Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules
Current-voltage characteristics of real high-power LED chips and their defects were studied. Process of modeling LED matrix by using Monte Carlo method based on the measured real LED chips was considered and performed. It was shown that the risk of variating LED chip parameters for stability of a fi...
Збережено в:
| Дата: | 2015 |
|---|---|
| Автор: | |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2015
|
| Назва видання: | Semiconductor Physics Quantum Electronics & Optoelectronics |
| Онлайн доступ: | https://nasplib.isofts.kiev.ua/handle/123456789/121145 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules / V.V. Shynkarenko // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2015. — Т. 18, № 1. — С. 200-204. — Бібліогр.: 5 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-121145 |
|---|---|
| record_format |
dspace |
| spelling |
nasplib_isofts_kiev_ua-123456789-1211452025-02-23T17:31:34Z Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules Shynkarenko, V.V. Current-voltage characteristics of real high-power LED chips and their defects were studied. Process of modeling LED matrix by using Monte Carlo method based on the measured real LED chips was considered and performed. It was shown that the risk of variating LED chip parameters for stability of a final LED matrix as a result of the non-uniform heating up of individual elements in a series-parallel circuit. The solution allowing to significantly reducing the influence of LED chips input parameters variationon the final parameters of LED matrix was proposed. The author expresses his sincere gratitude to the corresponding member of NAS of Ukraine V.M. Sorokin for useful discussions and interest to the work, professor R.V. Konakova for discussions and her help in writing this paper, and senior researcher Ya.Ya. Kudryk for substantial assistance in performing the experiments. 2015 Article Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules / V.V. Shynkarenko // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2015. — Т. 18, № 1. — С. 200-204. — Бібліогр.: 5 назв. — англ. 1560-8034 DOI: 10.15407/spqeo18.02.1200 PACS 85.60.Jb https://nasplib.isofts.kiev.ua/handle/123456789/121145 en Semiconductor Physics Quantum Electronics & Optoelectronics application/pdf Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
Current-voltage characteristics of real high-power LED chips and their defects were studied. Process of modeling LED matrix by using Monte Carlo method based on the measured real LED chips was considered and performed. It was shown that the risk of variating LED chip parameters for stability of a final LED matrix as a result of the non-uniform heating up of individual elements in a series-parallel circuit. The solution allowing to significantly reducing the influence of LED chips input parameters variationon the final parameters of LED matrix was proposed. |
| format |
Article |
| author |
Shynkarenko, V.V. |
| spellingShingle |
Shynkarenko, V.V. Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Shynkarenko, V.V. |
| author_sort |
Shynkarenko, V.V. |
| title |
Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules |
| title_short |
Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules |
| title_full |
Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules |
| title_fullStr |
Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules |
| title_full_unstemmed |
Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules |
| title_sort |
development of modeling methods and algorithm for calculating the current-voltage characteristics of led modules |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
2015 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/121145 |
| citation_txt |
Development of modeling methods and algorithm for calculating the current-voltage characteristics of LED modules / V.V. Shynkarenko // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2015. — Т. 18, № 1. — С. 200-204. — Бібліогр.: 5 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
| work_keys_str_mv |
AT shynkarenkovv developmentofmodelingmethodsandalgorithmforcalculatingthecurrentvoltagecharacteristicsofledmodules |
| first_indexed |
2025-11-24T02:25:03Z |
| last_indexed |
2025-11-24T02:25:03Z |
| _version_ |
1849636792769183744 |
| fulltext |
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2015. V. 18, N 2. P. 200-204.
doi: 10.15407/spqeo18.02.1200
© 2015, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
200
PACS 85.60.Jb
Development of modeling methods and algorithm for calculating
the current-voltage characteristics of LED modules
V.V. Shynkarenko
V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine,
41, prospect Nauky, 03028 Kyiv, Ukraine; e-mail: shynkarenko@isp.kiev.ua
Abstract. Current-voltage characteristics of real high-power LED chips and their defects
were studied. Process of modeling LED matrix by using Monte Carlo method based on
the measured real LED chips was considered and performed. It was shown that the risk
of variating LED chip parameters for stability of a final LED matrix as a result of the
non-uniform heating up of individual elements in a series-parallel circuit. The solution
allowing to significantly reducing the influence of LED chips input parameters variation
on the final parameters of LED matrix was proposed.
