L4978
Figure 22. Line transient.
Figure 21. Load transient.
V
CC
D97IN786
(V)
30
20
10
V
(mV)
O
1
IO
= 1A
100
fsw = 100KHz
2
0
-100
1ms/DIV
Figure 24. Softstart capacitorselectionvs. In-
ductorand Vccmax.
Figure 23. Soft start capacitor selection Vs in-
ductor and Vccmax.
D97IN745
L
D97IN746
L
(µH)
680nF
(µH)
56nF
fsw=200KHz
470nF
fsw=100KHz
400
300
200
100
0
47nF
330nF
300
33nF
22nF
220nF
200
100
100nF
0
15 20 25 30 35 40 45 50 V
(V)
CCmax
15 20 25 30 35 40 45 50 V max(V)
CC
Figure 25. Openloop frequency andphase of er-
ror amplifier
GAIN
(dB)
D97IN787 Phase
50
GAIN
0
0
45
90
-50
-100
-150
-200
Phase
135
2
3
4
5
6
7
8
10 10 10 10 10 10 10 10 f(Hz)
9/12
STMICROELECTRONICS [ ST ]
