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Copyright (C) Siam Bee Technologies 2015 1
Lithium Ion CapacitorSimplified SPICE Behavioral Model
LTspice Version
Bee Technologies
Contents
1. Benefit of the Model
2. Model Feature
3. Concept of the Model
4. Parameter Settings
5. Li-Ion Capacitor Specification (Example)
5.1 Charge Time Characteristic
5.2 Discharge Time Characteristic
Simulation Index
Copyright (C) Siam Bee Technologies 2015 2
1. Benefit of the Model
• The model enables circuit designer to predict and optimize Li-Ion Capacitor runtime and circuit performance.
• The model can be easily adjusted to your own Li-Ion Capacitor specifications by editing a few parameters that are provided in the datasheet.
• The model is optimized to reduce the convergence error and the simulation time
Copyright (C) Siam Bee Technologies 2015 3
• This Li-Ion Capacitor Simplified SPICE Behavioral Model is for users who require the model of a Li-Ion Capacitor as a part of their system.
• Capacitor Voltage(Vcap) vs. Capacitor Capacity Level (SOC) Characteristic, that can perform capacitor charge and discharge time at various current rate conditions, are accounted by the model.
2. Model Feature
Copyright (C) Siam Bee Technologies 2015 4
Equivalent circuit of Li-Ion Capacitor model
Ca
pac
ity
Rs
elf-
Dis
ch
arg
e
S O C
+-
G 1
G V A L U E
-+
+-
E 2
E
0
R D C
E S RC A CP L U S
M I N U S
d s c h
IN+IN-
OUT+OUT-
E 9E V A L U E
1 0 5
+-
G 3
G V A L U E
3. Concept of the Model
Copyright (C) Siam Bee Technologies 2015 5
Li-Ion capacitorSimplified SPICE Behavioral Model
[Spec: CAP, ESR, RDC, NS]
Adjustable SOC [ 0-100 (%) ]
+
-
• The model is characterized by parameters: CAP, which represent the capacitor capacity and SOC, which represent the capacitor initial capacity level.
• Open-circuit voltage (VOC) vs. SOC is included in the model as an analog behavioral model (ABM).• NS (Number of Cells in series) is used when the Li-ion capacitor cells are in series to increase voltage level.
Output Characteristics
4. Parameter Settings
CAP is the amp-hour capacity [F]– e.g. C = 1, 10, or 1000 [F]
ESR is the equivalent series resistance of capacitors– e.g. C = 0.1m, 1m, or 10m []
RDC is the DC resistance of capacitors– e.g. C = 0.1m, 1m, or 10m []
NS is the number of cells in series– e.g. NS=1 for 1 cell capacitor, NS=2 for 2 cells capacitor
(capacitor voltage is double from 1 cell)
SOC is the initial state of charge in percent– e.g. SOC=0 for a empty capacitor (0%), SOC=1 for a full
charged capacitor (100%)
TSCALE turns TSCALE seconds into a second– e.g. TSCALE=60 turns 60s or 1min into a second,
TSCALE=3600 turns 3600s or 1h into a second
• From the Li-Ion Capacitor specification, the model is characterized by setting parameters CAP, ESR, RDC, NS, SOC and TSCALE.
Copyright (C) Siam Bee Technologies 2015 6
Model Parameters:
(Default values)
5. Li-Ion Capacitor Specification (Example)
Copyright (C) Siam Bee Technologies 2015 7
Capacitance capacity, ESR and DCR are input as a
model parameter
Capacitance capacity, ESR and DCR are input as a
model parameter
Rated Voltage 3.8V
Minimal Operating Voltage (Cutoff Voltage)
2.2V
Capacitance/Capacity 1000F
ESR 0.8m
DCR 1.2m
5.1 Charge Time Characteristic
Copyright (C) Siam Bee Technologies 2015 8
• Rated Voltage: 3.8V• Cutoff Voltage: 2.2V• Charging Current: 5A
Capacity=100%
(second)
Measurement Simulation
SOC=0 means capacitor start from 0% of capacity (empty)
SOC=0 means capacitor start from 0% of capacity (empty)
5.1 Charge Time Characteristic Simulation Circuit and Setting
Copyright (C) Siam Bee Technologies 2015 9
TSCALE turn 1 is equaled 1 second into a second
TSCALE turn 1 is equaled 1 second into a second
Charging CurrentCharging Current
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Measurement Simulation
(second)
• Rated Voltage: 3.8V• Cutoff Voltage: 2.2V• Discharge Current: 5A
SOC=0 means capacitor start from 100% of capacity (Full)
SOC=0 means capacitor start from 100% of capacity (Full)
5.2 Discharge Time Characteristic
5.2 Discharge Time Characteristic Simulation Circuit and Setting
Copyright (C) Siam Bee Technologies 2015 11
Discharging CurrentDischarging Current
Copyright (C) Siam Bee Technologies 2015 12
[Active Profile Index]
Simulations Folder name
1. Charge Time Characteristic.................................
2. Discharge Time Characteristic.............................
Charge_Time
Discharge_Time