OB2212

OB2211/OB2212 Primary-Side Regulation PWM Power Switch GENERAL DESCRIPTION OB2211/OB2212 is an offline PWM Power switch for low power AC/DC charger and adaptor applications. It operates in primary-side sensing and regulation. Consequently, opto-coupler and TL431 could be eliminated from design. Proprietary Constant Voltage (CV) and Constant Current (CC) control is integrated as shown in the figure below. In CC control, the current and output power setting can be adjusted externally by the sense resistor Rs at CS pin. In CV control, multi-mode operations are utilized to achieve high performance and high efficiency. Device operates in fixed frequency mode at large load conditions, frequency reduction mode at light/medium load and ‘Extended burst mode’ at No/light load conditions. OB2211/OB2212 offers power on soft start control and complete protection coverage with auto-recovery features including Cycle-by-Cycle current limiting, VDD over-voltage clamp and UVLO, fail-safe protection for open loop fault condition. Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique together with soft switching control at the totem pole gate drive output with No-Y cap design. FEATURES „ Primary-side Sensing and Regulation With No TL431 and Opto-coupler „ Multi-mode Operation for High Efficiency „ Programmable CV and CC Regulation „ Adjustable Constant Current and Output Power setting „ Frequency Shuffling and Adjustable Gate Drive Greatly Improving EMI ...