SD4938 SILAN | Alldatasheet
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Technical content
SD4938_Datasheet HANGZHOU SILAN MICROELECTRONICS CO.,L TD Rev.:1.0 http: //www.silan.com.cn Page 1 of 8 150V CURRENT MODE PWM CONTROLLER
DESCRIPTION
SD4938 is a current mode PWM controller with 150V MOSFET used for SMPS. SD4938 integrates high-voltage start-up circuit. It enters burst mode at light load to reduce the system standby power dissipation; the fr equency reduction function optimizes the conversion efficiency at light load; the soft startup function reduces the stress of device to avoid transformer saturation. SD4938 features various protections, including VDD undervoltage protection, VDD overvoltag e protection, lead edge blanking, over current protection, over temperature protection, etc. Meanwhile, if any protection occurs, the circuit will continue to restart automatically until the system recovers.
FEATURES
Input voltage: 20V~150V Adjustable output voltage including: 12V, 15V and 18V Output current: 0.5A High-voltage self-startup Burst mode at light load Frequency reduction Soft startup VDD undervoltage protection VDD overvoltage protection Leading edge blanking Output overload protection Over current protection Over temperature protection SOP-8-225-1.27
APPLICATIONS
Balance wheel PoE E-bike Electric tool
ORDERING INFORMATION
Part No. Package Marking Hazardous Substance Control Packing Type SD4938 SOP-8-225-1.27 SD4938 Halogen free Tube SD4938TR SOP-8-225-1.27 SD4938 Halogen free Tape&reel
SD4938_Datasheet HANGZHOU SILAN MICROELECTRONICS CO.,L TD Rev.:1.0 http: //www.silan.com.cn Page 2 of 8 BLOCK DIAGRAM DRAIN GND VDD + -+ - VSET 12.5V 0.576V VDD undervoltage protection + -23V VDD overvoltage protection HV startup CCS Driver Oscillator Logic controller LEB Frequency reduction OTP Output OLP Protectio n control circuit PWM Soft startup + - 6.5V VDD lock DRAIN VDD divider + - 2V EA + - OCP ABSOLUTE MAXIMUM RATING Characteristics Symbol Ratings Unit HV Input (DRAIN to SOURCE) VHV,MAX 155 V Power Supply (VDD to SOURCE) VDD,MAX 30 V Power Dissipation PD 0.8 W Thermal Resistance, Junction-to-Ambient θja 140 C/W Thermal Resistance, Junction-to-Case θjc 28 C/W Operating junction temperature TJ 150 C Operating temperature range Tamb -40~+125 C Storage temperature range TSTG -55~+150 C
SD4938_Datasheet HANGZHOU SILAN MICROELECTRONICS CO.,L TD Rev.:1.0 http: //www.silan.com.cn Page 3 of 8 ELECTRICAL CHARACTERISTICS(UNLESS OTHERWISE SPECIFIED, VDD=12V, Tamb=25C) Characteristics Symbol Test conditions Min. Typ. Max. Unit HV Startup Charging Current IHVC VDD=0V, VDRAIN=150V -- 1.5 -- mA Shutdown Drain Current IHVS VDD=18V, VDRAIN=150V -- 3 -- uA Operating Voltage Operating Voltage Range VDD After startup 10 -- 21 V Current in Protection State IDD0 -- 0.3 -- mA Operating Current IDD1 -- 0.9 -- mA Current Below VDD Off Voltage IDDOFF -- 0.15 -- mA VDD On Voltage VDDON 12.1 13 13.9 V VDD Off Voltage VDDOFF 7.9 8.7 9.5 V VDD Restart Threshold VDDRESTART 6 6.5 7 V Overvoltage Protection Threshold VDDOVP 21.5 23 24.5 V VDD Clamp Voltage VDDCLAMP 28 31 35 V Operating Frequency Normal Switching Frequency fSW1 54 60 66 KHz Frequency Jitter Range FD ±5 % Max. Duty Ratio DMAX 74 80 86 % Minimum Switching Frequency fSW2 -- 20 -- KHz Overload Protection Overload Protection Delay Td_olp -- 68 -- mS Peak Current Limit Peak Limiting Threshold IPKLIM 1.4 1.6 1.8 A Current Sensing Turn-off Delay td ID = 0.2A -- 200 -- ns LEB Time tLEB -- 300 -- ns Min. Turn-on Time tONMIN -- 500 -- ns Soft Startup Time tSS -- 8.5 -- ms MOSFET On Resistance Rdson -- 1.3 -- Ω Over Temperature Protection Over Temperature Detection TSD -- 180 -- C Over Temperature Hysteresis THYS -- 20 -- C
SD4938_Datasheet HANGZHOU SILAN MICROELECTRONICS CO.,L TD Rev.:1.0 http: //www.silan.com.cn Page 4 of 8 PIN CONFIGURATION VDD SD4938 NC NC NC DRAIN DRAIN VSET GND PIN DESCRIPTION Pin No. Pin Name I/O Function description
