ISL62883HRTZ-T Datasheet, PDF (14/37 Pages) Intersil Corporation – Multiphase PWM Regulator for IMVP-6.5™ Mobile CPUs

ISL62883, ISL62883B
VID6
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
VID5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
TABLE 1. VID TABLE (Continued)
VID4 VID3 VID2 VID1 VID0
0
1
1
1
1
1
0
0
0
0
1
0
0
0
1
1
0
0
1
0
1
0
0
1
1
1
0
1
0
0
1
0
1
0
1
1
0
1
1
0
1
0
1
1
1
1
1
0
0
0
1
1
0
0
1
1
1
0
1
0
1
1
0
1
1
1
1
1
0
0
1
1
1
0
1
1
1
1
1
0
1
1
1
1
1
0
0
0
0
0
0
0
0
0
1
0
0
0
1
0
0
0
0
1
1
0
0
1
0
0
0
0
1
0
1
0
0
1
1
0
0
0
1
1
1
0
1
0
0
0
0
1
0
0
1
0
1
0
1
0
0
1
0
1
1
0
1
1
0
0
0
1
1
0
1
0
1
1
1
0
0
1
1
1
1
1
0
0
0
0
1
0
0
0
1
1
0
0
1
0
1
0
0
1
1
1
0
1
0
0
1
0
1
0
1
1
0
1
1
0
1
0
1
1
1
1
1
0
0
0
1
1
0
0
1
V_O (V)
0.5125
0.5000
0.4875
0.4750
0.4625
0.4500
0.4375
0.4250
0.4125
0.4000
0.3875
0.3750
0.3625
0.3500
0.3375
0.3250
0.3125
0.3000
0.2875
0.2750
0.2625
0.2500
0.2375
0.2250
0.2125
0.2000
0.1875
0.1750
0.1625
0.1500
0.1375
0.1250
0.1125
0.1000
0.0875
0.0750
0.0625
0.0500
0.0375
0.0250
0.0125
0.0000
0.0000
VID6
1
1
1
1
1
1
VID5
1
1
1
1
1
1
TABLE 1. VID TABLE (Continued)
VID4 VID3 VID2 VID1 VID0
1
1
0
1
0
1
1
0
1
1
1
1
1
0
0
1
1
1
0
1
1
1
1
1
0
1
1
1
1
1
V_O (V)
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
COMP
RDROOP
FB
VDROOP
IDROOP
E/A
Σ
DAC
VDAC
INTERNAL TO IC
X1
VCCSENSE
VR LOCAL
VO
“CATCH”
RESISTOR
VIDS
VID<0:6>
RTN
VSS
VSSSENSE
“CATCH”
RESISTOR
FIGURE 9. DIFFERENTIAL SENSING AND LOAD LINE
IMPLEMENTATION
As the load current increases from zero, the output voltage will
droop from the VID table value by an amount proportional to the
load current to achieve the load line. The ISL62883 can sense the
inductor current through the intrinsic DC Resistance (DCR)
resistance of the inductors Figure 1 shows on page 10 or through
resistors in series with the inductors as Figure 2 shows also on
page 10. In both methods, capacitor C_n voltage represents the
inductor total currents. A droop amplifier converts C_n voltage into
an internal current source with the gain set by resistor R_i. The
current source is used for load line implementation, current
monitor and overcurrent protection.
Figure 9 shows the load line implementation. The ISL62883
drives a current source I_droop out of the FB pin, described by
Equation 1.
I_droop
=
2_----x_----V_---C----n-
R_i
(EQ. 1)
When using inductor DCR current sensing, a single NTC element
is used to compensate the positive temperature coefficient of the
copper winding thus sustaining the load line accuracy with
reduced cost.
I_droop flows through resistor R_droop and creates a voltage drop
of:
V_droop = R_droop × I_droop
(EQ. 2)
V_droop is the droop voltage required to implement load line.
Changing R_droop or scaling I_droop can both change the load line
slope. Since I_droop also sets the overcurrent protection level, it is
recommended to first scale I_droop based on OCP requirement,
then select an appropriate R_droop value to obtain the desired
load line slope.
14
FN6891.4
June 21, 2011