High Precision CC/CV Primary-Side Power Switch
OB2500P
GENERAL DESCRIPTION
OB2500P is a high performance offline PSR power
switch 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, multi-mode operations
are utilized to achieve high performance and high
efficiency. In addition, good load regulation is
achieved by the built-in cable drop compensation.
Device operates in PFM in CC mode at large load
condition and it operates in PWM with frequency
reduction at light/medium load. The chip
consumes very low operation current. It achieves
less than 75mW standby power to meet strict
standby power standard.
OB2500P offers comprehensive protection
coverage with auto-recovery feature 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), OTP etc.
OB2500P is offered in SOP7 packages.
FEATURES
Primary-side sensing and regulation without
TL431 and opto-coupler
High precision constant voltage and current
regulation at universal AC input
Multi-mode PWM/PFM operation for efficiency
improving
Integrated 2A 650V MOSFET
Good dynamic response
Programmable CV and CC regulation
Built-in primary winding inductance
compensation
Programmable cable drop compensation
No need for control loop compensation
Audio noise free operation
Built-in leading edge blanking (LEB)
Ultra low start-up current and low operating
current
Comprehensive protection coverage with
auto-recovery
On-chip OTP and external OTP
VDD over voltage protection
VDD under voltage lockout with
hysteresis (UVLO)
Cycle-by-Cycle current limiting
Feedback loop open protection
Output short circuit protection
nf
Figure.1. Typical CC/CV Curve
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TYPICAL APPLICATION
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APPLICATIONS
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
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Datasheet
OB_DOC_DS_2500PA1
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High Precision CC/CV Primary-Side Power Switch
OB2500P
GENERAL INFORMATION
Pin Configuration
The pin map is shown as below for SOP7.
Absolute Maximum Ratings
Parameter
Drain Voltage (off state)
VDD Voltage
FB Input Voltage
CS Input Voltage
Min/Max Operating Junction
Temperature T
J
Operating
Ambient
Temperature T
A
Min/Max
Storage
Temperature T
stg
Lead
Temperature
(Soldering, 10secs)
Value
-0.3V to Bvdss
-0.3 to 28V
-0.3 to 7V
-0.3 to 7V
-40 to 150
℃
-40 to 85
℃
High Precision CC/CV Primary-Side PWM
Power Switch
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OB2500P
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X
X
X
Package
C:SOP7
Package Pb free
P:Pb-free
Packing
Blank:Tube
A: Tape/Reel
Recommended Operating Condition
Symbol
Parameter
Range
VDD
VDD Supply Voltage
8 to 25V
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Package Dissipation Rating
Package
RθJA (℃/W)
SOP7
95
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.
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Ordering Information
Part Number
Description
OB2500PCP
SOP7, Pb-free, Tube
OB2500PCPA
SOP7, Pb-free in T&R
乙
-55 to 150
℃
260
℃
Datasheet
OB_DOC_DS_2500PA1
辰
High Precision CC/CV Primary-Side Power Switch
OB2500P
ELECTRICAL CHARACTERISTICS
(TA = 25℃, VDD=15V, if not otherwise noted)
Symbol
Parameter
Supply Voltage (VDD) Section
I start-up
Start up current
I static
UVLO(OFF)
UVLO(ON)
Static current
VDD under voltage lockout exit
VDD under voltage lockout
enter
VDD over voltage protection
16.0
6.5
26.0
Test Conditions
VDD=UVLO_OFF-1V
Min
Typ.
5
0.85
18.2
7.0
27.0
1.0
20.5
7.5
Max
Unit
uA
mA
V
O
VDD_OVP
Max. Operating
Voltage
Current Sense Input Section
TLEB
LEB time
Vth_ocp_min
Minimum over current threshold
Maximum
over
current
Vth_ocp_max
threshold
FB Input Section
Reference voltage for feedback
Vref_FB
threshold
Tpause_min
Minimum Toff
F_min
Minimum frequency
F_max
Maximum frequency
Maximum cable compensation
Icomp_cable
current
Vth_cc_shutdown CC mode shut down threshold
Td_cc_shutdown CC mode shut down debounce
Output Over Voltage Protection
V_OVP
Output Over voltage threshold
RT Section
I_otp
RT pin source current
Over
temperature
trigger
V_otp
voltage
MOSFET Section
Mosfet
Drain-Source
BVdss
Breakdown Voltage
Static drain to source on
Rdson
resistance
乙
300
500
590
2.0
780
45
1.55
3.0
72
1.0
4
to
485
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700
90
40
1024
2.85
650
2.475 2.500 2.525 V
860
50
2048
3.15
us
Hz
KHz
uA
V
cycle
V
uA
V
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©On-Bright Electronics
Confidential
Datasheet
OB_DOC_DS_2500PA1
辰
V
28.5
25
V
V
ns
mV
mV
515
V
Ώ
单片机
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