Maker : ETC
Part No. : SG6846A

  Datasheet PDF : SG6846A.pdf
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Product Information

Product Specification Highly Integrated Green-Mode PWM Controller SG6846A consumption, a proprietary green-mode function provides off-time modulation to continuously decrease the switching frequency under light-load conditions. Under zero-load conditions, the power supply enters burst-mode. The SG6846A is especially designed for SMPS with surge-current output, incorporated with a two-level OCP function. Besides the cycle-by-cycle current limiting, if the switching current is higher than two thirds the peak-current threshold for 1700ms, over-current protection is activated and the SG6846A latches off. If the switching current is higher than two thirds the peak-current threshold for 100ms and the voltage on the VDD pin is higher than VDD-OFF + 1V, the PWM pulses are latched off immediately once VDD voltage is lower than VDD-OFF + 1V; useful if an output short-circuit occurs. SG6846A also integrates a frequency hopping function that reduces EMI emission of a power supply with minimum line filters. Its built-in synchronized slope compensation provides proprietary internal compensation for constant output power limit over a universal AC input range. Also, the gate output is clamped at 18V to protect the external MOSFET from over-voltage damage. Internal soft-start is built-in to reduce stress on the MOSFET and start-up current during power-on period. Other protection functions include: AC input brownout protection with hysteresis, VDD over-voltage protection, and over-temperature protection. For over-temperature protection, an external NTC thermistor can be applied to sense the ambient temperature. When OCP, VDD OVP, or OTP are activated, an internal latch circuit is used to latch-off the controller. The PWM pulses stay latched off until the power supply is unplugged from the main outlet. SG6846A is available in an 8-pin SOP package. FEATURES Two-level OCP with 1700ms delay time Output short-circuited delay time: 100ms Low start-up current (8µA) Low operating current (3.7mA) Peak-current mode operation with cycle-by-cycle current limiting www.DataSheet4U.com Programmable PWM frequency with frequency hopping PWM frequency continuously decreasing with burst mode at light loads VDD over-voltage protection (OVP) AC input brownout protection with hysteresis and constant output power limit Constant output power limit (full AC input range) Internal latch circuit for OVP, OTP, and OCP Built-in soft-start Open-loop protection with 1700ms delay time APPLICATIONS General-purpose switch-mode power flyback power converters, including: Power adapters Open-frame SMPS Specifically fit for SMPS with surge-current output (such as for printers, scanners, motor drivers, etc.) supplies and DESCRIPTION The highly integrated SG6846A series of PWM controllers provides features to enhance the performance of flyback converters. To minimize standby power TYPICAL APPLICATION © System General Corp. Version 1.1.1 (IAO33.0059.B1) -1- www.sg.com.tw • www.fairchildsemi.com September 26, 2007 Product Specification Highly Integrated Green-Mode PWM Controller SG6846A PIN CONFIGURATION MARKING DIAGRAMS F: L=OCP Latch, C=OCP auto-recovery T: S=SOP P : Z=Lead Free Null=regular package XXXXXXXX: Wafer Lot Y: Year; WW: Week V: Assembly Location GND FB VIN RI GATE VDD SENSE RT SG6846AFTP XXXXXXXXYWWV www.DataSheet4U.com ORDERING INFORMATION Part Number SG6846ALSZ SG6846ACSZ (Preliminary) OCP Latch Yes No Pb-Free Package 8-Pin SOP 8-Pin SOP PIN DESCRIPTIONS Pin No. Symbol 1 2 GND FB Function Ground Feedback Line-voltage Detection Reference Setting Temperature Detection Description Ground. The signal from the external compensation circuit is fed into this pin. The PWM duty cycle is determined in response to the signal from this pin and the current-sense signal from Pin 6. Line-voltage detection. The line-voltage detection is used for brownout protection with hysteresis. Constant output power limit over a universal AC input range is also achieved us...

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