High Precision CC/CV Primary-Side PWM Power Switch
OB2535
GENERAL DESCRIPTION
OB2535 is a high performance offline PWM 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.
OB2535 offers power on soft start control and
protection coverage with auto-recovery features
including Cycle-by-Cycle current limiting, VDD
OVP, VDD clamp and UVLO. Excellent EMI
performance is
achieved
with On-Bright
proprietary frequency shuffling technique.
High precision constant voltage (CV) and constant
current (CC) can be achieved by OB2535.
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
Adjustable Constant Current and Output
Power Setting
Built-in Secondary Constant Current Control
with Primary Side Feedback
Built-in Adaptive Current Peak Regulation
Built-in Primary winding inductance
compensation
Programmable Cable drop Compensation
Power on Soft-start
Built-in Leading Edge Blanking (LEB)
Cycle-by-Cycle Current Limiting
VDD Under Voltage Lockout with Hysteresis
(UVLO)
VDD OVP
VDD Clamp
.
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
OB2535 is offered in SOP8 package.
Fig.1. Typical CC/CV Curve
TYPICAL APPLICATION
©On-Bright Electronics
Confidential
-1-
Datasheet
OB_DOC_DS_2535A2
High Precision CC/CV Primary-Side PWM Power Switch
OB2535
GENERAL INFORMATION
Pin Configuration
The pin map is shown as below for SOP8.
Package Dissipation Rating
Package
RθJA (℃/W)
SOP8
90
Note:
Drain Pin Connected 100mm
2
PCB copper
clad.
Absolute Maximum Ratings
Parameter
Drain Voltage (off state)
VDD Voltage
VDD Zener Clamp
Continuous Current
COMP Voltage
CS Input Voltage
INV Input Voltage
Max Operating Junction
Temperature T
J
Min/Max Storage
Temperature T
stg
Lead Temperature
(Soldering, 10secs)
Value
-0.3V to Bvdss
-0.3 to V
DD
_clamp
10 mA
-0.3 to 7V
-0.3 to 7V
-0.3 to 7V
-40 to 150
o
C
-55 to 150
o
C
260
o
C
VDD
1
8
GND
COMP
2
7
GND
INV
3
6
DRAIN
CS
4
5
DRAIN
Ordering Information
Part Number
Description
OB2535CP
SOP8, Pb-free, Tube
OB2535CPA
SOP8, 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.
©On-Bright Electronics
Confidential
-2-
Datasheet
OB_DOC_DS_2535A2
High Precision CC/CV Primary-Side PWM Power Switch
OB2535
Marking Information
TERMINAL ASSIGNMENTS
Pin Num
1
2
3
4
5/6
7/8
Pin Name
VDD
COMP
INV
CS
DRAIN
GND
I/O
P
I
I
I
O
P
Description
Power Supply
Loop Compensation for CV Stability
The voltage feedback from auxiliary winding. Connected to resistor
divider from auxiliary winding reflecting output voltage. PWM duty cycle
is determined by EA output and current sense signal at pin 4.
Current sense input
HV MOSFET Drain Pin. The Drain pin is connected to the primary lead
of the transformer
Ground
OUTPUT POWER TABLE
Product
OB2535
230VAC±15%
Adapter
1
6W
85-264VAC
Adapter
1
5W
Notes:
1.
Maximum practical continuous power in an Adapter design with sufficient drain pattern as a heat sink, at 50℃ ambient. Higher
output power is possible with extra added heat sink or air circulation to reduce thermal resistance.
©On-Bright Electronics
Confidential
-3-
Datasheet
OB_DOC_DS_2535A2
High Precision CC/CV Primary-Side PWM Power Switch
OB2535
ELECTRICAL CHARACTERISTICS
(T
A
= 25
O
C, VDD=VDDG=16V, if not otherwise noted)
Symbol
Parameter
Test Conditions
Supply Voltage (VDD) Section
I
DD ST
I
DD op
UVLO(ON)
UVLO(OFF)
V
DD
_clamp
OVP
Standby Current
Operation Current
VDD=13V
Operation supply current
INV=2V, CS=0V,
VDD=VDDG=18V
Min
Typ
Max
Unit
5
-
8.2
13.5
27
26
2
9.0
14.8
28.5
27.5
20
3
10.5
16.0
30
29
uA
mA
V
V
V
V
VDD Under Voltage Lockout
VDD falling
Enter
VDD Under Voltage Lockout
VDD rising
Exit
Maximum
voltage
VDD
operation
I
DD
=10mA
Over voltage
Threshold
LEB time
protection Ramp VDD until gate
shut down
Current Sense Input Section
TLEB
Vth_oc
Td_oc
Z
SENSE
_IN
T_ss
Freq_Max
Note 1
Freq_Nom
Freq_startup
△f/Freq
Vref_EA
Gain
I_COMP_MAX
Frequency shuffling range
Reference voltage for EA
DC gain of EA
Max. Cable compensation
current
MOSFET
Drain-Source
Breakdown Voltage
On Resistance
Static, Id=0.4A
INV=2V, Comp=0V
1.97
Error Amplifier section
2
60
37.5
2.03
V
dB
uA
625
880
50
17
55
60
50
INV=0V, Comp=5V
14
+/-6
65
910
110
940
ns
mV
ns
Kohm
ms
KHz
KHz
KHz
%
Over current threshold
OCP Propagation delay
Input Impedance
Soft start time
IC Maximum frequency
System Nominal
frequency
switch
Frequency Section
Power MOSFET Section
BVdss
Rdson
Note:
1. Freq_Max indicates IC internal maximum clock frequency. In system application, the maximum operation frequency of 50Khz
nominal occurs at maximum output power or the transition point from CV to CC.
600
12
15
V
Ώ
©On-Bright Electronics
Confidential
-5-
Datasheet
OB_DOC_DS_2535A2
电机控制
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