A water ionizer (also known as an alkaline ionizer) is a home appliance which claims to raise the pH of drinking water by using electrolysis to separate the incoming water stream into acidic and alkaline components. The alkaline stream of the treated water is called alkaline water. Here we develop special SMPS that operate at the variable output voltage to control different acidic and alkaline components in water. The main feature is that, it will operate with analog input voltage to set output voltage reference from microcontroller of that machine.