1 VDD I/O Power supply for control circuit
2,3,4 NC NC No connection 5,6 DRAIN O Drain of power MOSFET
7 VSET I
SET different output voltage. If floating, output 12V. If short to GND, output 15V. If connect a 51K resistor to GND, output 18V
8 GND G Source of power MOSFET and reference ground of control circuit
SD4938 is a current mode PWM controller with built -in high voltage MOSFET used for SMPS. It enters burst mode at light load to reduce the system standby power dissipation. S D4938 features frequency reduction and soft startup function, various protections, including VDD undervoltage protection, VDD overvoltage protection, lead edge blanking, output overload protection, over current protection, over temperature protection, etc. High-voltage startup and under-voltage protection SD4938 features a high-voltage startup circuit. When the IC is powered, AC input voltage activates the built -in constant current source from pin DRAIN, and charges the VDD capacitor with charging current of 1.5mA. When the VDD voltage reaches12.5V, the high-voltage start-up constant current source is off and VDD is no longer charged but is powered by inductor voltage through diode; if VDD voltage drops below 8V, the MOSFET is turned off, VDD drops to 6.5V and high -voltage start-up constant current source is on again. Then VDD is charged through pin DRAIN and it reaches to 12.5V. Constant voltage control SD4938 detects the change of output voltage by VDD pin and internal error amplifier , when Vout drops, the output of error amplifier is raised to increase the width of PWM ，finally makes Vout rise to balance itself. Vout is approximately equal to VDD voltage. The VSET pin is used to set different output voltage. If it is floating, Vout is equal to12V. If it is short to GND, Vout is equal to 15V .If it is connected a 51K resistor to GND, Vout is equal to 18V. Burst mode at light load When VDD rises to a value that is more than the reference voltage at light load, the MOSFET will be turned off that
SD4938_Datasheet HANGZHOU SILAN MICROELECTRONICS CO.,L TD Rev.:1.0 http: //www.silan.com.cn Page 5 of 8 makes the VDD drops, and the MOSFET will be turned on when VDD drops to a value. If the above process occurs constantly, SD4938 enters burst mode that can decrease the number of switches and reduce the system standby power dissipation effectively. PWM VOUT Waveforms at burst mode Soft startup SD4938 enables the maxi mum peak current of DRAIN to increase restrictedly step by step within 8.5ms soft startup time, hence, it can reduce the stress of devices and prevent the transformer from turning into saturation. VDD overvoltage protection SD4938 turns off the MOSFET once the VDD voltage reaches OVP voltage (2 3V), and is locked out till the VDD voltage decreases to VDD restart voltage (6.5V), and then the circuit restarts. Leading edge blanking As soon as internal MOSFET is turned on, a high current spike will appear due to the parasitic capacitor at DRAIN. If this spike is sensed, the over current protection will be activated. To avoid this false trigger, SD4938 senses the current of DRAIN pin after the LEB time of 300ns since MOSFET is turned on. Output Over-load Protection When VDD is much less than the setting voltage and output of EA is high, the over-load protection is activated . VDD decreases and IC restarts when VDD drops to 6.5V. Cycle by cycle over current protection SD4938 senses the current of MOSFET cycle by c ycle, if the current of MOSFET is higher than 1.6A, the c ycle by cycle over current protection will be activated. Over temperature protection SD4938 turns off the switch once the temperature reaches to OTP threshold 180 °C, and turns on the switch if the temperature decreases by 20°C.
