Liteon Semiconductor Corporation
LSP4303
Low Power Off Line SMPS Primary Switcher
Rev1.0
1/7
FEATURES
z 85V to 265V wide range AC voltage input
z 700V high voltage MOSFET on the same chip
z high voltage start up current source
z current mode control
z 9V to 38V wide range VDD voltage
z fixed 100KHZ switching frequency
z automatic skip cycle mode in low load condition
z over temperature, over current and over voltage
protection with autorestart
z auxiliary under voltage lockout with hysteresis
APPLICATIONS
z off line low power SMPS, such as
DVD/DVB/STB/Electronic Oven/Air conditioner
z AC/DC adapter for battery charger
z AC/DC LED driver power
z standby power supplies for TV or monitors
z auxiliary supplies for motor control
GENERAL DESCRIPTION
The LSP4303 combines a dedicated current mode PWM
controller with a high voltage Power MOSFET on the
same silicon chip. The internal control circuit offers the
following benefits:
– Large input voltage range on the VDD pin
accommodates changes in auxiliary supply voltage. This
feature is well adapted to battery charger adapter
configurations.
– Automatic burst mode in low load condition.
– Overvoltage protection in hiccup mode.
FUNCTIONAL BLOCK DIAGRAM
Liteon Semiconductor Corporation
LSP4303
Low Power Off Line SMPS Primary Switcher
Rev1.0
2/7
ELECTRICAL CHARACTERISTICS
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
VDS(sw) Switching Drain Source Voltage -0.3~730 V
ID Continuous Drain Current Internally limited A
VDD Supply Voltage 0~50 V
Icomp Feedback Current 3 mA
VESDMM Electrostatic Discharge:
Machine Model (R=0W; C=200pF) 200 V
VESDHBM Electrostatic Discharge:
HBM 2000 V
Tj Junction Operating Temperature Internally limited ℃
Tc Case Operating Temperature -40 to 150 ℃
Tstg Storage Temperature -55 to 150 ℃
ELECTRICAL CHARACTERISTICS (Tj=25°C, VDD=18V, unless otherwise specified)
POWER SECTION
Symbol Parameter Test Conditions Min. Typ. Max. Unit
BVDSS Drain-Source Voltage ID=1mA;VCOMP=2V 730 V
IDSS Off State Drain Current VDS=500V; VCOMP=2V;
Tj=125°C 0.1 mA
RDSon Static Drain-Source
On State Resistance ID=0.4A; 15 17 Ω
RDSon Static Drain-Source
On State Resistance ID=0.4A; Tj=100°C 31 Ω
tf Fall Time ID=0.2A; VIN=300V 100 ns
tr Rise Time ID=0.4A; VIN=300V 50 ns
Coss Drain Capacitance VDS=25V 40 pF
SUPPLY SECTION
Symbol Parameter Test Conditions Min. Typ. Max. Unit
IDDch Start Up Charging Current VDS=100V; VDD=0V -1 mA
IDDoff Start Up Charging Current in
Thermal Shutdown
VDD=5V; VDS=100V
Tj > TSD - THYST 0.2 mA
IDD0 Operating Supply Current;
Not Switching ICOMP=2mA 3 5 mA
Liteon Semiconductor Corporation
LSP4303
Low Power Off Line SMPS Primary Switcher
Rev1.0
3/7
IDD1 Operating Supply Current;
Switching ICOMP=0.5mA; ID=50mA 4.5 mA
OSCILLATOR SECTION
Symbol Parameter Test Conditions Min. Typ. Max. Unit
FOSC Oscillator Frequency
Total Variation
VDD=VDDoff≤35V;
Tj=0~100°C 90 100 110 KHZ
FEEDBACK SECTION
Symbol Parameter Test Conditions Min. Typ. Max. Unit
Icomp Feedback Shutdown Current Vcomp=0V 0.9 mA
Rcomp COMP Pin Input Impedance ID=0mA 1.2
kΩ
PWM COMPARATOR SECTION
Symbol Parameter Test Conditions Min. Typ. Max. Unit
GID Icomp to ID Current Gain 560
IDlim Peak Current Limitation VCOMP=0V 0.56 0.7 0.84 A
td Current Sense Delay to
Turn-Off ID=0.4A 200 ns
tb Blanking Time 500 ns
tONmin Minimum Turn On Time 700 ns
OVERTEMPERATURE SECTION
Symbol Parameter Test Conditions Min. Typ. Max. Unit
TSD Thermal Shutdown
Temperature 140 170
℃
THYST Thermal Shutdown
Hysteresis 40
℃
Liteon Semiconductor Corporation
LSP4303
Low Power Off Line SMPS Primary Switcher
Rev1.0
4/7
DETAIL DESCRIPTIONS
1. Startup
This device includes a high voltage start up current source connected on the drain of the device. As soon as a voltage is
applied on the input of the converter, this start up current source is activated as long as VDD is lower than VDDon. When
reaching VDDon, the start up current source is switched off and the device begins to operate by turning on and off its main
power MOSFET. As the COMP pin does not receive any current from the optocoupler, the device operates at full current
capacity and the output voltage rises until reachingthe regulation point where the secondary loop begins to send a current
in the optocoupler. At this point, the converter enters a regulated operation where the COMP pin receives the amount of
current needed to deliver the right power on secondary side.
