SG6841 90VAC 264VAC 373VDC IRO33 SG6842 SG6841TP SG6841S SG6841D SG6841SZ

SG6841 High-integrated Green-mode PWM Controller FEATURES DESCRIPTION Green-mode PWM to support "Blue Angel" Norm Low

Product Specification SG6841 SG6841 High-integrated Green-mode PWM Controller FEATURES DESCRIPTION Green-mode PWM to support "Blue Angel" Norm Low start up current 30uA Low operation current 3mA Leading-edge blanking Built-in synchronized slope compensation Constant output power limit for universal AC input Current mode operation Cycle-by-cycle current limiting Under voltage lockout (UVLO) Programmable PWM frequency GATE output maximum voltage clamped at 18V Totem pole output includes soft driving for better EMI Build-in limited-power-control to meet safety requirement Programmable over-temperature protection Few external components & low cost solution This highly integrated PWM controllers, SG6841 SG6841 series, provides several features to enhance the performance of low power flyback converters. To minimize standby power consumption, the proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency under light-load conditions. This green-mode function assists the power supply to easily meet the power conservation requirement. Due to BiCMOS process, the start-up current and operation current is reduced to 30uA and 3mA, respectively, to improve power conversion efficiency. Large start-up resistance can be used for further power saving. Built-in synchronized slope compensation ensures the stability of peak current mode control. A proprietary internal compensation ensures constant output power limit for universal AC input voltage from 90VAC 90VAC to 264VAC 264VAC. SG6841 SG6841 provides many protection functions. Pulse by pulse current limit ensures a constant output current under short circuit. If a short circuit failure or over load happens, the SG6841 SG6841 will shut off after a continuous high voltage detection on FB pin. The gate output is clamped at 18V to protect the power MOS from over voltage damage. An external NTC thermistor can be applied to sense the ambient temperature for over-temperature protection. The SG6841 SG6841 series are available in 8-pin DIP and SO packages. APPLICATIONS General-purpose switching mode power supplies and flyback power converters, and Power Adapter Open-frame SMPS Battery Charger Adapter TYPICAL APPLICATION From bridge rectifier 127~ 373VDC 373VDC D1 RIN C IN VIN RT VDD From auxiliary winding Rg Q1 GATE RA RI RT RI Version 2.1 (IRO33 IRO33.0001.B5) SENSE RS FB ©System General Corp. SG6842 SG6842 GND -1- www.sg.com.tw Jun.15,2006 Product Specification SG6841 SG6841 High-integrated Green-mode PWM Controller MARKING DIAGRAMS PIN CONFIGURATION GND P: Z = Lead Free SG6841TP SG6841TP Null=regular package XXXXXXXYYWWV XXXXXXX: Wafer Lot GATE FB T: D = DIP, S = SOP VDD VIN YY: Year; WW: Week V: Assembly Location RI SENSE RT ORDERING INFORMATION Part Number Package SG6841S SG6841S 8-Pin SOP SG6841D SG6841D 8-Pin DIP SG6841SZ SG6841SZ 8-Pin SOP(Lead Free) SG6841DZ SG6841DZ 8-Pin DIP(Lead Free) PIN DESCRIPTIONS Pin No. Symbol Function 1 GND Ground 2 FB Feedback Description Ground. The signal from external compensation circuit is feed into this pin. The PWM duty cycle is determined by this FB pin and current sense signal from Pin 6. This pin is pulled high to the rectified line input through a resistor for start-up. Since the 3 VIN Start-Up Input start-up current requirement for SG6841 SG6841 is very small, a large start-up resistance can be used to minimize power loss. Under normal operation, this pin is also used to detect line voltage to compensate for constant output power limit for universal AC input. A resistor from RI pin to ground will generate a constant current source forSG6841. This current is used to charge an internal capacitor and hence the switching frequency are 4 Ri Reference Setting determined. Increasing the resistance will decrease the current source and reduce the switching frequency. A 26k resistor Ri creates a 50uA constant current Ii and generates 65kHz switching frequency. 5 RT Temperature Protection 6 SENSE Current Sense 7 VDD Power supply 8 GATE Driver Output ©System General Corp. Version 2.1 (IRO33 IRO33.0001.B5) For over-temperature protection. An external NTC thermistor is connected from this pin to ground. The impedance of the NTC will decrease under high temperature. Once the voltage on RT pin drops below a fixed limit, the PWM output will be disabled. Current sense. The sensed voltage is used for current mode control and pulse-by-pulse current limiting. Power Supply. The totem-pole output driver for the power MOSFET. A soft driving waveform is implemented to improve EMI. -2- www.sg.com.tw Jun.15,2006 Product Specification SG6841 SG6841 High-integrated Green-mode PWM Controller BLOCK DIAGRAM RI 4 VDD 0.85V VIN ON/OFF Driver + 3 Internal BIAS VDD + 7 Q OSC S 8 GATE 6 _ SENSE 2 FB Green Mode Controller R UVLO _ 16V/10V Comp Slope Compensation 2R I RT RT 6V 5 Limited Power Controller + _ Comp R 4.2V 0.65V 1 GND ©System General Corp. Version 2.1 (IRO33 IRO33.0001.B5) -3- www.sg.com.tw Jun.15,2006 Product Specification SG6841 SG6841 High-integrated Green-mode PWM Controller ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit DC Supply Voltage 30 V Zener clamp 32 V Zener current 10 mA IOUT Gate Output Current 500 mA VFB Input Voltage to FB Pin -0.3 to 7V V VSense Input Voltage to SENSE Pin -0.3 to 7V V VRT Input Voltage to RT Pin -0.3 to 7V V VRI Input Voltage to Ri Pin -0.3 to 7V V PD Power Dissipation 1 W DIP 82.5 °C /W SOP 141 VDD Thermal Resistance Junction-air R j-a TJ Operating Junction Temperature 150 °C TA Operating Ambient Temperature -30 to 85 °C Tstg Storage Temperature Range -55 to +150 °C TL Lead Temperature (Wave soldering or IR, 10 seconds) ESD Capability, HBM model 260 3.0 °C KV ESD Capability, Machine model 250 V RECOMMENDED OPERATING CONDITIONS Symbol Parameter Value Unit VDD DC Supply Voltage