Document
OB2535
High Precision CC/CV Primary-Side PWM Power Switch
GENERAL DESCRIPTION
OB2535 is a high performance offline PWM Power switch for low power AC/DC charger and adaptor 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, 5% 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 Adaptor Auxiliary Power for PC, TV etc. Linear Regulator/RCC Replacement
OB2535 is offered in SOP8 package.
Fig.1. Typical CC/CV Curve
TYPICAL APPLICATION
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OB_DOC_DS_253502
OB2535
High Precision CC/CV Primary-Side PWM Power Switch
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 100mm2 PCB copper
clad.
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
Absolute Maximum Ratings
Parameter
Value
Drain Voltage (off state) -0.3V to Bvdss
VDD Voltage
-0.3 to VDD_clamp
VDD Zener Clamp
10 mA
Continuous Current
COMP Voltage
-0.3 to 7V
CS Input Voltage
-0.3 to 7V
INV Input Voltage
-0.3 to 7V
Min/Max Operating
-20 to 150 oC
Junction Temperature TJ Min/Max Storage
-55 to 150 oC
Temperature Tstg Lead Temperature
260 oC
(Soldering, 10secs)
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
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OB_DOC_DS_253502
Marking Information
OB2535
High Precision CC/CV Primary-Side PWM Power Switch
OB2535CP
YWW S
C:SOP8 Package P:Pb-free Package Y:Year Code(0-9) WW:Week Code(01-52) S:Internal Code(Optional)
TERMINAL ASSIGNMENTS
Pin Num Pin Name 1 VDD 2 COMP
3 INV
4 CS 5/6 DRAIN 7/8 GND
I/O Description
P Power Supply
I Loop Compensation for CV Stability
The voltage feedback from auxiliary winding. Connected to resistor divider
I from auxiliary winding reflecting output voltage. PWM duty cycle is
determined by EA output and current sense signal at pin 4.
I Current sense input
O
HV MOSFET Drain Pin. The Drain pin is connected to the primary lead of the transformer
P Ground
OUTPUT POWER TABLE
Product OB2535
230VAC±15% Adapter1 6W
85-264VAC Adapter1 5W
Notes:
1. Maximum practical continuous power in an Adapter design with sufficient drain pattern as a heat sink, at 50℃ ambient.
©On-Bright Electronics
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Confidential
OB_DOC_DS_253502
OB2535
High Precision CC/CV Primary-Side PWM Power Switch
BLOCK DIAGRAM
VDD 1
POR UVLO
Internal 5V Supply
Gate Driver
DRAIN 5/6
Power MOSFET
CC Controller
Drop Comp
2V
INV 3 Sampler
EA
PWM Generator
CLK Genterator
Sampling Controller
Frequency Shuffling
2 COMP
Soft start
OCP LEB
CS 4
GND 7/8
©On-Bright Electronics
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OB_DOC_DS_253502
OB2535
High Precision CC/CV Primary-Side PWM Power Switch
ELECTRICAL CHARACTERISTICS
(TA = 25OC, VDD=VDDG=16V, if not otherwise noted)
Symbol
Parameter
Test Conditions
Min Typ Max Unit
Supply Voltage (VDD) Section
I DD ST
Standby Current
VDD=.