FAIRCHILD FAN400A_2

FAN400A — Low-Power Green-Mode PWM Flyback Power
Controller without Secondary Feedback
Features
Description
ƒ Linearly Decreasing PWM Frequency
ƒ Green Mode Under Light-Load and Zero-Load
This highly integrated PWM controller provides several
features to enhance the performance of low-power
flyback converters. To minimize standby power
consumption, a proprietary green-mode function
provides off-time modulation to linearly decrease the
switching frequency under light-load and zero-load
conditions. This green mode enables the power supply
to meet international power conservation requirements.
The supply voltage VDD is also used for feedback
compensation, to regulate the output voltage without
requiring a conventional TL431 and a photo-coupler.
Another advantage of the FAN400A is that the typical
startup current is only 8μA, while the typical operating
current can be as low as 3.6mA. A large startup
resistance can be used to achieve even higher power
conversion efficiency.
Conditions
ƒ Constant Voltage (CV) and Constant Current (CC)
ƒ No Secondary Feedback
ƒ Low Startup Current: 8μA
ƒ Low Operating Current: 3.6mA
ƒ Leading-Edge Blanking
ƒ Constant Power Limit
ƒ Universal AC Input Range
ƒ Synchronized Slope Compensation
ƒ 140°C OTP Sensor with Hysteresis
ƒ VDD Over-Voltage Clamping
ƒ Cycle-by-Cycle Current Limiting
ƒ Under-Voltage Lockout (UVLO)
ƒ Fixed PWM Frequency with Hopping
ƒ Gate Output Maximum Voltage Clamped at 17V
ƒ Small SSOT-6 Package
Applications
General-purpose, switching mode, power supplies and
flyback power converters, such as:
ƒ Battery Chargers for Cellular Phones, Cordless
Phones, PDAs, Digital Cameras, Power Tools
ƒ Power Adapters for Ink Jet Printers, Video Game
Consoles, Portable Audio Players
ƒ Open-Frame SMPS for TV/DVD Standby and
Auxiliary Supplies, Home Appliances, Consumer
Electronics
ƒ Replacement for Linear Transformers and RCC SMPS
ƒ PC 5V Standby Power
FAN400A integrates a frequency hopping function
internally to reduce EMI emissions with minimum line
filters. Built-in synchronized slope compensation
maintains the stability of peak current-mode control.
Proprietary internal compensation ensures constant
output power limiting over a universal range of AC input
voltages, from 90VAC to 264VAC.
The FAN400A provides many protection functions.
Pulse-by-pulse current limiting ensures constant output
current, even if a short circuit occurs. The internal
protection circuit disables PWM output if VDD exceeds
22.7V. The gate output is clamped at 17V to protect the
power MOS from over-voltage damage. The built-in
over-temperature protection (OTP) function shuts down
the controller at 140°C with a 30°C hysteresis.
The FAN400A is designed to provide a low-cost total
solution for flyback converters. It is available in a smallfootprint, 6-pin, SSOT-6 package.
Related Resources
ƒ
AN-400A Low-Power Green-Mode PWM Flyback
Power Controller without Secondary Feedback
Ordering Information
Part Number
Packing Method
Operating Temperature Range
Package
FAN400ATY
-40°C to +105°C
SSOT-6
Green
Tape & Reel
FAN400ANY
-40°C to +105°C
DIP-8
Green
Tube
Eco Status
For Fairchild’s definition of “green” please visit: http://www.fairchildsemi.com/company/green/rohs_green.html.
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
www.fairchildsemi.com
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
October 2008
V IN
DO
R IN
D1
CO
W AU X
VDD
G ATE
C IN
Q1
S EN SE
GN D
Figure 1.
RS
Typical Application
Internal Block Diagram
Figure 2.
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
Functional Block Diagram
VO
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Application Diagram
www.fairchildsemi.com
2
XXX: AAT=FAN400A
TT : Die run code
. . . : Year code
- - - : Week code
1’st line
Z: Assembly plant code
X: Year code
Y: Week code
TT: Die run code
3’rd line
T: N=DIP
P: Y=Green package
M: Manufacture flow code
Figure 3.