Keywords: LED, modeling, current-voltage characteristics.
Manuscript received 09.12.14; revised version received 23.03.15; accepted for
publication 27.05.15; published online 08.06.15.
Transition from the LED chips to LED modules has led
to the need to solve a number of additional tasks –
analysis of heat distribution in a similar module [1-3],
but it ignores the fact that the LED chips that are the
basis for LED modules have variation of parameters,
which leads to the non-uniform current flow. To
estimate this factor, it is necessary to have software to
predict the effect of the connecting the real LED chips
on the parameters of the future LED module. It is
important to take into account the possible defects of
LED chips (their errors on quality control, the influence
of defects location, variation of parameters) and to
calculate their effect on the general characteristics of the
final LED module. This paper describes the stages of
creating and first results of operating such a program
that allows to simulate the behavior of the final LED
module, in dependence on the number and charac-
teristics of the elements in each circuit of series-parallel
connection.
To obtain information about the actual LED chips,
the LED modules prepared in the conditions of domestic
production based on the chips of company “EDISON
Optocorporation” before filling them with phosphor
described in [4] were investigated. An appearance of the
LED module is shown in Fig. 1. The module is made on
the basis of the printed circuit board with an aluminum
basis, on which LED chips were mounted and connected
to each other by a series-parallel circuit shown in Fig. 2.
Two identical modules were studied.
To study the current-voltage characteristics (CVC)
of real chips on the given module, the connect tracks of
one LED module were cutted and wire terminals were
connected to each individual chip. The direct
measurements of each chip were performed with taking
into account the chip location on the printed circuit
board and its connection.
The CVC measurements of LED module chip are
shown in Fig. 3. A number of anomalies in the current-
voltage characteristics were detected. These anomalies
were caused by soldering defects (Fig. 3a, chips with
abnormally low currents at the applied voltage 3 V, their
photo is shown in Fig. 4), as well as defects in these
chips (Fig. 3, three curves for relatively high direct
currents with the applied forward (a, b) and reverse (c)
voltages 1 V), which can accelerate their degradation.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2015. V. 18, N 2. P. 200-204.
doi: 10.15407/spqeo18.02.1200
© 2015, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
201
a)
b)
Fig. 1. Appearance of the LED module (a), the numbering
chips (b).
Fig. 2. The series-parallel circuit connection of chips in the
LED module.
Two chips with higher values of series resistance
attracted attention to them (see the dotted curves in
Fig. 3a). The current through these chips was
significantly lower than that through the middle chips. It
leads to overloading the neighboring, parallel to them,
LED chips and, as a result, to acceleration of their
degradation during operation.
For further analyzing, each CVC of LED chip
seemed to be approached in the approximation of two
parallel ideal diodes and serial nonlinear resistance
(Fig. 5).
In this case, CVC of high-power LED is described
by the equation (1)
1
2
21010
11
10
URURReIeI
I
UCUC
, (1)
where I1 and І0 are the cut-off currents for diodes D1 and
D0, C0 and C1 are the corresponding exponential factors,
R1 is the coefficient associated with resistance as well as
R0 and R2 take into account the non-linearity of the
resistance on heating.
In the program, to simplify the calculations, this
formula evolves to the form
.
1
10101010
1
1
2
210
1100
URURR
I
UCiUCi
(2)
0 1 2 3 4
10
-11
10
-9
10
-7
10
-5
10
-3
10
-1
I,
A
U, V
Normal CVC
CVC with
high current
CVC of chip with
soldering defect
a)
1 2 3 4
0.00
0.05
0.10
0.15 Normal CVC
CVC with
high current
CVC of chip with
soldering defect
I,
A
U, V
b)
0 1 2 3 4
10
-11
10
-9
10
-7
10
-5
10
-3
10
-1
Normal CVC
CVC with high current
CVC of chip with soldering defect
I,
A
U, V
c)
Fig. 3. Forward (a, b) and reverse (c) branches of CVC of LED
module chips: (a) in linear coordinates, (b) in semi-logarithmic
ones. The numbering is the same as that in Fig. 1b.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2015. V. 18, N 2. P. 200-204.
doi: 10.15407/spqeo18.02.1200
© 2015, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
202
Study of coefficients of real chips indicated the
clear (more than 0.95) linear correlation between the
parameters of each element model (i0 and C0, i1 and C1,
R0, R2 and R2, respectively). Basic values of coefficients
are listed in Table 1.
