Problems that should not be neglected in the application of buck module power supply(2)






module power supply

Power Active Filter
When the traditional alternating current-direct current (AC-DC) converter is put into operation, a large amount of harmonic current will be injected into the power grid, which will cause harmonic loss and interference. For example, when uncontrollable rectification is added with capacitor filtering, the third harmonic content on the grid side can reach (70~80)%, and the power factor on the grid side is only 0.5~0.6.

For  buck module power supply products with trim or adj (schedulable) output pins, the output voltage can be scheduled within a certain plan through resistors or potentiometers. The general scheduling plan is ± 10%. For the trim output pin, connect the base of the potentiometer to trim. In the power module with all + s and - s pins, the other ends are connected to + s and - s respectively. If there is no + s or - s, connect both ends to the output positive and negative poles of the corresponding main circuit respectively (+ s is connected to + VIN and - s is connected to - VIN), and then adjust the potentiometer. The resistance value of the potentiometer is generally 5 ~ 10K Ω, which is suitable for comparison. The adj output pins are divided into input side scheduling and output side sections. The output side scheduling is the same as the trim pin scheduling method. The input side dispatcher can only increase the output voltage. At this moment, one end of the potentiometer is connected to the base, and the other end is connected to the ground of the input end.