Input Inductors

DEFON Electronics Input Inductors – Clean Power Starts at the Input

In switching power supply design, the quality of the input current directly impacts overall system performance, efficiency, and regulatory compliance. DEFON Electronics manufactures precision input inductors specifically engineered to provide low AC ripple current to the input of switching power supplies used across diverse industries. From industrial drives to medical electronics, our input inductors ensure clean, stable power conversion from the very first stage.

What Are Input Inductors?

Input inductors are magnetic components placed at the front end of switching power supplies, between the AC or DC input source and the switching stage. Their primary function is to filter AC ripple current, reduce harmonic distortion, and provide a stable current source for the power conversion circuitry.

DEFON input inductors work by leveraging fundamental electromagnetic principles:

• Current Smoothing: When the input current attempts to rise suddenly, the inductor generates an electromotive force (EMF) in opposition to the current change, effectively reducing the rate of current increase.

• Current Support: Conversely, when the input current drops suddenly, the inductor generates an EMF in the same direction as the current flow, helping to maintain current levels and prevent abrupt decreases.

This bidirectional current stabilization results in significantly reduced AC ripple current at the power supply input, which translates to:

• Lower conducted EMI emissions

• Reduced stress on input capacitors

• Improved power factor

• Enhanced overall power supply efficiency

• Longer component life

How Input Inductors Work

DEFON input inductors operate on the principle of electromagnetic induction. A conductor is wound into a coil around a magnetic core, creating a component that stores energy in a magnetic field. The relationship between current and voltage in an inductor is defined by the equation V = L × (di/dt), where:

• V is the voltage across the inductor

• L is the inductance value

• di/dt is the rate of change of current

This fundamental relationship means that an inductor resists changes in current. When the current attempts to change rapidly, the inductor generates a counter-electromotive force that opposes the change. This property makes inductors ideal for smoothing current waveforms and filtering out high-frequency ripple.

In a typical switching power supply input stage, DEFON input inductors work in conjunction with input capacitors to create a low-pass filter that attenuates high-frequency switching noise while allowing the fundamental AC or DC power to pass through with minimal loss.

Applications for DEFON Input Inductors

DEFON input inductors serve critical functions across a wide range of industries and applications:

• Switching Power Supplies: Input filtering for AC-DC and DC-DC converters requiring low input ripple and conducted EMI compliance.

• Power Factor Correction (PFC) Circuits: Boost inductors for active PFC stages that shape input current to meet harmonic regulations.

• Industrial Drives and Motor Controls: Input filtering for variable frequency drives and servo systems operating in demanding environments.

• Medical Electronics: Low-leakage input inductors for patient-connected equipment requiring stringent safety and EMC performance.

• Telecommunications Equipment: Input filtering for network power supplies and base station equipment.

• Renewable Energy Systems: Input inductors for solar inverters, wind turbine converters, and battery energy storage systems.

• Electric Vehicle Chargers: EMI filtering and current smoothing for onboard and off-board charging infrastructure.

• Test and Measurement Instruments: Precision input filtering for laboratory equipment requiring clean power for accurate measurements.

• Manufacturing Equipment: Robust input inductors for industrial machinery operating in harsh electrical environments.

Advantages of DEFON Input Inductors

DEFON input inductors offer specific advantages for power supply designers:

• Low AC Ripple Current: Engineered to minimize input ripple current, reducing stress on input capacitors and improving overall power supply performance.

• High Saturation Current: Designed to handle peak currents without core saturation, ensuring stable operation under transient conditions.

• Low Core Loss: Optimized core materials minimize losses at switching frequencies, improving efficiency.

• Compact Design: High power density packaging saves valuable board space while delivering required performance.

• Thermal Management: Designs account for temperature rise, ensuring reliable operation under full load conditions.

• Custom Configurations: Available in a wide range of inductance values, current ratings, and mechanical configurations.

Input Inductor vs. Output Inductor: Understanding the Difference

While both input and output inductors serve filtering functions in power supplies, they address different challenges:

• Input Inductors: Focus on filtering AC ripple from the input source, reducing conducted EMI, and providing current stabilization for the switching stage. They often handle higher voltage stresses and must withstand input transients.

• Output Inductors: Focus on filtering switching ripple from the output, providing energy storage for load transients, and maintaining output voltage regulation.

DEFON Electronics manufactures both input and output inductors, allowing our customers to source complete magnetic solutions from a single trusted partner.

Technical Specifications

DEFON Electronics offers input inductors in a range of configurations to suit diverse application requirements:

• Size Range / Form Factor: Available in a broad range of sizes and bobbin types, including self-leaded, surface mount (SMT), and through-hole configurations to accommodate various PCB layouts and assembly processes.

• Output Range: Built to meet industry standards and customer requirements, with custom electrical specifications tailored to your application’s voltage, current, and frequency needs.

• Inductance Range: Custom values optimized for your specific switching frequency and ripple current requirements.

• Current Handling: Designed for continuous and peak current demands with appropriate saturation margins.

• Operating Temperatures: Multiple insulation classes available to match your thermal environment: 130°C, 155°C, 180°C, and 200°C.

• Packaging Options: Flexible packaging to support your manufacturing process, including tray, bulk, and tape-and-reel formats for automated assembly.

Compliance and Standards

DEFON Electronics is committed to manufacturing products that meet industry standards for quality and environmental responsibility:

• IPC-A-610: Manufactured in accordance with IPC-A-610 acceptability standards for electronic assemblies, ensuring consistent quality and reliability.

• RoHS3 and Conflict-Free: All inductors comply with RoHS3 environmental standards and Conflict-Free sourcing requirements, supporting ethical and sustainable supply chains.

Custom Engineering for Your Specific Requirements

At DEFON Electronics, we understand that input filtering requirements vary significantly depending on the power supply topology, switching frequency, and regulatory environment. Our engineering team works closely with you to develop custom input inductors that meet your exact specifications:

• Custom Inductance Values: Tailored to your specific switching frequency and ripple current requirements.

• Optimized Core Materials: Selected for optimal performance at your operating frequencies and power levels.

• Current Rating Customization: Designed for your exact continuous and peak current demands.

• Mechanical Customization: Custom footprints, mounting options, and form factors for unique PCB layouts.

• EMI Optimization: Designs tuned to meet specific conducted emissions standards.

Why Choose DEFON Electronics for Input Inductors?

With decades of combined experience in magnetic component design and power electronics, DEFON Electronics understands the critical role input inductors play in power supply performance and regulatory compliance. We combine precision manufacturing with deep technical expertise to deliver input inductors that provide reliable filtering, high current handling, and long-term dependability.

From initial concept and prototyping to full-scale production, we partner with you to ensure your power supply designs achieve optimal input current quality, efficiency, and EMC compliance.

Contact DEFON Electronics Today

DEFON Electronics designs, prototypes, and manufactures input inductors and inductor input filters to each customer’s exact requirements. When you’re ready to get started, you can rely on our extensive contract manufacturing experience to get it done right.

Contact DEFON Electronics today to discuss your input inductor requirements. Our engineering team is ready to assist you with technical questions, custom designs, and production requirements.