Aspects of the disclosure are directed toward systems and methods for performing deionization of a fluid. A capacitive deionization (CapDI) module including a fluid inlet and a fluid outlet can be placed in a fluid flow system. The CapDI module can include a plurality of CapDI cells arranged in series with one another. A power MOSFET polarity circuit can receive power from a switching regular and provide bidirectional electrical power to the CapDI module for performing deionization and module regeneration processes. A controller can control the providing the electrical power from the switching regulator to the power MOSFET polarity circuit based on a signal received from a conductivity sensor positioned in the fluid flow path.