High Precision CC/CV Primary-Side Controller
OB2540
Product Specification
GENERAL DESCRIPTION
OB2540 is a high performance offline PSR
controller for low power AC/DC charger and
adapter applications. It operates in primary-side
sensing
and
regulation.
Consequently,
opto-coupler and TL431 could be eliminated.
Proprietary Constant Voltage (CV) and Constant
Current (CC) control is integrated as shown in the
figure below.
In CC control, the current and output power setting
can be adjusted externally by the sense resistor
Rs at CS pin. In CV control, PFM operations are
utilized to achieve high performance and high
efficiency. In addition, good load regulation is
achieved by the built-in cable drop compensation.
The chip consumes very low operation current
(typical 400uA), it can achieve low standby power
and high efficiency.
OB2540
offers
comprehensive
protection
coverage with auto-recovery features including
Cycle-by-Cycle current limiting, VDD over voltage
protection, feedback loop open protection, short
circuit protection, built-in leading edge blanking,
VDD under voltage lockout (UVLO), etc.
OB2540 is offered in SOT23-6 package.
FEATURES
±5%
Constant Voltage Regulation at
Universal AC input
High precision Constant Current Regulation at
Universal AC input
Primary-side Sensing and Regulation Without
TL431 and Opto-coupler
Programmable CV and CC Regulation
Built-in Primary winding inductance
compensation
Audio Noise Free Operation
Programmable Cable Drop Compensation
Driver BJT Switch
Ultra Low Start-up Current (Typ. 1uA)
VDD Over Voltage Protection
Built-in Feedback Loop Open Protection
Built-in Short Circuit Protection
Built-in Leading Edge Blanking (LEB)
Cycle-by-Cycle Current Limiting
VDD Under Voltage Lockout with Hysteresis
(UVLO)
Figure.1. Typical CC/CV Curve
ig
TYPICAL APPLICATION
ht
C
on
fid
en
tia
lt
APPLICATIONS
N
P
VDD
FB
VC
GND
BASE
CS
R
S
Low Power AC/DC offline SMPS for
Cell Phone Charger
Digital Cameras Charger
Small Power Adapter
Auxiliary Power for PC, TV etc.
Linear Regulator/RCC Replacement
o
Br
O
n-
~
AC
+
+
+
N
AUX
©On-Bright Electronics
Confidential
-1-
奥
海
N
S
+ C
O
V
O
Preliminary Datasheet
OB_DOC_DS_254001
High Precision CC/CV Primary-Side Controller
OB2540
GENERAL INFORMATION
Pin Configuration
The pin map is shown as below for SOT23-6.
Package Dissipation Rating
Package
RθJA (℃/W)
SOT23-6
200
.
VC
1
6
VDD
CS
2
5
GND
en
tia
lt
Confidential
-2-
Ordering Information
Part Number
Description
OB2540MP
SOT23-6, Pb-free, T&R
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.
O
n-
©On-Bright Electronics
Br
ig
ht
C
on
fid
o
BASE
3
4
FB
Absolute Maximum Ratings
Parameter
VDD Voltage
VC Voltage
BASE Voltage
CS Input Voltage
FB Input Voltage
Min/Max Operating
Junction Temperature T
J
Min/Max Storage
Temperature T
stg
Lead Temperature
(Soldering, 10secs)
奥
海
-40 to 150
℃
-55 to 150
℃
260
℃
Preliminary Datasheet
OB_DOC_DS_254001
Value
-0.3 to 30V
-0.3 to 7V
-0.3 to 7V
-0.3 to 7V
-0.3 to 7V
High Precision CC/CV Primary-Side Controller
OB2540
ELECTRICAL CHARACTERISTICS
(TA = 25℃, VDD=15V, if not otherwise noted)
Symbol
Parameter
Supply Voltage (VDD) Section
I start-up
I static
UVLO(OFF)
UVLO(ON)
VDD_OVP
Max. Operating
Voltage
Current Sense Input Section
TLEB
Vth_ocp
Td_oc
Ics_max
LEB time
Over current threshold
OCP propagation delay
Start up current
Static current
VDD under voltage lockout exit
VDD under voltage lockout enter
VDD over voltage protection
VDD=11V
VDD=15V
11.5
25
1
400
3
500
uA
uA
Test Conditions
Min
Typ
Max Unit
en
tia
lt
485
From ocp comparator to
base drive
41
1.98
575
20
0.5
-5-
o
0.5
500
100
45
49
515
uS
mV
nS
uA
Maximum source current to CS
pin
Reference voltage for feedback
threshold
FB Input Section
Vref_fb
Tpause_min
Tpause_max
Icable
Maximum
current
fid
on
C
Maximum pause
cable
compensation
BASE Drive Section
Is_max
Is_preoff
Rdson_l
ig
Base sourcing maximum current
Base sourcing current after pre-off
ht
Br
Base drive low side on resistor
O
n-
©On-Bright Electronics
Confidential
奥
海
6.0
6.8
27
7.6
29
25
2.0
640
27
705
30
1
1
40
1.5
12.5 13.5 V
V
V
V
2.00 2.02 V
uS
uS
uA
mA
mA
ohm
Preliminary Datasheet
OB_DOC_DS_254001
工作这点儿事
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
