SW253G CURRENT MODE PWM CONTROLLER WITH BUILT-IN HIGH VOLTAGE MOSFET DESCRIPTION SW253G is a current mode PWM controller with low standby power and low start current for power switch. In standby mode,the circuit enters burst mode to reduce the standby power dissipation. The switch frequency is 67KHz with ±2.5 KHz jitter frequency for low EMI. The stress on transformer during power on is reduced by the builtin 15ms soft start circuit to avoid the saturation of transformer. SW253G includes under voltage lock-out, over voltage protection , leading edge blanking, over current protection and the temperature protection. The circuit will restart automatically until the system is normal after the protection is active. FEATURES APPLICATIONS * Lower start-up current (Typ.6μA) * Switch power * Frequency jitter for low EMI * Overcurrent protection * Overvoltage protection * Undervoltage lockout * Built-in temperature protection * Built-in high voltage MOSFET * Auto restart mode * Built-in soft start * Burst mode operation * Cycle by cycle current limit ORDERING INFORMATION Part No. SW253GP67K65 Package DIP-8-300-2.54 Marking SW253G Note: P denotes it is available in DIP8 package, 67k denotes 67KHz, and 65 denotes withstand voltage is 650V. SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 1 页 共 10 页 SW253G-E-02 SW253G TYPICAL OUPUT POWER CAPABILITY 190~265VAC Device SW253GP67K65 85~265VAC Adapter Open 21W 25W Adapter Open 18W 21W BLOCK DIAGRAM ABSOLUTE MAXIMUM RATING Characteristics Drain-Gate Voltage (RGS=1MΩ) Gate-Source (GND) Voltage Drain Current Pulse (note1) SW253GP67K65 Symbol Rating Unit VDGR 650 V VGS ±30 V IDM 14 SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 2 页 共 10 页 A SW253G-E-02 SW253G Characteristics Continuous Drain Current (Tamb=25°C) Signal Pulse Avalanche Energy(note 2) Symbol Rating Unit SW253GP67K65 ID 4 A SW253GP67K65 EAS 200 mJ Power Supply Voltage VCC,MAX 21 V Analog Input Voltage VFB -0.3~ VSD V PD 1.4 W Darting 0.017 W/°C TJ +160 °C Operating Temperature Tamb -25~ +85 °C Storage Temperature TSTG -55~+150 °C Total Power Dissipation Operating Junction Temperature Note: 1. Pulse width is limited by maximum junction temperature. 2. L=51mH, starting Tj=25°C ELECTRICAL CHARACTERISTICS (sense MOSFET part, unless otherwise specified, Tamb=25°c) Characteristics Drain-Source Breakdown Voltage Symbol Test conditions BVDSS VGS=0V, ID=50μA VDS=Max. VGS=0V Zero Gate Voltage Drain Current IDSS VDS=0.8Max. VGS=0V Tamb=125°C Min. Typ. Max. Unit 650 -- -- V -- -- 50 μA -- -- 200 μA -- 3.0 3.6 Ω Static DrainSource On SW253GP67K65 RDS(ON) VGS=10V, ID=0.5A Resistance Input Capacitance Output Capacitance SW253GP67K65 Ciss VGS=0V, VDS=25V, f=1MHz -- 840 -- pF SW253GP67K65 Coss VGS=0V, VDS=25V, f=1MHz -- 44 -- pF SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 3 页 共 10 页 SW253G-E-02 SW253G Characteristics Symbol Test conditions Min. Typ. Max. Unit Crss VGS=0V, VDS=25V, f=1MHz -- 40 -- pF -- 40 -- nS VDD=0.5BVDSS, ID=25mA -- 25 -- nS td(OFF) VDD=0.5BVDSS, ID=25mA -- 90 -- nS -- 42 -- nS Reverse Transfer SW253GP67K65 Capacitance Turn On Delay Time Rise Time Turn Off Delay Time Fall Time SW253GP67K65 SW253GP67K65 SW253GP67K65 SW253GP67K65 td(ON) VDD=0.5BVDSS, ID=25mA tr tf VDD=0.5BVDSS, ID=25mA ELECTRICAL CHARACTERISTICS (unless otherwise specified, Tamb=25°c) Characteristics Symbol Test conditions Min. Typ. Max. Unit Undervoltage Section Start Threshold Voltage Vstart 11 12 13 V Stop Threshold Voltage Vstop 7 8 9 V Oscillate Frequency FOSC 61 67 73 KHz Frequency Jitter FMOD ±1.5 ±2.0 ±2.5 KHz -- ±5 ±10 72 77 82 % 0.7 0.9 1.1 mA 5.5 6.0 6.5 V 3.5 5.0 6.5 μA Oscillator Section Frequency Change With Temperature Maximum Duty Cycle -- 25°C≤Tamb≤+85°C Dmax % Feedback Section Feedback Source Current IFB Shutdown Feedback Voltage VSD Shutdown Delay Current Idelay 0V≤VFB≤3V 5V≤VFB≤VSD SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 4 页 共 10 页 SW253G-E-02 SW253G Characteristics Symbol Built-in Soft Start Time ts Test conditions Min. Typ. Max. Unit VFB=4V 10 15 20 ms Max. inductor current 1.35 1.50 1.65 A Current Limit Peak Current Limit Iover SW253GP67K65 Burst mode Burst Mode High Voltage VBURH 0.4 0.5 0.6 V Burst Mode Low Voltage VBURL 0.25 0.35 0.45 V Overvoltage Protection Vovp 18 19 -- V Thermal Shutdown Tsd 125 140 -- °C TLEB 200 -- -- ns Protection Section Leading-edge Blanking Time Total Standby Current Start Current Istart VCC=11V -- 6 20 μA Iop VCC=12V 1 3 5 mA Supply Current (Control Part) PIN CONFIGURATION SW253G PIN DESCRIPTION Pin No. Pin Name I/O 1 SGND - Ground for control part. Function description 2 PGND - MOSFET Ground. 3 4 VCC - Power supply pin. FB I/O 5 NC - Not connected. 6,7,8 Drain O Drain pins. Feedback input pin. SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 5 页 共 10 页 SW253G-E-02 SW253G FUNCTION DESCRIPTION SW253G is designed for off-line SMPS, consisting of high voltage MOSFET, optimized gate driver and current mode PWM controller which includes frequency oscillator and various protections such as undervoltage lockout, overvoltage protection, overcurrent protection and overtemperature protection. Frequency jitter generated from oscillator is used to lower EMI and built-in soft start is used for reducing transformer stress when the circuit is powered on. Burst mode is adopted during light load to lower standby power dissipation, and function of lead edge blanking eliminates the MOSFET error shutdown caused by interference through minimizing MOSFET turning on time. Few peripheral components are needed for higher efficiency and higher reliability and it is suitable for flyback converter and forward converter. 