Simulating dc-dc converters with QSPICE

Explore the basics of spice and Q spice for beginners, covering installation, a quick tour, essential commands, components, parameters, and running a basic simulation.

Download and install Q spice on Windows 10 or 11 by filling a form to receive the download link, then run as administrator and accept the license.

Explore the qspice circuit simulator, access quick start guides, third-party models, and active forums, and learn to navigate libraries, run simulations, and use help documentation.

Explore essential links and references for using QSPICE, including online SPICE references, forums, guidance on importing third-party modules, and helpful videos to start simulating circuits.

Place a ground reference and write a SPICE directive to run a transient simulation in QSPICE. Learn to specify stop time and use dot run for basic circuit tests.

Learn to generate and customize plots in Qspice, visualize node voltages and currents, and use expressions and net names to label nets for clearer waveform comparisons.

Learn to configure the sine voltage source in QSPICE, including peak amplitude, frequency in hertz, delay, damping theta, phase phi, and cycle count, to simulate ac grid or three-phase signals.

Learn to create jagged voltages with a piecewise linear voltage source using time–voltage pairs. Explore using it to control passive components, emulate a load resistor, and perturb input voltage.

Simulate a dc-dc circuit in qspice using an r-l-c network and a behavioural resistor to model a variable load, with net names linking subcircuits and a piecewise linear drive.

Create and persist waveform plots in QSPICE using plot commands as SPICE directives. Label nets, plot voltages and currents, and compare signals across simulations for consistent analysis.

Corrects a previous simulation by adjusting the piecewise linear voltage source and extending the transient to five seconds, illustrating the envelope of the load current in QSPICE.

Harness the true power of q spice by blending GUI-based schematic editing with a command-line language to fine-tune parameters and model parasitics.

Explore the buck converter, its topology and operation, using qspice with ideal switches and pulsed gate voltages. Prepare for MOSFET-based simulations, PWM control blocks in C++, and Infineon spice models.

Build the buck converter topology from active switches using PWM and a sawtooth waveform carrier, and explain how the duty ratio and switching frequency regulate a stepped-down output.

Explore how a buck converter operates in on and off states, applying Kirchhoff's voltage law to derive how energy flows through the inductor and output capacitor via the duty ratio.

Open a schematic in QSPICE, draw buck converter by placing a 24V source, an ideal switch, mosfet, diode, inductor with ESR, capacitor with ESR, load, then ground the circuit.

Explain diode and voltage control switch parameters in Qspice, using inbuilt models via the selection guide, and set a 100 nanosecond max time step for dc-dc simulations.

Explore setting up a gate pulse for a voltage control switch in qspice, define threshold and hysteresis, and plot input, output, and inductor current in a buck converter.

Analyze the buck converter simulation in QSPICE by examining gate, inductor, and diode currents for a 24 v input with a 0.5 duty cycle, noting the output near 12 v.

Implement pwm logic in qspice by coding a c++ control block within a hierarchical pwm component that uses a duty ratio and carrier to drive the gate.

Explore how a custom C++ PWM block generates gate pulses from a duty ratio and a sawtooth carrier, verify results, and compare output voltage and inductor current with prior simulations.

Replace the control voltage switch with an n-channel MOSFET in the QSPICE converter. Use the selection guide to pick a MOSFET and review the gate-to-source voltage from the datasheet as an exercise.

Simulate an n-channel MOSFET in QSPICE, selecting a device with suitable Vds and Id, drive the gate with isolated ±10 V and a series resistor, and examine gate threshold.

Windows defender blocks the dot dll created from the c++ code that QSPICE uses; restore the file from quarantine and add an exception so the simulation runs smoothly.

Verify spice mosfet models with a separate test bench against data-sheet characteristics like gate threshold, using qspice, and manage startup transients by ramping duty cycle with a piecewise linear source.

Conclude a QSPICE dc-dc buck converter simulation and explore variations in duty cycle, load and input voltage, while recognizing practical designs require snubbers and careful timing for reliable hardware implementation.

Concludes the buck converter simulation section with a step-by-step approach using a simple control switch and pulse waveform, then introduces a C++ control block and MOSFET implementation.

Introduce the boost converter, linking it to the buck converter, and analyze energy exchange and topology while simulating with qspice, mosfet models, and a C++ pwm block, noting initial conditions.

Describe the boost converter topology, explain how it differs from a buck converter, and show how the inductor stores and releases energy to boost the output voltage.

Learn to build and simulate a boost converter in QSPICE by adapting a buck schematic, configuring PWM, and creating a cpp interface to generate a DLL for simulation.

Analyze boost converter simulation results in qspice by verifying gate PWM, noting the duty cycle ramp, and confirming the output tracks Vin/(1-d) with startup transient considerations.

Apply a gradual duty ratio ramp to avoid large di/dt transients that spike the output capacitor in qspice simulations of a boost converter.

