Timer Compliant Controller proje

After optimization of structural solution ， I  must prepare the bom and  drawing circuit diagram as soon as possible.

1selection the suitable components.

At first，The power circuits  core component is LNk 306 and LDO, I must find the datasheet and typical circuit. and  compare the components lib of our company.as shown in the following  figure.  input  100-250V AC power (wide voltage input) , The diode is protect  the circuit， The output is 12V @ 200mA （ test the voltage was stable ）

In addition ，Mcu power is 3.3V ，so  we need a DC-DC  buck  IC ，I choice  LDO ，becase  it‘s  very affordable and useful，as we know，Intraditionaldesign，we also  use 7805 and 7803， But our products are powered by batteries for 3.3V，and we use a ups circuits toswitching power supply  automatic.the LDO output power drop issuperior to 7805。

2 Drawing   circuits

I use the Altium designer ， as we know ， Set up  the schematic library ，herewillnotcarefullydescribed。