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OB2283
High Performance Current Mode PWM Controller
GENERAL DESCRIPTION
OB2283 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 OB2283.
OB2283 offers comprehensive protection
coverage with auto-recovery including Cycle-by-
Cycle current limiting (OCP), over load protection
(OLP), and VCC under voltage lockout (UVLO). It
also provides the protections with latched shut
down including 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 25KHz is minimized in
the design and audio noise is eliminated during
operation.
OB2283 is offered in SOT23-6 package.
APPLICATIONS
Offline AC/DC flyback converter for
Printer, Storage power supply
Power Adapter
FEATURES
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
Peak load operation with increased 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 External (if NTC resistor is connected at
PRT pin)or internal Over Temperature
Protection (OTP) with latched shut down
o Output Over Voltage Protection(Output
OVP) with latched shut down, and the
OVP triggered voltage can be adjusted by
the resistor connected between auxiliary
winding and PRT pin
o Output diode short protection with auto-
recovery
o GND open protection with auto-recovery
TYPICAL APPLICATION
AC IN
EMI
Filter
OB2283
6 FB VCC 1
5 PRT
CS 2
4 GND GATE 3
Vaux
DC
Out
©On-Bright Electronics
Confidential
-1-
Preliminary Datasheet
OB_DOC_DS_228300

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OB2283
High Performance Current Mode PWM Controller
GENERAL INFORMATION
Pin Configuration
VCC
CS
Gate
1
2
3
6 FB
5 PRT
4 GND
Ordering Information
Part Number
OB2283MP
Description
SOT23-6, Pb-free in T&R
Package Dissipation Rating
Package
RJA(/W)
SOT23-6
200
Recommended operating condition
Symbol Parameter
Range
VCC
VCC Supply Voltage 12 to 28V
TA
Operating Ambient
Temperature
-20 to 85
Absolute Maximum Ratings
Parameter
Value
VCC DC Supply Voltage
FB Input Voltage
VOVP-1V
-0.3 to 7V
CS Input Voltage
-0.3 to 7V
PRT Input Voltage
-0.3 to 7V
Min/Max Operating
Junction Temperature TJ
-40 to 150
Min/Max Storage
Temperature Tstg
-55 to 150
Lead
Temperature
(Soldering, 10secs)
260
Note: Stresses beyond those listed under “absolute
maximum ratings” may cause permanent damage to the device.
These are stress ratings only, functional operation of the device
at these or any other conditions beyond those indicated under
“recommended operating conditions” is not implied. Exposure
to absolute maximum-rated conditions for extended periods
may affect device reliability.
OB2283 X
X
High Performance Current Mode PWM
Controller
Package
Package Pb-free
M:SOT23-6 P:Pb-free
Marking Information
83YWW S
. ZZZ
©On-Bright Electronics
Y:Year Code
WW:Week Code(01-52)
s: Internal code
ZZZ: Lot code
Confidential
-2-
Preliminary Datasheet
OB_DOC_DS_228300

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OB2283
High Performance Current Mode PWM Controller
TERMINAL ASSIGNMENTS
Pin Name
VCC
CS
Gate
GND
PRT
FB
I/O Description
P Power Supply
I Current sense input
O Totem-pole gate driver output for power MOSFET
P Ground
Dual functions pin. Connecting a NTC resistor to ground for OTP detection.
I
Connecting a resistor from Vaux can adjust OVP trigger voltage. If both OTP and
OVP are needed, a diode should be connected between PRT pin and the NTC
resistor.
I
Feedback input pin. The PWM duty cycle is determined by voltage level into this pin
and the current-sense signal at Pin CS.
©On-Bright Electronics
Confidential
-3-
Preliminary Datasheet
OB_DOC_DS_228300

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FUNCTIONAL BLOCK DIAGRAM
OB2283
High Performance Current Mode PWM Controller
OVP
OVP
SQ
R
Logic
Control
Soft Driver
UVLO
Vref&
Iref
GND
open
Temp
sense
EX OTP
AVDD
Internal
blocks
OSC
Diode
short
OLP
OCP
Comparator
PK/Green/
Burst
PWM
Comparator
Timer
OTP
OVP
Latch
EX OVP
Diode
short
Diode
short
compSelonpseation
Vocp
OLP
LEB
AVDD
©On-Bright Electronics
Confidential
-4-
Preliminary Datasheet
OB_DOC_DS_228300

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OB2283
High Performance Current Mode PWM Controller
ELECTRICAL CHARACTERISTICS
(TA = 25, VCC=18V, unless otherwise noted)
Symbol
Parameter
Test Conditions
Min Typ Max
Supply Voltage (VDD)
Istartup
VCC Start up Current
VCC=UVLO(OFF)-1V,
measure
leakage
current into VCC
I_VCC_Operation Operation Current
VDD=18V,CS=4V,
FB=3.5V,measure
I(VCC)
I_VCC_Burst
Burst Current
CS=0V,FB=0.5V,
measure I(VCC)
UVLO(ON)
VCC Under Voltage Lockout
Enter
7
UVLO(OFF)
VCC Under Voltage Lockout
Exit (Recovery)
19
Vpull-up
Pull-up PMOS active
OVP
VCC Over Voltage
threshold voltage
Protection
FB=3V,CS=0V. Slowly
ramp VCC, until no
gate switching.
29
Vlatch_release
Latch release voltage
3 10
2.5 3
0.55 0.65
89
21 23
10
30 31
5
Feedback Input Section(FB Pin)
VFB_Open
VFB Open Loop Voltage
Avcs
PWM input gain VFB/VCS
Maximum
cycle
duty Max duty cycle @
VCC=18V,VFB=3V,VCS=0V
75
Vref_green
The threshold enter green mode
Vref_burst_H
The threshold exits burst mode
Vref_burst_L
The threshold enters burst
mode
IFB_Short
FB pin short circuit current
Short FB pin to GND
and measure current
VTH_OLP
Open loop protection, FB
Threshold Voltage
Td_OLP
Open loop protection,
Debounce Time
ZFB_IN
Input Impedance
Current Sense Input(CS Pin)
SST_CS
Soft start time for CS peak
T_blanking
Leading edge blanking time
Td_OC
Over Current
Control Delay
Detection
From Over Current
and Occurs till the Gate
driver output start to
turn off
VTH_OC
Internal Current Limiting
Threshold Voltage with zero
duty cycle
0.43
VTH_OC_Clamp OCP CS voltage clamper
5.1
3.5
78
1.85
1.33
1.23
0.3
4.4
15
16
4
250
90
0.45
0.69
81
0.47
Vdiode_scp
Diode short protection voltage
1.4
Unit
uA
mA
mA
V
V
V
V
V
V
V/V
%
V
V
V
mA
V
ms
Kohm
ms
ns
ns
V
V
V
Td_dio
Diode short debounce time
8 Cycles
©On-Bright Electronics
Confidential
-5-
Preliminary Datasheet
OB_DOC_DS_228300