RS2120 High Precision CC/CV Primary-Side Controller DESCRIPTION RS2120 is a high performance offline PSR 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, PFM operations are utilized to achieve high performance and high efficiency. In addition, good load regulation is achieved by the built-in cable drop compensation. The chip consumes very low operation current (typical 350µA), it can achieve less than 30mW standby power to meet strict standby power standard. RS2120 offers comprehensive protection coverage with auto-recovery features including Cycle-by-Cycle current limiting, VDD over voltage protection, feedback loop open protection, short circuit protection, built-in leading edge blanking, VDD under voltage lockout (UVLO), etc. 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 • Built-in primary winding inductance compensation • Programmable cable drop compensation • Driver BJT switch • Ultra low start-up current (Typ. 1µA) • VDD over voltage protection • Built-in feedback loop open protection • Built-in short circuit protection • Built-in leading edge blanking (LEB) • Cycle-by-cycle current limiting • VDD under voltage lockout with hysteresis (UVLO) 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 TYPICAL CC/CV CURVE Tel: 886-66296288‧Fax: 886-29174598‧ http://www.princeton.com.tw‧2F, No. 233-1, Baociao Rd., Sindian Dist., New Taipei City 23145, Taiwan RS2120 BLOCK DIAGRAM V1.0 2 March 2013 RS2120 APPLICAION CIRCUIT ORDER INFORMATION Device RS2120 Y Z V1.0 Device Code Y is package & Pin Assignments designator: N : SOT-23-6L Z is Lead Free designator: P: Commercial Standard, Lead (Pb) Free and Phosphorous (P) Free Package G: Green (Halogen Free with Commercial Standard) 3 March 2013 RS2120 PIN ASSIGNMENTS SOT-23-6L PIN DESCRIPTION Pin Name GND CS BASE FB VC VDD V1.0 Description Ground. Current sense input. Base drive with current limit for power BJT. The voltage feedback from auxiliary winding. Connected to resistor divider from auxiliary winding reflecting output voltage. Low pass filter capacitor for cable compensation. Power supply. 4 Pin No. 1 2 3 4 5 6 March 2013 RS2120 IMPORTANT NOTICE Princeton Technology Corporation (PTC) reserves the right to make corrections, modifications, enhancements, improvements, and other changes to its products and to discontinue any product without notice at any time. PTC cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a PTC product. No circuit patent licenses are implied. Princeton Technology Corp. 2F, 233-1, Baociao Road, Sindian Dist., New Taipei City 23145, Taiwan Tel: 886-2-66296288 Fax: 886-2-29174598 http://www.princeton.com.tw V1.0 12 March 2013