Lithium-ion Charger Controller# Technical Documentation: FAN7563DTF Power Factor Correction Controller
Manufacturer : FSC (Fairchild Semiconductor, now part of ON Semiconductor)
## 1. Application Scenarios
### Typical Use Cases
The FAN7563DTF is a critical-mode power factor correction (PFC) controller IC designed for AC-DC power supplies requiring high power factor and low total harmonic distortion (THD). Its primary function is to shape the input current waveform to follow the input voltage waveform, thereby maximizing real power delivery from the AC mains.
Primary Applications Include:
* Switched-Mode Power Supplies (SMPS): For desktop computers, servers, workstations, and gaming consoles where compliance with international power quality standards (like IEC 61000-3-2) is mandatory.
* LED Lighting Drivers: High-power LED drivers for commercial and industrial lighting, where efficient power usage and reduced line current harmonics are essential.
* Adapter/Charger Systems: For high-power (>75W) laptop adapters, telecom rectifiers, and industrial battery chargers.
* Industrial Power Systems: As the front-end PFC stage in motor drives, welding equipment, and uninterruptible power supplies (UPS).
### Industry Applications & System Integration
The component is typically deployed as the control core of a boost converter topology placed between the input bridge rectifier and the main DC-DC converter stage.
* Consumer Electronics: Ensures products meet Energy Star and EU ErP directives for energy efficiency.
* IT & Telecom: Used in server power supplies and telecom rectifiers to improve facility power utilization and reduce infrastructure costs.
* Industrial Automation: Enhances the performance and reliability of motor controllers and PLC power modules by providing a stable, high-voltage DC bus (typically 385-400V).
### Practical Advantages and Limitations
Advantages:
* Critical Conduction Mode (CRM): Operates at the boundary between continuous and discontinuous conduction modes. This eliminates the reverse recovery loss of the boost diode, improving efficiency, especially at high line voltages.
* Integrated Functions: Includes an internal start-up timer, over-voltage protection (OVP), open-loop protection, and zero-current detection (ZCD), reducing external component count.
* Low Start-up Current: Features a low start-up current (~30 µA typical), which eases design for the start-up circuit and improves system efficiency at light loads.
* Improved THD: The variable frequency operation in CRM helps achieve low total harmonic distortion across a wide load range.
Limitations:
* Variable Frequency Operation: The switching frequency varies with line voltage and load. This can complicate EMI filter design, as the noise spectrum is broad.
* Higher Peak Currents: Compared to Continuous Conduction Mode (CCM) PFC controllers, CRM operation results in higher peak switch currents for the same output power, which may require a MOSFET with a higher current rating.
* Power Range: Best suited for low to medium power applications (typically up to 300-400W). For very high power applications, CCM controllers are often preferred for their lower RMS currents.
## 2. Design Considerations
### Common Design Pitfalls and Solutions
1. Pitfall: Unstable Operation or Oscillation at Light Load.
* Cause: Improper setting of the ZCD pin parameters or noise coupling.
* Solution: Ensure the ZCD auxiliary winding voltage is correctly scaled with a resistive divider. Use a small RC filter (e.g., 1kΩ, 100pF) at the ZCD pin to suppress noise. Verify the minimum on-time of the internal gate driver is not being violated.
2. Pitfall: Failure to Meet THD Targets at High Line/Light Load.
* Cause
