OB2730 High Frequency Quasi-Resonant(QR) Controller

OB2730 is a highly integrated high frequency Quasi-Resonant(QR) controller with adaptive multi-mode regulation, optimized for high performance, low EMI, low standby power consumption and wide output voltage range PD adapter solutions, together with PD secondary controller, such as OB2613. The controller is as well compatible with cost effective offline flyback converter applications covering a wide output range. With On-Bright proprietary technology, OB2730 operates in QR Valley lockout operation in high line input voltage at normal load condition. To minimize switching loss, the maximum average switching frequency in QR mode is internally limited to 225KHz. As the load decreases, at light load, it operates in Fast frequency decreasing mode with lower frequency for high power conversion efficiency. When the load is very small, the IC operates in ‘Extended Burst Mode’ to minimize the standby power loss. Additionally, in the low line input voltage, the IC operates in fixed frequency (100KHz) CCM mode at the heavy loading. As a result, high conversion efficiency can be achieved in the whole loading range. High voltage startup is implemented in OB2730, which features with short startup time and low standby power loss. OB2730 offers complet e protection including brownout protection, cycle-by-cycle current limiting (OCP), over load protection (OLP), over temperature protection (OTP), output short protection (SCP), output and VDD over voltage protection. Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique. The tone energy at below 22KHz is minimized to avoid audio noise during operation. OB2730 is offered in SOP8 package

Key Features

• ■
• Multi-Mode Operation
• 225KHz max. average frequency
• in QR mode @
• high line
• 100KHz min. average frequency in CCM mode @ low line
• Valley lockout operation @ Green Mode
• Fast frequency decreasing(FFD) @Light load
• Burst Mode @ Deep Light Load & No Load
• Adaptive loop gain compensation with load detection
• Extended burst mode control for improved efficiency and low standby power
• Power on soft start reducing MOSFET Vds stress
• Adaptive frequency shuffling for EMI
• Low operating current at no/light load

Applications

• Offline AC/DC flyback converter for
• ■
• High power density PD adapters
• Wide output ran
• ge adapters

Part Numbers and Specifications

Product family: On-Bright official page