Background

AC-CD converter usage

・ Decreasing switching loss

and conduction Loss

Goal

Good!Bad!Very good!

● Change module in Bridge

Diodes → MOSFETs

Efficiency increases 5.0%

● Optimal Vlim choice

Causes efficiency down！

Diode Bridge

Generating reverse current

Problem

• Easier use• Low cost

Good point

• Constant Loss(conduction voltage 1V ）

Bad point

Vin

/ V

-100

50

Iin /

A

-6

2

Vo /

V

473

476

time/mSecs 5mSecs/div

500 505 510 515 520 525 530 535 540

Io /

mA

910

916

Time(ms)

Vin

(V

)V

o (

V)

Io (

mA

)Ii

n(A

)

4A

3V

4mA

142V

Vin

/ V

-100

50

Iin

/ A

-6

2

Vo2 / V

401

405

409

time/mSecs 5mSecs/div

500 505 510 515 520 525 530 535 540

Iout / A

1.21

1.225

Vin

(V

)V

o (

V)

Io (

mA

)Ii

n(A

)

Time(ms)

4A

4V

10μA

142V

Conventional PFC Half-Bridgeless PFC

Vin

/ V

-100

50

Iin /

A

-6

2

Vo /

V

390

398

time/mSecs 5mSecs/div

65 70 75 80 85 90 95 100

Iout

/ A

1.3

1.325

Time(ms)

Vin

(V

)V

o (

V)

Io (

mA

)Ii

n(A

) 4A

8V

25μA

142V

Full-Bridgeless PFC

Efficiency 94.2% 97.2% 99.6%

98.9

99

99.1

99.2

99.3

99.4

99.5

99.6

99.7

40 50 60 70 80 90 100 110 120

eff

icie

ncy

VLimVin=AC100 (V) Vin=AC85 (V)

(%)

(V)

Vlim smaller

→ generate reverse current

Vlim larger

→Nearly Half-Bridgeless operation

Not Boost Voltage!

Efficiency Down!

[2] H. Kobayashi, T. Nabeshima (Editors), Handbook of Power Management Circuit, Pan Stanford Publisher (2016).

[3] N. Miki, N. Tsukiji, K. Asaishi, Y. Kobori, N. Takai, H. Kobayashi, “EMI Reduction Technique With Noise Spread Spectrum Using Swept Frequency

Modulation for Hysteretic DC-DC Converters”, IEEE International Symposium on Intelligent Signal Processing and Communication Systems, Xiamen,

China (Nov. 2017)

Vin

PFCcircuit

sw1

sw2

sw3

sw4

Rout

VLim

Controler

Limit switching operation (Vlim)

U6-O

UT

/ V

0

1

2

3

4

5

time/mSecs 5mSecs/div

25 30 35 40 45

U32-O

UT

/ V

0

1

2

3

4

Time(ms)4035302520 45

5

0

5

5

5

0

0

0

SwitchingPulse at sw1

SwitchingPulse at sw2

SwitchingPulse at sw3

SwitchingPulse at sw4

(V)

(V)

(V)

(V)

(V)

Limit Switching

Switching limits by Vin value

➡ Add safety time

Best point : Vlim 40~50V

PFCcircuit

sw1

sw2

sw3

sw4

RoutVin

Only normal switching

→ Not Boost

Because reverse current generate!

As replaced by MOSFETs, efficiency is increased.

Full-Bridgeless PFC

PFC: Power Factor Correction

2B-08

Output increases gradually