EVALA5972D STMicroelectronics, EVALA5972D Datasheet - Page 11

• Manufacturer Part Number: EVALA5972D
• Description: Power Management Modules & Development Tools EVAL BOARD A5972 Auto Grade
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of EVALA5972D

• Input Voltage: 4.4 V to 36 V
• Output Voltage: 1.235 V to 35 V
• Board Size: 23 mm x 20 mm
• Product: Power Management Modules
• Supply Current: 2 A
• Dimensions: 23 mm x 20 mm
• For Use With/related Products: AN1517
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN1517
4
4.1
Closing the loop
Figure 9.
Error amplifier and compensation network
The output L-C filter of a step-down converter contributes with 180 degrees phase shift in
the control loop. For this reason a compensation network between the COMP pin and
GROUND is added. The simplest compensation network together with the equivalent circuit
of the error amplifier are shown in
open loop gain. CP does not significantly affect system stability but it is useful to reduce the
noise of the COMP pin.
The transfer function of the error amplifier and its compensation network is:
Equation 2
where A
A
vo
0
s ( )
= G
Block diagram of the loop
=
m
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
s
· R
2
•
o
R
0
•
(
C
0
+
C
p
) R
•
Figure
c
•
A
C
V0
10. R
c
+
•
s
(
•
1
C
(
+
R
and C
s
0
•
•
R
C
c
c
C
•
+
C
introduce a pole and a zero in the
R
c
0
)
•
(
C
0
+
C
p
)
+
R
Closing the loop
c
•
C
c
)
+
1
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