SAMWIN SW 8900

SAMWIN
Semiconductors
SW 8900
SW 04-5-20-A V1.01
GREEN POWER
OFF LINE SMPS PRIMARY SWITCHER
Features
Applications
z 85v to 265v wide range AC voltage input
z Power AC/DC Adapters for Chargers
z A 700v MOSFET on the same silicon chip
z DVD/VCD power supplies
z Auto start up with high voltage current
z Electromagnetic Oven power supplies
z Air Conditioner power supplies
source
z PWM with current mode control
z STB power supplies
z 9v to 38v wide range VCC voltage
z AC/DC LED Driver Applications
z Fixed 60KHz switching frequency
z Automatic skip cycle mode in low load
Package
z SOP8 & DIP8
condition.
z Over temperature, over current and over
voltage protection
z Auxiliary under voltage lockout with
hysteresis
Typical Application Circuit
Samwin
SW 8900
8-1
SAMWIN
SW 8900
Semiconductors
SW 04-5-20-A V1.01
Pin Configuration
Pin Definitions
Pin Number
Pin Name
1,2
GND
3
COMP
Pin Function Description
Sense FET source terminal on primary side and internal control
ground.
Feedback input defines the peak drain MOSFET current.
Positive supply voltage input. Although connected to an auxiliary
transformer winding, current is supplied from SW via an internal
4
VCC
switch during startup (see Internal Block Diagram section). It is not
until VCC reaches them UVLO upper threshold (14.5V) that the
internal start-up switch opens and device power is supplied via the
auxiliary transformer winding.
5,6,7,8
SW
The SW pin is designed to connect directly to the primary lead of the
transformer and is capable of switching a maximum of 700V.
Internal Block Diagram
8-2
SAMWIN
SW 8900
Semiconductors
SW 04-5-20-A V1.01
Absolute Maximum Ratings
(Ta=25°C, unless otherwise specified)
Symbol
Parameter
Value
Unit
VSW
SW to GND Voltage (Tj=25-125°C)
-0.3 ... 730
V
ID
Continuous VDMOS Drain Current
Internally limited
A
VCC
Supply Voltage
0...50
V
ICOMP
Feedback Current
3
mA
200
V
2000
V
Internally limited
°C
VESDMM
VESDHBM
Electrostatic Discharge:
Machine Model ((R=0Ω; C=200pF)
Electrostatic Discharge:
HBM
Tj
Junction Operating Temperature
Tc
Case Operating Temperature
-40 to 150
°C
Tstg
Storage Temperature
-55 to 150
°C
Electrical Characteristic (Power)
Symbol
Parameter
BVDSS
VDMOS Breakdown Voltage
IDSS
Zero Gate Voltage Drain Current
RDSON
Static Drain-Source on Resistance
Tr
Rise Time
Tf
Fall Time
COSS
VDMOS Drain Capacitance
Condition
ID=1mA;
VCOMP=2V
Min.
Typ.
730
VCOMP=2V;
ID=0.4A;
ID=0.1A;
VIN=300V
ID=0.2A;
VIN=300V
VDS=25V
8-3
Unit
V
VDS=500V;
VGS=10V
Max.
15
100
μA
17
Ω
50
ns
100
40
pF
SAMWIN
SW 8900
Semiconductors
SW 04-5-20-A V1.01
Electrical Characteristic (Control)
(Ta=25°C, VCC=18V, unless otherwise specified)
Symbol
Parameter
Condition
Min.
Typ.
Max.
Unit
UVLO SECTION
VSTART
VCC Start Threshold Voltage
VCOMP=0V
13
14.5
16
V
VSTOP
VCC Stop Threshold Voltage
VCOMP=0V
7
8
9
V
VHYS
VCC Threshold Hysteresis
5.8
6.5
7.2
V
54
60
66
kHz
±5
±10
%
OSCILLATOR SECTION
FOSC
ΔF/ΔT
VSTOP≤VCC≤35
Initial Accuracy
Frequency
Change
V; 0≤Tj≤ 100°C
With
Temperature
-25°C ≤ Tj
≤ +85°C
FEEDBACK SECTION
ICOMP
Feedback Shutdown Current
RCOMP
COMP Pin Input Impedance
Tj=25°C,
VCOMP = 0V
ID=0mA
0.9
mA
1.2
kΩ
CURRENT LIMIT(SELF-PROTECTION)SECTION
GID
ICOMP to ID Current Gain
560
ILIM
Peak Current Limit
Tj = 25°C
TD
Current Sense Delay to Turn-Off
ID=0.2A
TB
TONMIN
0.56
0.70
0.84
A
200
ns
Blanking Time
500
ns
Minimum Turn On Time
700
ns
-
°C
PROTECTION SECTION
TSD
Thermal Shutdown Temperature
THYST
Thermal Shutdown Hysteresis
VOVP
Over Voltage Protection
140
170
40
38
42
°C
46
V
SUPPLY CURRENT SECTION
ICH
ICHOFF
Startup Charging Current
Start Up Charging Current
in Thermal Shutdown
-1
mA
VCC=5V;
0.2
VDS=100V
mA
Tj > TSD
Operating Supply Current
IOP0
(Control Part Only)
VCOMP = 0V
4.5
VCOMP = 2V
3
mA
Switching
Operating Supply Current
IOP1
(Control Part Only)
Not Switching
8-4
5
mA
SAMWIN
SW 8900
Semiconductors
SW 04-5-20-A V1.01
Functional Description
1.
rectifier diode reverse recovery.
