Poor light load efficiency

Report
Dual Switch Flyback Solution
Solution for High Efficiency & Low Standby Power to
meet 2013 EuP
Computing Product Line
Power Conversion Taiwan
Fairchild Semiconductor
1
www.fairchildsemi.com
Dual Switch QR Solution
Enabled by
 FAN6920 : CRM PFC + QR Controller Combo IC
 FAN7382 : HVIC
 FAN6204 : Syn. Rectifier IC
Q1
Q1
IDS
ISR
VOUT
IDS
n:1
FAN6920
FAN7382
Lm
Q2
3
R1
GATE
5
VDD
R3
LPC
RES
8
R2
2
FAN6204
4
GND
6
7
R4
AGND
www.fairchildsemi.com
Basic Operation of Dual Switch Flyback
+
Vds- high
+
Vi
n
Vi
n
+
+
Vi
n
nVo
+
iLm
Vin
-
Vds1
-
+
+
V
o
-
+
Vo
-
,
Vds2
vin
vin +nvo
2
nvo
vin
2
2
iL
m
-
-
+
Vds-low
-
Phase 1: Q1&Q2 On
Phase 3&4: Q1&Q2 off,
D1&D2 off
+
Q1 , Q2
gate
iLm
Vds-high
-
+
nVo
+
Vin
-
iLm
+
Vo
-
id1, id2
iLk
+
Vds-low
Phase 1
Phase 3
Phase 4
Phase 2
Phase 2: Q1&Q2 Off, D1, D2 on
3
www.fairchildsemi.com
Benefit of Dual Switch Flyback (1)
Snubber and Leakage Inductance Loss Improved
Np:Ns
No snubber loss and
heat problem

Leakage inductance is
recycled into bulk capacitor

R
ID
Vo
C
IDS
VIN
VDS
Single Flyback
+
Vds-high
iDS
-
+
nVo
+
iLK
Vin
iLm
+
Vo
-
iLk
+
Vds-low
-
-
Up to 70% of leakage inductance can be
recycled
Dual Flyback
4
www.fairchildsemi.com
Benefit of Dual Switch Flyback (2)
Low MOSFET Vds and Near ZVS switching
 Low MOSFET Drain Source Voltage  Good reliability
 Allow large n design  Near ZVS Switching  Low switching loss
Vds = Vin + n*Vo + Spike
V ds
V ds
VIN
Vo ×
n
Vo ×
n
Vds= Vin/2
Spike is clamped by two recycle diodes,
stress shared by two MOS
(Vo× n ) / 2
VIN
VIN /2
Vds of Single Flyback
Larger switching
loss
5
( Vo× n ) / 2
Vds of Dual Flyback
Near ZVS
Switching
www.fairchildsemi.com
Benefit of Dual Switch Flyback (3)
Low VDS of SR MOS for secondary conduction loss
Benefit of high turn ration n to SR MOSFET
ISR
 VDS of SR MOS is : Vin/n + Vout
Lm
Q2
 Large n  Lower VDS  Lower MOS
Ron in lower price  cost & efficiency
VDS
 VDS = 420V/12 + 12V = 47V
3
R1
GATE
5
VDD
R3
LPC
RES
8
R2
Example:
Vin = 420V, Vo = 12V, n= 12
VOUT
n:1
V
IN
/n+ V
FAN6204
4
GND
6
7
R4
AGND
O UT
VIN /n
Could choose 60V or 75V
SR MOSFET
VO U T
6
www.fairchildsemi.com
Benefit of Dual Switch Flyback (4)
Built in two level PFC output for low line efficiency
• Two Level PFC output to improve low line efficiency
When AC > 180V  M1 off  PFC Vo = 2.5V x (R1+R2)/R2
When AC < 150V  M1 on  R2//R3  PFC Vo= 2.5V x (R1+R2//R3))/(R2//R3)
PFC Vo
PFC Vo
Multi-vector
Error Amplifier
2.5V
R1
3
1.2V/1V
Debounce
100ms
2.45V/2.1V
INV
R3
CO
Brownout
RANGE
13
R2
1
Debounce
100ms
390V
300V
R4
VIN
AC line
CVIN
R5
150VRMS
M1
180VRMS
VAC
FAN6920 Block Diagram
7
www.fairchildsemi.com
Benefit of Dual Switch Flyback (5)
Deep extended valley switch for light load efficiency
• Deep extended valley switch ( 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
QR Operation without extended valley switch