Top Mark
Pin Configuration
DIP-8
SSOT-6
GND
FB
NC
GND
GATE
GATE
VDD
VDD
FB
SENSE
NC
NC
SENSE
Figure 4.
NC
Pin Configurations
Pin Definitions
DIP
Pin #
SSOT
Pin #
Name
Description
1
6
GATE
The totem-pole output driver to drive the power MOSFET
2
5
VDD
Power supply
3
4
NC
4
5
SENSE
No connection
Current sense senses the voltage across a sensed resistor. To provide overcurrent protection, PWM output is disabled if the voltage exceeds an internal
threshold. This pin also provides current information for current-mode control.
NC
No connection
6
3
NC
No connection
7
2
FB
The FB pin provides feedback information to the internal PWM comparator. This
feedback is used to control the duty cycle. When no feedback is provided, this
pin is left open.
8
1
GND
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Marking Information
Ground
www.fairchildsemi.com
3
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device
reliability. The absolute maximum ratings are stress ratings only.
Symbol
Parameter
Min.
(1, 2)
Max.
Unit
30
V
VVDD
DC Supply Voltage
VFB
Input Voltage to FB Pin
-0.3
7.0
V
Input Voltage to Sense Pin
-0.3
7.0
V
+150
°C
SSOT
263.3
°C/W
DIP
135.7
°C/W
+150
°C
+260
°C
4
kV
200
V
VSENSE
TJ
Operating Junction Temperature
ΘJA
Thermal Resistance (Junction-to-Air)
TSTG
Storage Temperature Range
TL
ESD
-55
Lead Temperature (Wave Soldering or IR, 10 Seconds)
Electrostatic Discharge Capability
Human Body Model
JESD22-A114
Machine Model
JESD22-A115
Notes:
1. All voltage values, except differential voltages, are given with respect to GND pin.
2. Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device.
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Absolute Maximum Ratings
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4
Unless otherwise noted, VDD=15V and TA=25°C.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
20
V
22.7
V
VDD Section
VDD-OP
With Secondary
Feedback
Continuously Operation Voltage
Without Secondary
Feedback
VDD-ON
Turn-on Threshold Voltage
16
17
18
V
VDD-OFF
Turn-off Threshold Voltage
7.5
8.0
8.5
V
IDD-ST
Startup Current
VDD=VDD-ON – 0.1V
IDD-OP
Operating Supply Current
CL=1nF
VDD-G OFF
VDD Low-threshold Voltage to Exit
Green-off Mode
8
20
μA
3.6
4.6
mA
VDD-OFF+1.2
V
0.3
V/V
4.6
kΩ
Feedback Input Section
AV
Input-Voltage to Current-Sense Attenuation
ZFB
Input Impedance
VFB-OPEN
VDD-FB
IFB=0.1mA to 0.2mA
Open-Loop Voltage
4.5
VDD Feedback Threshold Voltage
V
FB is Open
20.7
22.7
24.7
V
IFB=0.4mA
18.4
20.4
22.4
V
100
150
ns
Current-Sense Section
tPD
VSTHVA
VSTHFL
tLEB
Propagation Delay
Current Limit Valley Threshold Voltage
Current Limit Flat Threshold Voltage
VDD=18V
0.81
V
VDD=15V
0.73
V
VDD=10V
0.58
V
VDD=18V
1.10
V
VDD=15V
1.01
V
VDD=10V
0.81
V
Leading-Edge Blanking Time
250
Figure 5.
