Maker : ETC
Part No. : SG6848

  Datasheet PDF : SG6848.pdf
  Cross Reference : SG6848 Cross Reference
  Buy Component : SG6848 Find Stock and Price

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Product Information

Product Specification Low Cost Green-Mode PWM Controller for Flyback Converters SG6848 FEATURES Green-Mode PWM Supports the “Blue Angel” Standard Low Start-up Current (5uA) Low Operating Current (2mA) Leading-Edge Blanking Constant Output Power Limit Universal Input Built-in Synchronized Slope Compensation Current Mode Operation Cycle-by-cycle Current Limiting Under Voltage Lockout (UVLO) Programmable PWM Frequency Gate Output Voltage Clamped at 15V Low Cost Few External Components Required Small SOT-26 Package DESCRIPTION This highly-integrated PWM controller provides several special enhancements designed to meet the low standby-power needs of low-power SMPS. 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 enables the power supply to easily meet even the strictest power conservation requirements. The BiCMOS fabrication process enables reducing the start-up current to 5uA, and the operating current to 2mA. To further improve power conservation, a large start-up resistance can be used. Built-in synchronized slope compensation ensures the stability of peak current mode control. Proprietary internal compensation provides a constant output power limit over a universal AC input range (90VAC to 264VAC). Pulse-by-pulse current limiting ensures safe operation even during short-circuits. To protect the external power MOSFET from being damaged by supply over voltage, the SG6848’s output driver is clamped at 15V. SG6848 controllers can be used to improve the performance and reduce the production cost of power supplies. The SG6848 is the best choice for replacing linear and RCC-mode power adapters. It is available in 8-pin DIP and 6-pin SOT-26 packages. APPLICATIONS General-purpose switching mode power supplies and flyback power converters, such as Battery chargers for cellular phones, cordless phones, PDAs, digital cameras, and power tools Power adapters for ink jet printers, video game consoles, and portable audio players Open-frame SMPS for TV/DVD standby and other auxiliary supplies, home appliances, and consumer electronics Replacements for linear transformers and RCC SMPS PC 5V standby power. TYPICAL APPLICATION From bridge rectifier 120~ 380VDC From auxiliary winding RIN 1.5M VDD FB C6 472p OUTPUT CIN 10u R7 100 SG6848 SENSE R9 95k RI GND RS 4.7 © System General Corp. Version 1.2(IRO33.0010.B0) -1- www.sg.com.tw May.06, 2003 Product Specification Low Cost Green-Mode PWM Controller for Flyback Converters SG6848 MARKING DIAGRAMS PIN CONFIGURATION SOT-26 MAYWW M: Mask Version Y: Year; WW: Work Week GND FB 1 8 XXXXXXX: Wafer Lot YY: Year; WW: Week V: Assembly Location GATE VDD NC 1 SENSE 1 2 3 4 RI 1 2 3 6 5 4 GATE VDD SENSE DIP-8 8 7 6 5 GND FB NC RI XXXXXXXYYWWV SG6848D ORDERING INFORMATION Part Number SG6848T SG6848D PWM Frequency 70kHz 70kHz Package 6-Pin SOT-26 8-pin DIP-8 PIN DESCRIPTIONS Name GATE VDD NC SENSE Pin No. DIP-8 / (SOT-26) Type Driver Output Supply Function The totem-pole output driver for driving the power MOSFET. Power supply. NC pin. Current sense. This pin senses the voltage across a resistor. When the voltage reaches 1 / (6) 2 / (5) 3 4 / (4) Analog Input the internal threshold, PWM output is disabled. This activates over-current protection. This pin also provides current amplitude information for current-mode control. A resistor connected from the RI pin to ground will generate a constant current source for the SG6848. This current is used to charge an internal capacitor, to determine the switching frequency. Increasing the resistance will reduce the amplitude of the current source and reduce the switching frequency. A 95kΩ resistor Ri results in a 50uA constant current Ii and a 70kHz switching frequency. NC pin. RI 5 / (3) Analog Input/Output NC FB GND 6 7 / (2) 8 / (1) Analog Input Supply Feedback. The FB pin prov...

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