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Free Power Electronics Calculators
Design tools for DC-DC, flyback, LLC, DAB and PFC converters, control loops, protection, filters and thermal design, each with its method, formulas and a worked example. Everything runs in your browser.
Converter Design
DC-DCBuck / Boost / Buck-Boost Power StageSize the inductor and output capacitor of a buck, boost or inverting buck-boost converter across its input range, with switch and diode currents, the CCM/DCM boundary and the inductor current waveform.LLCLLC Resonant Converter Calculator: Tank Design and Gain CurveDesign an LLC resonant tank from input range, output and power: turns ratio, m, Qmax, Lr, Cr and Lm, with the FHA gain curve and a ZVS check.DABDAB Converter DesignDesign a dual active bridge with single, dual or triple phase shift (SPS, DPS, TPS): series inductance, phase shift, inductor peak currents, transferred power and the ZVS conditions.PFCCCM Boost PFC DesignSize the boost inductor, output capacitor and current stresses of a continuous-conduction-mode PFC stage, and see the inductor current envelope at low and high line.FLYFlyback Converter DesignTurns ratio, magnetizing inductance, primary and secondary currents, MOSFET and diode stress and the RCD clamp of a CCM or DCM flyback, with current and V_ds waveforms at both input extremes.
Control
LOOPLLC Plant + PI Controller Bode PlotSee how PI gains shape the LLC voltage loop: Bode plot, crossover, phase and gain margin, auto-tuning and closed-loop step response.PFC LOOPPFC Current and Voltage LoopDesign the average-current-mode current loop and the voltage loop of a CCM boost PFC, check both on Bode plots, and see how much 2·f_line ripple reaches the current reference and the input current.COMPBuck/Boost Type II / Type III CompensatorDesign an op-amp Type II or Type III error amplifier for a voltage-mode buck or boost with Venable's k factor, round to standard parts and check crossover and margins on a Bode plot.PIDPID Controller Code GeneratorGenerate discrete PID controller code in C and other languages with anti-windup options.PI zPI Discretization Calculator (Tustin, Euler, ZOH)Turn a continuous PI controller Kp + Ki/s into the two coefficients of a difference equation, and see how much each method, and the sampling delay, shifts gain and phase at your crossover.
Protection & Startup
INRInrush Current Limiter Calculator: Resistor and NTC SizingSize a DC-link precharge resistor or NTC thermistor: peak inrush, pulse energy, charge time and temperature rise, plus NTC hot-restart peak and plots.DTDead Time Calculator for MOSFET and IGBT Half-BridgesMinimum and recommended dead time from datasheet switching times or gate charge, with temperature and driver margins, and MCU timer register values.RC SNBRC Snubber CalculatorFind the parasitic L and C of a ringing switch node from two frequency measurements, size the RC snubber, estimate its loss, and compare the simulated ring-down with and without it.
Filters & Signal
Components & Thermal
FETMOSFET Loss Calculator (Conduction, Switching, Body Diode)Estimate MOSFET conduction, switching, C_oss, body-diode and gate losses from datasheet values, iterate the junction temperature, and find the switching frequency where switching loss overtakes conduction.RθHeatsink and Thermal Resistance CalculatorJunction temperatures of several devices on one heatsink, the largest heatsink R_θSA that keeps them under T_j,max, TIM resistance, and pulsed junction temperature from a Foster Z_th network.CAPCapacitor Ripple Current and Lifetime CalculatorCombine ripple current at several frequencies, estimate the self-heating and expected life of aluminum electrolytic capacitors with the manufacturer formulas, and check the hot spot and voltage derating of film capacitors.
Latest guides
All guides →- SMCSliding-Mode Control for DC-DC ConvertersA practical look at sliding-mode voltage control of buck and boost converters: choosing the sliding surface, the reaching and existence conditions, why a hysteresis implementation changes frequency with input voltage, what chattering means in a converter, and how equivalent control turns it into fixed-frequency PWM. Includes an interactive phase-plane simulation.Published 2026-11-01
- SRSynchronous Rectifier Timing in LLC ConvertersWhen to turn the secondary-side synchronous rectifiers of an LLC converter on and off: how the current shape changes below and above resonance, why drain-voltage sensing turns off early, what package inductance does to the threshold, and how SR controllers deal with it. Includes an interactive timing chart.Published 2026-11-01
- DC LINKSizing the DC-Link Capacitor of a Three-Phase Inverter by RMS CurrentHow much ripple current a three-phase PWM inverter puts into its DC-link capacitor, why the worst case sits near M = 0.6, a formula checked against simulation, and how to choose film or electrolytic parts.Published 2026-11-01
- FILTERDamping an LC Filter: Sizing the R_d–C_d LegWhy an LC filter rings, why its impedance peak can destabilize a regulated converter, and how to size the parallel R_d–C_d damping leg, with a worked 10 µH / 10 µF example and an interactive |Z_o| plot.Published 2026-11-01