MAX17082GTL+ Maxim Integrated Products, MAX17082GTL+ Datasheet - Page 41

• Manufacturer Part Number: MAX17082GTL+
• Description: IC CTLR PWM DUAL IMVP-6.5 40TQFN
• Manufacturer: Maxim Integrated Products
• Series: Quick-PWM™r

Specifications of MAX17082GTL+

• Applications: Controller, Intel IMVP-6.5™
• Voltage - Input: 4.5 ~ 5.5 V
• Number Of Outputs: 1
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Lead Free Status / Rohs Status: Details

Figure 11. Gate Drive Circuit
Alternatively, shoot-through currents can be caused by
a combination of fast high-side MOSFETs and slow low-
side MOSFETs. If the turn-off delay time of the low-side
MOSFETs are too long, the high-side MOSFETs can
turn on before the low-side MOSFETs have actually
turned off. Adding a resistor less than 5Ω in series with
BST_ slows down the high-side MOSFET turn-on time,
eliminating the shoot-through currents without degrad-
ing the turn-off time (R
the high-side MOSFET also reduces the LX_ node rise
time, thereby reducing EMI and high-frequency cou-
pling responsible for switching noise.
Firmly establish the input-voltage range and maximum
load current before choosing a switching frequency
and inductor operating point (ripple-current ratio). The
primary design trade-off lies in choosing a good switch-
ing frequency and inductor operating point, and the fol-
lowing four factors dictate the rest of the design:
(R
(C
BST_
NL
)* OPTIONAL—THE CAPACITOR REDUCES LX_ TO DL_ CAPACITIVE
)* OPTIONAL—THE RESISTOR LOWERS EMI BY DECREASING THE
SWITCHING NODE RISE TIME.
COUPLING THAT CAN CAUSE SHOOT-THROUGH CURRENTS.
IMVP-6+/IMVP-6.5 CPU Core Power Supplies
PGND
BST_
DH_
DL_
______________________________________________________________________________________
LX_
V
DD
Multiphase Quick-PWM
Dual-Phase, Quick-PWM Controllers for
BST_
(R
C
BYP
C
(C
BST_
BST_
NL
Design Procedure
in Figure 11). Slowing down
)*
)*
N
N
H
L
INPUT (V
L
IN
)
• Input-voltage range: The maximum value
• Maximum load current: There are two values to
• For multiphase systems, each phase supports a
• Switching frequency: This choice determines the
• Inductor operating point: This choice provides
(V
AC adapter voltage. The minimum value (V
must account for the lowest input voltage after drops
due to connectors, fuses, and battery selector
switches. If there is a choice at all, lower input volt-
ages result in better efficiency.
consider. The peak load current (I
mines the instantaneous component stresses and fil-
tering requirements, and thus drives output
capacitor selection, inductor saturation rating, and
the design of the current-limit circuit. The continuous
load current (I
es and thus drives the selection of input capacitors,
MOSFETs, and other critical heat-contributing com-
ponents. Modern notebook CPUs generally exhibit
I
fraction of the load, depending on the current bal-
ancing. When properly balanced, the load current is
evenly distributed among each phase:
where η
basic trade-off between size and efficiency. The
optimal frequency is largely a function of maximum
input voltage, due to MOSFET switching losses that
are proportional to frequency and V
mum frequency is also a moving target due to rapid
improvements in MOSFET technology that are mak-
ing higher frequencies more practical.
trade-offs between size vs. efficiency and transient
response vs. output noise. Low inductor values pro-
vide better transient response and smaller physical
size, but also result in lower efficiency and higher
output noise due to increased ripple current. The
minimum practical inductor value is one that causes
the circuit to operate at the edge of critical conduc-
tion (where the inductor current just touches zero
with every cycle at maximum load). Inductor values
lower than this grant no further size-reduction bene-
fit. The optimum operating point is usually found
between 20% and 50% ripple current.
LOAD
IN(MAX)
= I
TOTAL
LOAD(MAX)
) must accommodate the worst-case high
I
LOAD PHASE
LOAD
is the total number of active phases.
(
) determines the thermal stress-
x 80%.
)
=
η
I
LOAD
TOTAL
LOAD(MAX)
IN
2
. The opti-
IN(MIN)
) deter-
41
)