Active-PFC Constant-Voltage Controller with Primary-Side Regulation


Update Alert Share

The RT7339P is a constant voltage controller with the active Power Factor Correction (PFC), which is designed to meet the line current harmonic regulations. It drives the converter in Quasi-Resonant (QR) mode to achieve higher efficiency. By using the Primary-Side Regulation (PSR), the RT7339P controls the output voltage accurately without a shunt regulator and an opto-coupler at the secondary side, reducing the external component counts, the costs, and the volume of the driver board.

The RT7339P is compatible with the external depletion N-MOSFET to achieve fast startup and ultra-low standby power consumption.

The totem-pole gate driver with the 400mA sourcing current and 500mA sinking current provides the powerful driving capability for a power MOSFET to improve the conversion efficiency. In addition, the built-in soft drive at the turn-on transition is better for the EMI improvement.

The RT7339P integrates comprehensive protection functions for robust designs, including output over voltage protection, output short-circuit protection, output diode short-circuit protection, VDD under voltage lockout (UVLO), VDD over voltage protection (VDD OVP), input under / over voltage protection, external / internal over temperature protection (OTP), and cycle-by-cycle high/low line current limitation.


  • LED Lighting
  • AC-DC Adapter/Charger
Key Spec.
Status Active
Supply Voltage (min) (V) -0.3
Supply Voltage (max) (V) 40
Topology Flyback;PSR
Output C.V.
MOSFET Integrated No
Current Sense Threshold (mV) 600
Features COT Control;Cycle-by-Cycle Current Limit;Fast Transient Response;OCP;OVP;SCP;Thermal Protection;UVP
Package Type SOT-26
  • Tight Voltage Regulation
  • Power Factor Correction
  • THD Optimization (THD < 10%)
  • Quasi-Resonant (QR) Operation
  • Fast Startup
  • Fast Dynamic Response
  • Ultra-Low Standby Power Consumption
  • Soft Drive for the Better EMI Performance
  • Wide Supply Voltage Range (Up to 34V)
  • Maximum Frequency Limitation (117kHz)
  • Multiple Protection Features
    ► Output Over Voltage Protection
    ► Output Short-Circuit Protection
    ► Input Under / Over Voltage Protection
    ► Output Diode Short-Circuit Protection
    ► VDD Over Voltage Protection
    ► VDD Under Voltage Lockout (UVLO)
    ► External / Internal OTP
    ► Cycle-By-Cycle High / Low Line Current Limitation (0.5V/0.6V typ.)
Technical Documents
TitleLast UpdateShareDownload
Power Solutions for LED Lighting Applications2018/11/22