AIC1574 AIC [Analog Intergrations Corporation], AIC1574 Datasheet - Page 19

• Manufacturer Part Number: AIC1574
• Description: 5-bit DAC, Synchronous PWM Power Regulator with Triple Linear Controllers
• Manufacturer: AIC [Analog Intergrations Corporation]

The compensation network consists of the error
amplifier and built in compensation networks.
The goal of the compensation network is to
provide for fast response and adequate phase
margin. Phase Margin is the difference between
the closed loop phase at 0dB and 180 degree.
Closed Loop Gain(dB) = Modulation Gain(dB) +
Compensation Gain (dB)
Modulation Gain(dB)
where
The break frequency of Internal Compensation
F
F
Q
1
LC
ESR
10
20
log
log
C
2
L
O
O
2
1
V
V
L
1
OSC
IN
O
R
R
F
C
ESR
F
LC
ESR
O
1
;
2
10
C
2
log
C
O
L
O
O
;
1
F
LC
R
F
LOAD
F
1
ESR
Q
F
2
2
Gain are given by
Sampling theory shows that F
that half the switching frequency for the loop
stables. But it must be considerably less than
that, or there will be large amplitude switching
frequency ripple at the output. Thus, the usual
practices is to fix F
frequency.
F
F
F
F
Z
Z
P
P
1
2
1
-20
2
60
40
20
0
100
20log(V
Modulation
Gain
2
30
24
400
6 .
Bode Plot of Converter Gain
KHz
KHz
KHz
IN
KHz
/ V
1k
F
F
OSC
;
LC
;
;
F
)
Z1
F
Frequency (KHz)
ESR
0dB
10k
F
Z2
at 1/4 to 1/5 the switching
F
F
OdB
P1
Compensation Gain
100k
F
P2
Closed Loop
Gain
0dB
must be less
1M
AIC1574
10M
19