Isolation transformer type selection

We use isolation transformers in many places. What is common is the choice of isolation transformers. So, how to choose isolation transformer? Next, Xiaobian will tell you about this and the advantages of isolation transformers.

First, isolation transformer selection
1.PCB type isolation transformer, printed circuit board (printed circuit board) type isolation transformer can omit the winding skeleton, increase the heat dissipation area, reduce the eddy current loss caused by the skin effect and proximity effect during high-frequency operation, increase the current density, the current density is as high as 20A/mm, high power, simple process. However, with PCB, the window utilization rate is only 0.25 to 0.3, while the window utilization rate of the traditional isolation transformer is 0.4, and the volume is also large. The power of the PCB isolation transformer can reach 20kW and the frequency can reach the order of megahertz. Using pulse plane technology. Multi-layer PCB clamp magnetic core, thin gaoxiao ferrite plane for isolation transformer. Its bottom area is small, the height is only 7.4mm, the operating frequency is 150~750kHz, the operating temperature is -400~1300.

2. Thick film isolation transformer, thick film isolation transformer is proposed in order to overcome the defect of high conductor resistance in thin film isolation transformer. The primary and secondary windings are printed on the upper and lower surfaces by a thick film process using alumina as the base. When the plane isolation transformer made of ferrite is at 2MHz and the output power is 75W, the efficiency can reach 85 points. The efficiency of plane isolation transformer produced by thick film process is generally low, seeking further technical improvement of plane isolation transformer production thick film process is the key to achieve plane isolation transformer high frequency yitihua.

Two, isolation transformer advantages
1. The current distribution is equal, and the typical plane isolation transformer secondary winding has several parallel coils. Each secondary winding is coupled to the same primary winding. Therefore, the number of ampere-turns generated by the secondary current is equal to the number of ampere-turns generated by the primary winding (ignoring the excitation current). This feature is particularly useful for parallel rectifier circuits. The current distribution in each winding is equal and does not affect other components in the parallel rectifier circuit.

2. High current density, plane isolation transformer with chuse temperature rise characteristics design. Due to these characteristics, it can achieve a higher current density in a smaller package volume, and because of its structural characteristics, fully meet the working characteristics of high-frequency current, so it is suitable for high-frequency applications.

3. High efficiency and low leakage inductance make it have fast switching time and low cross loss, which can make it achieve high efficiency. The isolation transformer secondary winding has high efficiency and low loss due to its close contact with the primary winding and high coupling coefficient.