Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

ISL6322 Datasheet(PDF) 34 Page - Intersil Corporation

Part No. ISL6322
Description  Four-Phase Buck PWM Controller with Integrated MOSFET Drivers and I2C Interface for Intel VR10, VR11, and AMD Applications
Download  41 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  INTERSIL [Intersil Corporation]
Homepage  http://www.intersil.com/cda/home
Logo 

ISL6322 Datasheet(HTML) 34 Page - Intersil Corporation

Zoom Inzoom in Zoom Outzoom out
 34 / 41 page
background image
34
FN6328.0
August 21, 2006
following steps to choose the component values for the
R-C current sensing network:
1. Choose an arbitrary value for C1. The recommended
value is 0.1µF.
2. Plug the inductor L and DCR component values, and the
value for C1 chosen in step 1, into Equation 33 to
calculate the value for R1.
3. Resistor R2 should be left unpopulated.
If the desired overcurrent trip level, IOCP, is greater than the
minimum overcurrent trip level, IOCP,min, then a resistor
divider R-C circuit should be used to set the desired trip
level. Do the following steps to choose the component
values for the resistor divider R-C current sensing
network:
1. Choose an arbitrary value for C1. The recommended
value is 0.1
μF.
2. Plug the inductor L and DCR component values, the
value for C1 chosen in step 1, the number of active
channels N, and the desired overcurrent protection level
IOCP into Equations 34 and 35 to calculate the values for
R1 and R2.
Due to errors in the inductance or DCR, it may be necessary
to adjust the value of R1 and R2 to match the time constants
correctly. The effects of time constant mismatch can be seen
in the form of droop overshoot or undershoot during the
initial load transient spike, as shown in Figure 22. Do the
following steps to ensure the R-C and inductor L/DCR
time constants are matched accurately.
1. Capture a transient event with the oscilloscope set to
about L/DCR/2 (sec/div). For example, with L = 1µH and
DCR = 1m
Ω, set the oscilloscope to 500µs/div.
2. Record
ΔV1 and ΔV2 as shown in Figure 22.
3. Select new values, R1,NEW and R2,NEW, for the time
constant resistors based on the original values, R1,OLD
and R2,OLD, using Equation 36 and Equation 37.
4. Replace R1 and R2 with the new values and check to see
that the error is corrected. Repeat the procedure if
necessary.
Load-line Regulation Resistor
If load-line regulation is desired, the IDROOP pin should be
shorted to the FB pin in order for the internal average
sense current to flow out across the load-line regulation
resistor, labeled RFB in Figure 6. This resistor’s value sets
the desired load-line required for the application. The
desired load-line, RLL, can be calculated by Equation 38,
where VDROOP is the desired droop voltage at the full load
current IFL.
Based on the desired load-line, the load-line regulation
resistor, RFB, can be calculated from Equation 39 or
Equation 40, depending on the R-C current sense circuitry
being employed. If a basic R-C sense circuit consisting of C1
and R1 is being used, use Equation 39. If a resistor divider
R-C sense circuit consisting of R1, R2, and C1 is being
used, use Equation 40.
In Equations 39 and 40:
RLL is the load-line resistance,
N is the number of active channels,
DCR is the DCR of the individual output inductors, and
R1 and R2 are the current sense R-C resistors.
If no load-line regulation is required, the IDROOP pin should
be left open and not connected to anything. To choose the
value for RFB in this situation, see “Compensation without
Load-line Regulation” on page 35.
R
1
L
DCR C
1
-------------------------
=
(EQ. 33)
I
OCP
I
OCP min
,
=
R
1
LI
OCP
C
1 0.0375 N
⋅⋅
---------------------------------------
=
(EQ. 34)
I
OCP
I
OCP min
,
>
(EQ. 35)
R
2
LI
OCP
C
1
I
OCP D CR
0.0375 N
()
----------------------------------------------------------------------------------
=
FIGURE 22. TIME CONSTANT MISMATCH BEHAVIOR
ΔV1
VOUT
ITRAN
ΔV2
ΔI
R
1NEW
,
R
1OLD
,
V
1
Δ
V
2
Δ
----------
=
(EQ. 36)
R
2NEW
,
R
2OLD
,
V
1
Δ
V
2
Δ
----------
=
(EQ. 37)
R
LL
V
DROOP
I
FL
-------------------------
=
(EQ. 38)
R
FB
R
LL N 300
⋅⋅
DCR
----------------------------------
=
(EQ. 39)
(EQ. 40)
R
FB
R
LL N 300
R
1
R
2
+
()
⋅⋅
DCR R
2
----------------------------------------------------------------
=
ISL6322


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41 


Datasheet Download




Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn