Flyback Converter Solution - 아이씨뱅큐€¦ · Dual Switch Flyback Converter Solution: The Ideal Solution for 75~200W Power Supplies >90% Efficiency and Meets 2013 ErP:

Dual Switch Flyback Converter Solution:

The Ideal Solution for 75~200W Power Supplies

>90% Efficiency and Meets 2013 ErP: < 0.5W @ 0.25W load

www.fairchildsemi.com1

Agenda

• Challenges for designing 75~200W power supplies

• Fairchild’s Dual Switch Flyback Solution

• Topology Comparison

• Evaluation Boards Test Results

• Ideal Solution for Both Efficiency and Standby Power


• Ideal Solution for Both Efficiency and Standby Power

Consumption

Challenges in Designing

Switching Power Supplies

Low Standby Power Consumption

High Efficiency

High Power Density


High Power Density

High Reliability

Low Cost

Existing Single Flyback Converter Solution –

Does Not Meet All Design Challenges


High Efficiency

High Power Density

• Poor Efficiency, difficult

to achieve > 90%

• Low Power Density


High Power Density

High Reliability

Low Cost

• Low Power Density

Existing LLC Converter Solution –

Does Not Meet All Design Challenges


High Efficiency

High Power Density

• Does not meet 2013 ErP

Lot 6 (<[email protected])

without auxiliary power


High Power Density

High Reliability

Low Cost

• Sensitivity to the

transformer tolerance and

gate drive timing.

Single Flyback

- Poor efficiency

- Good standby power

What If you had a solution that met all of

your design challenges...

What if you had…

- Good efficiency

- Excellent standby power

performance

LLC Resonant

- Excellent heavy load

efficiency

- Poor medium and light load

efficiency

- Poor standby power

consumption


Introducing the

Dual Switch Flyback Solution (75~200W)


FAN6920: BCM PFC +

QR PWM Combo

FAN7382: H/L Driver

FAN6204: SR Controller

Key Features –

Dual Switch QR Flyback Converter


• Meet 2013 ErP Lot 6

• PIN<0.5W @230Vac with PO=0.25W)

• PIN<0.25W@ 230Vac with no load

High Efficiency

• Leakage inductance energy is recycled to the input and snubber circuitry is not required

• 500V MOSFETs can be used in the primary side

• Low switching loss with valley switching in the primary side

• Lower voltage stress on the secondary side rectifier


• Lower voltage stress on the secondary side rectifier

• Variable PFC output voltage technique can be used to improve low line efficiency of the

entire system

Easy Design

• Same as well known conventional Flyback converter design

• Easy transformer mass production

• Ultra low profile transformer can be used without concern of leakage inductance

Low EMI

• Drain voltage overshoot is clamped to input voltage

• Valley switching

Basic Operation of Dual Switch Flyback


Phase 1: Q1&Q2 On

Phase 2: Q1&Q2 Off, D1, D2 on

Phase 3&4: Q1&Q2 off,

D1&D2 off

Vo

+

-

Vin

+

-

iLk

iLmnVo

-

+

+

Vds-low

-

+

Vds-high

-

Dual Switch Flyback Benefits –

Improvement in Energy Loss

• No snubber loss or heat problem

• Leakage inductance energy is

recycled into bulk capacitor


Single Flyback

Dual Flyback

iLK

iDS


High Reliability and Low Switching Loss

Vds

VDS max = VIN + n*VO + Spike VDS max= VIN

• Low MOSFET Drain Source Voltage Good reliability

• Allow large n design Near ZVS Switching Low switching loss


VIN

Vo×

Vo× n

n

VDS of Single Flyback VDS of Dual Flyback Larger switching

loss

Near ZVS

Switching


Reduction in Secondary-Side Conduction Loss

• Benefit of high turn ration n to SR MOSFET

• VDS of SR MOSFET is : VIN/n + VOUT

• Large n Lower VDS Lower MOSFET Ron

in lower price cost & efficiency


Example:

VIN = 420V, Vo = 12V, n= 12

VDS = 420V/12 + 12V = 47V

Could choose 60V or 75V SR MOSFET


Improvement in Low Line Efficiency

• Two Level PFC output to improve low line efficiency


PFC stage efficiency with different PFC output

voltages at 115VAC


Improved Light Load Efficiency

• Deep extended Valley switching ( up to 12th valley) to allow low operating

frequency in light load Improved light load efficiency

Load ↓ Freq↑ Poor light load

efficiency

Freq. nearly

constant


First valley detect

5th valley detect

12th valley detect

QR Operation without extended valley switch Other IC: QR Operation with extended valley ( up to 4th valley)

FAN6920 Deep extended valley switch


Achieves Low Standby Power Consumption

• Dual Switch Flyback Meets < 0.5W @ 0.25W ( 2013 ErP)

• PFC Stage:

• High line/light load Turn off PFC

• Low line/light load burst mode

• QR Stage:

• enter into burst mode when light load

• No snubber loss


• No snubber loss

• SR Stage:

• Turn off SR when light load

Voltage

VAC PO= 0W PO=0.25W

115V 0.186W 0.482W

230V 0.195W 0.486W

Load

Standby Power Consumption

Dual Switch Flyback Single Flyback

- Easy design

- Poor Efficiency

- Good standby power

A topology that meets all of your design

challenges...

VDD

RES

AGNDGND

LPC

VOUT

Lm

IDS ISR

R1

R2 R4

R3

n:1

GATE

8

3 5

7

64

Q2

Q1

IDS

Q1

FAN7382FAN6920

FAN6204

LLC Resonant

- Complicated design

-Excellent heavy load

efficiency

- Poor medium and light load

efficiency

- Poor standby power

consumption


- Ideal for 75~200W

- Easy Design

- Good Efficiency with OFF

time modulation

- Excellent standby power

performance with burst

operation

consumption

Dual Switch QR Flyback Converter vs.

Single SwitchSingle Switch QR Flyback- RCD snubber is required to dissipate leakage

inductance energy

- When reflected output voltage (VO×Np/Ns) is larger

than input voltage, ZVS is achieved

- High voltage MOSFET is required (700~800V)

Dual Switch QR Flyback- Leakage inductance energy is recycled to input

- If the reflected output voltage (VO×Np/Ns) is larger than

the input voltage, energy is not transferred to the output

(ZVS is not allowed)

- 500V MOSFETs can be used


Lower clamping

voltage requires more

loss in RCD snubber

VDS is clamped

to VIN without

lossTDTON

TS

VINVo×Np/Ns

IDS

VDS

Vo×Np/Ns

ID×NS/NP

Dual-Switch QR Flyback vs.

LLC resonant ConverterDual Switch QR Flyback

- Primary side current reduces as load decreases

- Near ZVS (Valley switching)

- Simple transformer design same as conventional

flyback converter

- No shoot through issue

LLC Resonant Converter

- Large circulating current in the primary side

even at light load condition (high standby power

consumption)

- Full ZVS

- Complicated transformer design

- Inherent shoot through issue

Q2+

VO

Ip

Lr

Im

ID


Q1 IDS1

Vin

-

n:1

LmCr

Ip

IDS1

Im

ID

Light Load Condition

Ip

IDS1

Im

ID

Heavy Load Condition

IDS1

ID

Light Load Condition

VDS1

IDS1

ID

Heavy Load Condition

VDS1



Dual Switch QR Flyback Converter LLC Resonant Converter

Full load efficiency Good (Valley switching) Best (Full ZVS)

Light load efficiency Good (same as Flyback converter) Poor (Due to the large circulating current)

Applying burst mode operation Easy (same as Flyback converter) Difficult (Due to gain curve characteristics)

Decrease PFC output voltage with line

voltage to improve PFC efficiency

Easy to incorporate due to wider

allowable input voltage range

Difficult to incorporate due to narrow allowable

input voltage range

Synchronous rectification Easy to control Difficult to control

Conventional Current Mode Control VCO based PFM


Feedback control

Conventional Current Mode Control

- Easy to design compensation network

- Good line / load transient response

VCO based PFM

- Difficult to design compensation network

- Poor line / load transient response

Design Easy (same as Flyback converter) Complicated (Resonant network design)

Transformer Manufacturing Not sensitive to transformer tolerance Very sensitive to transformer tolerance

Reliability

Good

-No concern about shoot-through of

primary side switches

Poor

-Shoot-through of primary side MOSFETs

results in catastrophic failure

- Operation in capacitive region can also

result in MOSFET failure

Power Range Suitable for <200W application Suitable for >200W application



89.0

90.0

91.0

92.0

93.0

94.0

95.0

96.0

Efficiency (%)

LLC Resonant (VIN=115Vac)

Efficiency Comparison

90W/19V Demo Board


86.0

87.0

88.0

0 20 40 60 80 100

% Load

Dual Switch QR (VIN=115Vac)

LLC Resonant (VIN=230Vac)

Dual Switch QR (VIN=230Vac)

Table 1 Key Components for Each TopologyFunction LLC Resonant Half-Bridge Converter Dual Switch QR Flyback Converter

PFC MOSFET

PFC Diode

DC-DC MOSFETS

SR MOSFETS 2 FDB045AN08A0 (75V, 4.5mΩ typ.) ×2 FDB031N08 (75V, 2.4mΩ typ.) ×1

FQI13N50 (Rdson=0.39Ω typ.)

ES3J (600V/3A)

FQI13N50 (Rdson=0.39Ω typ.) ×2

Dual Switch Flyback Schematic


90W/19V Slim Adapter

60mm 95mm

16.5mm

89.37

90.6990.5191.58

90.0890.88

89.0

90.0

91.0

92.0

93.0

94.0

Efficiency (%)

VIN=115Vac

VIN=230Vac


22.5W 45W 67.5W 90W

115VAC 89.37% 90.69% 90.51% 89.87%

230VAC 91.58% 90.08% 90.88% 91.01%

Input Power @ No Load

VAC(RMS) P

IN(W)

90 0.190

115 0.186

230 0.195

264 0.210

VAC(RMS) PIN(W)

115 0.478

230 0.482

Input Power @ 0.25W

PIN<0.5W

2013 EUP spec.PIN<0.2W@230VAC

88.0

89.0

0 20 40 60 80 100% Load

(Note)18AGW-1.5m cable is included (63mΩ impedance), which

results in 1.41W loss at 100% load.

130W/19V All-In-One PC power

100mm 145mm

Input Power @ no load

92.1592.3291.65

92.15

93.59

90.0

91.0

92.0

93.0

94.0

Efficiency (%)

VIN=115Vac

VIN=230Vac


Spec: PIN<0.5W 2013 EUP

Input Power @ 0.25W

Efficiency 20%

26W

50%

65W

100%

130W

3 point

AVG.

115Vac/60Hz 89.29% 92.15% 92.32% 91.25%

230Vac /50Hz 91.65% 92.15% 93.59% 92.56%

VAC (RMS) PIN(W)

115 0.478

230 0.482

VAC (RMS) PIN(W)

90 0.19

115 0.186

230 0.195

264 0.21

Input Power @ no load89.29

88.0

89.0

0 20 40 60 80 100% Load

200W/19V All-In-One PC Power

90.01

91.62

90.76

92.16

91.76

92.60

90.0

91.0

92.0

93.0

94.0

Efficiency (%)

VIN=115Vac

VIN=230Vac


Efficiency 20%

40W

50%

100W

100%

200W

3 point

AVG.

