A7431A
DC-DC CONVERTER BUCK (STEP-DOWN)
42V 3A CC/CV
AiT Semiconductor Inc.
www.ait-ic.com
diode must have current rating higher than the maximum output current and a reverse voltage rating higher
than the maximum input voltage.
STABILITY COMPENSATION
Figure 5: Stability Compensation
CCOMP2 is needed only for high ESR output capacitor The feedback loop of the IC is stabilized by the
components at the COMP pin, as shown in Figure 5.
The DC loop gain of the system is determined by the following equation:
0.808V
AVDC
=
AVEAGCOMP
I
OUT
The dominant pole P1 is due to CCOMP
:
G
EA
∫
=
P1
2πAVEA
C
COMP
The second pole P2 is the output pole:
I
OUT
∫
P2
=
2πVOUT
C
OUT
The first zero Z1 is due to RCOMP and CCOMP
:
1
∫
=
Z1
2πRCOMP
CCOMP
And finally, the third pole is due to RCOMP and CCOMP2 (if CCOMP2 is used):
1
∫
=
P3
2πRCOMPCCOMP2
The following steps should be used to compensate the IC:
STEP 1. Set the cross over frequency at 1/10 of the switching frequency via RCOMP
:
REV1.0
- SEP 2016 RELEASED -
- 10 -
AITSEMI [ AiT Semiconductor ]
