OB2203
Quasi-Resonant Flyback PWM Controller
GENERAL DESCRIPTION
OB2203 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 is achieved.
A built-in P-channel MOSFET and its control are
integrated to automatically turn on or off PFC stage
according to the load conditions. When used with
OB6563 (On-Bright’s PFC controller), the standby
power consumption of less than 400mW can be
achieved in typical 150W SMPS.
OB2203 offers comprehensive protection coverage
including Cycle-by-Cycle Current Limiting(OCP),
VCC Under Voltage Lockout(UVLO), Over Voltage
Protection(OVP), VCC Clamp, Gate Clamp, Over
Load Protection(OLP), On-chip Thermal Shutdown,
Programmable Soft Start, and External Latch
Triggering, Max On-time Limit, etc.
OB2203 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
■ Burst Mode at No Load
■ Direct Control of the Power Supply of PFC
Controller for Improved Standby Power at
No/Light Load
■ 40KHz Minimum Frequency Limit at QR Mode
■ 130KHz Maximum Frequency Limit
■ Internal Minimum T_off for Ringing Suppression
■ 45us Maximum On Time Limit
■ Adaptive Slope Compensation
■ Internal Leading Edge Blanking
■ Programmable Soft-start
■ External Latch Triggering
■ Internal Temperature Shutdown
■ 1A Peak Current Sink/Source Capability
■ Programmable Over Voltage Protection (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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