The Advantages and Disadvantages of LLC Transformers

LLC is one of many switch mode topologies for power supply and battery charging. The LLC transformer is critical in determining an LLC resonant converter’s efficiency. Resonant tanks are circuits comprised of inductors (L) and capacitors (C) that oscillate at a fixed frequency known as the resonant frequency. LLC transformers have two inductors and one capacitor, a configuration that creates resonance at the switching frequency.

Here we’ll explain the pros and cons of LLC transformers, as well as their common applications.

What Is LLC Topology?

Half Bridge LLC Resonant Transformers
LLC is one of several switch mode topologies used in power supply and battery charging operations. The LLC transformer helps determine an LLC resonant converter’s efficiency. An LLC resonant power conversion topology reduces switching losses by enabling zero voltage switching (ZVS), which reduces needless power waste in switches. Power dissipation can be limited to as little as 2%, ensuring 98% total efficiency.

Advantages of LLC Transformers

These are some of the advantages of LLC transformers.

Cost Savings

LLC resonant converters are extensively used in industrial applications because they can integrate two resonant elements into one transformer. This helps designers save money on construction and supplies.

Regulation Compliance

Energy efficiency is critical for decreasing environmental impact while saving money. Even a 2% increase in total efficiency can significantly impact energy costs. With federal Energy Star criteria becoming increasingly stringent, LLC transformers are ideal solutions to achieve optimum efficiency.

Energy Efficiency & Sustainability

The market demands greater efficiency in server farms, LED lighting, gate automation, vending machines, battery chargers, and other areas. LLC resonant topology has an efficiency of 94-96% in the most basic circuit solutions, and it can improve further through synchronous rectification and other precautionary measures.

Compact & Effective

Compared to other topologies, LLC-LCC power supplies are smaller and have significantly lower electromagnetic interference (EMI) concerns, reducing EMI and harmonic pollution.

Aids EMI Design

It can control the output across a wide range of line and load fluctuations with very little difference in switching frequency, making basic EMI filters considerably easier to build.

Applications of LLC Transformers

LCC topology is the best choice for applications requiring a broad output voltage range, such as power supply for variable length LED strings (including deep dimming) or high-performance battery chargers.

Electronics industries rely on LLC transformers for their:

  • Electrical isolation
  • High energy density
  • High operation frequency
  • Low voltage stress
  • Magnetic integration
  • Wide output ranges

A precision LLC transformer is best for converters in a variety of energy-sensitive applications, such as:

  • Computers
  • High-end audio
  • Home appliances
  • Industrial LED lighting
  • LED/LCD televisions
  • Military

Drawbacks of LLC Transformers

These are some potential drawbacks to keep in mind when working with LLC topology.

Requires Sensitive Customization

The best design of a switch mode power supply (SMPS) transformer must inevitably address the limits associated with magnetic components; otherwise, it may result in a significant drop in efficiency.

Not Suitable for Operating Voltage Variations

Resonant topologies’ major shortcoming is in applications with substantial input or output operating voltage changes.

If the tank is appropriately designed, ZVS can be maintained even in the face of relatively high voltage changes. However, the benefits are reduced compared to alternative topologies due to the negative influence on cost and performance. The magnitude of this influence is often tolerable, but it does grow generally in proportion with voltage range expansion.

Contact MPS Industries for More on LLC Transformers

MPS Industries takes pride in offering high-quality LLC transformers and other magnetic components to clients in the automotive, aerospace, military, industrial, electronics, medical, and telecommunications industries. MPS is committed to meeting and surpassing client expectations as a leading manufacturer of standard and custom electronic components like transformers, common mode chokes, inductors, power supplies, and current sensors. Our strict quality management system and ISO certifications demonstrate our dedication to quality.

For additional information, contact us today, or request a quote for your next project.

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