ISL6322_07 INTERSIL [Intersil Corporation], ISL6322_07 Datasheet - Page 14

• Manufacturer Part Number: ISL6322_07
• Description: Four-Phase Buck PWM Controller with Integrated MOSFET Drivers and I2C Interface for Intel VR10, VR11, and AMD Applications
• Manufacturer: INTERSIL [Intersil Corporation]

If the R-C network components are selected such that the
RC time constant matches the inductor L/DCR time
constant, then V
DCR multiplied by the ratio of the resistor divider, K. If a
resistor divider is not being used, the value for K is 1.
The capacitor voltage V
sense resistor R
proportional to the inductor current. Equation 7 shows that
the proportion between the channel current and the sensed
current (I
the resistor divider ratio, and the DCR of the inductor.
Output Voltage Setting
The ISL6322 uses a digital to analog converter (DAC) to
generate a reference voltage based on the logic signals at
the VID pins. The DAC decodes the logic signals into one of
the discrete voltages shown in Tables 2, 3, 4 and 5. In Intel
modes of operation, each VID pin is pulled up to an internal
1.2V voltage by a weak current source (40μA), which
K
I
V
SEN
C
MOSFET
DRIVER
FIGURE 5. INDUCTOR DCR CURRENT SENSING
=
s ( )
ISL6322 INTERNAL CIRCUIT
-------------------- -
R
=
SAMPLE
2
=
R
+
K I
2
SEN
------------------------------------------------------- - K DCR I
⎛
⎜
⎝
I
R
n
⋅
s
1
L
⋅
(
----------------------- - C
) is driven by the value of the sense resistor,
⋅
R
CONFIGURATION
R
⎛
⎝
----------------- -
R
UGATE(n)
-------------
DCR
1
LGATE(n)
DCR
I
1
s L
SEN
ISEN
+
C
ISEN
⋅
⋅
R
R
is equal to the voltage drop across the
2
2
+
)
+
-
. The current through R
⋅
1
⎞
⎠
C
+
, is then replicated across the
1
V
R
⎞
⎟
⎠
V
IN
ISEN
C
⋅
(s)
14
⋅
-
INDUCTOR
R
1
L
V
ISEN-(n)
ISEN+(n)
⋅
L
I
(s)
L
L
V
C
DCR
R
*R
-
(s)
C
2*
2
ISEN
-
is OPTIONAL
is
C
V
OUT
(EQ. 7)
OUT
(EQ. 5)
(EQ. 6)
ISL6322
decreases to 0A as the voltage at the VID pin varies from 0
to the internal 1.2V pull-up voltage. In AMD modes of
operation the VID pins are pulled low by a weak 20μA
current source. External pull-up resistors or active-high
output stages can augment the pull-up current sources, up to
a voltage of 5V.
The ISL6322 accommodates four different DAC ranges: Intel
VR10 (Extended), Intel VR11, AMD K8/K9 5-bit, and AMD
6-bit. The state of the VRSEL and VID7 pins decide which
DAC version is active. Refer to Table 1 for a description of
how to select the desired DAC version.
VID4
VR10(Extended)
TABLE 2. VR10 (EXTENDED) VOLTAGE IDENTIFICATION
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
DAC VERSION
AMD 5-Bit
AMD 6-Bit
VR11
VID3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
TABLE 1. ISL6322 DAC SELECT TABLE
CODES
VID2
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0.8V < VRSEL < 3.0V
3.0V < VRSEL < VCC
3.0V < VRSEL < VCC
VID1
VRSEL < 0.6V
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
VRSEL PIN
VID0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
VID5
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
VID6
VID7 PIN
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
high
low
February 15, 2007
-
-
1.60000
1.59375
1.58750
1.58125
1.57500
1.56875
1.56250
1.55625
1.55000
1.54375
1.53750
1.53125
1.52500
1.51875
1.51250
1.50625
1.50000
1.49375
1.48750
1.48125
1.47500
1.46875
1.46250
1.45625
VDAC
FN6328.1