UC3855AN

The UC3855AN from Texas Instruments is a high-performance integrated circuit designed to control boost Pulse Width Modulation (PWM) converters, enabling near-unity power factor. It utilizes a fixed frequency average current mode control method to minimize line current distortion, offering stable operation without the need for slope compensation.

This controller features built-in active snubbing (ZVT) technology, allowing operation up to 500kHz. This capability leads to reduced diode recovery and MOSFET turn-on losses, resulting in lower EMI emissions and improved efficiency. The UC3855AN incorporates an inductor current synthesizer that supports single current transformer current sensing, enhancing efficiency and noise margin. It also includes an accurate analog multiplier with line compensation for universal input voltage operation.

Key features include overvoltage and overcurrent protection, UVLO with hysteresis, and a precision 1% 7.5V reference. The device is available in a 20-PDIP through-hole package, suitable for applications requiring robust power factor correction.

Applications for the UC3855AN include high power, high frequency PFC boost converters where stable, low distortion AC line current programming is essential. Its design facilitates higher power applications by improving signal-to-noise ratio and minimizing current sensing losses.