OB5282A

GENERAL DESCRIPTION

OB5282A is a highly integrated current mode PWM control IC with high voltage startup, optimized for high performance, low standby power consumption and cost effective offline flyback converter applications. The controller ‘s HV pin is used for high voltage startup, AC off detection, and X-cap Voltage discharge , this structure allows the brownout detection as well.

At full loading, the IC operates in fixed frequency (65KHz) mode. When the loading goes low, it operates in Green mode with valley switching for high power conversion efficiency. When the load is very small, the IC operates in ‘Extended Burst Mode’ to minimize the standby power loss. As a result, high conversion efficiency can be achieved in the whole loading range.

High voltage startup is implemented in OB5282A, which features with short startup time and low standby power loss.

OB5282A offers complete protection coverage including cycle-by-cycle current limiting (OCP), over load protection (OLP), over temperature protection (OTP), output and VDD over voltage protection. Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique.

The tone energy at below 25KHz is minimized to avoid audio noise during operation.

OB5282A is offered in SOP8 package.

FEATURES

■ High voltage startup

■ Power on soft start reducing MOSFET Vds stress

■ Frequency shuffling for EMI

■ Multi-Mode Operation

125KHz max frequency mode @ Peak Load

65KHz fix frequency mode @ Full Load

Valley switching operation @ Green mode

Burst Mode @ Light Load & No Load

■ Audio noise free operation

■ Peak power delivery for peak load

■ Tighten and programmable output over current protection

■ Comprehensive protection coverage

o VDD under voltage lockout with hysteresis (UVLO)

o Cycle-by-cycle over current protection (OCP) with auto-recovery

o Overload protection (OLP) with auto-recovery

o Over temperature protection (OTP) with auto-recovery

o VDD over voltage protection with auto-recovery

o Output over voltage protection with auto-recovery

o Brownout protection with auto-recovery

o Output diode short protection with auto-recovery

■ Intelligent AC off detection with X-CAP discharge function

APPLICATIONS

Offline AC/DC flyback converter for

■ Power adaptor

■ Open-frame SMPS

■ PK Load Application

TYPICAL APPLICATION