Datasheet

Device description PM6641
24/47 Doc ID 13510 Rev 3
7.3 SW regulators control loop
The PM6641 switching regulators are buck converters employing a constant frequency,
peak current mode PWM control loop, as shown in the following figure:
In the current mode constant frequency loop the power stage is represented by a controlled
current generator feeding the power stage output capacitor and load. The equivalent
transfer function is:
Equation 1
with Co and Res being the output capacitance and its equivalent series resistance and Ro
representing the output load.
Figure 28. SW regulator control loop
gm
a
KL
IL
RES
CO
RO
RC
CC
VREF
Power Stage
VC
VO
Signal Stage
CRO
gm
a
KL
IL
RES
CO
RO
RC
CC
VREF
Power Stage
VC
VO
Signal Stage
CRO
(
)
()
O
OESO
ESO
L
O
R
1RRsC
1RsC
)s(I
)s(V
)s(H
++
+
==