EVALPM6680 STMicroelectronics, EVALPM6680 Datasheet - Page 37
EVALPM6680
Manufacturer Part Number
EVALPM6680
Description
BOARD EVALUATION FOR PM6680
Manufacturer
STMicroelectronics
Datasheet
1.PM6680TR.pdf
(49 pages)
Specifications of EVALPM6680
Mfg Application Notes
PM6680 Eval Kit, AN2566 App Note
Main Purpose
DC/DC, Step Down with LDO
Outputs And Type
3, Non-Isolated
Power - Output
13.25W
Voltage - Output
1.05V, 1.5V, 5V
Current - Output
5A, 5A, 100mA
Voltage - Input
6 ~ 28V
Regulator Topology
Buck
Frequency - Switching
200kHz, 300kHz
Board Type
Fully Populated
Utilized Ic / Part
PM6680
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
497-6241
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
PM6680
7.13.6
Closing the integrator loop
The design of external feedback network depends on the output voltage ripple. If the ripple
is higher than approximately 30 mV, the feedback network (
keep the loop stable.
Figure 36. Circuitry for output ripple compensation
The stability of the system depends firstly on the output capacitor zero frequency. The
following condition should be satisfied:
Equation 23
where k is a design parameter greater than 3 and R
determinates the minimum integrator capacitor value C
Equation 24
where gm = 50 us is the integrator transconductance.
In order to ensure stability it must be also verified that:
Equation 25
OUTPUT
VOLTAGE
Vr
t
COMP PIN
VOLTAGE
D
D
? V
f
L
L
t
sw
C
INT
C
C
R
R
? V
C
>
O
O
O
O
U
U
U
U
INT
k
>
C
C
T
T
T
T
F
F
×
I
I
C
C
R
R
2
L
L
T
T
I
I
I
I
f
N
N
N
N
π
>
Zout
T
T
T
T
×
2
⎛
⎜
⎝
π
f
=
sw
g
×
g
k
V
V
m
m
f
C
C
C
2
C
R
R
R
R
Zout
I
−
O
O
I
N
N
2
1
π
2
1
M
M
T
T
O
O
f
P
P
×
Zout
U
U
T
T
C
×
F
F
B
B
out
out
⎞
⎟
⎠
V
k
×
Vr
OUT
I=gm(V1-Vr)
is the ESR of the output capacitor. It
INT
×
V
V
V
R
Vr
OUT
r
r
:
g
out
g
Figure 35
m
m
+
V
V
1
1
V
V
r
r
+
C
C
-
o
) is usually enough to
o
m
m
P
P
p
p
W
W
Device description
a
a
M
M
r
r
a
a
t
t
o
o
r
r
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