We all know Switching power supply The primary heat‑generating components in a switching power supply include semiconductor switching transistors, power diodes, high‑frequency transformers (switching‑mode power‑supply transformers), and filter inductors. Each component has its own methods for controlling heat generation. In general, switching‑mode power‑supply transformers tend to heat up over prolonged operation. So what causes this phenomenon? Today, we’ll explain the underlying reasons why switching‑mode power‑supply transformers generate heat and outline the various approaches available to reduce that heat.
In fact, the reason is quite simple: a switch-mode power supply transformer incorporates a switching transistor. In the circuit, in addition to the voltage‑transforming function of a conventional transformer, it also provides electrical isolation and power transfer, typically used in applications such as switch-mode power supplies that involve high‑frequency circuits. Accordingly, the heating of a switch-mode power supply transformer stems from the heat generated by the switching transistor, which in turn arises from losses. These losses consist of switching losses and conduction losses; therefore, reducing the heat can be achieved through the following approaches.
Method 1: More importantly, losses can be reduced by designing superior control strategies and buffer techniques; for example, employing soft-switching technology can significantly minimize such losses.
Method 2: For losses caused by high-frequency magnetic materials, the skin effect should be minimized. To mitigate its impact, one can employ the technique of winding multiple strands of fine enameled wire in parallel.
Method 3: Reducing conduction losses can be achieved by selecting switching devices with low on-state resistance.
Method 4: For the rectification on the transformer’s secondary side, a higher-efficiency synchronous rectification technique can be employed to reduce losses.
Method 5: Switching losses arise from the magnitude of gate charge and the switching time. To reduce these losses, one can select devices with faster switching speeds and shorter recovery times.
Method 6: Reduce the heat dissipation of power diodes. For AC rectifier and snubber diodes, there is generally no superior control technique to minimize losses; however, selecting high‑quality diodes can help reduce losses.
