OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
FEATURES
OB2513x 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 as well at
large load condition and it operates in PWM with
frequency reduction at light/medium load. The chip
consumes very low operation current, it can
achieve less than 75mW standby power.
OB2513x offers comprehensive protection
coverage with auto-recovery features including
Cycle-by-Cycle current limiting, VDD over voltage
protection, short circuit protection, built-in leading
edge blanking, VDD under voltage lockout (UVLO),
OTP etc.
OB2513x is offered in SOP7 package.
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
Good dynamic response
Programmable CV and CC regulation
Built-in line voltage and primary winding
inductance compensation
Programmable cable drop compensation
No need for control loop compensation
Audio noise free operation
Internal BJT switch
Built-in leading edge blanking (LEB)
Comprehensive protection coverage with
auto-recovery
VDD over voltage protection
VDD under voltage lockout with
hysteresis (UVLO)
Cycle-by-cycle current limiting
Feedback loop open protection
Output short circuit protection
Over temperature protection (OTP)
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GENERAL DESCRIPTION
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APPLICATIONS
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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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Figure.1. Typical CC/CV Curve
TYPICAL APPLICATION
VO
NS
~
AC
+
+ CO
NP
+
+
NAUX
VDD
GND
FB
RS
©On-Bright Electronics
NC
C
CS
C
OB2513x
Confidential
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
GENERAL INFORMATION
Pin Configuration
Value
800V
-0.3 to 20V
-0.3 to 7V
-0.3 to 7V
-40 to 150 ℃
-20 to 85 ℃
-55 to 150 ℃
260 ℃
特
Absolute Maximum Ratings
Parameter
OB2513x CB Voltage
VDD Voltage
FB Input Voltage
CS Input Voltage
Min/Max Operating Junction
Temperature TJ
Operating
Ambient
Temperature TA
Min/Max Storage
Temperature Tstg
Lead Temperature
(Soldering, 10secs)
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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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Recommended Output power Table
AdapterNote1
Product
90V~264V
OB25132
3.5W
OB25133
5.0W
OB25134
7.5W
Notes: 1. Maximum practical continuous power in an adapter
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Package Dissipation Rating
Package
RθJA (℃/W)
SOP7
95
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Ordering Information
Part Number
Description
OB2513xJP
SOP7, Pb-free, Tube
OB2513xJPA
SOP7, Pb-free, T&R
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Recommended Operating Condition
Symbol
Parameter
Range
VDD
VDD Supply Voltage
5 to 16V
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design with sufficient drain pattern as a heat sink, at 40℃
ambient
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
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Marking Information
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YWWZZZ
OB25134JP
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S
Y:Year Code
WW:Week Code(01-52)
ZZZ:Lot Code
J:SOP7 Package
P:Pb-free Package
S:Internal Code(Optional)
TERMINAL ASSIGNMENTS
Pin Num
1
Pin Name
VDD
I/O
P
2
FB
I
3
4
NC
CS
I
Current sense input
5、6
C
P
HV BJT collector pin.
7
GND
P
Ground
©On-Bright Electronics
Description
Power Supply
The voltage feedback from auxiliary winding. Connected to resistor
divider from auxiliary winding reflecting output voltage.
Confidential
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
BLOCK DIAGRAM
VDD
UVLO
Power
Supply
POR
Internal
Supply
C
Base
Driver
OVP
NC
Output
OVP
Logic core
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CC
Controller
FB
OCP
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Drop
Comp
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Vref
CV
Controller
EA
LEB
GND
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sampler
CS
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
ELECTRICAL CHARACTERISTICS
(TA = 25℃, VDD=15V, if not otherwise noted)
Symbol
Parameter
Supply Voltage (VDD) Section
I start-up
Start up current
Test Conditions
Min
VDD=UVLO_OFF-1V
Operation
current
without
switching
UVLO(OFF)
VDD under voltage lockout exit
UVLO(ON)
VDD under voltage lockout enter
VDD_OVP
VDD over voltage protection
VDD_max
Max. Operating Voltage
Current Sense Input Section
TLEB
LEB time
Vth_ocp_min Minimum over current threshold
Vth_ocp_max Maximum over current threshold
Ton_max
Maximum Ton
Td_oc
OCP propagation delay
FB Input Section
Reference voltage for feedback
Vref_fb
threshold
Tpause_min
Minimum Toff
F_min
Minimum frequency
Maximum cable compensation
Icomp_cable
current
Output Over Voltage Protection
Vovp
Output Over voltage threshold
On chip Over temperature Section
Over temperature protection
T_otp
trigger point
Over temperature protection
T_otp_rec
recovery point
I op
12
3.5
17
特
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Max
Unit
1
3
uA
0.77
1.0
mA
13
3.7
18
14
3.9
19
20
V
V
V
V
0.33
500
555
40
100
485
515
2.500 2.525
V
450
2.0
500
us
Hz
550
53
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us
mV
mV
us
ns
2.475
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Typ.
3.00
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2.85
uA
3.15
V
165
℃
130
℃
Power BJT Section
Parameter
Product
Vceo(V) Note1
Vcbeo(V)Note2
Collector-emitter breakdown
voltage
Collector-base
voltage
Min.
