Question 10.SP.9: For the buck converter of Example 10.5, (a) calculate the pe......

Schaum’s Outline of Electronic Devices and Circuits [1089587]

For the buck converter of Example 10.5, (a) calculate the percent voltage ripple by (4) of Problem 10.8 and (b) formulate a SPICE simulation to numerically determine the percentage ripple.

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(a) By (4) of Problem 10.8 with the values of Example 10.5 and using (10.5),
$G_{V} = {\frac{V_{2}}{V_{1}}} = D$ (10.5)

{\frac{\Delta v_{2}}{V_{2}}} = {\frac{(1  –  D)}{8f_{s}^{2}L C}} {100 \% = \frac{(1  –  0.5)}{8(25  \times  10^{3})^{2}(100  \times  10^{-6})(50  \times  10^{-6})} 100 \% = 2 \%}

(b) Execute 〈Ex10_5.CIR〉 and use the Probe feature of PSpice to plot $v_2 = V(3)$ with marked values shown in Fig. 10-11. Then,

$V_{2} \simeq {\frac{6.064 + 5.943}{2}} = 6.0035$
$\Delta v_{2} = 6.064 – 5.943 = 0.121$
${\frac{\Delta v_{2}}{V_{2}}} = {\frac{0.121}{6.0035}} 100 \% = 2.01 \%$

The error in the two methods is much less than 1 percent.

10.11

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