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
310
370
ns
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Electrical Characteristics
Saw Limit
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5
Unless otherwise noted, VDD=15V and TA=25°C.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
60
65
70
±4.1
±4.6
±5.1
Units
Oscillator Section
fOSC
Frequency
tHOP
Hopping Period
Center Frequency
Hopping Range
4
kHz
ms
fOSC-G
Green Mode Frequency
14.5
17.0
19.5
KHz
VFB-N
Green Mode Entry FB Voltage
2.3
2.6
2.9
V
VFB-G
Green Mode Ending FB Voltage
VFB-Z
Zero Duty Cycle FB Voltage
SG
Green Mode Modulation Slope
40
fDV
Frequency Variation vs. VDD Deviation
VDD=10 to 22V
fDT
Frequency Variation vs. Temperature Deviation
TA=-20 to 85°C
VFB-N 0.75
V
1.4
V
70
100
Hz/mV
2
%
1.5
5.0
%
73
78
%
1.5
V
Output Section
DCYMAX
Maximum Duty Cycle
68
VGATE-L
GATE Low Voltage
IO=10mA
VGATE-H
GATE High Voltage
IO=-10mA
tr
GATE Rising Time
CL=1nF
150
200
250
ns
tf
GATE Falling Time
CL=1nF
70
90
110
ns
GATE Output Clamping Voltage
VDD=20V
16
17
18
V
VGATECLAMP
8
V
Over Temperature Protection (OTP)
TOTP
TOTPRESTART
Protection Junction Temperature
140
°C
Restart Junction Temperature
110
°C
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Electrical Characteristics (Continued)
www.fairchildsemi.com
6
8.6
16.8
8.4
V DD-OFF (V)
V DD-ON (V)
17
16.6
16.4
16.2
8.2
8
7.8
16
7.6
-40
-25
-10
5
20
35
50
65
80
95
110
125
-40
-25
-10
5
T emperature (℃ )
Turn-on Threshold Voltage (VDD-ON)
vs. Temperature
Figure 7.
9
4
8
3.8
IDD-OP (mA)
IDD-ST (μA)
Figure 6.
7
6
5
35
50
65
80
95
110
125
Turn-off Threshold Voltage (VDD-ON)
vs. Temperature
3.6
3.4
3.2
4
3
-40
-25
-10
5
20
35
50
65
80
95
110
125
-40
-25
-10
5
T emperature (℃ )
Figure 8.
20
35
50
65
80
95
110
125
T emperature (℃ )
Startup Current (IDD-ST)
vs. Temperature
Figure 9.
Operating Supply Current (IDD-OP)
vs. Temperature
75
68
67
74
66
DCY MAX (%)
fOSC (KHz)
20
T emperature (℃ )
65
64
73
72
71
63
62
70
-40
-25
-10
5
20
35
50
65
80
95
110
-40
125
-25
T emperature (℃ )
Figure 10.
5
20
35
50
65
80
95
110
125
T emperature (℃ )
Center Frequency (fOSC)
vs. Temperature
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
-10
Figure 11.
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Typical Performance Characteristics
Maximum Duty Cycle (DCYMAX)
vs. Temperature
www.fairchildsemi.com
7
2.2
2.8
2
V FB-G (V)
V FB-N (V)
3
2.6
2.4
2.2
1.8
1.6
1.4
2
1.2
-40
-25
-10
5
20
35
50
65
80
95
110
125
-40
-25
-10
5
T emperature (℃ )
Figure 12.
Green-Mode Entry FB Voltage
(VFB-N) vs. Temperature
Figure 13.
300
35
50
65
80
95
110
125
Green-Mode Ending FB Voltage
(VFB-G) vs. Temperature
5
4.5
IDD-OP (mA)
280
tLEB (ns)
20
T emperature (℃ )
260
240
220
4
3.5
3
2.5
2
200
-40
-25
-10
5
20
35
50
65
80
95
110
12
125
13
14
Figure 14.
Leading-Edge Blanking Time (tLEB)
vs. Temperature
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
15
16
17
18
19
20
21
22
23
V DD (V)
Temperature (℃ )
Figure 15.
Operating Supply Current
vs. VDD Voltage
24
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Typical Performance Characteristics
www.fairchildsemi.com
8
FAN400A devices integrate many useful functions for
low-power switch-mode power supplies. The following
descriptions highlight the key features of the FAN400A.
Oscillator Operation
Startup Current
Leading-Edge Blanking (LEB)
The required startup current is only 8μA. This allows a
high-resistance, low-wattage startup resistor to supply
the controller’s startup power. A 1.5 MΩ/0.25W startup
resistor can be used over a wide input range (100V240VAC) with very little power loss.
Each time the power MOSFET is switched on, a turn-on
spike occurs at the sense-resistor. To avoid premature
termination of the switching pulse, a 310ns leadingedge blanking time is built in. Conventional RC filtering
is not necessary. During this blanking period, the
current-limit comparator is disabled and cannot switch
off the gate drive.
The oscillation frequency is fixed at 65KHz.
