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OB2262
GENERAL DESCRIPTION
OB2262 is a highly integrated current mode PWM
control IC optimized for high performance, low
standby power and cost effective offline flyback
converter applications in sub 30W range.
PWM switching frequency at normal operation is
externally programmable and 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.
www.DataSheeVt4DUD.comlow startup current and low operating current
contribute to a reliable power on startup design with
OB2262. A large value resistor could thus be used in
the startup circuit to minimize the standby power.
The internal slope compensation improves system
large signal stability and reduces the possible sub-
harmonic oscillation at high PWM duty cycle output.
Leading-edge blanking on current sense(CS) input
removes the signal glitch due to snubber circuit diode
reverse recovery and thus greatly reduces the external
component count and system cost in the design.
OB2262 offers complete protection coverage with
automatic self-recovery feature including Cycle-by-
Cycle current limiting (OCP), over load protection
(OLP), VDD over voltage clamp and under voltage
lockout (UVLO). The Gate-drive output is clamped
to maximum 18V to protect the power MOSFET.
Excellent EMI performance is achieved soft
switching control at the totem pole gate drive output.
TYPICAL APPLICATION
Current Mode PWM Controller
The tone energy at below 20KHZ is minimized in the
design and audio noise is eliminated during operation.
OB2262 is offered in SOT23-6, SOP-8 and DIP-8
packages.
FEATURES
Extended Burst Mode Control For Improved
Efficiency and Minimum Standby Power Design
Audio Noise Free Operation
External Programmable PWM Switching
Frequency
Internal Synchronized Slope Compensation
Low VDD Startup Current and Low Operating
Current (1.4mA)
Leading Edge Blanking on Current Sense Input
Good Protection Coverage With Auto Self-
Recovery
o VDD Over Voltage Clamp and Under Voltage
Lockout with Hysteresis (UVLO)
o Gate Output Maximum Voltage Clamp (18V)
o On-Bright Proprietary Line Input Compensated
Cycle-by-Cycle Over-current Threshold Setting
For Constant Output Power Limiting Over
Universal Input Voltage Range.
o Overload Protection (OLP).
APPLICATIONS
Offline AC/DC flyback converter for
Battery Charger
Power Adaptor
Set-Top Box Power Supplies
Open-frame SMPS
AC IN
EMI
F i l te r
4
2
+
+
V DD
GATE
OB2262
RI SENSE
FB GND
+ DC OUT
OB431
©On-Bright Electronics
Confidential to Micro Bridge
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OB2262
Current Mode PWM Controller
GENERAL INFORMATION
Pin Configuration
The OB2262 is offered in SOT23-6, DIP8 and SOP8
packages, shown as below.
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Ordering Information
Part Number
Description
OB2262MP
SOT23-6, Pb-free
OB2262AP
DIP8, Pb-free
OB2262CP
SOP8, Pb-free
Package Dissipation Rating
Package
RθJA
DIP8
(°C/W)
90
SOP8
150
SOT23-6
200
Absolute Maximum Ratings
Parameter
Value
VDD DC Supply Voltage 30 V
VDD Zener Clamp
VoltageNote
VDD_Clamp+0.1V
VDD DC Clamp Current 10 mA
VFB Input Voltage
VSENSE Input Voltage to
Sense Pin
-0.3 to 7V
-0.3 to 7V
VRI Input Voltage to RI Pin -0.3 to 7V
Min/Max Operating
-20 to 150 oC
Junction Temperature TJ
Min/Max Storage
-55 to 160 oC
Temperature Tstg
Note: VDD_Clamp has a nominal value of 34V.
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.
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Confidential to Micro Bridge
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Marking Information
OB2262
Current Mode PWM Controller
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TERMINAL ASSIGNMENTS
Pin Name
GND
FB
RI
SENSE
VDD
GATE
I/O Description
P Ground
I Feedback input pin. The PWM duty cycle is determined by voltage level into this pin and
the current-sense signal at Pin 6.
I Internal Oscillator frequency setting pin. A resistor connected between RI and GND sets
the PWM frequency.
I Current sense input pin. Connected to MOSFET current sensing resistor node.
P Chip DC power supply pin.
O Totem-pole gate drive output for the power MOSFET.
RECOMMENDED OPERATING CONDITION
Symbol
VDD
RI
TA
Parameter
VDD Supply Voltage
RI Resistor Value
Operating Ambient Temperature
Min
Max
10 to 30
100
-20 to 85
Unit
V
Kohm
oC
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BLOCK DIAGRAM
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OB2262
Current Mode PWM Controller
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OB2262
Current Mode PWM Controller
ELECTRICAL CHARACTERISTICS
(TA = 25OC if not otherwise noted)
Symbol
Parameter
Test Conditions
Min Typ Max Unit
Supply Voltage (VDD)
I_VDD_Stup VDD Start up Current VDD =12.5V, RI=100K
3 20 uA
Measure Leakage current
into VDD
I_VDD_Ops Operation Current
VDD=16V,
1.4 mA
UVLO(ON)
VDD Under Voltage
RI=100Kohm, VFB=3V
7.8 8.8 9.8 V
Lockout Enter
www.DataSheetU4UV.cLoOm(OFF) VDD Under Voltage
13 14 15 V
Lockout Exit
(Recovery)
VDD_Clamp
VDD Zener Clamp
Voltage
IVDD = 5 mA
34 V
Feedback Input Section(FB Pin)
AVCS
PWM Input Gain
VFB_Open
VFB Open Loop Voltage
IFB_Short
FB pin short circuit
current
VTH_0D
Zero Duty Cycle FB
Threshold Voltage
VTH_PL
Power Limiting FB
Threshold Voltage
TD_PL
Power limiting
Debounce Time
ZFB_IN
Input Impedance
DC_MAX
Maximum Duty Cycle
ΔVFB /ΔVcs
Short FB pin to GND and
measure current
VDD = 16V,
RI=100Kohm
VDD=18V,
RI=100Kohm, FB=3V,
CS=0
2.0 V/V
4.8 V
1.2 mA
0.75 V
3.7 V
35 mSec
6 Kohm
75 %
Current Sense Input(Sense Pin)
T_blanking
Leading edge blanking RI = 100 Kohm
300 ns
time
ZSENSE_IN
TD_OC
Input Impedance
Over Current Detection VDD = 16V,
and Control Delay
CS>VTH_OC, FB=3.3V
40
75
Kohm
nSec
VTH_OC
Over-Current
Threshold Voltage or
FB=3.3V, RI=100 Kohm 0.70 0.75 0.80 V
Equivalent maximum
input voltage at SENSE
Oscillator
FOSC
f_Temp
f_VDD
RI_range
V_RI_open
Fosc_BM
Normal Oscillation
Frequency
Frequency Temperature
Stability
Frequency Voltage
Stability
Operating RI Range
RI open load voltage
Burst Mode Base
Frequency
RI = 100 Kohm
VDD = 16V,
RI=100Kohm, TA -20oC
to 100 oC
VDD = 12-25V,
RI=100Kohm
VDD = 16V, RI =
100Kohm
60
50
65 70 KHZ
5%
5%
100 150 Kohm
2V
22 KHZ
©On-Bright Electronics
Confidential to Micro Bridge
- 5 - OB_DOC_DS_62B5