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onsemi Power Management for Switch Mode Power Supplies (SMPS)

Featured products, solutions and more

onsemi’s Offline SMPS System Solutions Guide features the basics about offline SMPS, together with the featured products and solutions provided by our supplier partner.

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Featured Product Series


The NCP4390 by onsemi is an advanced Pulse Frequency Modulated (PFM) controller for LLC resonant converters with Synchronous Rectification (SR) that offers best-in-class efficiency for isolated DC/DC converters.

It employs a current mode control technique based on charge control, where the triangular waveform from the oscillator is combined with the integrated switch current information to determine the switching frequency.

This provides a better control-to-output transfer function of the power stage simplifying the feedback loop design while allowing true input power limit capability. Closed-loop soft-start prevents saturation of the error amplifier and allows monotonic rising of the output voltage regardless of load condition.

A dual-edge tracking adaptive dead time control minimizes the body diode conduction time thus maximizing efficiency.

Download the Application Note


  • Secondary-Side PFM Controller for LLC Resonant Converter with Synchronous-Rectifier Control
  • Charge-Current Control for Better Transient Response and Easy Feedback-loop Design
  • Synchronous-Rectification Control with Dual-Edge Tracking
  • Closed-Loop Soft-Start for Monotonic Build-up of the Output Voltage
    • Wide Operating-Frequency Range (39kHz ~ 690kHz)
    • Green Functions to improve Light-Load Efficiency
    • Symmetric PWM control at Light Load to Limit the Switching Frequency while ReducingSwitching Losses
    • Programmable PWM-Mode Entry Point
    • SR Gate-Signal Shrinking at Light-Load Condition to Prevent Negative Resonant Current
  • Disabling SR at Extremely Light-Load Condition
  • Protection Functions with Auto-Restart
    • Non-ZVS Prevention by Frequency Shift
    • Power Limit by Frequency Shift
    • Over-Current Protection (OCP)
    • Output-Short Protection (OSP)
    • Over-Load Protection (OLP) with Programmable Shutdown Delay Time
    • Programmable Dead Time for Primary Side Switches and SR Switches
    • Wide Operating Temperature Range –40°C To 125°C


More Information

onsemi features Offline Switch Mode Power Supplies (SMPS), which are switching power supplies with an isolation transformer that is powered by the grid ranging from low wattage laptop battery chargers to many kilowatts for server power supplies.

The worldwide focuses on improving energy efficiency with standards like the European Union Executive Committee's latest CoC V5 and the U.S. Department of Energy DoE VI have clear requirements on the power loss and efficiency during not only full load, but light load/no load to achieve energy saving and emission reduction. Higher efficiency can be achieved by using power switches with better performance or by implementing different control strategies. In addition, choose the most appropriate topology in different conditions.


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