A7431
DC-DC CONVERTER BUCK (STEP-DOWN)
42V 3A CC/CV
AiT Semiconductor Inc.
www.ait-ic.com
Rectifier Diode
Use a Schottky diode as the rectifier to conduct current when the High-Side Power Switch is off. The Schottky
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
IOUT
AVDC
=
AVEAGCOMP
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
REV1.1
- JAN 2016 RELEASED, SEP 2016 UPDATED -
- 10 -
AITSEMI [ AiT Semiconductor ]
