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while in the Off-state, the inductor is connected to the output load and capacitor, so energy is transferred from L to C and R. Continuous mode [ edit ] Fig 3: Waveforms of current and voltage in a buck–boost converter operating in continuous mode. Both of them can produce a range of output voltages, ranging from much larger (in absolute magnitude) than the input voltage, down to almost zero.

The load current I o {\displaystyle I_{o}} is equal to the average diode current ( I D {\displaystyle I_{D}} ). In figure 4, Δ I L on {\displaystyle \Delta I_{L_{\text{on}}}} is proportional to the area of the yellow surface, and Δ I L off {\displaystyle \Delta I_{L_{\text{off}}}} to the area of the orange surface, as these surfaces are defined by the inductor voltage (red lines). With V L {\displaystyle V_{\text{L}}} equal to V i − V o {\displaystyle V_{\text{i}}-V_{\text{o}}} during the on-state and to − V o {\displaystyle -V_{\text{o}}} during the off-state. The term T V i L {\displaystyle \scriptstyle {\frac {T\,V_{i}}{L}}} is equal to the maximum increase of the inductor current during a cycle; i.

The conceptual model of the buck converter is best understood in terms of the relation between current and voltage of the inductor.

Where I L ¯ {\displaystyle {\overline {I_{\text{L}}}}} is the average value of the inductor current. Qualitatively, as the output capacitance or switching frequency increase, the magnitude of the ripple decreases. We note that V c-min (where V c is the capacitor voltage) occurs at t on/2 (just after capacitor has discharged) and V c-max at t off/2. The current through the inductor rises linearly (in approximation, so long as the voltage drop is almost constant). A buck converter or step-down converter is a DC-to-DC converter which decreases voltage, while increasing current, from its input ( supply) to its output ( load).One possible drawback of this converter is that the switch does not have a terminal at ground; this complicates the driving circuitry.