Operating Current
The operating current is normally 3.6mA, which results
in higher efficiency and reduces the required VDD holdup capacitance. A 10μF/25V VDD hold-up capacitor can
be used over a wide input range (100V-240VAC) with
very little power loss.
Constant Output Power Limit
When the SENSE voltage across the sense resistor RS
reaches the threshold voltage (around 1.0V), the output
GATE drive is turned off following a small propagation
delay, tPD. This propagation delay introduces an
additional current proportional to tPD•VIN/LP. The
propagation delay is nearly constant regardless of the
input line voltage VIN. Higher input line voltages result in
larger additional currents. Under high input-line voltages
the output power limit is higher than under low input-line
voltages. Over a wide range of AC input voltages, the
variation can be significant. To compensate for this, the
threshold voltage is adjusted by adding a positive ramp
(Vlimit_ramp). This ramp signal can vary from 0.73V to
1.01V and flattens out at 1.01V. A smaller threshold
voltage forces the output GATE drive to terminate
earlier, reducing total PWM turn-on time and making the
output power equal to that of the low line input. This
proprietary internal compensation feature ensures a
constant output power limit over a wide range of AC
input voltages (90VAC to 264VAC).
Green-Mode Operation
The proprietary green-mode function provides off-time
modulation to linearly decrease the switching frequency
under light-load and zero-load conditions. The on-time
is limited to provide better protection against brownouts
and other abnormal conditions. Power supplies using
the FAN400A can meet international restrictions
regarding standby power-consumption.
Constant Voltage (CV) and Constant
Current (CC) without Feedback
The FAN400A can tightly regulate the output voltage
and provide over-current protection without requiring
secondary-side feedback signals. For improved CV and
CC accuracy, the transformer leakage inductance
should be reduced as much as possible.
Under Voltage Lockout (UVLO)
The turn-on/turn-off thresholds are fixed internally at
17V and 8V. To enable the FAN400A during startup, the
hold-up capacitor must first be charged to 17V through
the startup resistor. The hold-up capacitor continues to
supply VDD before energy can be delivered from the
auxiliary winding of the main transformer. VDD must not
drop below 8V during this startup process. This UVLO
hysteresis window ensures that the hold-up capacitor
can adequately supply VDD during startup.
Over-Temperature Protection (OTP)
The FAN400A has a built-in temperature sensing circuit
to shut down PWM output once the junction
temperature exceeds 140°C. While PWM output is shut
down, the VDD voltage gradually drops to the UVLO
voltage. Some of the internal circuits are shut down,
and VDD gradually starts increasing again. When VDD
reaches 17V, all the internal circuits, including the
temperature sensing circuit, operate normally. If the
junction temperature is still higher than 140°C, the
PWM controller shuts down immediately. This situation
continues until the temperature drops below 110°C. The
PWM output is then turned back on. The temperature
hysteresis window for the OTP circuit is 30°C.
Gate Output
The BiCMOS output stage is a fast totem-pole gate
driver. Cross-conduction is avoided to minimize heat
dissipation, increase efficiency, and enhance reliability.
The output driver is clamped by an internal 17V Zener
diode to protect the power MOSFET transistors against
any harmful over-voltage gate signals.
VDD Over-Voltage Clamping
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Operation Description
VDD over-voltage clamping is built in to prevent damage
from over-voltage conditions. When VDD exceeds 22.7V,
PWM output is shut down. Over-voltage conditions may
be caused by an open photo-coupler loop or a short
circuit in the output.
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
www.fairchildsemi.com
9
Slope Compensation
Noise Immunity
The sensed voltage across the current sense resistor is
used for current mode control and pulse-by-pulse
current limiting. The built-in slope compensation
improves power supply stability. Furthermore, it
prevents sub-harmonic oscillations that normally would
occur because of peak current mode control. A
positively sloped, synchronized ramp is activated with
every switching cycle. The slope of the ramp is:
0.33 × Duty
(1)
Duty(max.)
Noise from the current sense or the control signal may
cause significant pulse-width jitter, particularly in
continuous-conduction mode. Slope compensation
helps alleviate this problem. Good placement and
layout practices should be followed. The designer
should avoid long PCB traces and component leads.
Compensation and filter components should be located
near the FAN400A. Finally, increasing the power-MOS
gate resistance is advised.