Startup
Excessive voltage
This device includes a high voltage start up current
across the sense resistor would lead to false feedback
source connected on the SW of the device. As soon as a
operation in the current mode PWM control. To counter
voltage is applied on the input of the converter, this
this effect, the device employs a leading edge blanking
start up current source is activated and to charge the
(LEB) circuit. This circuit inhibits the PWM comparator
VCC capacitor as long as VCC is lower than VSTART.
for a short time (typically 500ns) after the Sense FET is
When reaching VSTART, the start up current source is
turned on.
cut off by UVLO&TSD and the device begins to
4. Under Voltage Lock Out
operate by turning on and off its main power MOSFET.
Once fault condition occurs, switching is terminated and
As the COMP pin does not receive any current from the
the Sense FET remains off. This causes VCC to fall.
opto-coupler, the device operates at full current
When VCC reaches the UVLO stop voltage, 8V, the
capacity and the output voltage rises until reaching the
protection is reset and the internal high voltage current
regulation point where the secondary loop begins to
source charges the VCC capacitor. When VCC reaches the
send a current in the opto-coupler. At this point, the
UVLO start voltage, 14.5V, the device resumes its normal
converter enters a regulated operation where the COMP
operation. In this manner, the auto-restart can alternately
pin receives the amount of current needed to deliver the
enable and disable the switching of the power Sense FET
right power on secondary side.
until the fault condition is eliminated.
5. Thermal Shutdown (TSD)
The Sense FET and the control IC are integrated in the
same chip, making it easier for the control IC to detect the
temperature of the Sense FET. When the temperature
exceeds approximately 170°C, thermal shutdown is
activated, the device turn off the Sense FET and the high
voltage current source to charge VCC. The device will go
Fig 1
back to work when the lower threshold temperature about
Startup circuit
140°C is reached.
2. Feedback
6. Over Voltage Protection (OVP)
A feedback pin controls the operation of the device.
In case of malfunction in the secondary side feedback
Unlike conventional PWM control circuits which use a
circuit, or feedback loop open caused by a defect of solder,
voltage input, the COMP pin is sensitive to current.
the current through the opto-coupler transistor becomes
Figure 2 presents the internal current mode structure.
almost zero. Because excess energy is provided to the
The Power MOSFET delivers a sense current which is
output, the output voltage may exceed the rated voltage,
proportional to the main current. R2 receives this
resulting in the breakdown of the devices in the secondary
current and the current coming from the COMP pin.
side. In order to prevent this situation, an over voltage
The voltage across R2 VR2 is then compared to a fixed
protection (OVP) circuit is employed. If VCC exceeds
reference voltage. The MOSFET is switched off when
42V, OVP circuit is activated resulting in termination of
VR2 equals the reference voltage.
the switching operation. In order to avoid undesired
3. Leading Edge Blanking (LEB)
activation of OVP during normal operation, VCC should
At the instant the internal Sense FET is turned on, there
be properly design to be below 42V.
usually exists a high current spike through the Sense
FET, c primary side capacitance and secondary side
8-5
SAMWIN
SW 8900
Semiconductors
Fig 2
SW 04-5-20-A V1.01
Feedback circuit
8-6
SAMWIN
SW 8900
Semiconductors
SW 04-5-20-A V1.01
Package Dimensions（DIP8）
Size
Size
Min(mm)
Max(min)
symbol
Min(mm)
Max(min)
symbol
A
9.30
A1
1.524
A2
0.39
A3
9.50
C2
0.50
C3
3.3
C4
1.57TYP
2.54
D
8.2
8.8
A4
0.66TYP
D1
0.2
0.35
A5
0.99TYP
D2
7.62
7.87
B
6.3
Θ1
8ºTYP
C
7.2
Θ2
8ºTYP
C1
3.3
Θ3
5ºTYP
0.53
6.5
3.5
8-7
SAMWIN
SW 8900
Semiconductors
SW 04-5-20-A V1.01
IMPORTANT NOTICE
Samwin Microelectronics Co. Ltd. reserves the right to make changes without further notice to any products or
specifications herein. Samwin Microelectronics Co. Ltd. does not assume any responsibility for use of any its products for
any particular purpose, nor does Samwin Microelectronics Co. Ltd assume any liability arising out of the application or use
of any its products or circuits. Samwin Microelectronics Co. Ltd does not convey any license under its patent rights or
other rights nor the rights of others.
8-8