STMicroelectronics has unveiled the L6462A, a transition-mode (TM) power factor correction (PFC) controller designed to lower bill-of-materials (BOM) costs and enhance efficiency in power supplies up to 250W. The device is well-suited for applications including battery chargers, power adapters, LED drivers, and television power supplies, helping manufacturers meet modern energy-efficiency and environmental standards.
A key innovation of the L6462A is its multiplier-less design. Instead of relying on a traditional analog multiplier and external voltage-sensing circuitry to create the sinusoidal current reference required for PFC operation, the controller uses an integrated current-generation and shaping mechanism. This reduces the number of external components needed, simplifying design and lowering overall system costs.
The controller also streamlines inductor demagnetization detection by obtaining the required information directly from the gate-driver output, eliminating the need for auxiliary windings and additional sensing circuits. This approach enables more compact and cost-effective power-supply designs without compromising performance.
Beyond reducing component count, the L6462A is engineered to deliver improved efficiency and lower total harmonic distortion (THD), particularly at light and medium load levels. It also features an ultra-low standby current of less than 60 µA, helping designers comply with strict energy-saving regulations and standby power requirements.
At maximum load, the L6462A operates in quasi-resonant mode with valley switching, helping reduce switching losses and maximize power-conversion efficiency. When load demand decreases, the controller automatically lowers its switching frequency using valley-skipping techniques, ensuring efficient performance over a broad operating range. For LED lighting systems, a built-in deep burst mode enables smooth and stable dimming at low power levels.
The device is compatible with universal AC input voltages ranging from 90V to 264V and is commonly configured to produce a 400V output bus. It also incorporates several advanced features, including a precise voltage reference, improved transient response, direct MOSFET gate-drive support with active pull-down protection, remote enable/disable functionality, and comprehensive protection mechanisms covering overcurrent, overvoltage, feedback-loop faults, and inductor saturation.
To support faster product development, STMicroelectronics offers the EVL6462A-250W-M evaluation board, showcasing a compact 250W PFC pre-regulator capable of delivering peak efficiency exceeding 97% while maintaining low total harmonic distortion (THD) across various operating conditions. The L6462A is currently available in a space-saving SOT23-6L package.
