Boost converters boost the input voltage higher

Circuit Diagram Edit

TydPicture 1

Analysis Edit

$ V_dDT_s = V_0T_S(1-D) $ $ \frac{V_o}{V_D} = \frac{D}{1-D} $

Boundary between dis and cts ConductionEdit

Discontinuous conduction mode is the preferred method of operation for a buck-boost converter. $ I_{LB} = \frac{V_dT_sD}{2L} $

note $ V_d = \frac{V_o(1-D)}{D} $ & $ I_o = I_L - I_d $ average current through inductor equates to the current through the inductor minus that which flows back to the source. The capacitor has zero average current.

$ \therefore I{oB} = \frac{V_o(1-D)^2T_s}{2LD} $

Output Voltage Ripple Edit

The diode current $ i_D $ carries both the ripple current from capacitor and the average current through the load. Hence $ \Delta V_o = \frac{\Delta Q}{C} = \frac{I_o D T_s}{C} = \frac{V_oDT_S}{RC} $

Practical Considerations and Ratings Edit

Transformer Considerations Edit

Switch Ratings Edit