Demonstrate the boost converter by storing energy in the inductor and delivering it with the input to the output, validated with MOSFET PWM simulations, and discuss initial conditions for stability.

Explore the simple buck-boost converter topology and the energy exchange between input, inductor, and output capacitor. Use QSPICE to verify buck-boost theory, and preview the Chuck converter.

Explore the buck-boost converter topology and operation, showing energy exchange between input, inductor, and output that yields voltages both below and above Vin using a simple switch, diode, and capacitor.

Set up a buck-boost converter simulation in qspice, reorganize components with a floating MOSFET source, and configure the C++ interface and PWM gate logic before running and analyzing results.

Analyze buck and boost operation in a buck-boost converter using QSPICE, comparing results at duty cycles below and above 0.5, and verify inductor current and negative output voltage behavior.

Examine how initial conditions influence buck boost converter simulations, including startup dynamics, inductor current, and output capacitor behavior under varying duty ratios.

Conclude that buck and buck-boost converters decouple input and output to enable buck-boost operation through energy storage in inductors and capacitors, with q spice simulations.

Explore the Chuck converter, a buck-boost topology that decouples input and output and uses a capacitor for energy storage. Compare capacitor advantages over inductors and outline topology and simulations.

Explore the topology of the Chu converter, a capacitor-based energy transfer that combines a boost stage and a buck stage with two inductors, enabling reduced ripple and negative output voltage.

Set up a Cuk converter simulation in QSPICE, configure PWM gating, arrange inductors, capacitors, diodes, and resistors, and plot capacitor voltage and inductor current to verify basic operation.

Analyze the simulation results of a QSPICE dc-dc converter, confirming boost operation and detailing ripple reduction, inductor currents, and verification of Vout = Vin/(1-d).

Conclude section by examining the chuck converter with two inductors and two capacitors. Validate theory with mOSFET PWM simulations and discuss startup, steady state, negative output voltage, and floating ground.

Introduce the Sepic converter, a buck-boost topology with two inductors and an energy-transfer capacitor that yields same-polarity output and partial decoupling, with q spice simulations.

Learn the Sepic converter topology, its energy transfer via two inductors and a blocking capacitor, and how decoupling yields a buck-boost output with the same polarity as the input.

Set up a sepic simulation by transforming a spark converter, moving the inductor and diode between series and shunt branches, and verify energy transfer through the decoupling capacitor and inductors.

Analyze a SEPIC simulation in QSPICE, focusing on capacitor voltage, inductor currents, and gate pulses. Show how duty changes yield 4 V and 16 V outputs, confirming boost operation.

Demonstrate how SEPIC uses a midpoint capacitor for forward-path pseudo decoupling, yielding the same polarity at input and output, unlike the chuck converter, and preview Zetta converter with QSPICE simulations.

Explore the zeta buck-boost converter topology, compare the decoupling method via the midpoint capacitor with the sepik design, and simulate its operation in QSPICE to verify results.

Outline the zeta converter topology, its buck–boost operation, and how two interchanges charge capacitor c1 to the output voltage, yielding the same-polarity buck-boost.

Learn to simulate the Zeta converter in QSPICE, including circuit rearrangement, proper file setup, cpp file naming and function naming, and running the simulation.

Analyze zeta converter simulation results in QSPICE, confirming boost and buck operation and the output's relation to input voltage. Note that mutual inductance from dual windings reduces ripple.

Concludes the zeta converter section, showing the decoupling capacitor charges to the output voltage, canceling output voltage, with simulations of current and voltage ramps across switching intervals aligning with theory.

Expand q-space models by incorporating hardware details and manufacturer spice models for a buck converter. Align gate drive voltages with microcontroller levels and build hierarchical blocks for hardware-accurate simulations.

Learn to create a gate driver subcircuit in QSPICE by building a hierarchical entry with two ports, isolating gate and source, and integrating a behavioral source for gate drive.

Select a suitable isolated gate driver for a floating MOSFET in a dc-dc converter simulation, matching 3.3V/5V microcontroller PWM to a high-side driver with a spice model.

Download the gate driver SPICE model, verify it works despite manufacturer disclaimers, then copy it into your schematic, include the entire file, and test the subcircuit before use.

Learn to wire a gate driver spice model in QSPICE, identify pins and active low signals, and connect the non-inverting input and power pins from the microcontroller.

Connect the gate driver SPICE model with plus ten and minus ten volt supplies to VCC2 and V2, ground the desaturation input, and use outH/outL for the gate drive.

Correct gate driver connections in the spice model by adding ten ohm resistors to ground; ensure UVLO thresholds from the datasheet and apply at least 15 V to VCC.

Wrap up this section by integrating third-party spice models and gate drivers into dc-dc converter simulations, verify hardware behavior, and work with hierarchical circuit blocks.

Apply q spice to simulate dc-dc converters and analyze energy exchange in inductors and capacitors; leverage manufacturer spice models and application notes to bring simulations closer to hardware prototypes.