EECS 4600
Experiment #9: POWER
MOSFET
Name: Gokarna Jung Bhandari
12/08/2022
Objective: The primary objective of this lab is to study various characteristics of a
power MOSFET. We will be studying the conduction and switching behavior, and
Energy loss characteristics of two different types of power MOSFET with same Voltage
rating.
Theory: MOSFET is a type of Field-Effect Transistor. It has an insulated Gate. The
voltage in the Gate Determines the conductivity of the Device. Transconductance is the
ratio of the change in current at the output terminal to the change in the voltage at the
input terminal of an active device. Drain Resistance is the Resistance between Drain
and Source of the MOSFET when the MOSFET Is conducting. Power devices are
typically switched in the linear region of operation. The linear relationship is
representative of a resistance value which is RDS(ON). There is no steady-state gate
current under typical operation. The gate structure consists of a non-conducting oxide
layer sandwiched between a conducting gate plate and doped semiconductor. This
results in capacitor-like behavior and is represented by input capacitance Ciss. Because
of this capacitance it takes some time to switch state and loses energy. It is now known
that the transistor consumes energy at a constant rate during steady-state conduction
and consumes some additional energy at each switching event. It is desirable for power
application to be in high frequencies as it allows size reduction of passive components.
Circuit Diagrams:
Following are the circuit diagrams of the circuits being used in the experiment:
Material and equipment List:
1. MOSFETs (IRF510 and IRF520)
2. Voltmeter
3. Ammeter
4. Oscilloscope
5. Resistors
6. Connecting wires, boards, sources
Result analysis:
From our experiment we get the following:
Conduction Characteristics:
Following is the data collected from our experiment for Conduction Characteristics for
IRF510:
VIN
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
IRF510
VDS [V]
ID [mA]
0
0.00019
0.0004
0.896
0.0004
0.896
0.0009
2
0.0018
4
0.0023
5.005
0.0028
6.011
0.0032
7.015
0.0037
8.022
0.0042
9.029
0.0046
10.04
0.0051
11.054
0.0056
12.208
0.006
13.232
0.0066
14.27
0.0071
15.3
0.0071
15.31
0.008
17.37
0.0086
18.43
0.009
19.49
0.0095
20.54
0.0101
21.6
0.0105
22.65
0.011
23.73
0.0116
24.79
0.0121
25.87
Following is the Graph we got form plotting VDS vs ID for IRF510:
VDS [V] vs ID [mA] for IRF510
0,014
0,012
y = 0,0005x - 5E-05
0,01
0,008
0,006
0,004
0,002
0
0
5
10
15
20
25
30
-0,002
ID vs VDS
Линейная (ID vs VDS)
From the plot we can the equation of the best fit line of the linear region as:
VDS = 0.5ID-5X10-2 comparing it to equation of linear line (y=mx+c) we get,
RDS = 0.5
Following is the data collected from our experiment for Conduction Characteristics for
IRF520:
VIN
0
1
2
3
4
5
6
7
8
9
10
11
12
IRF520
VDS [V]
ID [mA]
0
0.0001
0.0003
0.884
0.0007
1.98
0.0011
2.98
0.0015
3.96
0.0019
4.96
0.0023
5.977
0.0027
7
0.0031
8.014
0.0034
9.025
0.0039
10.03
0.0043
11.04
0.0048
12.19
13
14
15
16
17
18
19
20
21
22
23
24
25
0.0051
0.0056
0.006
0.0064
0.0068
0.0072
0.0076
0.008
0.0085
0.0089
0.0093
0.0097
0.0102
13.222
14.25
15.29
16.32
17.37
18.42
19.45
20.5
21.57
22.62
23.63
24.79
25.88
Following is the Graph we got form plotting VDS vs ID for IRF520:
VDS [V] vs ID [mA] for IRF520
0,012
y = 0,0004x - 7E-05
0,01
0,008
0,006
0,004
0,002
0
0
5
10
15
20
25
-0,002
From the plot we can the equation of the best fit line of the linear region as:
VDS = 0.4ID-7X10-2 comparing it to equation of linear line (y=mx+c) we get,
RDS = 0.4
30
Switching Behavior:
Following is the signal on a oscilloscope when the gate is driven with a square wave of
amplitude 5 V, offset 2.5 V, duty cycle 50%, and frequency 100 kHz in IRF510:
Following is the signal on a oscilloscope when the gate is driven with a square wave of
amplitude 5 V, offset 2.5 V, duty cycle 50%, and frequency 100 kHz in IRF520:
Following is comparison table we got from the data Sheet and our experiment:
Paramerters
VDS
RDS(ON)
Ciss
Trise
IRF510
Rated
Computed
100V
X
0.54Ω @ 10V
0.5Ω @ 5V
180 pF
X
X
243ns
IRF520
Rated
Computed
100V
X
0.27Ω @ 10V
0.4Ω @ 5V
360 pF
X
X
489ns
Ciss of IRF520 is double of IRF510 which is also reflected in the Trise of the MOSFETS. The Trise of IRF520 is
almost the double of IRF510. I expect IRF520 to larger switching losses as the Trise representative of the
Ciss value is greater than the corresponding values of IRF510 as it takes more energy is lost if more time
is required to switch.
Conclusion: From our we learned to measure various parameters of a power MOSFET
and the parameter’s implication in performance and application of the MOSFET. Also
from the comparisons from the two MOSFETS IRF510 would be more efficient in Power
applications.