48V Telecom Power Supply Inductor Design Example

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Telecom and networking equipment commonly operate from a 48V DC power bus.

Routers, switches, wireless infrastructure, and data center equipment often require efficient DC-DC converters to generate lower voltages for internal electronics.

One of the most important magnetic components in these converters is the power inductor.

In this example, we will walk through the design process for a telecom power supply inductor operating from a 48V bus.

Power inductor used in a 48V telecom DC-DC converter supplying networking and communications equipment.
Telecom power supplies rely on efficient inductors to convert 48V bus power into lower voltages used by networking equipment.

Design Requirements

Input Voltage:

48V

Output Voltage:

12V

Output Current:

20A

Switching Frequency:

250 kHz

Target Ripple Current:

25%

Maximum Temperature Rise:

40°C

Quick Design Estimate

Before beginning detailed calculations, engineers often evaluate several candidate magnetic solutions.

Inductor Quick Feasibility Checker

Use this quick estimator to check peak current, stored energy, and preliminary design difficulty.

Peak Current: A

Ripple Current: A p-p

Stored Energy: mJ

Preliminary Difficulty:

Likely Core Direction:

This is a quick educational estimate only. Final design requires core geometry, gap, winding, loss, fill factor, and thermal checks.

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Step 1: Determine Output Current

The converter must deliver:

20A

at:

12V

This establishes the baseline current requirement.

Step 2: Select Ripple Current

A common design target is:

20% to 30% ripple current.

For this example:

25% ripple current

Ripple current:

20A × 0.25

= 5A

Calculate Ripple Current

Buck Converter Ripple Current Calculator

Estimate duty cycle, inductor ripple current, and peak current for a buck converter.

Duty Cycle: %

Ripple Current: A p-p

Ripple Percentage: %

Peak Current: A

Need a full CAD-ready inductor design?

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Why Ripple Current Matters

Ripple current influences:

  • Peak current
  • RMS current
  • Copper losses
  • Saturation margin
  • Thermal performance

👉 Related Guide: Ripple Current Explained

Step 3: Determine Peak Current

Peak current becomes:

20A + (5A ÷ 2)

= 22.5A

This value will be used during saturation analysis.

Step 4: Verify Saturation Margin

The core must remain below saturation under:

  • Full load
  • Maximum ambient temperature
  • Worst-case ripple conditions

👉 Related Guide: Understanding Magnetic Saturation

Check Saturation Margin

Inductor Saturation Risk Checker

Estimate flux density from inductance, peak current, turns, and effective core area.

Estimated Flux Density: T

Risk Level:

Approximation: B ≈ L × Ipk / (N × Ae). Final design should use actual core data, gap, material Bsat, and temperature limits.

Need a full saturation and gap-checked design?

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Step 5: Select Core Material

Potential materials include:

  • Ferrite
  • Powdered Iron
  • Nanocrystalline

At 250 kHz:

Ferrite is often preferred because of:

  • Low core losses
  • Excellent high-frequency performance
  • Broad availability

👉 Related Guide: How to Choose the Right Core Material

Step 6: Select Wire Size

The winding must safely carry:

20A average current

while minimizing losses.

Possible options include:

  • AWG12
  • AWG11
  • Parallel AWG14
  • Copper foil

Evaluate Wire Options

Wire Current Density Calculator

Estimate required copper area and approximate AWG size from RMS current and target current density.

Total Copper Area Required: mm²

Area Per Conductor: mm²

Approximate Suggested AWG:

This is a first-pass estimate. Real winding design also requires insulation diameter, window fill, AC loss, bend radius, and thermal checks.

Want optimized winding and CAD output?

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Step 7: Estimate Losses

Major losses include:

  • Copper losses
  • Core losses
  • AC winding losses

These losses directly affect:

  • Efficiency
  • Reliability
  • Temperature rise

Estimate Losses

Inductor Loss Estimator

Estimate copper loss, core loss, and total loss for a preliminary inductor design.

Copper Loss: W

Core Loss: W

Total Loss: W

Thermal Concern:

Need a thermal-checked design package?

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Step 8: Evaluate RMS Current

RMS current determines conductor heating.

👉 Related Guide: How to Calculate RMS Current in Power Inductors

Proper RMS current evaluation is critical for thermal design.

Step 9: Thermal Evaluation

The target is:

Less than 40°C temperature rise

under worst-case operating conditions.

👉 Related Guide: How to Reduce Inductor Temperature Rise

Thermal performance often drives final design decisions.

Practical Optimization Process

A real engineering workflow may evaluate:

  • Multiple core sizes
  • Multiple conductor arrangements
  • Multiple gap configurations
  • Multiple thermal solutions

before selecting the final design.

Conclusion

Telecom power supply inductors must balance:

  • Efficiency
  • Saturation margin
  • Temperature rise
  • Manufacturability
  • Cost

A systematic design process helps engineers develop reliable and efficient magnetic solutions for networking and telecom equipment.

Need Help Designing Telecom Magnetics?

The SolidMagnetics platform helps engineers optimize:

  • Core selection
  • Wire sizing
  • Saturation margin
  • Thermal performance
  • Manufacturability

while automatically generating CAD models, engineering drawings, BOMs, and production-ready outputs.

Ready to Generate Your Custom Magnetic Design?

Upload your electrical requirements and receive:

  • 3D CAD model
  • Manufacturing drawings
  • BOM
  • Build-ready geometry
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