Typ.
Max.
Min.
Typ.
Ic (A)
breakdown
Max.
Collect Peak Current
Min.
Typ.
OB25132
450
800
0.35
OB25133
450
800
0.50
OB25134
450
800
0.8
Max.
Note1：Test condition：Ic=10mA, Ib=0
Note2：Test condition：Ic=10mA
©On-Bright Electronics
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
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CHARACTERIZATION PLOTS
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
OPERATION DESCRIPTION
OB2513x is a cost effective PSR power switch
optimized for off-line low power AC/DC
applications including battery chargers. It operates
in primary side sensing and regulation, thus
opto-coupler and TL431 are not required.
Proprietary built-in CV and CC control can achieve
high precision CC/CV control meeting most
charger application requirements.
Startup Current and Startup Control
Startup current of OB2513x is designed to be very
low so that VDD can be charged up quickly. A
large value startup resistor can therefore be used
to minimize the power loss in application.
Figure 2 Auxiliary voltage waveform
Via a resistor divider connected between the
auxiliary winding and FB (pin 2), the auxiliary
voltage is sampled at the middle of the
de-magnetization and it is hold until the next
sampling. The sampled voltage is compared with
Vref (typical 2.5V) and the error is amplified. The
error amplifier output reflects the load condition
and controls the switching off time to regulate the
output voltage, thus constant output voltage can
be achieved.
When the sampled voltage is below Vref and the
error amplifier output reaches its minimum, the
switching frequency is controlled by the sampled
voltage to regulate the output current, thus the
constant output current can be achieved.
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Operating Current
The operating current of OB2513x is as low as
550uA (typical). Good efficiency and low standby
power is achieved with the low operating current.
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CC/CV Operation
OB2513x is designed to produce good CC/CV
control characteristic as shown in the Figure. 1.
In charger applications, a discharged battery
charging starts in the CC portion of the curve until
it is nearly full charged and smoothly switches to
operate in CV portion of the curve. The CC portion
provides output current limiting. In CV operation,
the output voltage is regulated through the primary
side control. In CC operation mode, OB2513x will
regulate the output current constant regardless of
the output voltage drop.
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Adjustable CC Point and Output Power
In OB2513x, the CC point and maximum output
power can be externally adjusted by external
current sense resistor Rs at CS pin as illustrated in
typical application diagram. The larger Rs, the
smaller CC point is, and the smaller output power
becomes, and vice versa as shown in Figure.3.
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Principle of Operation
To support OB2513x proprietary CC/CV control,
system needs to be designed in DCM mode for
flyback system (Refer to Typical Application
Diagram on page1).
In the DCM flyback converter, the output voltage
can be sensed via the auxiliary winding. During
BJT turn-on time, the load current is supplied from
the output filter capacitor, Co. The current in the
primary winding ramps up. When BJT turns off, the
energy stored in the primary winding is transferred
to the secondary side such that the current in the
secondary winding is
IS
NP
IP
NS
Figure 3. Adjustable output power by changing Rs
(1)
On Time OCP Compensation
The variation of max output current in CC mode
can be rather large if no compensation is provided.
The OCP threshold value is self adjusted higher at
higher AC voltage. This OCP threshold slope
adjustment helps to compensate the increased
output current limit at higher AC voltage. In
OB2513x, a proprietary OCP compensation block
is integrated and no external components are
needed. The OCP threshold in OB2513x is a
The auxiliary voltage reflects the output voltage as
shown in Figure.2 and it is given by
V AUX
N AUX
(VO V )
NS
(2)
Where V indicates the drop voltage of the
output Diode.
©On-Bright Electronics
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
function of the switching ON time. For the ON time
less than 4.0us (typical), the OCP threshold
changes linearly from 500mV (typical) to 555mV
(typical). For the ON time larger than 4.0us
(typical), the OCP threshold is clamped to 555mV
(typical), as shown in Figure 4.
full-load to no-load, the offset voltage at FB will
increase. It can also be programmed by adjusting
the resistance of the divider to compensate the
drop for various cable lines used.
The percentage of maximum compensation is
6
V I comp _ cable R1 // R2 10
100%
Vout
2.5
V is load compensation voltage and Vout is
output voltage;
For example: R1//R2=5.1Kohm, the percentage of
maximum compensation is
特
V 53 5100 10 6
100% 10.8%
Vout
2.5
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Figure.4. On time OCP compensation
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1
LP FSW I p2
2
(3)
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Where Lp indicate the inductance of primary
winding and Ip is the peak current of primary
winding.
Refer to the equation 3, the change of the primary
winding inductance results in the change of the
maximum output power and the constant output
current in CC mode. To compensate the change
from variations of primary winding inductance, the
switching frequency is locked by an internal loop
such that the switching frequency is
Protection Control
Good power supply system reliability is achieved
with its rich protection features including
Cycle-by-Cycle current limiting (OCP), Output over
voltage protection, VDD over voltage protection,
short circuit protection, Under Voltage Lockout on
VDD (UVLO) and over temperature protection
(OTP).
