OB2277C

GENERAL DESCRIPTION

OB2277C is a highly integrated current mode PWM control IC optimized for high performance, low standby power and cost effective offline flyback converter applications.

PWM switching frequency at normal operation is internally fixed and is 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.

VCC low startup current and low operating current contribute to a reliable power on startup and low standby design with OB2277C.

OB2277C offers comprehensive protection coverage with auto-recovery including Cycle-by-Cycle current limiting (OCP), over load protection (OLP), VCC under voltage lockout (UVLO), over temperature protection (OTP), and over voltage protection (OVP).  Excellent EMI performance is achieved with On-Bright proprietary frequency shuffling technique.

The tone energy at below 23KHz is minimized in the design and audio noise is eliminated during operation.

OB2277C is offered in SOT23-6 package.

FEATURES

■   Level 6 compliance with<75mW standby power at universal AC input.

■   Power on soft start reducing MOSFET Vds stress

■   Frequency shuffling for EMI

■   Extended burst mode control for improved efficiency and low standby power design

■   Audio noise free operation

■   Forced pulse generation

■   Fixed 65KHz (typical) switching frequency

■   Comprehensive protection coverage

o    VCC Under Voltage Lockout with hysteresis (UVLO)   

o    VCC Over Voltage Protection (VCC OVP)  

o    Cycle-by-cycle over current threshold setting for constant output power limiting over universal input voltage range

o    Over Load Protection (OLP) with auto-recovery

o    Brownout protection with auto-recovery

o    Output diode short protection with auto-recovery

 

APPLICATIONS

Offline AC/DC flyback converter for

■   General power supply

■   Power Adapter

TYPICAL APPLICATION