ISL6363_14 Datasheet, PDF (19/32 Pages) Intersil Corporation – Multiphase PWM Regulator for VR12™ Desktop CPUs

ISL6363
Modes of Operation
TABLE 2. VR1 MODES OF OPERATION
PWM4 PWM3 ISEN2 CONFIG.
To Ext To Ext To Power 4-phase
Driver Driver Stage CPU VR
Config.
Tie to
5V VCC
3-phase
CPU VR
Config.
Tie to
5V VCC
2-phase
CPU VR
Config.
Tie to 5V 1-phase
VCC CPU VR
Config.
PS MODE
0 4-PH CCM
1 2-PH CCM
2 1-PH DE
3
0 3-PH CCM
1 2-PH CCM
2 1-PH DE
3
0 2-PH CCM
1 2-PH CCM
2 1-PH DE
3
0 1-PH CCM
1
2 1-PH DE
3
OCP
THRESHOLD
(µA)
60
30
20
60
40
20
60
60
30
60
VR1 can be configured for 4, 3, 2 or 1-phase operation. Table 2
shows VR1 configurations and operational modes, programmed
by the PWM4, PWM3 pins and the ISEN2 pin status, and the PS
command. For 3-phase configuration, tie the PWM4 pin to 5V. In
this configuration, phases 1, 2 and 3 are active. For 2-phase
configuration, tie the PWM4 and PWM3 pin to 5V. In this
configuration, phases 1 and 2 are active. For 1-phase
configuration, tie the PWM4, PWM3 and the ISEN2 pin to 5V. In
this configuration, only phase 1 is active.
In 4-phase configuration, VR1 operates in 4-phase CCM in PS0
mode. It enters 2-phase CCM operation in PS1 mode. It enters
1-phase DE operation in PS2 and PS3 modes.
In 3-phase configuration, VR1 operates in 3-phase CCM in PS0
mode. It enters 2-phase CCM operation in PS1 mode. It enters
1-phase DE operation in PS2 and PS3 modes.
In 2-phase configuration, VR1 operates in 2-phase CCM in PS0
and PS1 mode. It enters 1-phase DE mode in PS2 and PS3
modes.
In 1-phase configuration, VR1 operates in 1-phase CCM in PS0
and PS1, and enters 1-phase DE mode in PS2 and PS3.
TABLE 3. VR2 MODES OF OPERATION
PS
MODE
OCP THRESHOLD
0
1-phase CCM
60µA
1
2
1-phase DE
3
Table 3 shows VR2 operational modes, programmed by the PS
command. VR2 operates in 1-phase CCM in PS0 and PS1, and
enters 1-phase DE mode in PS2 and PS3 mode.
VR2 can be disabled completely by tying ISUMNG to 5V, and all
communication to VR2 will be blocked.
Dynamic Operation
VR1 and VR2 behave the same during dynamic operation. The
controller responds to VID changes by slewing to the new voltage
at a slew rate indicated in the SetVID command. There are three
SetVID slew rates, namely SetVID_fast, SetVID_slow and
SetVID_decay.
SetVID_fast command prompts the controller to enter CCM and
to actively drive the output voltage to the new VID value at a
minimum 10mV/µs slew rate.
SetVID_slow command prompts the controller to enter CCM and
to actively drive the output voltage to the new VID value at a
minimum 2.5mV/µs slew rate.
SetVID_decay command prompts the controller to enter DE
mode. The output voltage will decay down to the new VID value at
a slew rate determined by the load. If the voltage decay rate is
too fast, the controller will limit the voltage slew rate at
SetVID_slow slew rate.
ALERT# will be asserted low at the end of SetVID_fast and
SetVID_slow VID transitions.
S etV ID_decay
S etV ID_fast/slow
VO
t1
ALERT#
V ID
T _ a le rt
t3
t2
FIGURE 13. SETVID DECAY PRE-EMPTIVE BEHAVIOR
Figure 13 shows SetVID Decay Pre-Emptive behavior. The
controller receives a SetVID_decay command at t1. The VR
enters DE mode and the output voltage V_O decays down slowly.
At t2, before V_O reaches the intended VID target of the
SetVID_decay command, the controller receives a SetVID_fast (or
SetVID_slow) command to go to a voltage higher than the actual
V_O. The controller will turn around immediately and slew V_O to
the new target voltage at the slew rate specified by the SetVID
command. At t3, V_O reaches the new target voltage and the
controller asserts the ALERT# signal.
The R3 modulator intrinsically has voltage feed-forward. The
output voltage is insensitive to a fast slew rate input voltage
change.
19
FN6898.1
September 5, 2013