OB6561PX is an active transition-mode (TM) power factor correction (PFC) controller for AC-DC switching mode power supply applications.

OB6561PX features a one quadrant multiplier with THD optimizer for near unity power factor, zero current detector (ZCD) to ensure TM operation, a current sensing comparator with built-in leading-edge blanking, and a totem pole output ideally suited for driving a power MOSFET.

OB6561PX offers great protection coverage including system over-voltage protection (OVP) to eliminate runaway output voltage due to load removal, VCC under voltage lockout (UVLO), cycle-by-cycle current limiting, multiplier output clamping that limit maximum peak switch current, and gate drive output clamping for external power MOSFET protection.

With added system open loop protection feature, OB6561PX shuts down system when the feedback loop is open.


·         Transition Mode (TM) Operation

·         One quadrant multiplier with THD optimizer

·         Low Start-up Current and Operating Current

·         Cycle-by-Cycle Current Limiting

·         Internal RC Filter

·         Under Voltage Lockout with Hysteresis

·         Very Precise Adjustable Output Overvoltage Protection

·         Disable Function

·         Totem Pole Output with High State Clamping

·         System Open Loop Protection

·         Audio Noise Free

·         9.5V to 28V wide range of VCC voltage



·         Electronic Ballast

·         AC-DC SMPS