2. Feedback
A feedback pin controls the operation of the device. Unlike conventional PWM control circuits which use a voltage input
(the inverted input of an operational amplifier), the COMP pin is sensitive to current. Figure 9 presents the internal current
mode structure.
In a real application, the COMP pin is driven with an optocoupler which acts as a pull up. So, it is not possible to really
short this pin to ground and the above drain current value is not achievable. Nevertheless, the capacitor C is averaging the
voltage on the COMP pin, and when the optocoupler is off (start up or short circuit), it can be assumed that the
corresponding voltage is very close to 0 V.
3. Leading Edge Blanking(LEB)
At the instant the internal sense FET is turned on,there usually exists a high current spike through the sense FET,caused
by the primary side capacitance and secondary side rectifier diode reverse recovery.Excessive voltage across the sense
resistor would lead to false feedback operation in the current mode PWM control.To counter this effect,the device employs
a leading edge blanking(LEB) circuit. This circuit inhibits the PWM comparator for a short time(typically 500ns)after the
sense FET is turned on.
4. Under Voltage Lock Out(UVLO)
Once fault condition occurs,switching is terminated and the sense FET remains off. This causes VDD to fall. When VDD
reaches the UVLO stop voltage 8V, the protection is reset and the internal high voltage current source charges the VDD
capacitor. When VDD reaches the UVLO start voltage 14.5V, the device resumes its normal operation, In this manner, the
auto-restart can alternately enable and disable the switching of the power sense FET 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 ,thermal shutdown is activated. The ℃
device turn off the sense FET and the high voltage current source charge VDD. The device will go back to work when the
lower threshold temperature about 145 is reached.℃
6. Over Voltage Protection(OVP)
An overvoltage detector on the VDD pin allows the LSP4303 to reset itself when VDD exceeds VDDovp. Note that this
event is only latched for the time needed by VDD to reach VDDoff, and then the device resumes normal operation
automatically.
Liteon Semiconductor Corporation
LSP4303
Low Power Off Line SMPS Primary Switcher
Rev1.0
5/7
PIN ASSIGNMENT AND PACKAGE
TO252-5L
PIN Number PIN name Pin Function Description
1,2 GND Power MOSFET source and circuit ground referencep.
3 SW
Power MOSFET drain. Also used by the internal high voltage current source during
start up phase for charging the external VDD capacitor.
4 COMP
Feedback input. The useful voltage range extends from 0V to 1V, and defines the peak
drain MOSFET current. The current limitation, which corresponds to the maximum
drain current, is obtained for a COMP pin shorted to the GND pin.
5 VCC
Power supply of the control circuits. Also provides a charging current during start up
thanks to a high voltage current source connected to the drain. For this purpose, an
hysteresis comparator monitors the VDD voltage;
Metal Tab Connected with SW
PS：European(195~265Vac) for 20W, US(85~265Vac) for 12W;
TYPICAL APPLICATION CIRCUITS
Liteon Semiconductor Corporation
LSP4303
Low Power Off Line SMPS Primary Switcher
Rev1.0
6/7
ORDERING INFORMATION
MARKING INFORMATION
Liteon Semiconductor Corporation
LSP4303
Low Power Off Line SMPS Primary Switcher
Rev1.0
7/7
PACKAGE INFORMATION
Dimensions In Millimeters Dimensions In Inches
Symbol Min. Max. Min. Max.
A 2.200 2.400 0.087 0.094
A1 0.000 0.150 0.000 0.006
b 0.400 0.630 0.016 0.025
c 0.450 0.580 0.018 0.023
c1 0.450 0.580 0.018 0.023
D 6.350 6.850 0.250 0.270
D1 5.200 5.500 0.205 0.217
E 5.400 6.200 0.213 0.244
e 1.270TYP. 0.050TYP.
e1 2.540TYP. 1.000TYP.
L1 9.000 11.300 0.360 0.452
L2 0.900 1.630 0.035 0.064
L3 2.200 2.800 0.087 0.110
V 3.800REF 0.150REF
UPDATE HISTORY
Date Version Descriptions
D1
D
e
e1
b
L1
c1
A
EL3
c
L2
A1
V