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Operation Description (Continued)
www.fairchildsemi.com
10
Figure 16.
Reference Circuit (without Secondary-Side Feedback)
BOM
Reference
BD1
Component
BD DI106 1A/600V
Reference
F1
Component
R 1Ω/0.5W
CX1 (Option)
YC 4.7nF/400V (Y1)
L1
Inductor 20mH 6*8mm
CY1 (Option)
YC 2.2nF/250V (Y1)
L2
Inductor 10μH 6mm
C1
EC 4.7μF/400V 105°C
Q1
MOSFET 1A/600V
C2
EC 4.7μF/400V 105°C
R1,R2
R 750kΩ/1206
C3
CC 1nF/1kV
R3,R4
R 47kΩ/1206
C4
EC 10μF/50V
R5
R 47Ω/1206
C7 (Option)
CC 1nF/100V 1206
R6
R 4.7Ω/0.5W
C8
EC 470μF/10V 105°C
R7
R 100Ω/0805
C9
EC 220μF/10V 105°C
R8
R 10Ω/1206
D1
Diode FRI07
R10 (Option)
R 10Ω/1206
D2
Diode FR102
T1
Transformer EE-16
D4
Diode SB360
U4
IC FAN400A (Green PWM IC)
D5 (Option)
ZD 6.8V/0.5W
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Applications Information
www.fairchildsemi.com
11
Figure 17.
Reference Circuit (with Secondary-Side Feedback)
BOM
Reference
Component
Reference
Component
BD1
BD DI106 1A/600V
L2
Inductor 10μH 6mm
CY1 (Option)
YC 2.2nF/250V (Y1)
Q1
MOSFET 1A/600V
C1
EC 4.7μF/400V 105°C
R1,R2
R 750kΩ/1206
C2
EC 4.7μF/400V 105°C
R3,R4
R 47kΩ/1206
C3
CC 1nF/1kV
R5
R 47Ω/1206
C4
EC 10μF/50V
R6
R 4.7Ω/0.5W
C6
CC 4.7nF/0805
R7
R 100Ω/0805
C7 (Option)
CC 1nF/100V 1206
R8
R 10Ω/1206
C8
EC 470μF/10V 105°C
R10
R 10Ω/1206
C9
EC 470μF/10V 105°C
R11
R 100Ω/ 1/8W
C10
CC 2.2nF/0805
R12
R 33kΩ/0805
D1
Diode FRI07
R13
R 33kΩ/ 1/8W
D2
Diode FR102
R14
R 4.7kΩ/0805
D4
Diode SB360
T1
Transformer EE-16
D5 (Option)
ZD 6.8V/0.5W
U1
IC FAN400A (Green PWM IC)
F1
R 1Ω/0.5W
U2
IC PC817
L1
Inductor 20mH 6*8mm
U3
IC TL431
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Applications Information (Continued)
www.fairchildsemi.com
12
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Physical Dimensions
9.83
9.00
6.67
6.096
8.255
7.61
3.683
3.20
5.08 MAX
7.62
0.33 MIN
3.60
3.00
(0.56)
2.54
0.56
0.355
0.356
0.20
1.65
1.27
9.957
7.87
7.62
NOTES: UNLESS OTHERWISE SPECIFIED
A) THIS PACKAGE CONFORMS TO
JEDEC MS-001 VARIATION BA
B) ALL DIMENSIONS ARE IN MILLIMETERS.
C) DIMENSIONS ARE EXCLUSIVE OF BURRS,
MOLD FLASH, AND TIE BAR EXTRUSIONS.
D) DIMENSIONS AND TOLERANCES PER
ASME Y14.5M-1994
E) DRAWING FILENAME AND REVSION: MKT-N08FREV2.
Figure 18.
8-Pin Dip-8 Package
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify
or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically
the warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
www.fairchildsemi.com
13
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
Physical Dimensions (Continued)
Figure 19.
6-Pin SSOT-6 Package
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify
or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically
the warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2
www.fairchildsemi.com
14
FAN400A — Low-Power Green-Mode PWM Flyback Power Controller without Secondary Feedback
15
www.fairchildsemi.com
© 2008 Fairchild Semiconductor Corporation
FAN400A Rev. 1.0.2