|
RS2138 Datasheet, PDF (1/10 Pages) Orister Corporation – High Precision CC/CV Primary‐Side PWM Power Switch | |||
|
RS2138
High Precision CC/CV PrimaryâSide PWM Power Switch
Page No. : 1/10
General Description
RS2138 is a high performance offline PWM Power switch for low power AC/DC charger and adaptor applications. It operates in primaryâ
side sensing and regulation. Consequently, optoâcoupler 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, multiâ
mode operations are utilized to achieve high performance and high efficiency. In addition, good load regulation is achieved by the builtâ
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.
RS2138 offers power on soft start control and protection coverage with autoârecovery features including CycleâbyâCycle current limiting,
VDD OVP, VDD clamp and UVLO. Excellent EMI performance is achieved with Frequency Jiggling.
Features
Applications
â 5% Constant Voltage Regulation, 5% Constant Current â Cell Phone Charger
Regulation at Universal AC input
â Digital Cameras Charger
â
Primaryâside Sensing and Regulation Without 431 and Optoâ
â
â
Small Power Adaptor
Auxiliary Power for PC, TV etc.
coupler
â Linear Regulator/RCC Replacement
â Power on Softâstart
â Builtâin Leading Edge Blanking (LEB)
â CycleâbyâCycle Current Limiting
â VDD Under Voltage Lockout with Hysteresis (UVLO)
â Programmable CV and CC Regulation
â Adjustable Constant Current and Output Power Setting
â Builtâin Secondary Constant Current Control with Primary Side
Feedback
â Builtâin adaptive current peak regulation
â Builtâin Primary winding inductance compensation
â Program cable drop compensation
â VDD OVP and VDD Clamp
â Available in an DIPâ8 Package
â RoHS Compliant and 100% Lead (Pb)âFree and Green (Halogen
Free with Commercial Standard)
DSâRS2138â03 September, 2009
Fig.1. Typical CC/CV Curve
www.Orister.com
|
▷ |