GENERAL DESCRIPTION
OB3655x is an offline LED lighting 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. It significantly simplifies the LED lighting system design by eliminating auxiliary winding.
The system uses the 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 and load compensation are built in OB3655x for high precisely constant output
current control.
OB3655x 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.
OB3655x is offered in DIP8 package.
FEATURES
High precision constant current regulation at universal AC input
Fast start-up (<0.5s)
Primary-side sensing and regulation without auxiliary winding
Low system cost and high efficiency
Quasi-resonant operation
Programmable CC regulation
Built-in primary winding inductance compensation
Built-in line compensation
Built-in load compensation
LED short circuit protection
LED open loop protection
Cycle-by-cycle current limiting
Built-in leading edge blanking (LEB)
VDD under voltage lockout with hysteresis
VDD over voltage protection
Over temperature protection (OTP)
Thermal fold-back control
APPLICATIONS
LED lighting