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OB2532
High Precision CC/CV Primary-Side PWM Controller
Product Specification
GENERAL DESCRIPTION
OB2532 is a high performance offline PWM
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, 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.
OB2532 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 OB2532.
.
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
OB2532 is offered in SOT23-6 package.
Fig.1. Typical CC/CV Curve
TYPICAL APPLICATION
©On-Bright Electronics
Confidential
-1-
Datasheet
OB_DOC_DS_2532A0

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OB2532
High Precision CC/CV Primary-Side PWM Controller
GENERAL INFORMATION
Pin Configuration
The pin map is shown as below for SOT23-6.
Ordering Information
Part Number
Description
OB2532MP
SOT23-6, Pb-free, T&R
Package Dissipation Rating
Package
RθJA (/W)
SOT23-6
200
.
Absolute Maximum Ratings
Parameter
Value
VDD Voltage
VDD Zener Clamp
Continuous Current
-0.3 to VDD_clamp
10 mA
COMP Voltage
-0.3 to 7V
CS Input Voltage
-0.3 to 7V
INV Input Voltage
-0.3 to 7V
Max Operating Junction
Temperature TJ
Min/Max Storage
Temperature Tstg
Lead Temperature
(Soldering, 10secs)
150 oC
-55 to 150 oC
260 oC
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
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Datasheet
OB_DOC_DS_2532A0

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Marking Information
OB2532
High Precision CC/CV Primary-Side PWM Controller
TERMINAL ASSIGNMENTS
Pin Num
1
2
3
Pin Name
GND
GATE
CS
4 INV
5 COMP
6 VDD
I/O Description
P Ground
O Totem-pole gate drive output for power MOSFET.
I
Current sense input. Connected to MOSFET current sensing resistor
node.
The voltage feedback from auxiliary winding. Connected to resistor
I divider from auxiliary winding reflecting output voltage. PWM duty cycle
is determined by EA output and current sense signal at pin 3.
I Loop Compensation for CV Stability
P Power Supply
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Datasheet
OB_DOC_DS_2532A0

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BLOCK DIAGRAM
OB2532
High Precision CC/CV Primary-Side PWM Controller
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Datasheet
OB_DOC_DS_2532A0

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OB2532
High Precision CC/CV Primary-Side PWM Controller
ELECTRICAL CHARACTERISTICS
(TA = 25, VDD=16V, if not otherwise noted)
Symbol
Parameter
Test Conditions
Min Typ Max Unit
Supply Voltage (VDD) Section
I DD ST
I DD op
Standby Current
Operation Current
VDD=13V
Operation supply current
INV=2V, CS=0V,
-
VDD=18V
5
2
20 uA
3 mA
UVLO(ON)
VDD Under Voltage Lockout
Enter
VDD falling
8.2 9.0 10.5 V
UVLO(OFF) VDD Under Voltage Lockout Exit VDD rising
13.5 14.8 16.0 V
VDD_clamp
OVP
Maximum VDD operation voltage IDD=10mA
Over voltage protection
Threshold
Ramp VDD until gate
shut down
27 28.5 30
26 27.5 29
V
V
Current Sense Input Section
TLEB
LEB time
625 ns
Vth_oc
Over current threshold
880 910 940 mV
Td_oc
OCP Propagation delay
110 ns
ZSENSE_IN
T_ss
Input Impedance
Soft start time
50
17
Kohm
ms
Frequency Section
Freq_MaxNote 1 IC Maximum frequency
55 60 65 KHz
Freq_Nom
System Nominal switch
frequency
50 KHz
Freq_startup
INV=0V, Comp=5V
14 KHz
f/Freq
Frequency shuffling range
+/-6 %
Error Amplifier section
Vref_EA
Reference voltage for EA
1.97 2
2.03 V
Gain
DC gain of EA
60 dB
I_COMP_MAX
Max. Cable compensation
current
INV=2V, Comp=0V
37.5
uA
Gate Drive Output Section
VOL
Output Low Level
Io=20mA
1V
VOH
Output High Level
Io=20mA
8
V
V_clamp
Output Clamp Voltage Level
16 V
T_r Output Rising Time
CL=0.5nF
650 nS
T_f Output Falling Time
CL=0.5nF
40 nS
Note:
1. Freq_Max indicates IC internal maximum clock frequency. In system application, the maximum operation frequency of 60Khz
nominal occurs at maximum output power or the transition point from CV to CC.
©On-Bright Electronics
Confidential
-5-
Datasheet
OB_DOC_DS_2532A0