115Vac/60Hz 90.01% 91.62% 90.76% 90.79%

230Vac /50Hz 92.16% 91.76% 92.60% 92.17%

Input Power @ 0.5W

VAC (RMS) PIN(W)

115 0.762

230 0.781

VAC (RMS) PIN(W)

90 0.168

115 0.183

230 0.206

264 0.223

Input Power @ no load Input Power @ 0.25W

VAC (RMS) PIN(W)

115 0.484

230 0.487

90.01

88.0

89.0

0 20 40 60 80 100% Load

Example Circuit (19V/90W)

C40.33μ/450V C50.33μ/450V

+C7

47μ

/450V

1

23

Q4FQI13N50C

2 1

D1ES3J

1

23

Q2FQI13N50C

R104.7M±1%

1

23

Q1

FQI13N50C

21

D4ES1H

21

D2ES1JH

VSPFCVSPWM

R94.7M±1%

AC

AC -

+

BD1

DF08S PFC_VO

R747K

R847K

+ C1533μ/50V2

1

D9RS1D

1

2

CN1

CN/2pin AC inlet

MOV1MOV/U07 470

C1

XC/0.47u/250VL

F1

F/4A/250V

R2

1.5M/1206

R1

1.5M/1206

+

C8820μ/25V VO+

VO+1

VO-1

R16

0R15 R17

0R27

L2

DET1

HG

LG

D7S1M

D6S1M

PFCZCD

VDD

VS

VBO

AUX

R5 100R4 100R3 100

C17102P/100V

R20220K±1%

C18104P/50V

12

56

411

TX1

+C6

47μ

/450V

U1

1

2 3

Q5FDB031N08

21

D11

NCR19

R/0R

SRDET

SRDET

VO1

C10

YC/102P/250V

+

C9820μ/25V

C11YC/102P/250V

C3NC

C2NC

AC

AC -

+

BD2DF08S

VBO1

L4

S047

VO

21

ZD118V/0.5W

21

ZD218V/0.5W

VLD

OPFC

2 1

D8LL4148

R1351

2

13

Q32N2907

R14

100

R15NC

PFC_GATE

84

3

5

6 1

7

2

11

TX2

2 1

L3A220μ/DR127

L1


D14LL4148

R46 51

YC/102P/250VD13LL4148

R47 51

R114.7M±1%

R124.7M±1%

R30154K±1%

R2278.7K±1%

D10RS1D

C27224P

C21NC

C25105P

R24220

C24

221P

C20102P

RANGE1

COMP2

INV3

CSPFC4

CSPWM5

OPFC6

VDD7

OPWM8

FB11

RT12

VIN13

ZCD14

N.C.15

HV16

GND9

DET10

U2

FAN6920

C29102P

R2647.5K

C23471P

R23220

VSPFC

R27 560

C26473P

OPFC

VSPWM

VS6

LO5

LIN3

HIN2

VB8

VCC1

COM4

HO7

U3

FAN7382

C30225P

VB

C31

104P

PFC_VO

TR1

NTC/100K

R313.6K

R298.2K±1%

R2847.5K±1%

C28NC

U4LTV357A

C33103P

R51330

R521.5K

R5068K, 1%

R5310K, 1%

R4910K

AK

RU5

KA431SAMF2TF

VO+

VO

2 1

D15ES1JH

HG

VBO

LGOPWM

OPWM

AUX

PFCZCD

FBPWM

FBPWM

VS

R219.1K±1%

R4811.3K±1%

R1847K±1%

C32NC

VO

C19104P

VDD

R6249K

R25 NC

C22474P

GATE3

PGND4

AGND6

LPC8

VDD5

RP/RES7

FAN6204/5

VDD

+ C1633uF/50V

VDD

OPWMR45NC

D12LL4148

2 1D5

SS16

PFC_GATE

Target Applications

• Power Range from 75W ~200W

• All in One (AIO) PC Power

• LED TV

• Notebook Adapter

• Game Console

• LED Lighting


• LED Lighting

• Applications that Require High Efficiency and Low Standby

Power Consumption for Single Output

Ideal Solution for Both Efficiency and

Standby Power Consumption

EfficiencyStandby

Power Efficiency

Standby

Power

LLCSingle

Flyback


LLCFlyback

Dual

Switch

Flyback

Excellent

Average

EfficiencyLow

Standby Power

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Documents

Flyback Converter Solution - 아이씨뱅큐€¦ · Dual Switch Flyback Converter Solution: The Ideal Solution for 75~200W Power Supplies >90% Efficiency and Meets 2013 ErP: