ISL6267HRZ-T Intersil, ISL6267HRZ-T Datasheet - Page 26

• Manufacturer Part Number: ISL6267HRZ-T
• Description: IC PWM CTRLR MULTIPHASE 48TQFN
• Manufacturer: Intersil

Specifications of ISL6267HRZ-T

• Applications: Converter, AMD Fusion™ CPU GPU
• Voltage - Input: 4.75 V ~ 5.25 V
• Number Of Outputs: 2
• Voltage - Output: 0.0125 V ~ 1.55 V
• Operating Temperature: -10°C ~ 100°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

should be determined through tuning the load transient response
waveforms on an actual board.
R
lower impedance path than R
and C
selection of R
i
100Ω. C
transient response waveforms on an actual board. The
recommended range for C
should be noted that the R
waveform. Instead of being triangular as the real inductor
current, i
affect i
OCP accuracy. User discretion is advised.
Resistor Current-Sensing Network
Figure 26 shows the resistor current-sensing network for a
2-phase solution. Each inductor has a series current sensing
resistor, R
accurately capture the inductor current information. The R
and R
form a filter for noise attenuation. Equations 24 thru 26 give the
V
Transfer function A
sensing resistor R
over-temperature, so there is no need for the NTC network.
The recommended values are R
V
ω
A
L
Cn
ip
Cn
, and V
Rsen
Rsen
RSEN
DCR
(s) expression.
and C
s ( )
PHASE1
L
ip
o
FIGURE 26. RESISTOR CURRENT-SENSING NETWORK
s ( )
droop
=
resistors are connected to capacitor C
=
do not have any effect at steady state. Through proper
ip
o
droop
---------------------------
ip
R
------------- -
RSEN
R
------------
sen
=
will not ring back. The recommended value for R
should be determined through tuning the load
DCR
sum
sen
N
N
form an R-C branch in parallel with R
----------------------
1
PHASE2 PHASE3
average value detection and therefore may affect
L
. R
I
ip
1
O
+
may have sharp spikes, which may adversely
×
×
1
and C
------------
ω
sum
I
C
o
sns
s
sen
n
RSEN
s ( )
Rsen
DCR
and R
ip
×
L
value does not have significant variation
A
values, i
(s) always has unity gain at DC. Current-
Rsen
ip
o
ip
are connected to the R
is 100pF~2000pF. However, it
-C
s ( )
i
26
R
R
R
at the beginning of i
ip
R
R
R
sum
droop
SUM
SUM
SUM
O
O
O
branch may distort the i
= 1kΩ and C
can resemble i
VCN
n
+
-
. R
n
i
sum
, providing a
= 5600pF.
CN
sen
o
o
RI
change. R
rather than
and C
pads to
droop
I
(EQ. 24)
(EQ. 25)
(EQ. 26)
I
sum
SUM+
SUM-
ip
ISL6267
n
is
ip
Overcurrent Protection
Refer to Equation 1 on page 20 and Figures 20, 24 and 26;
resistor R
internal OCP threshold. It is recommended to design I
without using the R
For example, the OCP threshold is 60µA for 3-phase solution.
I
is 1.5x of the full load current.
For inductor DCR sensing, Equation 27 gives the DC relationship
of V
Substitution of Equation 27 into Equation 1 gives Equation 28:
Therefore:
Substitution of Equation 19 and application of the OCP condition
in Equation 29 gives Equation 30:
where I
corresponding droop current. For example, given N = 3,
R
DCR = 0.88mΩ, I
Equation 30 gives R
For resistor sensing, Equation 31 gives the DC relationship of
V
Substitution of Equation 31 into Equation 1 gives Equation 32:
Therefore:
Substitution of Equation 33 and application of the OCP condition
in Equation 29 gives Equation 34:
where I
corresponding droop current. For example, given N = 3,
R
gives R
R
I
V
I
R
V
R
R
droop
droop
droop
cn
Cn
i
sum
Cn
sen
i
i
i
=
=
=
=
(s) and I
cn
=
=
-------------------------------------------------------------------------------------------------------------------------
N
= 1mΩ, I
------------------------------------------------------------------------------- -
N
2R
-------------------------- -
2R
------------------------------------- -
N
N
(s) and I
= 3.65kΩ, R
is designed to be 40.9µA at full load, so the OCP trip level
⎛
⎜
⎜
⎜
⎝
=
=
×
R
------------
×
i
omax
×
×
omax
---------------------------------------- -
R
sen
sen
= 831Ω.
sen
N
2
⎛
⎜
⎝
⎛
⎝
---- -
R
I
I
ntcnet
---- -
R
i
2
2
(
-------------------------------------------------- -
droop
droopmax
2R
R
sets the droop current, I
×
i
i
R
R
ntcnet
o
R
×
×
×
×
ntcs
ntcs
×
(
-------------------------------------------------- -
(s).
ntcnet
ntcnet
is the full load current and I
is the full load current and I
R
R
R
------------
---------------------------------------- -
R
I
I
I
o
o
omax
omax
o
ntcs
ntcs
sen
ntcnet
N
(s):
+
+
+
R
R
------------- -
omax
+
R
R
p
×
ntcnet
sum
+
+
N
×
R
------------- -
ntc
ntc
comp
= 51A and I
= 11kΩ, R
i
I
R
R
DCR
o
sum
+
= 606Ω.
N
ntc
ntc
)
+
R
------------- -
= 51A and I
×
×
sum
⎞
⎠
R
DCR
----------- -
N
)
resistor.
+
R
×
p
×
×
N
p
R
I
I
R
o
droop
p
+
×
⎞
⎟
⎟
⎟
⎠
p
R
------------- -
DCR
----------- -
ntcs
×
×
sum
droopmax
N
N
I
DCR
o
droop
droopmax
= 2.61kΩ, R
×
⎞
⎟
⎠
×
I
×
o
I
I
droopmax
. Tables 6 and 7 show the
omax
droopmax
droopmax
= 40.9µA, Equation 34
= 40.9µA.
ntc
is the
= 10kΩ,
is the
January 31, 2011
droop
FN7801.0
(EQ. 27)
(EQ. 28)
(EQ. 29)
(EQ. 30)
(EQ. 31)
(EQ. 32)
(EQ. 33)
(EQ. 34)