OB3338C is a dimmable offline controller with high constant current (CC) precision. It can achieve low system cost for an isolated lighting application by primary side control in a single stage converter.


The proprietary CC control scheme is used. Quasi-resonant (QR) operation and clamping frequency greatly improves the system efficiency. The advanced start-up technology is used to meet the start-up time requirement (<0.5s). The constant output current is compensated for tolerance of transformer inductance variation. And the line compensation is built in OB3338C for high precisely constant output current control.

OB3338C offers a dimmable function, the LED current can be controlled by setting the duty cycle of PWM waveform into the DIM pin.

OB3338C offers comprehensive protection coverage with auto-recovery features including LED open loop protection, LED short circuit protection, cycle-by-cycle current limiting, built-in leading edge blanking, VDD under voltage lockout (UVLO), etc.


OB3338C is offered in SOP8 package.


n Dimmable LED current control

n Primary-side sensing and regulation without TL431 and opto-coupler

n High precision constant current regulation

n Fast start-up

n Quasi-resonant operation

n Built-in line compensation

n LED short circuit protection

n LED open loop protection

n Cycle-by-cycle current limiting

n Built-in leading edge blanking (LEB)

n VDD under voltage lockout with hysteresis

n VDD over voltage protection

n Over temperature protection (OTP)



n LED lighting