12. DCDCコンバータによる昇圧回路
ESR
IN
L
1 2
Rload
OUT
R1
R2
Q1
QN_SW
V+
0
Cout
D1
PWM Control
Circuit PWM output
pulse
VOUT=9V
tON tOFF
VIN=5V
L: IL
12Copyright(C) MARUTSU ELEC 2015
3. 回路解析シミュレーションの活用事例
詳細設計
CLP
100pF
Rf
560k
ESR
0.103
Cin
220uF
L
150u
1 2
Rload
180
R1
9.1k
R2
150k
Q1
Q2SD2623
OUT
R3
0.8
U1
NJM2377
-IN
FB
GND
OUTV+
CS
CT
REF
Rt
24k
Ct
470pF
IC = 0
D1
HRU0302A
0
V+
5V
0
IN
Cout
220uF
Rsf
160k
CS
4.7uF
IC = 0
0
Rsr
180k
0
トポロジー(回路方式)
詳細設計
13. Time
86.810ms 86.816ms 86.822ms 86.828ms
I(L)
0A
50mA
100mA
150mA
200mA
(86.818m,140.985m)
(86.821m,40.531m)
• PSpice is used to verify the circuit design.
• IL, PK=140.985mA and
IL,PK=140.985m-40.531m=100.454mA
• IL, PK is calculated as below.
• And the current ripple - IL, PK is calculated
as below
140mA2.96μ
150μ2
5
5
0.059
2
ON
IN
IN
OUTOUT
L,PK t
L
V
V
IV
I
mA992.96μ
150μ
5
ON
IN
L,PK t
L
V
ΔI
• Add trace I(L)
• Zoom to check the peak value.
IL, PK
13Copyright(C) MARUTSU ELEC 2015
3. 回路解析シミュレーションの活用事例
詳細設計(昇圧用コイル)
14. • PSpice is used to verify the circuit design.
• IL,PK=101.168mA, ton=3μs.
• Vripple =14.8mVp-p
• Irms
*=53.856mArms.
Irms is larger than calculated value due to feedback loop
response ripple current.
Time
87.5484ms 87.5684ms
V(OUT)
9.06V
9.07V
9.08V
9.09V
SEL>>
(87.556m,9.0792)
(87.553m,9.0644)
I(L) rms(I(Cout))
0A
100mA
200mA
(87.556m,141.564m)
(87.553m,40.396m)
• COUT is determined from the Vripple Spec
(30mVp-p).
• If COUT >> IOUTton/Vripple
(50m2.96μ/30m=4.933μF), Vripple will
mainly caused by ESR.
• Select the capacitor that can handle the
ripple current Irms.
• COUT=220μF, ESR=103m is selected.
m103
99m
30m
)(
L
ppripple
I
V
ESR
IL, PK
13mArms
6.67μ
2.96μ
32
99m
32
t
tonI
I
L
rms
Irms
Vripple
14Copyright(C) MARUTSU ELEC 2015
3. 回路解析シミュレーションの活用事例
詳細設計(出力電解コンデンサのリップル現象)
15. • Simulation result shows output start-up time of the circuit. This circuit needs
55ms to reach steady state.
Time
0s 20ms 40ms 60ms 80ms 90ms
V(OUT)
4V
5V
6V
7V
8V
9V
10V
I(Rload)
20mA
30mA
40mA
50mA
SEL>>
V(OUT)
I(Rload)
15Copyright(C) MARUTSU ELEC 2015
3. 回路解析シミュレーションの活用事例
詳細設計
出力電流
出力電圧