Wiring of the power supply part of the microcontroller

Using a high-precision voltage regulator and
correctly wiring it with the isolation transformer and low-pass filter can further improve
the anti-interference ability of the power supply. The wiring is shown in Figure 20-48
and Figure 20-49. In the figure, the choke coil (Li,
Lz) uses
an MX0-2000 magnetic ring with an inner diameter of 18mm, an outer diameter of 24mm, and a thickness of 8mm as the magnetic core. Li
and L2 are each wound with 50 to 70 turns.