Philippines the switching frequency of the AC-DC switching power supply module?(2)
Philippines Choosing the switching frequency of the Marine boost voltage power supply does not mean choosing the switching frequency of the Marine boost voltage power supply with a good switching frequency, but the choice is suitable for your own use. Most of the current market is like this. The frequency of the AC-DC switching Marine boost voltage power supply module is between 50K and 135K, and this frequency range can meet most applications. Let's discuss it. Some of the problems that AC-DC encounters when choosing switching frequency:
1. Why generally do not choose a switching frequency lower than 50K
input protection circuit
General module power products have built-in filters, which can meet the requirements of general power supply applications. If a more demanding power system is required, an input filter network should be added. An LC or π-type network can be used, but care should be taken to choose a smaller inductance and larger capacitance as much as possible.
In order to prevent the transient high voltage of the input power supply from damaging the power supply of the module, it is recommended that the user connect a transient absorption diode at the input end and use it with a fuse to ensure that the module is within a safe input voltage range. In order to reduce common-mode noise, Y (Cy) capacitors can be added, and a few nf high-frequency capacitors are generally selected. R is a fuse, D1 is a protection diode, and D2 is a transient absorption diode (P6KE series).
We know that the lower the switching frequency, the smaller the switching loss, but on the other hand, with the reduction of the switching frequency, the volume of the Marine boost voltage power supply equipment will be reduced to the maximum, which is not conducive to miniaturization. When the switching Marine boost voltage power supply is working, due to the switching of the switching device, the magnetic core will vibrate, and the frequency range that the human ear can hear is about 20~20000Hz. In order to avoid audible noise, we usually choose to stay away from the 20 frequency KHz.