VDD is supplied by transformer auxiliary winding
output. The output of OB2513x is shut down when
VDD drops below UVLO (ON) and the power
converter enters power on start-up sequence
thereafter.
To prevent the circuit being damaged under
abnormal conditions, OB2513x provides over
thermal protection function. When the die
temperature rises above over temperature
threshold T_otp, the OB2513x will shut down the
base output and then latch the power supply off.
The controller will remains latched until the die
temperature drops below the recovery threshold
T_otp_rec and the OB2513x will reset at the same
time.
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1
O
FSW
2TDemag
(4)
Since TDemag is inversely proportional to the
inductance, as a result, the product Lp and fsw is
constant, thus the maximum output power and
constant current in CC mode will not change as
primary winding inductance changes. Up to ±7%
variation of the primary winding inductance can be
compensated.
Programmable Cable Drop Compensation
In OB2513x, cable drop compensation is
implemented to achieve good load regulation. An
offset voltage is generated at FB pin by an internal
current flowing into the resister divider. The current
is proportional to the switching off time, as a result,
it is inversely proportional to the output load
current, thus the drop due to the cable loss can be
compensated. As the load current decreases from
©On-Bright Electronics
Current Sensing and Leading Edge Blanking
Cycle-by-Cycle current limiting is offered in
OB2513x. The switch current is detected by a
sense resistor into the CS pin. An internal leading
edge blanking circuit chops off the sensed voltage
spike at initial power BJT on state so that the
external RC filtering on sense input is no longer
needed.
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Operation Switching Frequency
The switching frequency of OB2513x is adaptively
controlled according to the load conditions and the
operation modes.
For flyback operating in DCM, The maximum
output power is given by
Confidential
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
resistor should be placed as close as possible to
pin out. And the negative node of VDD capacitor
and the FB down resistor should be connected
directly to the IC GND pin before single point
connected to the negative node of the output
capacitor. (White region as shows in Fig.6)
Ground Path: The GND path of the input
power loop and IC controller path should be
separated and connected at the negative terminal
of input capacitor by single point, such as power
sense resistor, the negative of the auxiliary
winding and the IC GND. (White region as shows
in Fig.6)
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PCB Layout Consideration
The following rules should be followed in OB2513x
PCB Layout:
The Area of Power Loop: The area of the
main current loop should be as small as possible
to reduce EMI radiation, such as the primary
current loop, the snubber circuit and the secondary
rectifying loop (Red wire as shows in Fig.5). Drain
pin increases the copper area of the drain terminal
for heat dissipation (Green region as shows in
Fig.6). And the PCB trace must be wide and
short for thermal consideration.
Bypass Capacitor and FB divider resistor:
The bypass capacitor on VDD and the FB divider
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Fig.5 Flyback Schematic with OB2513x
Fig.6 Recommend PCB Layout of OB2513x
©On-Bright Electronics
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Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
PACKAGE MECHANICAL DATA
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SOP7 PACKAGE OUTLINE DIMENSIONS
A
A1
A2
b
c
D
E
E1
e
L
θ
Dimensions In Millimeters
Min
Max
1.350
1.750
0.050
0.250
1.250
1.650
0.310
0.510
0.100
0.250
4.700
5.150
3.800
4.000
5.800
6.200
1.270 (BSC)
0.400
1.270
0º
8º
nO
Symbol
©On-Bright Electronics
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Dimensions In Inches
Min
Max
0.053
0.069
0.002
0.010
0.049
0.065
0.012
0.020
0.004
0.010
0.185
0.203
0.150
0.157
0.228
0.244
0.050 (BSC)
0.016
0.050
0º
8º
Datasheet
OB_DOC_DS_2513XA0
OB2513x
High Precision CC/CV Primary-Side PWM Power Switch
IMPORTANT NOTICE
RIGHT TO MAKE CHANGES
On-Bright Electronics Corp. reserves the right to make corrections, modifications, enhancements,
improvements and other changes to its products and services at any time and to discontinue any product
or service without notice. Customers should obtain the latest relevant information before placing orders
and should verify that such information is current and complete.
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WARRANTY INFORMATION
On-Bright Electronics Corp. warrants performance of its hardware products to the specifications applicable
at the time of sale in accordance with its standard warranty. Testing and other quality control techniques
are used to the extent it deems necessary to support this warranty. Except where mandated by
government requirements, testing of all parameters of each product is not necessarily performed.
On-Bright Electronics Corp. assumes no liability for application assistance or customer product design.
Customers are responsible for their products and applications using On-Bright’s components, data sheet
and application notes. To minimize the risks associated with customer products and applications,
customers should provide adequate design and operating safeguards.
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LIFE SUPPORT
On-Bright Electronics Corp.’s products are not designed to be used as components in devices intended to
support or sustain human life. On-bright Electronics Corp. will not be held liable for any damages or claims
resulting from the use of its products in medical applications.
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MILITARY
On-Bright Electronics Corp.’s products are not designed for use in military applications. On-Bright
Electronics Corp. will not be held liable for any damages or claims resulting from the use of its products in
military applications.
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Datasheet
OB_DOC_DS_2513XA0
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