AIC1571 AIC [Analog Intergrations Corporation], AIC1571 Datasheet - Page 15

• Manufacturer Part Number: AIC1571
• Description: 5-bit DAC, Synchronous PWM Power Regulator with Dual Linear Controllers
• Manufacturer: AIC [Analog Intergrations Corporation]

The equations above do not model power loss
due to the reverse recovery of the lower
MOSFET’s body diode.
The R
equations even if the type devices is used for
both. This is because the gate drive applied to
the upper MOSFET is different than the lower
MOSFET. Logic level MOSFETs should be
selected based on on-resistance considera-
tions, R
and output voltage, allowable power dissipation
and maximum required output current. Power
dissipation should be calculated based pri-
marily on required efficiency or allowable ther-
mal dissipation.
Rectifier Schottky diode is a clamp that prevent
the loss parasitic MOSFET body diode from
P
P
UPPER
LOWER
DS(ON)
DS(ON)
=
=
I
I
OUT
OUT
is different for the two previous
2
should be chosen base on input
2
×
×
R
R
DS(ON)
DS(ON)
× +
× −
D
(1
I
D)
OUT
×
V
IN
2
×
t
SW
×
f
Linear Controller MOSFET Selection
The power dissipated in a linear regulator is :
Select a package and heatsink that maintains
junction temperature below the maximum rat-
ing while operation at the highest expected
ambient temperature.
Linear Output Capacitor
The output capacitors for the linear controller
provide dynamic load current. The linear con-
troller uses dominant pole compensation inte-
grated in the error amplifier and is insensitive to
output capacitor selection. C
should be selected for transient load regulation.
conducting during the dead time between the
turn off of the lower MOSFET and the turn on
of the upper MOSFET. The diode’s rated re-
verse breakdown voltage must be greater than
twice the maximum input voltage.
P
LINEAR
=
I
OUT
×
(V
IN2
−
V
OUT
OUT2
AIC1571
)
and C
15
OUT3