A back-light driving circuit controlling red (R), green (G), and blue (B) back lights providing light to a liquid crystal panel in a field sequential liquid crystal display. The back-light driving circuit includes a driving voltage generator that provides a driving voltage to each of the R, G, and B back-lights to cause them to emit light having a predetermined luminance. The back-light driving circuit also includes a pulse width modulation (PWM) signal generator for providing a PWM signal to each of the R, G, and B back-lights to control the chromaticity of the light emitted from each back-light. The driving voltages and/or PWM signals provided to each of the R, G, and B back-lights are catered to the particular characteristics of the corresponding back-light to cause them to emit color having a desired luminance and/or chromaticity.