MB3775 Datasheet, PDF (19/25 Pages) Fujitsu Component Limited. – SWITCHING REGULATOR CONTROLLER

MB3775
Reference data
If an aluminum electrolytic smoothing capacitor (RC 1.0Ω) is replaced with a low ESR semiconductor electrolytic
capacitor (OS-CON: RC 0.2 Ω), the phase shift is reduced by half (see Fig. 33 and 34).
Fig. 32 - DC/DC Converter AV vs. ϕ characteristic Test Circuit
VOUT
V0+
60
40
20
0
-20
-40
10
60
40
20
0
-20
-40
10
FB
0.1µF
+ IN
+
- IN
-
R1
Error Amp.
VREF
VIN
R2 _~
Fig. 33 - DC/DC Converter +5 V output
VCC=10V
RL=25Ω
CP=0.1µF
180
AV
ϕ
90
62°
0
-90
100
1K
10K
Frequency f(Hz)
-180
100K
Fig. 34 - DC/DC Converter +5 V output
VCC=10V
AV
RL=25Ω
CP=0.1µF
180
90
ϕ
27°
0
-90
100
1K
10K
Frequency f(Hz)
-180
100K
AV vs. ϕ characteristic
Between this point.
V0+
+
AI Capacitor
22µF(16V)
- RC 0.2Ω : fosc=1kHz
GND
V0+
+
OS-CON
220µF(16V)
- RC 1.0Ω : fosc=1KHz
GND
19