MC33368D

Power Factor Correction (PFC)

PFC stands for Power Factor Correction and is a technology used to rectify AC to DC without introducing harmonics and distortion. It is used in many different applications, but most notably, on a high voltage power supply where it is essential to reduce noise, harmonics, and regulation compliance. The most effective method of rectifying high voltage AC to regulated DC is to use a PFC circuit called the MC33368D.

Application of MC33368D

The MC33368D is an integrated high-efficiency PFC controller with a proprietary high-speed start-up algorithm. It is designed for applications requiring enhanced efficiency, such as those in white goods, office equipment and power supplies in chargers and adapters. The device is optimized and tested for a 270V AC input range, and is suitable for low harmonic ripple power factor correction. It operates over a wide supply voltage range, with a regulation range of up to 500V DC.

MC33368D Working Principle

The MC33368D is an asynchronous PFC controller, providing an active power factor corrector for AC-DC power management. It uses a symmetrical half-bridge with an auxiliary switching mode power supply for start-up. The device has non-volatile memory for feature settings, and the control loop is set up in the shade of the current-mode. The device contains a reset timer and power supply control logic, and a low side switch driver. In order to obtain the maximum operating efficiency, the device also includes a robust line voltage monitoring function.

The MC33368D is a synchronous rectifier two-step PFC controller, which can be used to realize quick current and power factor correction. During soft start, the device converts the input AC voltage to DC voltage by adjusting the duty cycle of the control signal. Then, it utilizes the zero-current-detection technique to switch off the synchronous rectifier. It will then help the power device to minimize power losses and maximize efficiency.

The MC33368D provides a PFC solution with high-efficiency, low harmonic distortion, and universal input voltage acceptance. It also meets EN61000-3-2 Class D requirements for harmonic suppression, and meets the EMC requirements of EN50178. Moreover, the device is capable of handling multiple input voltages, which makes it ideal for various applications, ranging from domestic to industrial.

Conclusion

The MC33368D is a high-efficiency PFC controller with a proprietary high-speed start-up algorithm. It is designed for applications such as white goods, office equipment and power supplies in chargers and adapters. The device uses a symmetrical half-bridge with an auxiliary switching mode power supply for start-up and can handle multiple input voltages. It can provide high efficiency, low harmonic distortion and universal input voltage acceptance. Additionally, it meets EN61000-3-2 Class D requirements for harmonic suppression and meets the EMC requirements of EN50178.