SG6203DZ [FAIRCHILD]
Synchronous Rectifier Controller for Flyback Converter; 同步整流控制器的反激式转换器
| 型号： | SG6203DZ |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | Synchronous Rectifier Controller for Flyback Converter |
| 文件： | 总13页 (文件大小：455K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Product Specification
Synchronous Rectifier Controller for Flyback Converter
FEATURES DESCRIPTION
SG6203
Low operation current (1.7mA)
The SG6203 is designed to control and drive the
synchronous rectifier for the flyback converter. The
synchronous signal of the primary switch is obtained by a
single diode connected between the transformer
secondary winding and the SG6203. Using the SG6203,
no additional transformer winding is required and the
circuit complexity can be minimized.
One resistor for timing setting
Internal automatic tracking for optimum dead time
No reverse energy flow at light load
Best suited for primary green-mode PWM IC
Wide supply voltage range from 6V to 20V
Built-in 18V Zener diode
Optional current sensing:
-
-
Current shunt
The power unit can be properly operated under
discontinuous conduction mode (DCM) or continuous
conduction mode (CCM). Problems such as
“shoot-through” or “cross conduction” in CCM and
energy-reverse from the secondary to the primary in DCM
are prevented by the SG6203 design.
RC network for better efficiency
APPLICATIONS
Flyback converters, such as:
Power adaptors
Open-frame SMPS
TYPICAL APPLICATION
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 1 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
MARKING DIAGRAMS
PIN CONFIGURATION
IN+
VCC
T: D=DIP, S=SOP
P : Z=Lead Free + ROHS
SG6203TP
Compatible
Output
IN-
XXXXXXXX: Wafer Lot
Y: Year; WW: Week
V: Assembly Location
XXXXXXXXYWWV
GND
VZ
RT
DET
ORDERING INFORMATION
Part Number
Pb-Free Package
SG6203SZ
8-Pin SOP
SG6203DZ
8-Pin DIP
PIN DESCRIPTIONS
Pin
Name
Function
1
Vcc
Supply voltage of gate driver and control circuits.
Totem-pole output to drive the synchronous power MOSFET. When the voltage on DET pin falls below 1.4V
from above 2.1V, the synchronous MSOFET is turned on. To prevent the reversed energy flow, this pin is
disabled once the voltage on IN+ pin is lower than that of IN- pin or the internal one-shot timer is terminated.
2
3
4
Output
GND
VZ
The power ground and signal ground. A 0.1µF decoupling capacitor placed between VCC and GND is
recommended.
Built-in 18V Zener diode. When the flyback output voltage is higher than 18V, this pin can be used to provide a
stable 18V to VCC pin. If the flyback output voltage is lower than 18V, this pin can be left open and the output
voltage connected directly to VCC pin.
Connecting a diode from this pin to the transformer secondary winding provides on/off information of the primary
switch. Low DET level indicates the secondary rectifier is conducted, therefore the synchronous MOSFET
should be turned on. DET stays high when the primary switch is conducting or secondary rectifier turns off and
the synchronous MOSFET should be turned off.
5
6
DET
RT
Current reference. Connecting a resistor from this pin to ground can program the internal current reference IRT
.
Three internal current sources, which are IIN+, IIN-, and IDET, are then mirrored from IRT. IRT determines the duration
of the internal one-shot signal, then the maximum on-time of the synchronous MOSFET is obtained by
subtracting the on-time of the primary switch from the one-shot signal duration. If the resistor is too small, the
synchronous MOSFET may be turned off even when the secondary rectifier is still conducting, which decreases
the system efficiency. However, if the resistor is too large, the output is shut off immediately once DET gets high.
In SG6203, an internal phase-locked-loop (PLL) modulates the duration of the internal one-shot signal to
maintain a suitable dead time between the primary switch and the synchronous MOSFET.
The inverting input of the current sense comparator. In discontinuous conduction mode, the secondary rectifier
turns off before the next switching cycle of the primary switch. Once the secondary rectifier is off, the
synchronous MOSFET must be turned off to prevent the reversed energy flow. A resistor connected between
IN+ and IN- can used to develop the zero current crossing signal of the secondary rectifier. Once the voltage on
IN+ is lower than IN-, the output is pulled low.
7
8
IN-
The non-inverting input of the current sense comparator. In discontinuous conduction mode, the secondary
rectifier turns off before the next switching cycle of the primary switch. Once the secondary rectifier is off, the
synchronous MOSFET must be turned off to prevent the reversed energy flow. A resistor connected between
IN+ and IN- can used to develop the zero current crossing signal of the secondary rectifier. Once the voltage on
IN+ is lower than IN-, the output is pulled low.
IN+
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 2 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
BLOCK DIAGRAM
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 3 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
VCC
DC Supply Voltage*
25
V
IOUT
VH
Gate Output Current
DET, OUT, VZ
RT, IN+, IN-
500
mA
V
-0.3 to 25.0
-0.3 to 7.0
400
VL
V
SOP8
DIP8
SOP8
DIP8
PD
Power Dissipation
mW
800
208.4
82.5
Thermal Resistance (Junction-to-Air)
°C/W
Rθ
JA
TJ
Operating Junction Temperature
150
°C
°C
°C
KV
V
TSTG
TL
Storage Temperature Range
-65 to +150
300
Lead Temperature (Soldering, 10 Seconds)
Electrostatic Discharge Capability, Human Body Model
Electrostatic Discharge Capability, Machine Model
2.0
ESD
200
* All voltage values, except differential voltages, are given with respect to GND pin.
* Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device.
RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Value Unit
VCC
DC Supply Voltage
<20
V
TA
Operating Ambient Temperature
Pulse Width of the One-shot Signal
-30~85
°C
RT
12~36
KΩ
ELECTRICAL CHARACTERISTICS
VCC=12V; RT=24KΩ ; TA=25°C, unless otherwise noted.
Timing Control Section
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
VRT
Voltage on RT Pin
1.14
1.20
1.26
V
6.5
13
7.5
15
8.5
17
µs
µs
µs
RT=12KΩ
RT=24KΩ
RT=36KΩ
TRT
Pulse Width of the One-shot Signal
19.5
22.5
25.5
RT=12KΩ ; RT=24KΩ ;
RT=36KΩ
Adjustable Range of the Pulse Width
Compared to TRT
+40
200
+60
+80
%
△ TRT
Timing Margin Between Output Turn-off
(Output Falling) and Next Switching Cycle
Start (DET Rising)
TDEAD
1000
ns
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 4 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
Synchronous Detection Section
Symbol
Parameter
Test Condition
Min.
1.9
Typ.
2.1
Max.
2.3
Unit
V
VTH
Threshold Voltage to Enable One-shot Signal
Threshold Voltage to Enable Output
VTL
IN+ - IN- > 5mV
1.2
1.4
1.6
V
IDET
Current Output from DET Pin
250
300
300
µA
ns
RT=24KΩ
TD_LOW
Debounce Time from DET Low to Enable Output
150
Current Detection Section
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
VOFFSET
Offset Voltage
10
mV
IIN+
Current Output from IN+
90
90
100
100
110
110
µA
µA
µA
RT=24KΩ
IIN-
Current Output from IN-
RT=24KΩ
IIN+ - IIN-
Differential Current of IN+ and IN-
1.5
12KΩ < RT < 36KΩ
TP
Propagation Delay (OUTPUT from Low to High) DET< VTL, IN+ - IN- > 5mV
Power Supply Rejection Ratio
200
ns
PSRR
CMRR
CMRR-f
65
65
32
dB
dB
dB
Common Mode Rejection Ratio
Common Mode Rejection Ratio at 70KHz
Zener Section
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
VZ
Zener Voltage
IVZ=0.1 ~ 3mA
18
19
20
V
Output Section
Symbol
Parameter
Test Condition
Min.
11.2
3.5
Typ.
Max.
Unit
V
VCC=12V, ISOURCE=50mA
VOH
Output Voltage High
V
CC=6V, ISOURCE=30mA
VCC=12V, ISINK=50mA
CC=6V, ISINK=30mA
V
1
V
VOL
Output Voltage Low
V
1.2
V
TA=25°C; CL=5nF,
VCC=12V
Tr
Tf
Rising Time
Falling Time
150
150
175
175
ns
ns
TA=25°C; CL=5nF,
VCC=12V
V
CC Section
Symbol
Parameter
Test Condition
Min.
Typ.
Max.
Unit
VOP
Continuously Operating Voltage
20
V
V
DD=12V, Output=open,
DET=50KHz,
ICC_OP
Operating Current
1.7
4.0
6.3
mA
IN-=IN+=open, RT=12KΩ
VTH(ON)
Start Threshold
6.0
5.1
V
V
VTH(OFF)
Minimum Operating Voltage
4.8
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 5 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
TYPICAL CHARACTERISTICS
Start Threshold (VTH(ON)) vs Temperature
Pulse width of the one-shot signal (TRT) vs Temperature
16.0
15.9
15.8
15.7
15.6
15.5
15.4
15.3
15.2
15.1
6.5
6.4
6.3
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
-40 -25 -10
5
20
35
50
65
80
95 110 125
-40 -25 -10
5
20
35
50
65
80
95 110 125
Temperature (
)
℃
Temperature (
)
℃
Minimum Operating Voltage (VTH(OFF)) vs Temperature
Debounce time form DET low to enable the output (TD_LOW
vs Temperature
)
5.85
5.80
5.75
5.70
5.65
5.60
5.55
5.50
5.45
5.40
5.35
350.0
300.0
250.0
200.0
150.0
100.0
50.0
0.0
-40 -25 -10
5
20
35
50
65
80
95 110 125
-40 -25 -10
5
20
35
50
65
80
95 110 125
Temperature (
)
℃
Temperature (
)
℃
Threshold voltage to enable an one shot signal (VTH) vs
Temperature
Operating Current (ICC_OP) vs Temperature
1.842
1.840
1.838
1.836
1.834
1.832
1.830
1.828
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-40 -25 -10
5
20
35
50
65
80
95 110 125
-40 -25 -10
5
20
35
50
65
80
95 110 125
Temperature (
)
Temperature (
)
℃
℃
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 6 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
Threshold voltage to enable the output (VTL) vs Temperature
1.56
1.54
1.52
1.50
1.48
1.46
1.44
1.42
-40 -25 -10
5
20
35
50
65
80
95
110 125
Temperature (
)
℃
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 7 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
OPERATION DESCRIPTION
shut off immediately once DET gets high. In SG6203, an
internal phase locked loop modulates the duration of the
internal one-shot signal to maintain a suitable dead time
between the primary switch and the synchronous
MOSFET. The duration of the one-shot signal can be
extended 80% compared with the original value decided
by RT resistor.
