isl6363 Intersil Corporation, isl6363 Datasheet - Page 13

• Manufacturer Part Number: isl6363
• Description: Multiphase Pwm Regulator For Vr12™ Desktop Cpus
• Manufacturer: Intersil Corporation

Figure 7 shows the operation principle in diode emulation mode at
light load. The load gets incrementally lighter in the three cases
from top to bottom. The PWM on-time is determined by the VW
window size, therefore is the same, making the inductor current
triangle the same in the three cases. The ISL6363 clamps the
ripple capacitor voltage V
inductor current. It takes the COMP voltage longer to hit V
naturally stretching the switching period. The inductor current
triangles move further apart from each other such that the
inductor current average value is equal to the load current. The
reduced switching frequency helps increase light load efficiency.
Start-up Timing
With the controller's V
start-up sequence begins when VR_ON exceeds the logic high
threshold. Figure 8 shows the typical start-up timing of VR1 and
VR2. The ISL6363 uses digital soft-start to ramp-up DAC to the
voltage programmed by the SetVID command. PGOOD is asserted
high and ALERT# is asserted low at the end of the ramp-up.
Similar results occur if VR_ON is tied to VCC, with the soft-start
sequence starting 800µs after VCC crosses the POR threshold.
ALERT#
PGOOD
VR_ON
Vcrs
Vcrs
Vcrs
VCC
DAC
iL
iL
iL
FIGURE 8. VR1 SOFT-START WAVEFORMS
FIGURE 7. PERIOD STRETCHING
3.8ms
CC
CCM/DCM BOUNDARY
VW
VW
VW
voltage above the POR threshold, the
crs
2.5mV/µs
in DE mode to make it mimic the
LIGHT DCM
DEEP DCM
13
SLEW RATE
VID
…...
VID COMMAND
VOLTAGE
crs
,
ISL6363
Voltage Regulation and Load Line
Implementation
After the start sequence, the ISL6363 regulates the output voltage
to the value set by the VID information per Table 1. The ISL6363
will control the no-load output voltage to an accuracy of ±0.5%
over the range of 0.75V to 1.52V. A differential amplifier allows
voltage sensing for precise voltage regulation at the
microprocessor die.
7
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
6
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
4
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
0
VID
TABLE 1. VID TABLE
3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
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
2
HEX
September 29, 2011
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
0
F
F
0.00000
0.25000
0.25500
0.26000
0.26500
0.28000
0.28500
0.29000
0.29500
0.30000
0.30500
0.32000
0.32500
0.33000
0.33500
0.34000
0.34500
0.35000
0.35500
0.36000
0.36500
0.38000
0.38500
0.39000
0.39500
0.40000
0.40500
0.27000
0.27500
0.31000
0.31500
0.37000
0.37500
V
FN6898.0
O
(V)