Isolated and Non-Isolated Switching Power Supplies: How to Choose the Right IC for AC-DC Applications

Switching power supplies are present in almost all modern electronic equipment, from IoT devices to fast chargers, notebooks, and industrial systems. One of the most critical design decisions in these power supplies is the selection of the power management integrated circuit (IC), which directly impacts cost, electrical safety, efficiency, and output power.

Among the most common architectures are isolated and non-isolated switching power supplies. Understanding the technical differences between these solutions is essential for making informed and strategic design choices.

Manufacturers specialized in power management ICs, such as Dongke Semiconductor, offer a wide range of solutions tailored to both isolated and non-isolated AC-DC applications.

What Are Non-Isolated Switching Power Supplies?

Non-isolated switching power supplies are characterized by the absence of galvanic isolation between input and output. In these architectures, the output voltage may be directly referenced to the mains input.

Main characteristics of non-isolated power supplies:

• Simplified architecture

• Reduced component count

• Compact size

• Lower overall cost

Typical power range:

Up to approximately 20 W

Common applications:

• LED lighting

• Home appliances

• Auxiliary internal power supplies

• IoT and residential automation devices

For applications where user access to the output is limited or controlled, non-isolated IC solutions provide an efficient and cost-effective approach.

What Are Isolated Switching Power Supplies?

Isolated switching power supplies use high-frequency transformers to provide full electrical isolation between the input and the output. This isolation is essential for meeting safety standards and regulatory requirements.

Main characteristics of isolated power supplies:

• Galvanic isolation between mains and load

• Higher electrical safety

• Support for higher output power

• Greater flexibility in voltage and current levels

Typical power range:

From 30 W to several hundred watts

Common topologies:

• Isolated flyback

• Active clamp flyback

• Asymmetric half-bridge

Dongke Semiconductor develops highly integrated ICs for isolated power supplies, combining advanced control circuits, high-voltage drivers, and power devices to achieve high power density and excellent efficiency.

Why Are Isolated Power Supplies More Expensive?

The higher cost of isolated power supplies is mainly due to technical factors such as:

• High-frequency transformers

• More complex control circuits

• Additional protection components

Despite the higher cost, isolated solutions are essential for applications requiring high power, reliability, and electrical safety, such as fast chargers, notebook adapters, televisions, and industrial power supplies.

How to Choose the Right IC for AC-DC Power Supplies?

When selecting the appropriate IC, designers should consider:

• Required output power

• Isolation requirements

• Cost and space constraints

• Target efficiency

• Applicable safety and regulatory standards

• Compliance with safety and certification standards

Working with specialized manufacturers like Dongke Semiconductor helps streamline the design process and ensures optimal performance for each application.

Conclusion

There is no universal solution for switching power supplies.

• Non-isolated power supplies are ideal for low-power, cost-sensitive applications.

• Isolated power supplies are mandatory when electrical safety, higher power, and regulatory compliance are critical.

The correct IC selection directly impacts product performance, development time, and long-term reliability.