HVAC Model Development Guide

23btree00

“HVAC Mini Model with Variable Speed Control.”

45 days

flux

1:03

Planning.

Thinking deeply about your request.

Creating an execution plan.

Working on your request.

Your goal is to build an “HVAC Mini Model with Variable Speed Control”: power input + fan/blower drive (N-channel MOSFET low-side) + speed control input (knob or PWM) + optional thermostat/sensor interface, ending with a manufacturable PCB.

I’ve created a plan (status: ready_to_execute).
Next steps in the plan:
1. Define architecture/requirements in the project description
2. Build the full schematic (power entry, MOSFET motor drive, control input, optional sensor/thermostat, connectors)
3. Set board outline/stackup, place connectors first, then place/route with separation of high-current vs signals
4. Run DRC/manufacturability checks and export Gerbers/BOM/assembly outputs

Click Start on the plan bar to run it. Let me know if you want the control input to be potentiometer knob or external PWM (or both).

Plan

#Goal

Design an HVAC mini model featuring a variable speed control for the fan/blower. The design must include a power input stage, a motor drive stage utilizing an N-channel MOSFET for low side switching, a control input stage (using either a potentiometer (knob) or PWM input), and an optional thermostat/sensor interface with proper connectors. The final deliverable must have a complete schematic and corresponding PCB layout prepared for fabrication.

#Implementation plan

Define the system architecture and requirements
1. Create a project description outlining the HVAC mini model's functionality (power input, motor drive, control input, and optional sensor interface).
2. Specify DC power input characteristics and operating voltage levels.
Develop the schematic
1. Add a power entry section including power connectors, protection devices, and voltage regulation.
2. Integrate a variable-speed motor drive stage using an N-channel MOSFET. Add gate drive components to control speed via PWM or analog signal.
3. Implement the control input section by adding a knob/PWM input interface, with conditioning and appropriate filtering.
4. Include an optional thermostat/sensor input section with proper connectors and interface circuitry.
5. Label all nets and run schematic sanity checks ensuring proper connectivity (without creating separate nets manually).
Prepare the PCB layout
1. Define board outline, set PCB dimensions, and configure the board stackup.
2. Place key connectors (power, control, sensor) and lock their positions.
3. Position remaining components suitably for motor high-current paths and low-current control signals.
4. Route the board ensuring that high current motor paths are adequately separated from control signal traces.
5. Run DRC and check layout for manufacturability.
Generate fabrication outputs
1. Export Gerber files, BOM, and assembly drawings ready for production.

#Success criteria

The HVAC mini model schematic includes all required blocks (power, motor drive, control, optional sensor) with appropriate connectors and MOSFET drive circuitry.
The PCB layout meets the design requirements with clearly defined board dimensions, component placement that segregates high-current paths, and no routing errors.
All design outputs (schematic and PCB layout) are complete and manufacturable.

Use potentiometer knob

Use external PWM input

Support both inputs

Inspect current schematic

Check DRC/ERC now

45 days

const gateId = "8ab52d23-74a4-a96d-73c7-d4764600905a";
const drainId = "6e8f3c1d-1999-92ed-3aa8-7486fa7ad8cc";
const sourceId = "dd05fdee-0b43-3d74-bce6-427f356659b7";
const gateTerminal = flux.getNodeById(gateId, "elementTerminal");
const drainTerminal = flux.getNodeById(drainId, "elementTerminal");
const sourceTerminal = flux.getNodeById(sourceId, "elementTerminal");
const vgs = flux.createOutputNode("Vgate");
const vds = flux.createOutputNode("Vdrain");
const drainToSource = flux.createOutputNode("I");
const vs = flux.createOutputNode("Vsource");
//setup event
flux.on("setup", () => {
    const threshold = Number(flux.properties.find((prop) => prop.name === "Threshold Voltage")?.value);
    const beta = Number(flux.properties.find((prop) => prop.name === "Beta")?.value);
    flux.simulationModel = simModel(beta, threshold);
});
// Property was changed event
flux.on("propertyChange", (event) => {

Reviews

Ground
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Generic Capacitor
A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF, 10pF, 100pF, 1000pF, 0.01uF, 0.1uF, 1.0uF, 10uF, 100uF, 1000uF, 10000uF 1.1pF, 11pF, 110pF, 1100pF 1.2pF, 12pF, 120pF, 1200pF 1.3pF, 13pF, 130pF, 1300pF 1.5pF, 15pF, 150pF, 1500pF, 0.015uF, 0.15uF, 1.5uF, 15uF, 150uF, 1500uF 1.6pF, 16pF, 160pF, 1600pF 1.8pF, 18pF, 180pF, 1800pF 2.0pF, 20pF, 200pF, 2000pF 2.2pF, 22pF, 220pF, 2200pF, 0.022uF, 0.22uF, 2.2uF, 22uF, 220uF, 2200uF 2.4pF, 24pF, 240pF, 2400pF 2.7pF, 27pF, 270pF, 2700pF 3.0pF, 30pF, 300pF, 3000pF 3.3pF, 33pF, 330pF, 3300pF, 0.033uF, 0.33uF, 3.3uF, 33uF, 330uF, 3300uF 3.6pF, 36pF, 360pF, 3600pF 3.9pF, 39pF, 390pF, 3900pF 4.3pF, 43pF, 430pF, 4300pF 4.7pF, 47pF, 470pF, 4700pF, 0.047uF, 0.47uF, 4.7uF, 47uF, 470uF, 4700uF 5.1pF, 51pF, 510pF, 5100pF 5.6pF, 56pF, 560pF, 5600pF 6.2pF, 62pF, 620pF, 6200pF 6.8pF, 68pF, 680pF, 6800pF, 0.068uF, 0.68uF, 6.8uF, 68uF, 680uF, 6800uF 7.5pF, 75pF, 750pF, 7500pF 8.2pF, 82pF, 820pF, 8200pF 9.1pF, 91pF, 910pF, 9100pF #generics #CommonPartsLibrary
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