Table 1. Parameters approximation coefficients of the 21
LED chips in (2).
P
ar
am
et
er
T
h
e
ar
it
h
m
et
ic
m
ea
n
M
ed
ia
n
(m
o
st
p
ro
b
ab
le
)
S
ta
n
d
ar
d
d
ev
ia
ti
o
n
A
sy
m
m
et
ry
co
ef
fi
ci
en
t
i0 –27.6983 –27.7038 0.600160 0.635762
i1 –19.4955 –19.4671 0.646147 1.341593
R0 1.5737 1.6687 0.374458 –0.914235
a)
b)
Fig. 4. Photos of chips with drawn contacts (a) and defect of
soldering the contact (b).
D1
D0
Rheat
Fig. 5. Model of high-power LED: D0, D1 – ideal diodes, Rheat
– non-linear resistance responsible for the heating up of a high-
power LED during operation.
By comparing the values of the arithmetic mean
and the median (Table 1), one can see that the
distribution of most coefficients is not significantly
different from normal one, although the parameter of
nonlinear resistance have small (about 10%) peak
asymmetry. It indicates a greater number of small
(close to the minimum values) R0 values. The
calculated values of the asymmetry coefficient indicate
distributions asymmetry of i1, i0 values and median bias
towards the smaller values. In general, the data
deviation from the normal distribution can be
considered as non-significant, which allows to use a
normal symmetrical distribution with the calculated
median as the expected value in the model.
Because of the complexity to account for the small
values of the terms, each of denominators of the
fractions were separately calculated, then compared with
others, the general current was calculated (Fig. 6) basing
on the comparison results.
Fig. 6. Algorithm for calculating the CVC for high-power LED
with known parameters.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2015. V. 18, N 2. P. 200-204.
doi: 10.15407/spqeo18.02.1200
© 2015, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
203
2 3
10
-10
10
-8
10
-6
10
-4
10
-2
10
0
I,
A
U, V
Fig. 7. Real current-voltage characteristics of LEDs (black)
and modeled current-voltage characteristics, based on them, by
the Monte-Carlo method (white).
10 12 14 16 18 20 22 24
1E-10
1E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
0.1
I,
A
U, V
Experiment
Modeling
Fig. 8. Comparison of current-voltage characteristics of the
LED module in the operation voltage range and the modeled
current-voltage characteristics of the LED module with a
variation of chip properties.
As in the most programming languages there is
only a random number generator with a uniform
distribution. For generating variation of LED parameters
coinciding with the normal distribution, we used the
formula [5]:
22
22
00
ln2
),(
ba
ba
axx
,
where х0 is the expected value, σ
2
– dispersion of a
random value, a and bare random variables with uniform
distribution, in which relations –1 < a < 1 and –1 < b < 1
are valid.
To test the results of modeling the LED CVC by
using the Monte Carlo method, we selected group of
initial parameters obeying the specified normal
distribution (Fig. 7, white curves). For comparison, in
the same Fig. 7 CVC of actual LED chips (excepting the
anomalous CVC of chips) are represented with black
colour. A good agreement of the model with the
experiment not only in the operation limits of voltages
(2.8…3 V), but also in the wider range is seen.
Table 2. Mean values and deviation of currents flowing
through LEDs in the LED matrix.
N
u
m
b
er
o
f
m
o
d
el
ed
L
E
D
M
ea
n
c
u
rr
en
t,
А
S
ta
n
d
ar
d
d
ev
ia
ti
o
n
M
in
im
u
m
v
al
u
e,
А
M
ax
im
u
m
v
al
u
e,
А
400 0.248206 0.045829 0.130364 0.390092
400 0.105404 0.017155 0.058014 0.153495
400 0.084945 0.013367 0.049298 0.126556
400 0.075775 0.012356 0.043098 0.115647
400 0.063335 0.009298 0.037065 0.089466
400 0.050814 0.007464 0.029898 0.07512
400 0.025733 0.002934 0.01736 0.033899
400 0.012698 0.000994 0.009763 0.015713
400 0.005002 0.000199 0.004354 0.00559
Calculating CVC of the group of high-power
LEDs, the size of the LED matrix and the type of their
connection were determined, and then the iterative
methods were used. Voltage was calculated on a group
of LEDs connected in parallel, and then, on the basis of
the obtained results, currents flowing through each LED
in the curcuit with accounting the general resistance
were measured.
