Preliminary R7304 1 Primary-Side Regulation PWM Controller for PFC LED Driver General Description RT7304 is an active power factor controller specifically designed for use as a constant current LED driver. It embeds a Critical Conduction Mode (CRM) control that supports high power factor across a wide range of line voltages. By using Primary Side Regulation (PSR), RT7304 controls the output current accurately without a shunt regulator and a photo coupler on the secondary side, reducing the external component count, the cost, and the volume of the driver board. RT7304 embeds comprehensive protection functions for robust designs, including LED open circuit protection, LED short circuit protection, output diode short circuit protection, VDD Under Voltage Lockout (UVLO), VDD Over Voltage Protection (OVP), Over Temperature Protection (OTP), and cycle-by-cycle current limitation. Ordering Information Application AC/DC LED Lighting driver Features Primary Side Regulation (PSR) Power Factor Correction (PFC) Tight LED Current Regulation (< ±5%) Critical Conduction Mode (CRM) Maximum/Minimum Switching Frequency Clamping Maximum/Minimum on Time Limitation Wide VDD Range (up to 25V) Multiple Protection Features: LED Open-Circuit Protection LED Short-Circuit Protection Output Diode Short-Circuit Protection VDD Under Voltage Lockout VDD Over Voltage Protection Over Temperature Protection Cycle-by-Cycle Current Limitation Marking Information Preliminary RT7304 2 Simplified Application Circu it Preliminary RT7304 3 Fu nctional Pin Description Pin No. Pin Name Pin Fu nction 1 GND Ground of the controller. 2 VDD Supply voltage input. The controller will be enabled when VDD exceeds VON...
