What is a buck converter and how does it work?
A buck converter is a DC-to-DC switching regulator that steps down voltage while maintaining high efficiency. It uses a switching transistor, inductor, diode, and capacitors to convert higher input voltage to lower output voltage by rapidly switching the input on and off. See also our Boost Converter Calculator.
How do you choose the switching frequency of a buck converter?
Higher switching frequencies allow smaller component sizes but increase switching losses. Typical frequencies range from 100kHz to 2MHz. Choose based on size constraints, efficiency requirements, and EMI considerations.
Why is my calculated inductor value different from the datasheet?
Datasheets often use different ripple current percentages or operating conditions. Our calculator uses your specific parameters. Always verify the inductor can handle the RMS and peak currents in your application.
Can I use a larger inductor than calculated?
Yes, using a larger inductor will reduce ripple current and improve efficiency, but increases size and cost. It also slows transient response. The calculated value is the minimum required for your ripple specification. You might also find our calculate Flyback Converter Duty Cycle useful.
Can a buck converter step up voltage?
No, a buck converter can only step down voltage. The output voltage is always less than the input voltage. For step-up conversion, you need a boost converter or buck-boost converter.
What's the minimum load for continuous conduction mode (CCM) operation?
CCM operation requires sufficient load current to keep the inductor current continuous. The boundary occurs when the minimum inductor current reaches zero. Light loads may cause discontinuous conduction mode (DCM).
How do I reduce output ripple further?
Increase the output capacitance, use capacitors with lower ESR (like ceramic or polymer caps), increase switching frequency, or add an LC output filter. Multiple capacitors in parallel can also help.
Should I use synchronous or asynchronous rectification?
Synchronous rectification (MOSFET instead of diode) improves efficiency, especially at high currents and low output voltages. Asynchronous (diode) rectification is simpler and cheaper but less efficient. Check out our calculate Buck-Boost Converter Duty Cycle as well.