1. Under Voltage Lockout and Self-Start At the beginning, the capacitor connected to pin VCC is charged via start resistor by high voltage AC and the circuit start to work if voltage at Vcc is 12V. The output is shutdown if there is any protection during normal operation and Vcc is decreased because of powering of auxiliary winding. The whole control circuit is shutdown if voltage at Vcc is 8V below to lower current dissipation and the capacitor is recharged for restarting. VCC Vstart Vstop t 0 ICC t 0 Powered by start resistor 2. Powered by Powered by start resistor assistant winding Built-In Soft Start Circuit In order to decrease transformer stress and to prevent its saturation during power on, it is recommended to increase peak current value of primary winding slowly by increasing feedback voltage slowly. After about 15ms, the soft start is completed and it has no effect on normal operation. SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 6 页 共 10 页 SW253G-E-02 SW253G 3. Frequency Jitter The oscillation frequency is kept changed for low EMI and decreasing radiation on one frequency. The oscillation frequency changes within a very small range to simplify EMI design. The rule of frequency changing: change from 65KHz to 69KHz. 4. Light Load Mode Working in this mode to reduce power dissipation. It works normally when FB is 500mV above and during 350mV<FB <500mV, there are two different conditions: when FB changes from low to high, there is no action for switch and it is the same with condition of FB lower than 350mV; the other is that FB changes form high to low, comparison value is increased for increasing turning on time to decrease switch loss. For this mode, during FB changes form high to low, the output voltage increases (increasing speed is decided by load) because of the high comparison value to decrease FB until it is 350mV below; when FB <350mV, there is no action for switch and output voltage decrease (decreasing speed is also decided by load) to increase FB. This is repeated to decrease action of switch for lower power dissipation. 5. Leading Edge Blanking For this current-controlled circuit, there is pulse peak current during the transient of switch turning on and there is an error operation if the current is sampled during this time. And leading edge blanking is adopted to eliminate this error operation. The output of PWM comparator is used for controlling shutdown after the leading edge blanking if there is any output drive. 6. Over Voltage Protection SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 7 页 共 10 页 SW253G-E-02 SW253G The output is shutdown if voltage at Vcc exceeds the threshold and this state is kept until the circuit is powered on reset. 7. Overload Protection FB voltage increase if there is overload and the output is shutdown when FB voltage is up to the feedback shutdown voltage. This state is kept until the circuit is powered on reset. 8. Peak Current Limit Cycle By Cycle During each cycle, the peak current value is decided by the comparison value of the comparator, which will not exceed the peak current limited value to guarantee the current on MOSFET will not be more than the rating current. The output power will not increase if the current reaches the peak value to limit the max. output power. The output voltage decreases and FB voltage increases if there is overload and corresponding protection occurs. 9. Abnormal Over Current Protection That secondary diode is short, or the transformer is short will cause this event. At this time, once it is over current in spite of the leading edge blanking (L.E.B) time, protection will begin after 350nS, and is active for every cycle. When the voltage on the current sense resistor is 1.6V, this protection will occur and the output is shut down. This state is kept until the under voltage occurs, and the circuit will start. 10. Thermal Shutdown If the circuit is over temperature, the over temperature protection will shut down the output to prevent the circuit from damage. This state is kept until the under voltage occurs, and the circuit will start. SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 8 页 共 10 页 SW253G-E-02 SW253G TYPICAL APPLICATION CIRCUIT SW ２５３Ｇ Note: The circuit and parameters are for reference only, please set the parameters of the real application circuit based on the real test. SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 9 页 共 10 页 SW253G-E-02 SW253G PACKAGE OUTLINE DIP-8-300-2.54 UNIT: mm MOS DEVICES OPERATE NOTES: Electrostatic charges may exist in many things. Please take following preventive measures to prevent effectively the MOS electric circuit as a result of the damage which is caused by discharge: z The operator must put on wrist strap which should be earthed to against electrostatic. z Equipment cases should be earthed. z All tools used during assembly, including soldering tools and solder baths, must be earthed. z MOS devices should be packed in antistatic/conductive containers for transportation. Note：Samwin reserves the right to make changes without notice in this specification for the improvement of the design and performance. Samwin will supply the best possible product for customers. SAMWIN 绿色电源的最佳选择 HTTP://WWW.SEMIPOWER.COM.CN 第 10 页 共 10 页 SW253G-E-02