Achieve Savings at No Load in Power Supplies for Netbook Adapters and LED Lighting
Fairchild's new FAN6921 is considered to be the best fit for power supplies ranging from 90W to 150W. These power supplies are found in notebook adapters and LED lighting applications.
This controller offers significant power savings, enabling power supply designs to meet <300mW at no load, and it also meets ENERGY STAR EPS 2.0 level 5. It features extended valley detection for light load efficiency improvements and integrated protection functions such as over voltage protection (OVP), over current protection (OCP), over temperature protection (OTP), over load protection (OLP) and brown out protections. Since it is a highly integrated solution, it can eliminate more than 30 components.
Features:
• Integrated PFC and Flyback Controller
• Critical Mode PFC Controller
• Zero-Current Detection for PFC Stage
• Quasi-Resonant Operation for PWM Stage
• Internal Minimum toff 8us for QR PWM Stage
• Internal 10ms Soft-Start for PWM
• Brownout Protection
• High / Low Line Over-Power Compensation
• Auto-Recovery Over-Current Protection
• Auto-Recovery Open-Loop Protection
• Externally Latch Triggering (RT Pin)
• Adjustable Over-Temperature Latched (RT Pin)
• VDD Pin and Output Voltage OVP (Latched)
• Internal Over-Temperature Shutdown (140°C)
Applications:
• AC/DC NB Adapters
• Open-Frame SMPS
• Battery Charger
The highly integrated FAN6921 combines Power Factor Correction (PFC) controller and Quasi-Resonant PWM controller. Integration provides cost effect design and allows for fewer external components.
For PFC, FAN6921 uses a controlled on-time technique to provide a regulated DC output voltage and to perform natural power factor correction. With an innovative THD optimizer, FAN6921 can reduce input current distortion at zero-crossing duration to improve THD performance.
For PWM, FAN6921 provides several functions to enhance the power system performance: valley detection, green-mode operation, high / low line over power compensation. FAN6921 provides many protection functions as well: secondary-side open-loop and over-current with auto recovery protection, external latch triggering, adjustable over-temperature protection by RT pin and external NTC resistor, internal over-temperature shutdown, Vdd pin OVP, and DET pin over-voltage for output OVP, and brown-in / out for AC input voltage UVP.
The FAN6921 controller is available in a 16-pin small outline package (SOP).
