ISL62883HRTZ Intersil, ISL62883HRTZ Datasheet - Page 23

• Manufacturer Part Number: ISL62883HRTZ
• Description: IC REG PWM 3PHASE BUCK 40TQFN
• Manufacturer: Intersil

Specifications of ISL62883HRTZ

• Applications: Controller, Intel IMVP-6.5™
• Voltage - Input: 5 V ~ 21 V
• Number Of Outputs: 1
• Voltage - Output: 0.0125 V ~ 1.5 V
• Operating Temperature: -10°C ~ 100°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Therefore:
Substitution of Equation 20 and application of the OCP
condition in Equation 30 gives Equation 31:
where I
corresponding droop current. For example, given N = 3,
R
R
I
For resistor sensing, Equation 32 gives the DC
relationship of V
Substitution of Equation 32 into Equation 1 gives
Equation 33:
Therefore:
Substitution of Equation 34 and application of the OCP
condition in Equation 30 gives:
where I
corresponding droop current. For example, given N = 3,
R
Equation 35 gives R
A resistor from COMP to GND can adjust the internal OCP
threshold, providing another dimension of fine-tune
flexibility. Table 3 shows the detail. It is recommended to
scale I
approximately the desired OCP level, then use R
fine tune the OCP level if necessary.
Load Line Slope
Refer to Figure 9.
I
droopmax
V
droop
sum
ntc
sen
V
R
R
R
I
R
Cn
droop
Cn
i
i
i
i
=
=
=
=
= 10kΩ, DCR = 0.88mΩ, I
= 1mΩ, I
=
= 3.65kΩ, R
=
--------------------------------------------------------------------------------- -
N
---------------------------------------------------------------------------------------------------------------------------- -
N
2R
---------------------------------------
N
droop
2R
--------------------------- -
N
=
⎛
⎜
⎜
⎜
⎝
omax
omax
R
-------------
=
×
×
×
------------------------------------------
R
×
---- -
R
sen
2
sen
sen
N
2
⎛
⎝
⎛
⎜
⎝
ntcnet
I
---- -
R
I
i
2
droopmax
2R
(
----------------------------------------------------
= 40.9µA, Equation 31 gives R
R
droop
×
×
R
R
i
R
ntcnet
×
×
such that the default OCP threshold gives
(
----------------------------------------------------
×
------------------------------------------
R
ntcs
ntcs
×
ntcnet
ntcnet
R
R
is the full load current, I
is the full load current, I
R
-------------
I
ntcnet
I
I
omax
omax
ntcs
ntcs
o
o
sen
+
N
R
cn
+
+
R
-------------- -
ntcnet
+
R
p
R
sum
(s) and I
+
+
N
×
×
R
-------------- -
ntc
ntc
+
= 11kΩ, R
= 51A and I
DCR
R
R
I
i
sum
N
o
R
-------------- -
= 831Ω.
ntc
ntc
)
×
+
sum
N
×
DCR
-------------
⎞
⎠
R
)
+
R
×
N
×
×
p
R
p
23
I
×
R
I
o
droop
p
o
+
⎞
⎟
⎟
⎟
⎠
DCR
-------------
p
(s).
R
-------------- -
×
N
×
ntcs
sum
N
I
DCR
omax
o
droopmax
×
⎞
⎟
⎠
I
= 2.61kΩ,
o
×
×
I
= 51A and
I
droopmax
omax
droopmax
droopmax
i
= 40.9µA,
ISL62883, ISL62883B
= 606Ω.
is the
is the
(EQ. 33)
(EQ. 34)
(EQ. 31)
(EQ. 29)
(EQ. 30)
(EQ. 32)
(EQ. 35)
comp
(EQ. 28)
to
For inductor DCR sensing, substitution of Equation 29
into Equation 2 gives the load line slope expression:
For resistor sensing, substitution of Equation 33 into
Equation 2 gives the load line slope expression:
Substitution of Equation 30 and rewriting Equation 36,
or substitution of Equation 34 and rewriting Equation 37
give the same result in Equation 38:
One can use the full load condition to calculate R
For example, given I
and LL = 1.9mΩ, Equation 38 gives R
It is recommended to start with the R
calculated by Equation 38, and fine tune it on the actual
board to get accurate load line slope. One should record
the output voltage readings at no load and at full load for
load line slope calculation. Reading the output voltage at
lighter load instead of full load will increase the
measurement error.
Current Monitor
Refer to Equation 18 for the IMON pin current
expression.
Refer to Figures 1 and 2, the IMON pin current flows
through R
Equation 39:
Rewriting Equation 38 gives Equation 40:
Substitution of Equation 40 into Equation 39 gives
Equation 41:
Rewriting Equation 41 and application of full load condition gives
Equation 42:
For example, given LL = 1.9mΩ, R
V
R
A capacitor C
the IMON pin voltage. The R
the user’s choice. It is recommended to have a time
Rimon
imon
LL
R
I
V
LL
R
V
droop
Rimon
droop
imon
Rimon
=
=
= 7.85kΩ.
V
------------------ -
V
------------------ -
= 963mV at I
=
=
droop
droop
=
I
=
I
=
o
o
imon
------------------ -
R
V
----------------------------------------------
----------------
I
3I
--------------------- -
droop
droop
Rimon
3
R
I
I
×
o
o
droop
o
imon
=
=
3I
×
I
. The voltage across R
droop
2R
---------------------- -
LL
o
2R
------------------------------------------ -
×
×
×
×
LL
LL
droop
R
sen
×
R
LL
can be paralleled with R
i
R
droop
N
×
omax
imon
omax
R
×
×
imon
R
×
R
droop
i
------------------------------------------
R
= 51A, I
ntcnet
= 51A, Equation 42 gives
R
imon
ntcnet
+
R
-------------- -
C
droop
sum
droopmax
N
imon
imon
droop
droop
×
DCR
-------------
= 2.37kΩ,
time constant is
N
is expressed in
= 2.37kΩ.
imon
value
= 40.9µA
(EQ. 38)
(EQ. 40)
(EQ. 41)
to filter
(EQ. 36)
(EQ. 37)
(EQ. 42)
(EQ. 39)
droop
FN6891.3
.