
The EMC (Electronic Motion Control) of ultraviolet (UV) therapy devices hinges on the ballast. The electronic ballast circuit should have a compact overall layout, minimizing the area of high-frequency current loops. An EMI filter consisting of a common-mode inductor (e.g., CMZ series) and X and Y capacitors should be installed at the AC input terminals. Lamp connection cables should be as short as possible, or shielded cables should be used. The device's microcontroller, used for timing and control, must have a reliable reset circuit. Small capacitors can be added to ground at the I/O ports to filter out high-frequency interference. The device's metal casing should be grounded; if it has a plastic casing, a grounded copper foil should be laid under the internal circuit board as a reference ground plane.