OB2500N PDF – Primary-Side Power Switch

Part Number: OB2500N

Function: High Precision CC/CV Primary-Side Power Switch

Manufacturer: On-Bright Electronics

Images:OB2500N pdf


OB2500N is a high performance offline PSR power switch 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, 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 at large load condition and it operates in PWM with frequency reduction at light/medium load. The chip consumes very low operation current. It achieves less than 75mW standby power to meet strict standby power standard. […]

OB2500N pinout datasheet


 Primary-side sensing and regulation without
TL431 and opto-coupler
 High precision constant voltage and current regulation at universal AC input
 Multi-mode PWM/PFM operation for efficiency improving
 Integrated 1A 650V MOSFET
 Good dynamic response
 Programmable CV and CC regulation
 Built-in primary winding inductance compensation
 Programmable cable drop compensation
 No need for control loop compensation


 Cell Phone Charger
 Digital Cameras Charger
 Small Power Adapter
 Auxiliary Power for PC, TV etc.
 Linear Regulator/RCC Replacement

OB2500N PDF Datasheet