Unformatted text preview: ATTACH THIS SHEET AS THE FIRST PAGE OF YOUR ASSIGNMENT Assignment 5, ECE 464, FS 08 Name: Due: Oct. 17, 2008; 9:00 AM READING: Chapter 4 Score: 5.1) Given a boost converter with an input voltage range of 3.6 V to 4.4 V and an output
of 12 V, determine the minimum values of inductance and capacitance to ensure current
ripple of less that 20% peak-to-peak and to ensure the voltage ripple is less that 5% peak-
to-peak. The switching frequency is 20 kHz and the maximum output power is 10 W.
Also, choose a ballast load resistor to ensure that the converter always stays in continuous
conduction mode. Assume the converter has ideal components. 5.2) Given a buck-boost converter with an input voltage of V,” , output voltage V0", ,
power P and a small resistance in series with its inductor rL , derive a general on! 9 expression for the efﬁciency . Assume continuous conduction mode and relatively small
current and voltage ripple. Plot the efﬁciency versus power output for VM 2 4 V , V0,”: -6V,and rL=0.l£2. output 5.3) A buck-boost converter has an adjustable input of 6 V to 12 V. The output voltage‘is "
-10 V. If the converter is in continuous mode and all components are ideal, what is the .
range of duty cycle required? If the output power is a maximum of 10 W, determine the
minimum voltage and current ratings (as applicable) required for each component
(switch, diode, inductor, capacitor). 5.4) A ﬂyback converter is to be used to converter a 170-V dc input to a 5-V dc output.
The output power is 100 W. Assume all components are ideal and the converter is in
continuous conduction mode. Using a duty cycle of 0.5, What is the turns ratio for the
transformer that is needed? ...
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