OB2736 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 GaN FETs 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, OB2736 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 OB2736, which features with short startup time and low standby power loss.
OB2736 offers complete 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.
OB2736 is offered in SOP8 package.
■ 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
■ Precise low voltage gate clamping to drive GaN Power FETs
■ 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
■ Audio noise free operation
■ High voltage startup integrating intelligent brownout detection, AC off detection with X-CAP discharge function
■ Comprehensive auto-recovery protection
o VDD under voltage lockout with hysteresis (UVLO)
o Cycle-by-cycle over current protection (OCP)
o Overload protection (OLP)
o Over temperature protection (OTP)
o VDD over voltage protection
o Output over voltage protection
o Output short protection (SCP)
o Brownout protection
o Output diode short protection
Offline AC/DC flyback converter for
■ High power density GaN FETs PD adapters