# switchmode.io > Web-based analytical design tool for multi-stage power converters. Vendor-neutral component selection from real datasheet parts, with connected loss, thermal, stability and magnetics analysis across every stage of a power chain. It sits between spreadsheets and manufacturer calculators on one side and full circuit simulation (LTspice, PLECS, PSIM, SIMBA) on the other. switchmode.io helps power electronics engineers make design decisions analytically before committing to simulation or hardware: - Design multi-stage power converter systems on a visual canvas - Select and compare components from any manufacturer under identical operating conditions - Analyse losses, thermals and stability with temperature-dependent models built from each part's datasheet curves - Open any result to see the curve, operating point and assumptions behind it, each graded for how far to trust it ## Positioning switchmode.io is a pre-simulation design tool, not a circuit simulator. It uses closed-form analytical models to calculate steady-state performance and small-signal stability, and complements time-domain simulation rather than replacing it. Its results are analytical estimates: check a design in simulation and on the bench before committing to it. ## Pages - [Home](https://switchmode.io): what the tool does, shown on a worked multi-stage design, and the waitlist - [Pricing](https://switchmode.io/pricing): the three tiers, a feature comparison table, how the numbers are computed, and what is recorded - [Calculators](https://switchmode.io/calculators): free power electronics calculators in the browser, no sign-up required - [Resources](https://switchmode.io/resources): worked articles and application notes on buck and boost converter design - [About](https://switchmode.io/about): who builds switchmode.io - [Privacy](https://switchmode.io/privacy): privacy policy, including the design activity a signed-in session records - [Terms](https://switchmode.io/terms): terms of service ## Core Features ### Design - Visual canvas with converter stages, buses, loads and component slots - Multi-stage systems analysed as one connected chain, each stage loaded by the stages it feeds - Vendor-neutral catalogue of real manufacturer parts, carrying datasheet curves rather than only scalar values - Custom magnetics: core and winding selection, with core loss from Steinmetz coefficients and the iGSE waveform correction - Input filter design, sized to an attenuation target and checked for stability against the converter it feeds (Middlebrook and GMPM criteria) - Parameter sweeps, side-by-side component comparison and design branching (Pro) ### Analysis - Loss: MOSFET conduction, switching, gate charge, output capacitance and dead time; diode forward and reverse recovery; inductor core and copper; capacitor ESR - Thermal: junction temperatures solved together with the losses they set, iterated to a steady state - Stability: loop gain with Type II and Type III compensation, in voltage mode and peak current mode, with crossover and phase margin - Provenance: each result names the curves, operating point and assumptions it rests on, an assumed gate driver included, and grades them ### Export - JSON design export and a bill of materials - CSV data export (Pro) ### Planned, not yet built - Stage-to-stage stability, the Middlebrook criterion between two converters: planned - Worst-case tolerance analysis over component tolerances: planned - EMI compliance checking against conducted-emission limits: planned - PDF design reports: planned - LTspice netlist export: planned - Planar magnetics: planned ## Supported Topologies - Buck - Boost Flyback, forward, half and full bridge, LLC, dual active bridge and PFC are planned for Pro. ## Pricing - **Free**: up to five converter stages, buck and boost, input filter design, efficiency, loss, thermal and stability analysis, custom magnetics, the full parts catalogue and a bill of materials. No card and no time limit. - **Pro** ($129, £99 or €115 per seat per month; $1,290, £990 or €1,150 per seat per year): everything in Free, plus unlimited stages, parameter sweeps, component comparison, design branching and CSV export. The advanced topologies, worst-case tolerance analysis, EMI compliance checking, protection circuits and a shared team workspace with templates and roles are planned for Pro. - **Enterprise** (quoted): for regulated industries. See the pricing page for what it adds. ## How It Runs - Analysis runs in the browser. - The part picker's catalogue search runs on switchmode.io's servers, ranking parts at the operating point of the slot being filled. - A signed-in session records which parts are evaluated and compared, at what operating point and with what results, under a random identifier rather than a name. The privacy policy lists exactly what is recorded. - Saved designs are stored in cloud storage, access-controlled to the user's account. - Built with Next.js on Vercel, with Supabase for accounts, saved designs and the component catalogue. ## Use Cases - Choose a topology and its components before setting up a simulation - Compare MOSFETs, inductors or capacitors from different manufacturers under identical operating conditions - Design custom magnetics with their loss and temperature in the same analysis as the rest of the converter - Analyse a multi-stage power chain (for example 48 V to 12 V, then 5 V and 3.3 V) as one connected system - Check a control loop: crossover, phase margin, and the compensator that sets them ## Free Calculators Available without sign-up, with results shareable by URL: - [Buck inductor calculator](https://switchmode.io/calculators/buck-inductor): minimum inductance for continuous or discontinuous conduction, with the peak and RMS currents and the duty cycle that follow from it - [Boost converter calculator](https://switchmode.io/calculators/boost-converter): duty cycle, inductance, peak and RMS currents, switch and capacitor stress at your efficiency, and the right-half-plane zero that limits the loop - [Input filter calculator](https://switchmode.io/calculators/input-filter): size a buck or boost converter's input filter to an attenuation target, then check it against the Middlebrook and GMPM stability criteria - [MOSFET power loss calculator](https://switchmode.io/calculators/mosfet-power-loss): a buck's or boost's MOSFET losses from datasheet values, with each junction temperature solved against its own loss, thermal runaway, and derating ## Company Built by Philip Bassett, a power electronics engineer with ten years' experience across defence and oil and gas. Solo-founded, UK-based. ## Status Pre-launch. The design tool is in private alpha; the calculators and articles are open to everyone. Join the waitlist from the home page.