The reasons for the small size of switching power supplies using high-frequency transformers mainly include the following aspects:
1. The high-frequency transformer in a high-frequency working switching power supply operates at a frequency much higher than the power frequency (such as 50/60Hz), typically ranging from a few kHz to tens of kHz or even MHz. According to the inductance formula, under a certain inductance value requirement, the higher the frequency, the fewer the number of coil turns needed, because the inductive reactance is directly proportional to the frequency.
2. Reducing the core size: At high frequencies, the losses of the transformer core (or magnetic core) mainly come from eddy current losses and hysteresis losses, both of which increase with the rise in frequency. To reduce these losses, high-frequency transformers use materials with high magnetic permeability and low loss, such as thin silicon steel sheets or amorphous alloys, and their cross-sectional area is much smaller than that of power frequency transformers, which greatly reduces the core volume of the transformer.
3. Optimizing the structure: High-frequency transformers can adopt more compact winding methods and efficient heat dissipation designs, such as planar transformers or toroidal transformers, further reducing space occupation.
4. Efficiency Improvement: High-frequency switching power supplies regulate the output voltage by controlling the duty cycle of switching elements through PWM (Pulse Width Modulation) technology, rather than relying solely on the electromagnetic induction ratio relationship. This allows for the use of simpler filter circuits and fewer energy storage components, thereby enhancing the overall integration of the power supply.
5. Output ripple suppression of high-frequency switching actions can provide rapid response and precise control, which is conducive to reducing output voltage ripple, thereby simplifying the subsequent filter circuit and making the entire power supply system more miniaturized. Due to its advantages in high-frequency operation characteristics, material selection and power conversion mechanism, high-frequency transformers can significantly reduce their volume while achieving the same functions, thus enabling the miniaturization and lightweight design of switching power supplies using high-frequency transformers.
Post time: Apr-23-2025