Analyzing Power Loss in Switching Power Supplies

Power efficiency is fundamental to any switching power supply. The measure of power efficiency indicates the quality of the device. High power efficiency means the system is good while lower power efficiency means the system must be redesigned or modified.

Maximum power efficiency is important for all switching power supplies, especially portable devices. We need to extend the battery life on portable devices so that users can enjoy movies and games for longer.

To understand power loss, embedded engineers must understand the power loss mechanisms of these converters first. Custom power supplies can go a long way to ensure uninterrupted power supply to such devices.

Once you understand the mechanism of power loss, you can take steps to control or reduce it. You need to know that power loss is inevitable in a energy conversion system. Note that 100 percent power efficiency is unattainable.

But it is also true that a well designed custom power supply can achieve remarkable efficiency, somewhere in the range of mid 90s. The first thing you have to do to analyze power loss is to look at the data sheet provided by your IC manufacturer. There you can see the benchmark efficiencies.

Note that most of the power loss occurs in the switching components. To a smaller extent, it occurs in the capacitors and inductors of the SMPS circuit. So there are many things you can do to reduce power loss like checking the pulse skipping architecture, synchronous rectification, low resistance integrated MOSFETS and so on.