EVALPM6680 STMicroelectronics, EVALPM6680 Datasheet - Page 38
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
Device description
38/49
In order to reduce ground noise due to load transient on the other section, it is
recommended to add a resistor R
low pass filter (see
times) than the switching frequency of the section:
Equation 26
Due to the capacitive divider (C
Equation 27
Where V
If the ripple is very small (lower than approximately 30 mV), a further compensation network,
named virtual ESR network, is needed. This additional part generates a triangular ripple
that is added to the ESR output voltage ripple at the input of the integrator network. The
complete control schematic is represented in
Figure 37. Virtual ESR network
? V
? V
RIPPLEout
OUTPUT
OUTPUT
VOLTAGE
VOLTAGE
D
D
D
D
? V
? V
t
t
1
1
is the output ripple and q is the attenuation factor of the output ripple.
Figure 36
R1
R1
R1
R1
V
C
C
C
C
RIPPLE
T NODE
T NODE
VOLTAGE
VOLTAGE
L
L
L
L
T
T
INT
R
R
R
R
). The cutoff frequency f
R
=
t
t
INT
INT
V
INT
RIPPLEout
, C
R
R
R
R
C
C
C
C
COMP PIN
COMP PIN
VOLTAGE
VOLTAGE
R
R
R
R
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
=
filt
and a capacitor C
C
C
INT
INT
C
C
INT
INT
2
Vr
Vr
), the ripple voltage at the COMP pin is given by:
FILT
FILT
FILT
FILT
π
×
×
f
CUT
t
t
C
Figure 37
INT
? V
? V
C
C
C
C
C
×
INT
INT
INT
INT
1
INT
C
+
C
1
1
R
R
R
R
R
R
R
R
R
R
R
R
INT
INT
C
2
2
2
2
2
2
1
1
1
1
1
1
COMP
COMP
COMP
COMP
CUT
filt
OUT
OUT
OUT
OUT
×
FB
FB
+
FB
FB
filt
.
=
C
C
must be much greater (10 or more
that, together with C
V
filt
filt
RIPPLEout
Vr
Vr
Vr
Vr
gm
gm
gm
gm
+
+
×
V1
V1
V1
V1
q
Vr
Vr
Vr
Vr
Comparator
Comparator
Comparator
Comparator
+
+
-
-
PWM
PWM
PWM
PWM
INT
, realize a
PM6680