DESCRIPTION
RS2138 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 figure 1.

FEATURES
• 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 DIP-8 Package
• RoHS Compliant and 100% Lead (Pb)-Free and
   Green (Halogen Free with Commercial Standard)

APPLICATIONS
• Cell Phone Charger
• Digital Cameras Charger
• Small Power Adaptor
• Auxiliary Power for PC, TV etc.
• Linear Regulator/RCC Replacement