Synchronization
The DET pin provides on/off information of the primary
switch. As shown in the following reference circuits, one
diode connected between the DET pin and the secondary
winding of the transformer is used to get this information.
Low DET voltage level indicates the secondary rectifier is
conducted; therefore, the synchronous MOSFET should
be turned on. The voltage on DET pin stays high when the
primary switch is conducting and the synchronous
MOSFET should be turned off. This innovative feature
requires no auxiliary winding and the circuit complexity
is greatly reduced.
Current Sense
In discontinuous conduction mode, the secondary rectifier
turns off before the next switching cycle of the primary
switch. Once the secondary rectifier is off, the
synchronous MOSFET must be turned off to prevent the
reverse energy flow. Therefore, a zero current crossing
detector is needed when the converter is operated under
DCM. The SG6203 provides two configurations to
achieve this: output capacitor ESR method (reference
Circuit-A) and current-sensing resistor method (reference
Circuit-B). When the secondary rectifier is turned off, the
voltage on IN+ is lower than that of IN-. Once this
happens, the driving signal for the synchronous MOSFET
is turned off.
Anticipation and Phase Lock Loop
A resistor from the RT pin to ground is used to determine
the internal current source reference. When the primary
switch is turned on with DET high, an internal one-shot
timer outputs high for a duration proportional to the RT
resistor. The duration of this one-shot signal can be
expressed as:
15×RT
(KΩ
)
(µs)
TRT
=
(1)
24
Under-Voltage Lockout (UVLO)
Primary Switch PWM
One-Shot Signal
The SG6203 has an internal UVLO circuit with hysteresis.
The IC is turned on if VCC is higher than 6V. Once turned
on, SG6203 is turned off if VCC is lower than 5.1V. When
the flyback output voltage is higher than 18V, the VZ pin
can be used to provide a stable 18V to VCC pin.
T
Output
The on-time of the synchronous MOSFET is obtained by
subtracting the on-time of the primary switch from the
one-shot signal duration. If the resistor is too small, the
synchronous MOSFET may be turned off when the
secondary rectifier is still conducting, which decreases
system efficiency. If the resistor is too large, the output is
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 8 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
REFERENCE CIRCUIT-A
BOM
Ref Des
C2
Part Number
Description
0.1µF
C5
22pF
D1
FR102
100V/1A
100V/1A
100V/0.2A
110V/75A; 15mΩ
2.2KΩ
D2
SB1100
D3
1N4148
Q1
R1
PSMN015-110P
R2
22Ω
R3
47KΩ
R4
1.8KΩ
R5
2KΩ
R6
0
R7
16.2KΩ
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 9 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
REFERENCE CIRCUIT-B
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 10 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
PACKAGE INFORMATION
8 PINS-SOP(S)
C
8
5
H
E
F
1
4
b
e
D
Θ
L
A
A1
Dimensions
Millimeter
Min.
1.346
Inch
Symbol
Typ.
Max.
1.752
0.254
Min.
0.053
0.004
Typ.
Max.
0.069
A
A1
b
0.101
0.010
0.406
0.203
0.016
0.008
c
D
E
e
4.648
3.810
1.016
4.978
3.987
1.524
0.183
0.150
0.040
0.196
0.157
0.060
1.270
0.050
F
0.381X45°
0.015X45°
H
L
5.791
0.406
0°
6.197
1.270
8°
0.228
0.016
0°
0.244
0.050
8°
θ˚
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 11 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
8PINS–DIP(D)
D
Θ
8
1
5
4
e
B
E
L
b1
b
e
Dimension
Millimeter
Min.
Inch
Min.
Symbol
Typ.
Max.
Typ.
Max.
A
5.334
0.210
A1
A2
b
0.381
3.175
0.015
0.125
3.302
1.524
0.457
9.271
7.620
6.350
2.540
3.302
9.017
7°
3.429
0.130
0.060
0.018
0.365
0.300
0.250
0.100
0.130
0.355
7°
0.135
b1
D
9.017
6.223
10.160
6.477
0.355
0.245
0.400
0.255
E
E1
e
L
2.921
8.509
0°
3.810
9.525
15°
0.115
0.335
0°
0.150
0.375
15°
eB
θ°
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 12 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
Product Specification
Synchronous Rectifier Controller for Flyback Converter
SG6203
© System General Corp.
Version 1.0.1 (IAO33.0010.B1)
- 13 -
www.sg.com.tw • www.fairchildsemi.com
September 24, 2007
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