AAT1102 Advanced Analog Technology, Inc., AAT1102 Datasheet - Page 11

• Manufacturer Part Number: AAT1102
• Description: ADVANCED PWM DC-DC CONVERTER WITH INTERNAL SWITCH AND SOFT-START
• Manufacturer: Advanced Analog Technology, Inc.

Current Sampling Transfer
Function
Error voltage to duty transfer function
Where
Therefore,
transfer function
frequency;
transresistance. For the boost converter
and
For AAT1102 ,
compensation,
The closed-current loop transfer function
The Voltage-Loop Gain With
Current Loop Closed
The control to output voltage transfer function
is :
The voltage-loop gain with current loop closed is:
T
T
w
F
L
icl
d
m
vi
s
(
(
(
(
=
s
s
s
s
)
)
M = (
)
)
2
=
=
π
=
=
w
2
v
.
v
sh
β
v
R
f
12
d
o
c
ei
T
s
cs
(
(
=
c
s
s
V -
T
F
R is the current-sense amplifier
=
f
(
)
)
3
s
O
pi
s
m
cs
π
2
w
=
T
)
0
2
T
V )/ L
pi
s
M =0.8 × 10
T
×
depends on duty to inductor current
R
T , and
d
f
0
⎛
⎜
⎝
IN
icl
(
s
cs
R
pi
(
a
1
1
s
2
s
(
cs
Advanced Analog Technology, Inc.
)
(
−
+
s
s
+
= 0.275 V/A,
s
)
2
α
α
T
(
(
w
s
s
+
p
⎞
⎟
⎠
2
zi
+
(
2
,
)
s
+
–
α
ξ
(
w
)
f is the clock switching
s
–
w
2
s
6.
zi
2
=
ξ
n
Advanced Analog Technology, Inc
)(
+
w
s
台灣類比科技股份有限公司
M
s
M
+
n
w
+
s
1
2
sh
w
+
w
+
−
s
n
M
w
2
sh
+
M
M
)
n
)
12
a
2
a
a
F
)
M =
is slope
,
T
m
f
s
icl
1
2
is:
)
V / L
is :
IN
T
Page 11 of 18
d
Where
The compensator transfer function
Fig.3. Voltage loop compensator
Compensator design guide:
1. Crossover frequency
2. Gain margin>10dB
3. Phase margin>40 ∘
4. The
the compensator resistance,
by:
T
=
c
β
(
(
s
s
g
ν
)
+
m
=
c
β
R
w
(
v
L
v
c
s
zi
=
c
fb
vi
s
)
+
(
(
V
Vo
+
s
=
s
w
FB
)
s
2
w
z
g
Comparator
1
+
=
m
,
)(
c
sw
1
R
s
12
c
−
R
at crossover frequency, Therefore,
s
s
h
cs
f
w
+
_
+
s
+
T
z
2
s
2
T
12
w
pi
–
f
)
ci
0
p
c
AAT1102 (BIN2)
ν
0
.
f
, where
<
s
–
×
2
1
2
R is determined
)
c
f
ν
s
O
w
c
=
R
c
1
C
c
V5.0