From the obtained data, the flowing current through
each LED in the matrix was modeled (Table 2), and the
distribution of currents was examined. The results
indicate that variation of the initial parameters of the
LED chips leads to a greater variation between them
immediately during operation, without effecting
significantly on the total current-voltage characteristics
(Fig. 8). At the same time, the integral luminosity of the
matrix is close to the nominal one. Even when an error
welding of conduction contacts to the chip occurs, the
chips in parallel will shine brighter due to the increased
current flow, which will result to 5…7% reduction in the
total integrated luminosity of general LED matrix. At the
same time, this variation leads to overheating and rapid
degradation of the individual LED chips, which can
significantly effect on the service life of the LED matrix.
Conclusions
Analysis of the current-voltage characteristics of high-
power LED chips of the company “EDISON
Optocorporation” in the composition of LED modules
had shown the presence of defects in connecting the
wires to the chip and abnormally high current flow upon
applied low voltages (the first of which is a defect of
manufacturer of LED modules, the second – defect of
chip supplier).
The developed software allows to simulate
numerically the behavior of LED modules connected
practically in any combination, to analyze the currents
through any part of a modeled switching circuits.
Modeling the LED chip by two parallel ideal diodes and
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2015. V. 18, N 2. P. 200-204.
doi: 10.15407/spqeo18.02.1200
© 2015, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
204
consistent nonlinear resistance, manifested in the heating
up stage of CVC, had shown high correlation
coefficients between the internal parameters of
individual elements and close to normal distribution of
the basic parameters of these elements. This result
confirms the correctness of the chosen model.
Analysis of existing switching-on of chips for a
series-parallel circuit had shown that verification of the
integrated luminosity or CVC of final product does not
allow to identify the defects of supply wires or
overvalued current transport due to the redistribution of
the current in the LED module. However, this
redistribution leads to an increase of current through the
neighboring LEDs and their local overheating on the
plate, which should lead to acceleration of degradation
of the LED module.
Addition of internal sorting lines grouping the LED
chips by the current value at operation voltages will
allow to reduce variation between the chips and to
increase the service life of finished products.
Acknowledgements
The author expresses his sincere gratitude to the
corresponding member of NAS of Ukraine V.M. Sorokin
for useful discussions and interest to the work,
professor R.V. Konakova for discussions and her help in
writing this paper, and senior researcher Ya.Ya. Kudryk
for substantial assistance in performing the experiments.
References
1. Luqiao Yin, Lianqiao Yang, Weiqiao Yang et al.,
Design and analysis of multi-chip LED module
with ceramic substrate // Solid-State Electronics,
54(12), p. 1520-1524 (2010).
2. Ye Huaiyu, SauKoh, Henk van Zeijl, A.W.J.
Gielen, Zhang Guoqi, A review of passive thermal
management of LED module // J. Semiconductors,
32(1), 014008 (2010).
3. Dun-Yen Kang, Enboa Wu, Da-Ming Wang,
Modeling white light-emitting diodes with
phosphor layers // Appl. Phys. Lett. 89(23), 231102
(2006); doi: 10.1063/1.2400111.
4. V.V. Shynkarenko, Ya.Ya. Kudryk, I.V. Mukha,
R.Ya. Kudryk, Modeling the characteristics of a
high-power LED module with real chips //
Abstracts of the 6-th Intern. Sci.-Techn. Conf.
“Sensor Electronics and Microsystem
Technologies” (SEMST-6). – Ukraine, Odessa,
2014, Sept. 29 – Oct. 3, p. 58 (in Ukrainian).
5. J. Bucknall, The Tomes of Delphi Algorithms and
Data Structures. Wordware Publ., Inc. Co., 2002.
|