OB3678

GENERAL DESCRIPTION

OB3678x is an active transition-mode (TM) power factor correction (PFC) controller for AC-DC switching mode power supply applications.

OB3678x features a demagnetization detector 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.

OB3678x 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, Inductor short protection (ISP), and gate drive output clamping for external power MOSFET protection.

With added system open loop protection feature, OB3678x shuts down system when the feedback loop is open.

FEATURES

· Transition Mode (TM) Operation

· Works without Transformer ZCD Winding(simple inductor)

· Low Start-up Current and Operating Current

· Cycle-by-Cycle Current Limiting

· Under Voltage Lockout with Hysteresis

· Very Precise Adjustable Output Overvoltage Protection

· Dynamic OVP &Static OVP function

· Totem Pole Output with High State Clamping

· System Open Loop Protection

· Inductor short protection

· Over temperature protection (OTP)

· Audio Noise Free

· 9V to 26V wide range of VCC voltage

APPLICATIONS

· LED lighting

OB3678

GENERAL DESCRIPTION

FEATURES

APPLICATIONS

TYPICAL APPLICATION