SD4938_Datasheet HANGZHOU SILAN MICROELECTRONICS CO.,L TD Rev.:1.0 http: //www.silan.com.cn Page 6 of 8 TYPICAL APPLICATION CIRCUIT VDD NC NC DRAIN VSET GND NC5 DRAIN VIN VOUT C2 C3 12V/0.3A output VIN VOUT C2 C3 VDD NC NCDRAIN VSET GND NC DRAIN 18V/0.3A output VIN VOUT C2 C3 VDD NC NC DRAIN VSET GND NC5 DRAIN 15V/0.3A output Note: The circuit and parameters are for reference only, please set the parameters of application circuits based on real tests.
SD4938_Datasheet HANGZHOU SILAN MICROELECTRONICS CO.,L TD Rev.:1.0 http: //www.silan.com.cn Page 7 of 8 PACKAGE OUTLINE SOP-8-225-1.27 Unit: mm L 0.25 b e D A2 A EE1 c A 1.35 1.55 1.75 A1 0.05 0.25 A2 1.25 1.65 b 0.32 0.42 0.52 c 0.15 0.2 0.26 D 4.70 4.90 5.30 E 5.60 6.00 6.40 E1 3.60 3.90 4.20 e 1.27BSC 0.15 L 0.30 __ 1.27 MAXNOMMIN MILLIMETER SYMBOL CAUTION ELECTROSTATIC SENSITIVE DEVICE DO NOT OPEN OR HANDLE EXPECT AT A STATIC-FREE WORKSTATION MOS DEVICES OPERATE NOTES: Electrostatic charges may exist in many things. Please take following preventive measure s to prevent effectively the MOS electric circuit as a result of the damage which is caused by discharge: The operator must put on wrist strap which should be earthed to against electrostatic. Equipment cases should be earthed. All tools used during assembly, including soldering tools and solder baths, must be earthed. MOS devices should be packed in antistatic/conductive containers for transportation.
SD4938_Datasheet HANGZHOU SILAN MICROELECTRONICS CO.,L TD Rev.:1.0 http: //www.silan.com.cn Page 8 of 8 Important notice : Part No.: SD4938 Document Type: Datasheet Copyright: HANGZHOU SILAN MICROELECTRONICS CO.,LTD Website: http: //www.silan.com.cn Rev.: 1.0 Revision History: 1. First release The instructions are subject to change without notice！ Customers should obtain the latest relevant information before placing orders and should verify that such information is complete and current. Our products are consumer electronic products, and / or civil electronic products. When using our products, please do not exceed the maximum rating of the products, otherwise the reliability of the whole machine will be affected. There is a certain possibility of failure or malfunction of any semiconductor product under specifi c conditions. The buyer is responsible for complying with safety standards and taking safety measures when using our products for system design, sample and whole machine manufacturing, so as to avoid potential failure risk that may cause personal injury or property loss. It is strongly recommended to identify the trademark when buying our products. Please conatus us if there is any question. When exporting, using and reselling our products, buyer must comply with the international export control laws and regulations of China, the United States, the United Kingdom, the European Union and other countries & regions. Product promotion is endless, our company will wholeheartedly provide customers with better products! Website: http: //www.silan.com.cn