MIKROE-957 mikroElektronika, MIKROE-957 Datasheet - Page 52

• Manufacturer Part Number: MIKROE-957
• Description: Other Development Tools ASLK PRO ANALOG DEVELOPMENT SYSTEM
• Manufacturer: mikroElektronika

Specifications of MIKROE-957

• Rohs: yes
• Product: Analog System Lab Kit PRO
• Tool Is For Evaluation Of: TL082, MPY634
• Operating Supply Voltage: 2.5 V to 5.5 V
• Description/function: Analog Lab Kit for Undergraduate Engineering
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C

9.1 Brief theory and motivation
The reader will benefit from viewing the recorded lecture at [24]. Also refer to the
application note, Design Considerations for Class-D Audio Power Amplifiers [15].
Function generator is the basic block for DC-DC converter. The triangular output
of the function generator with peak amplitude V
comparator whose other input is connected to the reference voltage Vref. The output
of this comparator is the PWM (Pulse width modulation) waveform whose duty cycle
is given by
equal to
If we connect the lossless low-pass filter (LC filter) at the output of the comparator
as shown in Figure 9.1, it is possible to get stable DC voltage
page 52
The goal of the experiment is to design a high-efficient DC-DC converter using
a general purpose OP-Amp and a comparator and study its characteristics.
We also aim to study the characteristics of a DC-DC converter IC, and for
this purpose we selected the wide-input non synchronous buck DC/DC
controller TPS40200 from Texas Instruments. This IC is included in ASLK
PRO as evaluation module.
V
V
T
T
V
!
V
x
x
T
x
T
f
ref
av
av
p
V
=
V
=
ss
T
=
ref
V
V
T
T
V
!
V
x
T
T
f
x
1
x
Generator
ref
av
av
p
Function
Goal of the experiment
-
1 1
2
V
=
V
=
T
ss
=
_
f
ref
V
1
. This duty cycle is directly proportional to reference voltage Vref.
ref
-
1 1
2
-
_
f
$
V
V V
V
ref
ref
ss
-
$
V V
V
V
ref
p
ss
p
i
Vref
Vg
V
p
p
i , where T is time period of triangular wave and is
+V
-V
SS
SS
V
O
L
!
V
T
T
V
V
x
x
T
x
T
f
ref
av
av
p
V
=
V
=
and frequency
ss
T
=
ref
1
2
-
1 1
_
f
V
ref
-
C
$
Figure 9.1: DC-DC Converter and PWM waveform
V
V V
V
V
T
T
V
!
V
x
x
T
x
T
f
ss
ref
ref
av
av
p
V
=
V
with high efficiency
=
T
ss
=
ref
V
1
p
R
p
-
1 1
2
i
L
_
f
V
V
T
T
V
!
V
V
Vav
T
T
x
f
x
x
p
ref
av
ref
av
V
-
=
V
is fed to the
=
ss
=
T
$
ref
V V
V
1
-
1 1
ref
2
ss
_
f
V
V
ref
p
-
p
i
$
V
V V
ss
ref
V
p
p
i
between
where
If we replace LC filter with MOSFET, and apply audio input as
then at output of the MOSFET amplified audio output is obtained, this is Class D
Power Amplifier operation.
Design a DC-DC converter which has 10 kHz oscillator whose triangular wave output
with peak amplitude Vp is fed to a comparator whose other input is connected to
Vref (reference voltage).
9.3.1 Time response
Obtain the time response of the system and plot
9.3.2 Transfer function
Obtain the
9.2 Specifications
9.3 Measurements to be taken
T
T
V
!
V
x
T
T
x
av
av
V
=
V
T
T
V
!
V
T
T
T
x
ss
=
x
ref
av
av
1
V
=
V
V
T
T
V
!
V
T
T
x
V
f
x
x
-
2
ss
=
T
p
ref
av
av
ref
V
=
V
1
f
depending upon the value of
=
T
V
ss
=
-
2
versus
ref
ref
1
f
-
1 1
2
V
$
ref
_
V V
f
V
ref
ss
$
ref
-
V V
$
ss
ref
V
V
T
T
V
!
V
T
T
x
f
x
x
V V
V
p
p
ref
av
av
p
.
V
ss
=
ref
V
=
ss
=
T
characteristics.
p
ref
p
1
V
-
1 1
2
p
p
i
_
f
V
ref
-
$
V
V V
ss
ref
V
p
p
i
V
V
T
T
V
!
V
x
T
T
f
x
x
ref
p
av
av
Analog System Lab Kit PRO
V
=
V
=
. Hence circuit becomes SMPS system
T
ss
=
ref
1
-
1 1
2
V
V
T
T
V
!
V
x
_
x
T
x
T
f
f
V
ref
av
av
p
V
=
ref
V
=
-
ss
T
=
ref
versus
$
1
V V
-
V
2
1 1
ref
ss
_
f
V
ref
V
-
p
p
$
i
V
V
T
T
V
!
V
x
x
T
x
T
f
V
V V
ref
av
av
p
ss
V
ref
=
V
V
T
T
V
!
V
V
T
T
x
f
x
x
=
ss
T
=
p
ref
av
av
ref
V
=
1
V
V
=
.
ss
=
T
-
p
1 1
2
ref
to the comparator
p
1
i
_
f
-
2
V
1 1
ref
_
f
-
V
$
ref
-
V V
V
$
ref
ss
V
V V
ss
ref
V
p
p
i
V
p
p
i