OB2338
High Performance Current Mode PWM Power Switch
GENERAL DESCRIPTION
OB2338 combines a dedicated current mode
PWM controller with a high voltage power
MOSFET. It is optimized for high performance, low
standby power, and cost effective off-line flyback
converter applications in sub 27W range.
OB2338 offers complete protection coverage with
automatic self-recovery feature including Cycle-
by-Cycle current limiting (OCP), over load
protection (OLP), over temperature protection
(OTP), over voltage protection and VDD under
voltage lockout (UVLO).
Excellent EMI
performance is achieved with On-Bright
proprietary frequency shuffling technique together
with soft switching control at the totem pole gate
drive output.
The tone energy at below 20KHZ is minimized in
the design and audio noise is eliminated during
operation.
OB2338 is offered in DIP8 package.
APPLICATIONS
Offline AC/DC flyback converter for
■ AC/DC adapter
■ PDA power supplies
■ Digital Cameras and Camcorder Adapter
■ VCR, SVR, STB, DVD&DVCD Player SMPS
■ Set-Top Box Power
■ Auxiliary Power Supply for PC and Server
■ Open-frame SMPS
TYPICAL APPLICATION
FEATURES
■ Level 5 compliance with < 100mW 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 minimum standby power design
■ Audio noise free operation
■ Fixed 55KHZ (typical) switching frequency
■ Internal synchronized slope compensation
■ Low VDD startup current and low operating
current
■ Leading edge blanking on current sense input
■ Comprehensive protection coverage
o VDD under voltage lockout with hysteresis
(UVLO)
o Over temperature protection (OTP) with
auto- recovery
o On-Bright proprietary line input
compensated
o Cycle-by-Cycle over-current threshold
setting for constant output power limiting
over universal input voltage range.
o Accurate Overload protection (OLP).
o Over voltage protection(OVP)
o Secondary Rectifier Short Protection
Output Power Table
Product
OB2338
230VAC±15%
Open Frame1
27W
85-265VAC
Open Frame1
16W
Notes: 1. Maximum practical continuous power in an open frame design with sufficient drain pattern as a heat sink, at 50℃
ambient. Higher output power is possible with extra added heat sink or air circulation to reduce thermal resistance.
©On-Bright Electronics
Confidential
-1-
Preliminary Datasheet
OB_DOC_DS_233801
