Download Lab3: DC-DC Boost Converter

San José State University
College of Engineering/Electrical Engineering
EE174: Analog Peripheral for Embedded Systems
Section 01, Spring 2017
LAB3 DC-DC Converter
Boost Converter
Switched mode supplies can be used for many purposes including DC to DC converters. Often, although a
DC supply, such as a battery may be available, its available voltage is not suitable for the system being
supplied. For example, the motors used in driving electric automobiles require much higher voltages than
could be supplied by a battery alone. The answer to this problem is to use fewer batteries and to boost
the available DC voltage to the required level by using a boost converter. The DC input to a boost converter
can be from many sources as well as batteries, such as rectified AC from the mains supply, or DC from
solar panels, fuel cells, dynamos and DC generators.
Fig. 3.2.1 illustrates the basic circuit of a Boost converter. However, in this example the
switching transistor is a power MOSFET, both Bipolar power transistors and MOSFETs are
used in power switching, the choice being determined by the current, voltage, switching speed
and cost considerations. The rest of the components are the same as those used in the buck
converter illustrated in Fig 8 below, except that their positions have been rearranged.
VOUT = VIN / (1 – D)
Boost converter Operation
Required Task:

Build the Boost converter circuit using Microchip MC34063 as shown above

Obtain the Line Regulation: Vary the input voltage from 3.5V to 4.0V and plot the
output voltage as the function of the input voltage for a constant output load.

Configure the on board evaluation module to generate a regulated output voltage
of 5V, observe and capture the waveforms mentioned in Figure 9 above and
compare with the simulation results.

Vary the input voltage for a regulated output voltage of 5V and observe the change
in the duty cycle of the PWM waveform. Use Table below to record the readings.
Compare the readings with simulation results and plot the graph between the input
voltage and duty cycle. Is the plot linear?

Vary the input voltage for a fixed load and observe the output voltage. Use Table
below for taking the readings for line regulation



Observe the inductor voltage and output voltage.
Observe output ripple voltage.
Conclusion of the lab.
References:
http://www.learnabout-electronics.org/PSU/psu32.php
http://www.ti.com/lit/an/slva252b/slva252b.pdf
http://www.electroschematics.com/12172/uc-li-ion-power-bank-w-mc34063/