Other IC: QR Operation with extended valley ( up to 4th valley)
Switching frequency (Hz)
fs,max
fs,min
5th valley detect
fs,g
First valley detect
20k
2k
VFB
1.2V
12th valley detect
2.1V
VFB,max
FAN6920 Deep extended valley switch
8
www.fairchildsemi.com
Benefit of Dual Switch Flyback (6)
Power Saving
• Dual Switch Flyback Could Meet < 0.5W @ 0.25W ( 2013 EuP)
• 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
• SR Stage:
• Turn off SR when light load
Power Saving
Load
VAC
Po = 0 W
Po= 0.25W
115V
0.186W
0.482W
230V
0.195W
0.486W
9
www.fairchildsemi.com
Target Application
• For Power Range from 75W ~200W
• All in One PC Power
• LED TV
• Notebook Adapter
• Game Console
• LED Lighting
10
www.fairchildsemi.com
Dual-switch Flyback Schematic
BCM Boost PFC
Dual-Switch Quasi Resonant Flyback
NBOOST
RHV
NCZD
VO
RPFC1
CINF2
+
CO.PFC
NB
RG1
NS
RPFC2
RCS1
FAN7382
-
FAN6920
CCOMP
CINF1
RCZD
1 RANGE
HV 16
2
NC 15
COMP
3 INV
RRT
VIN 13
5 CSPWM
RT 12
6 OPFC
FB 11
7 VDD
DET 10
8 OPWM
GND 9
VB 8
2 HIN
HO 7
3 LIN
VS 6
4 COM
LO 5
GATE VDD
3
LPC
NP
CRT
ZCD 14
4 CSPFC
1 VCC
8
5
FAN6204
4
RES
7
6
GND AGND
RCS2
NTC
RVIN1
RBIAS
CFB
RO1
VAC
RVIN2
NA
CVIN
RDET1
CDD
RDET2
RF
CF
KA431
RO2
11
www.fairchildsemi.com
Solution Comparison
Dual Switch QR Flyback
LLC
D2D stage : Nearly ZVS
switching
D2D stage: ZVS switching
PFC stage:
Better low line efficiency by
two level PFC output
PFC stage:
Poor low line efficiency due to high
PFC output
LLC could allow only narrow
input voltage range
Light load (~20%) :
Higher efficiency due to slow
freq. to reduce switching loss
Light load (~20%) :
Low efficiency due to high
frequency.
FAN6920 could do up to 12th
valley detection for slow
frequency
Good line transient response
Poor line transient response
Inherent characteristic of
topology
Good load transient
response
Poor load transient response
Inherent characteristic of
topology
Power Saving
<0.3W,
<0.5W,
LLC couldn’t allow PFC turn
off at light load.
Design
Easiness
Easy
Difficult
Resonant L & C control to
prevent ZVS fail
Manufacture
Easiness
Easy
Difficult
Resonant L & C control to
prevent ZVS fail
Efficiency
Dynamic
12
Note
www.fairchildsemi.com
Key Parts Comparison
MOSFET
3 (PFC and dual switch)
3 (PFC and LLC)
Transformer
1 for PFC
1 for D2D
1 for PFC
1 for D2D
1 for resonant L & C
FAN6920MR+FAN7382
(HVIC)
CRM PFC+ LLC controller
IC
FAN6204
2 SR controller
MOSFET
1
2 MOSFETs
-Lower transformer cost
-Lower MOSFET cost
-One SR MOSFET needed
-Higher transformer cost
-Might need additional resonant
T’mer
-Two SR MOSFET needed
-Might need additional std by
stage for power saving
75W~200W
100W~500W
IC
SR
Cost
Power Range
13
www.fairchildsemi.com
Dual Switch Flyback vs. LLC
Efficiency: test board 90W/19V
No load
14
www.fairchildsemi.com
Slim Type 19V/ 90W Dual Switch Flyback
Efficiency Test Result
Efficiency (18 AWG 1.2m wire include):
No Load Power Consumption:
22.5W
45W
