ST1S14 STMicroelectronics, ST1S14 Datasheet - Page 18

• Manufacturer Part Number: ST1S14
• Description: Up to 3 A step down switching regulator
• Manufacturer: STMicroelectronics

Closing the loop
6.4
18/42
A small signal capacitor in parallel to the upper resistor (see
divider implements a leading network (f
system phase margin:
Equation 14
where:
Total loop gain
In summary, the open loop gain can be expressed as:
Equation 15
Example: V
The resistor divider is R
C
Selecting L = 8.2 µH, C
diagrams are plotted respectively in
(V
R1
IN
=150nF implements a leading network (f
=6V to 48V, I
IN
= 12V, V
OUT
OUT
G
=3A)
DIV
= 3.3V, R
OUT
1
s ( )
G s ( )
=5.6K, R
Doc ID 17977 Rev 1
= 100 µF and ESR = 75 mΩ, the gain and phase bode
=
f
f
f
=
Z
P
------------------- -
R
Z
OUT
=
<
1
G
=
R
+
f
DIV
2
------------------------------------- -
2 π R
P
2
zero
---------------------------------------------------
2 π
=3.3K.
R
= 2
⋅ ⋅
⋅ ⋅
Figure 12
2
s ( ) G
⋅
< f
Ω
---------------------------------------------------------- -
⎛
⎝
------------------- - C
R
⋅
1
1
R
1
pole
1
(
+
1
1
⋅
CO
1
+
⋅
s
C
+
R
Z
R
), sometimes necessary to improve the
⋅
R1
s ( ) A
=190 kHz, f
s R
2
------------------- - C
R
2
R
and
⋅
1
⋅
1
⋅
+
⋅
1
R1
R
R
Figure 13
0
⋅
2
s ( )
2
C
⋅
R1
Figure
)
R1
P
⎞
⎠
=510 kHz).
over input voltage range
11.) of the voltage
ST1S14