An LED luminaire comprising LED arrays, a buck circuit with a switching portion comprising a transformer, and an LED driving circuit comprising a feedback control circuit is used to replace a conventional luminaire with a severe temporal light artifact. The buck circuit with the switching portion is configured to generate a variable DC voltage with a low-frequency ripple associated with AC mains. The feedback control circuit is configured to feedback a mixed voltage and current control signal to the buck circuit with the switching portion to compensate the low-frequency ripple so as to regulate an LED driving voltage with a ripple-reduced LED current to drive the LED arrays with a flicker-reduced light emission that may protect users of the LED luminaire from possible health hazards such as seizures, headaches, eyestrain, reduced visual performance, migraines, etc.