A buck converter is a highly efficient switch-mode DC-DC power converter that steps down an input voltage to a lower, regulated output voltage while maintaining high electrical efficiency (>90%). Controlled by a pulse-width modulated (PWM) duty cycle D = t_on / T_s, the active switch periodically connects the inductor to the input source, ramping inductor current; during the off-interval, a freewheeling diode maintains inductor current continuity, delivering a steady average output voltage.