A control circuit for a light source comprises: a light source, a drive circuit applying a pulse width modulated (PWM) drive signal to the light source; and a pulse width modulator generating the PWM drive signal having a PWM ON time ratio responsive to a control signal and a PWM drive frequency that varies over a range of frequencies repeatedly and substantially continuously. A method for controlling a light source comprises: applying a pulse width modulated (PWM) drive signal to the light source; generating the PWM drive signal having a PWM ON time ratio responsive to a control signal and having a PWM drive frequency that is varied over the range of frequencies repeatedly and substantially continuously. The PWM drive signal causes the light source to produce light at the varying frequency, whereby light at a frequency exhibited by a moving object does not continuously illuminate a moving object.