67.5W
90W
115VAC
89.48%
90.54%
90.40%
89.61%
230VAC
91.24%
90.04%
90.86%
90.88%
Input Power @ 0.25W
VAC (RMS)
PIN(W)
115
0.482
230
0.486
VAC(RMS)
PIN(W)
90
0.190
115
0.186
230
264
0.195
0.210
16.5mm
60mm
15
95mm
www.fairchildsemi.com
19V/180W Dual Flyback
FAN6204 + FDP032N08
16
www.fairchildsemi.com
130W/19V AIO power
AIO 130W
100mm
145mm
Input Power @ no load
VAC (RMS)
PIN(W)
90
0.19
115
0.186
230
0.195
264
0.21
Input Power @ 0.25W
VAC (RMS)
PIN(W)
115
0.478
230
0.482
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%
Spec: PIN<0.5W 2013 EUP
17
www.fairchildsemi.com
200W/19V AIO Power
Output Power @ no load
Output Power @ 0.25W
VAC (RMS)
PIN(W)
VAC (RMS)
PIN(W)
90
0.168
115
0.484
115
0.183
230
0.487
230
0.206
264
0.223
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%
Output Power @ 0.5W
VAC (RMS)
PIN(W)
115
0.762
230
0.781
18
www.fairchildsemi.com
Example Circuit (19V/90W)
L
C1
XC/0.47u/250V
F1
AC
AC
4
11
5
6
C5
0.33μ/450V
C4
0.33μ/450V
-
D1
ES3J
TX1
PFC_VO
2
HG
+
C6
+
C9
C8
VO+
820μ/25V
820μ/25V L4
S047
VO
VO1
R3 100
R4 100
R5 100
4
8
D9
RS1D
2
1
SRDET
+
C18
104P/50V
Q5
FDB031N08
3
ZD2
18V/0.5W
1
2
2
+ C15
33μ/50V
D11
NC
VO-1
1
R17
0R27
R10
4.7M±1%
SRDET
R19
R/0R
R20
220K±1%
1
D5
PFC_GATE
R11
4.7M±1%
U2
C22
474P
C21
NC
1
R25 NC
2
4
R12
4.7M±1%
D12
C23
LL4148 471P
R23
220
R24
220
C20
102P
VSPFC
VSPWM
5
C24
221P
C25
105P
OPFC
6
7
8
RANGE
COMP
N.C.
ZCD
CSPFC
VIN
CSPWM
RT
OPFC
FB
VDD
DET
OPWM
GND
14
R30
154K±1%
R26
47.5K
D13
LL4148
C27
224P
13
D15
ES1JH
12
11
R27 560
10
C26
473P
9
FBPWM
R31
3.6K
C29
102P
1
C30
225P
AUX
FAN6920
OPWM
2
3
TR1
NTC/100K
R28
47.5K±1%
1
4
VCC
HIN
7
HO
LIN
VS
COM
LO
C19
104P
C32
NC
R48
11.3K±1%
HG
C31
104P
6
5
VO
VS
R46 51
LG
U4
LTV357A
VDD
OPWM
R29
8.2K±1%
R45
NC
R21
9.1K±1%
6
4
AGND
RP/RES PGND
VBO
8
VB
8
LPC
VDD
7
R18
47K±1%
D10
RS1D
U3
FAN7382
VDD
R47 51
VB
2
YC/102P/250V
GATE
5
+ C16
33uF/50V
16
15
3
VO
PFCZCD
HV
INV
OPWM
U1
FAN6204/5
VDD
1
SS16
3
R22
78.7K±1%
2
R6
249K
PFC_VO
VO+1
DET1
VDD
3
VSPWM
+
C17
102P/100V
11
2
R16
0R15
Q2
FQI13N50C
D4
ES1H
1
LG
2
3
VSPFC
1
2
5
3
AUX
47μ/450V
2
R15
NC
R9
4.7M±1%
R8
47K
C7
VLD
2
Q3
2N2907
2
100
ZD1
18V/0.5W
TX2
1
OPFC
R13
51
R14
3
D7
S1M
R7
47K
Q4
FQI13N50C
1
D6
S1M
PFC_GATE
1
1
2
47μ/450V
D8
LL4148
-
BD2
DF08S
1
C10
C11
YC/102P/250V
YC/102P/250V
7
2
+
VBO
Q1
FQI13N50C 6
1
D2 VS
ES1JH
PFCZCD
2
AC
R1
R2
1.5M/1206
1.5M/1206
VBO1
1
3
CN/2pin AC inlet
L2
L1
1
2
1
2
2
1
L3A
220μ/DR127
C2 C3
NC NC 2
+
1
CN1
BD1
DF08S
AC
MOV1 MOV/U07 470
F/4A/250V
D14
LL4148
R51
330
FBPWM
VO+
C28
NC
R49
10K
R52
1.5K
C33
103P
K
U5
KA431SAMF2TF
R
A
19
R50
68K, 1%
R53
10K, 1%
www.fairchildsemi.com
Follow us on Twitter @ twitter.com/fairchildSemi
View product and company videos, listen to podcasts and comment on our blog @
www.fairchildsemi.com/engineeringconnections
Visit us on Facebook @ www.facebook.com/FairchildSemiconductor
20
www.fairchildsemi.com

similar documents