L6728D STMicroelectronics, L6728D Datasheet - Page 17

• Manufacturer Part Number: L6728D
• Description: IC CTLR PWM 1PH POWERGOOD 10DFN
• Manufacturer: STMicroelectronics

Specifications of L6728D

• Pwm Type: Voltage Mode
• Number Of Outputs: 1
• Frequency - Max: 330kHz
• Duty Cycle: 80%
• Voltage - Supply: 5 V ~ 12 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 10-DFN
• Frequency-max: 330kHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

L6728D
Figure 6.
●
●
To place the poles and zeroes of the compensation network, the following suggestions can
be followed:
Open loop converter singularities:
a)
b)
Compensation network singularities frequencies:
a)
b)
c)
d)
a)
Set the gain R
according to the approximated formula (suggested values for R
of a few kΩ):
F
F
F
F
F
F
----------
R
R
LC
ESR
Z1
Z2
P1
P2
FB
F
Example of type III compensation
=
=
=
=
=
=
compensation
converter gain
loop gain
open loop
=
EA gain
closed
------------------------------
2π R
---------------------------------------------------- -
2π
------------------------------------------------- -
2π R
------------------------------ -
2π R
open loop
--------------------------------- -
2π L C
F
------------
F
------------------------------------------- -
2π C
gain
0dB
LC
⋅
⋅
⋅
⋅
(
⋅
1
R
Gain
1
[dB]
0dB
1
F
⋅
F
S
⋅
FB
ΔV
------------------ -
OUT
⋅
⋅
⋅
F
C
⎛
⎝
1
C
V
OUT
1
1
/R
+
-------------------- -
C
OSC
C
F
IN
S
R
F
FB
F
⋅
+
ESR
S
⋅
) C
C
C
in order to obtain the desired closed loop regulator bandwidth
Doc ID 16498 Rev 1
⋅
P
P
⎞
⎠
S
F
Z1
F
F
LC
Z2
F
F
ESR
P1
F
0dB
F
P2
20log (R
F
/R
20log (V
FB
Log (Freq)
)
IN
Application details
/ΔV
FB
OSC
are in the range
)
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