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OB2269 Dataheets PDF



Part Number OB2269
Manufacturers Liteon
Logo Liteon
Description Current Mode PWM Controller
Datasheet OB2269 DatasheetOB2269 Datasheet (PDF)

OB2268 OB2269 Current Mode PWM Controller OB2268/9 is offered in SOP-8 and DIP-8 packages. GENERAL DESCRIPTION OB2268/9 is a highly integrated current mode PWM control IC optimized for high performance, low standby power and cost effective offline flyback converter applications in above 20W power level. PWM switching frequency at normal operation is externally programmable and trimmed to tight range. At no load or light load condition, the IC operates in extended ‘burst mode’ to minimize switch.

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OB2268 OB2269 Current Mode PWM Controller OB2268/9 is offered in SOP-8 and DIP-8 packages. GENERAL DESCRIPTION OB2268/9 is a highly integrated current mode PWM control IC optimized for high performance, low standby power and cost effective offline flyback converter applications in above 20W power level. PWM switching frequency at normal operation is externally programmable and trimmed to tight range. At no load or light load condition, the IC operates in extended ‘burst mode’ to minimize switching loss. Lower standby power and higher conversion efficiency is thus achieved. www.DataSheet4U.com VDD low startup current and low operating current contribute to a reliable power on startup design with OB2268/9. A large value resistor could thus be used in the startup circuit to minimize the standby power. The internal slope compensation improves system large signal stability and reduces the possible subharmonic oscillation at high PWM duty cycle output. Leading-edge blanking on current sense input removes the signal glitch due to snubber circuit diode reverse recovery. and greatly reduces the external component count and system cost in the design. OB2268/9 offers complete protection coverage with automatic self-recovery feature including Cycle-byCycle current limiting (OCP), over load protection (OLP), over temperature protection (OTP), VDD over voltage protection (OVP) and under voltage lockout (UVLO). The Gate-drive output is clamped to maximum 18V to protect the power MOSFET. Excellent EMI performance is achieved with OnBright proprietary frequency shuffling technique (OB2269 only) together with soft switching control at the totem pole gate drive output. The tone energy at below 20KHZ is minimized in operation. Consequently, audio noise performance is greatly improved. FEATURES Extended Burst Mode Control For Improved Efficiency and Minimum Standby Power Design ■ Audio Noise Free Operation ■ External Programmable PWM Switching Frequency ■ Internal Synchronized Slope Compensation ■ Low VIN/VDD Startup Current(4uA) and Low Operating Current (2.3mA) ■ Leading Edge Blanking on Current Sense Input ■ Complete Protection Coverage With Auto SelfRecovery o External Programmable Over Temperature Protection (OTP) o With or Without On-chip VDD OVP for Output Over Voltage Protection. o Under Voltage Lockout with Hysteresis (UVLO) o Gate Output Maximum Voltage Clamp (18V) o Line Compensated Cycle-by-Cycle Overcurrent Threshold Setting For Constant Output Current Limiting Over Universal Input Voltage Range (OCP) o Over Load Protection. (OLP) ■ On-Bright Proprietary Frequency Shuffling Technology for Improved EMI Performance (OB2269 only) ■ APPLICATIONS Offline AC/DC flyback converter for ■ Laptop Power Adaptor ■ PC/TV/Set-Top Box Power Supplies ■ Open-frame SMPS ■ Battery Charger TYPICAL APPLICATION ©On-Bright Electronics A Liteon Semiconductor Company -1- Confidential V2.1 OB2268 OB2269 Current Mode PWM Controller GENERAL INFORMATION Pin Configuration The OB2268/9 is offered in DIP and SOP packages shown as below. Package Dissipation Rating Package DIP8 SOP8 RθJA (°C/W) 90 150 www.DataSheet4U.com Ordering Information Part Number Description OB2268AP No Frequency Shuffling, DIP8, Pb-free OB2268APV No Frequency Shuffling, DIP8, Pb-free and no OVP OB2269CP With Frequency Shuffling, SOP8, Pb-free OB2269CPV With Frequency Shuffling, SOP8, Pb-free and no OVP Absolute Maximum Ratings Parameter Value VDD Input Voltage 36 V VIN Input Voltage 36 V VDD Clamp Continuous Current 10 mA VFB Input Voltage -0.3 to 7V VSENSE Input Voltage to Sense -0.3 to 7V Pin VRT Input Voltage to RT Pin -0.3 to 7V VRI Input Voltage to RI Pin -0.3 to 7V Min/Max Operating Junction -20 to 150 oC Temperature TJ Min/Max Storage Temperature -55 to 150 oC Tstg Note: Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute maximum-rated conditions for extended periods may affect device reliability. ©On-Bright Electronics A Liteon Semiconductor Company -2- Confidential V2.1 OB2268 OB2269 Current Mode PWM Controller Marking Information www.DataSheet4U.com TERMINAL ASSIGNMENTS Pin Num 1 2 3 4 5 6 7 8 Pin Name GND FB VIN RI RT SENSE VDD GATE I/O P I I I I I P O Description Ground Feedback input pin. PWM duty cycle is determined by voltage level into this pin and current-sense signal level at Pin 6. Connected through a large value resistor to rectified line input for Start up chip supply and line voltage sensing. Internal Oscillator frequency setting pin. A resistor connected between RI and GND sets the PWM frequency. Temperature sensing input pin. Connected through a NTC resistor to GND. Once the voltage of the RT pin drops below a fixed limit of 1.05V, PWM output will be disabled. Current sense input pin. Con.


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