OB2202
Quasi-Resonant Flyback PWM Controller
GENERAL DESCRIPTION
OB2202 is a highly integrated Quasi-Resonant (QR)
controller optimized for high performance offline
flyback converter applications.
At normal load condition, it operates in QR mode
with minimum drain voltage switching. To meet the
CISPR-22 EMI starting at 150KHz, the maximum
switching frequency is internally limited to 130KHz.
It operates in PFM mode for high power conversion
efficiency at light load condition. When the loading is
very small, the IC operates in ‘Extended Burst Mode’
to minimize the switching loss. As a result, lower
standby power consumption and higher conversion
efficiency can be achieved.
OB2202 offers comprehensive protection coverage
including Cycle-by-Cycle Current Limiting, VCC
Under Voltage Lockout(UVLO), Programmable
Output Over Voltage Protection(OVP), VCC Clamp,
Gate Clamp, Over Load Protection(OLP), On-chip
Thermal Shutdown, Programmable Soft Start,
Programmable Brownout Protection, Programmable
Over Power Protection (OPP) Compensation, and
External Latch Triggering, Max On-time Limit, etc.
OB2202 is offered in SOP-8 and DIP-8 packages.
FEATURES
■ Multi-Mode Operation
■ Quasi-Resonant Operation at Normal Loading
■ Pulse Frequency Modulation (PFM) Operation at
Light Load
■ Programmable Brownout Protection and Line
OVP Protection
■ Burst Mode at No Load
■ Excellent OPP Compensation
■ 20KHz Minimum Frequency Limit at QR Mode
■ 130KHz Maximum Frequency Limit
■ Internal Minimum T_off for Ringing Suppression
■ 35us Maximum On Time Limit
■ 50us Maximum Off Time Limit
■ Internal Leading Edge Blanking
■ Programmable Soft-start
■ Cycle-by-cycle Current Limiting
■ External Latch Triggering
■ Internal Thermal Shutdown
■ 1A Peak Current Sink/Source Capability
■ Programmable Output OVP
APPLICATIONS
Offline AC/DC flyback converter for
■ Power Adaptor and Open-frame SMPS
■ LCD Monitor/TV/PC/Set-Top Box Power
Supplies
■ NB/DVD/Portable DVD Power Supplies
TYPICAL APPLICATION
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