Onsemi FAN7930CMX-G: A High-Performance Critical Conduction Mode PFC Controller

In the realm of power electronics, achieving high efficiency and power factor correction (PFC) is paramount for modern switch-mode power supplies (SMPS). The Onsemi FAN7930CMX-G stands out as a highly integrated controller designed specifically for critical conduction mode (CrM) boost PFC pre-regulators. This controller is engineered to meet the stringent requirements of applications such as LED lighting drivers, industrial power systems, and consumer electronics, where efficiency, reliability, and compliance with energy standards are critical.

Key Features and Advantages

The FAN7930CMX-G operates in boundary conduction mode (BCM), also known as critical conduction mode, which ensures that the boost converter switch turns on when the inductor current reaches zero. This mode of operation minimizes switching losses and reduces electromagnetic interference (EMI), making it highly efficient for medium-power applications. The device supports a wide input voltage range, typically from 85 VAC to 265 VAC, and can deliver output power up to 300W, depending on the design and configuration.

One of the standout features of this controller is its innovative emulated current sensing technique. By eliminating the need for a physical current sense resistor, this technology reduces power dissipation and lowers component count, leading to a more cost-effective and compact design. Additionally, the FAN7930CMX-G incorporates internal startup circuitry and an active filter for the AC sense input, which enhances noise immunity and simplifies the overall circuit design.

The controller also includes comprehensive protection features to ensure system robustness. These include over-voltage protection (OVP), open-loop detection, and feedback fault protection, which safeguard the system against abnormal operating conditions. The built-in soft-start function minimizes inrush current during startup, reducing stress on components and enhancing reliability.

Performance and Application

The FAN7930CMX-G excels in achieving a near-unity power factor, typically greater than 0.98, which is essential for complying with international standards such as IEC 61000-3-2. Its high-performance error amplifier and precise internal reference contribute to excellent line and load regulation. The device is available in an SOIC-8 package, offering a compact footprint for space-constrained applications.

Designers will appreciate the reduction in external components required, thanks to the high level of integration. This not only simplifies the design process but also improves overall system reliability by minimizing potential failure points. The controller is ideal for use in a variety of power supplies, including those for LCD TVs, desktop computers, and adapters, where efficiency and power quality are paramount.

ICGOOODFIND: The Onsemi FAN7930CMX-G is a robust and efficient CrM PFC controller that combines high performance with design simplicity. Its emulated current sensing, comprehensive protection features, and high power factor correction make it an excellent choice for modern power supply designs aiming for efficiency and compliance.

Keywords:

Power Factor Correction (PFC)

Critical Conduction Mode (CrM)

Emulated Current Sensing

Over-Voltage Protection (OVP)

High Efficiency