High Performance synchronous rectification controller
OB2301
GENERAL DESCRIPTION
OB2301 is a high performance and tightly
integrated
secondary
side
synchronous
rectification controller and driver used for
secondary side rectification in switch mode power
supply system. It drivers a much lower voltage
drop N-channel MOSFET to emulate the
traditional diode rectifier at the secondary side of
Flyback converter, which can reduce heat
dissipation, increases output current capability and
efficiency, and simplify thermal design. OB2301
can support low system output voltage down to 2V
at constant current mode.
It is suitable for multiple mode applications
including discontinuous conduction mode and
quasi-resonant mode. With its versatility and
optimization, OB2301 can be used in various
switch mode power supply topologies including
secondary-side control topology and primary-side
control topology.
From the information on the secondary side of the
isolation transformer, OB2301 generates a driving
signal with dead time with respect to the primary
side PWM signal to turn the integrated N-channel
SR switch on and off in proximity of the zero
current transition with the help of smart driver
voltage control. It is optimized for 5V output
voltage. In primary-side control topology, OB2301
can detect the output voltage and feed back a
series of warning pulses to primary side controller
when the output voltage is lower than an inner-
determined threshold to awaken the primary-side
power switch to improve dynamic response.
The externally adjustable minimum on time and
property off time control scheme effectively avoid
the ring impact induced by parasitic elements so
that a reliable and noise free operation of the SR
system is insured.
OB2301 is offered in SOT23-6 package.
FEATURES
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TYPICAL APPLICATION
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Secondary-side synchronous rectification
controller optimized for 5V output system
Suitable for DCM, QR operation
Accurate secondary side MOSFET Vds
sensing
Low cost small size CC/CV mode support
Up to 200kHz operation frequency
3A/2A peak current sink/source driver
capability
Output voltage over-shoot and under-shoot
control
Enhanced dynamic response with firing
warning pulses scheme
VDD UVLO protection
APPLICATIONS
AC/DC 5V adaptors
Cell phone charger
5V Bias supply
Low voltage rectification circuits
ia
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Preliminary Datasheet
OB_DOC_DS_2301A1-06
同
维
OB2301
High Performance synchronous rectification controller
W
GENERAL INFORMATION
Pin Configuration
The OB2301 is offered in SOT23-6 package,
shown as below.
SOT23-6
Absolute Maximum Ratings
Parameter
Value
Vin pin
-0.6V to 7V
VDD pin
-0.6V to 7V
VD pin
-2.5V to 50V
Note2
Gate pin
-0.6V to 7V
RT pin
-0.6V to 7V
Min/Max
Operating
-40 to 150
℃
Junction Temperature TJ
Operating
Ambient
-20 to 85
℃
Temperature T
A
Min/Max
Storage
-55 to 150
℃
Temperature Tstg
Lead
Temperature
260
℃
(Soldering, 10secs)
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Package Dissipation Rating
Package
RJA(℃/W)
SOT23-6
200
OB2301
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High Performance Synchronous
Rectifier Controller
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Package
M:SOT23-6
Ordering Information
Part Number
Description
OB2301MP
SOT23-6, Pb-free in T&R
Note1:
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.
Note2:
-2.5V applies to minimum duty cycle during normal
operation only.
Recommended Operating Range
Symbol Parameter
Min/Max
VDD
VDD Supply Voltage
4V to 5.5V
ia
P:Pb-free
Package Pb-free
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Preliminary Datasheet
OB_DOC_DS_2301A1-06
同
维
OB2301
High Performance synchronous rectification controller
W
ELECTRICAL CHARACTERISTICS
(T
A
= 25℃, VDD=5V, unless otherwise noted)
Symbol
Parameter
Test Conditions
Frequency@Vd=65KHz,VD
D=5V,1nF Cap load at
GATE.
Frequency@Vd=2KHz,VDD
=5V,No load at GATE.
Min Typ Max Unit
Supply Voltage (VDD)
1.5
0.5
4.2
I_Vdd_operation
Operation current
nf
id
Minimum
Vdd
regulation
voltage
VDD Under Voltage Lockout
UVLO(ON)
Entry
VDD Under Voltage Lockout
UVLO(OFF)
Exit (Recovery)
VD Detection Section
SR MOSFET turn on threshold
Vth_SR_act
voltage detection at VD
SR MOSFET turn off threshold
Vth_SR_deact
voltage detection at Vd
SR
MOSFET
turn-on
Tdelay_on
propagation delay
SR
MOSFET
turn-off
Tdelay_off
propagation delay
Vdd_regulation_mini
T_minimum_on
RT Section
Vrt
同
2.8 3.0
2.9 3.1
-200
-5
1.9
0.95 1
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SR MOSFET minimum on time RT=25KΩ
Voltage reference at RT pin
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Over/Under Shoot Control Section
Output delta variation in system
Vo_delta
output undershoot control
Output delta variation detection
Vo_delta_enb
enable voltage
Output delta variation detection
Fsample
Sample frequency
System output undershoot
Vo_low_clamp
clamp control trigger voltage
System output 1st overshoot
clamp control trigger voltage at
Vo_High_clamp_1
st
Vin with SR frequency lower
than 7.5KHz
System output 2
nd
overshoot
Vo_High_clamp_2
nd
clamp control trigger voltage at
Vin
System output overshoot clamp
IVo_High_clamp
current
Ivd_pulse
Warning current pulse peak
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4.5 4.6
4.7
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6.15
100
150
©On-Bright Electronics
Confidential
Preliminary Datasheet
OB_DOC_DS_2301A1-06
维
2.0 mA
0.7 mA
V
3.2 V
3.3 V
mV
mV
100 ns
75
ns
Us
1.05
V
mV
V
KHz
V
V
V
mA
mA
ARM技术
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