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RS2135
High Precision CC/CV Primary‐Side PWM Power Switch
General Description
RS2135 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 431 could be eliminated. Proprietary Constant Voltage (CV) and Constant
Current (CC) control is integrated as shown in the Fig.1.
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.
RS2135 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 Frequency Jiggling.
Features
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Applications
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Cell Phone Charger
Digital Cameras Charger
Small Power Adaptor
Auxiliary Power for PC, TV etc.
Linear Regulator/RCC Replacement
5% Constant Voltage Regulation, 5% Constant Current
Regulation at Universal AC input
Primary‐side Sensing and Regulation Without 431 and Opto‐
coupler
Power on Soft‐start
Built‐in Leading Edge Blanking (LEB)
Cycle‐by‐Cycle Current Limiting
VDD Under Voltage Lockout with Hysteresis (UVLO)
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
Program cable drop compensation
VDD OVP and VDD Clamp
Available in an SOP‐8 Package
RoHS Compliant and 100% Lead (Pb)‐Free and Green (Halogen
Free with Commercial Standard)
Fig.1. Typical CC/CV Curve
DS‐RS2135‐03
September,
2009
www.Orister.com
ORISTER [ ORISTER CORPORATION ]
