Component layout design, want to see you LED switching power supply circuit board components has the best layout. Need full consideration to circuit board size problem first. When the switch is in the power supply circuit board size is too large, because the printing line is too long, can lead to resistance, reduced noise, and this will increase costs.
I also need to take into account the components distributed parameter problems after you completed the design of circuit board size. This is especially important for working in high frequency circuits. General circuit components in parallel as possible, not only in appearance, and welding easier, easier to mass production.