ISL6267 Datasheet, PDF (22/33 Pages) Intersil Corporation – Multiphase PWM Regulator for AMD Fusion Mobile CPUs

ISL6267
REP RATE = 10kHz
REP RATE = 25kHz
REP RATE = 50kHz
REP RATE = 100kHz
REP RATE = 200kHz
FIGURE 18. CURRENT BALANCING DURING DYNAMIC
OPERATION. CH1: I_L1, CH2: I_LOAD, CH3: I_L2, CH4:
I_L3
Modes of Operation
TABLE 6. CORE VR MODES OF OPERATION
PWM3 ISEN2 CONFIG.
To
To Power 3-phase
External Stage CPU VR
Driver
Config.
Tied to 5V
2-phase
CPU VR
Config.
Tied to
5V
1-phase
CPU VR
Config.
PSL_L
MODE
1 3-phase CCM
0 1-phase DE
1 2-phase CCM
0 1-phase DE
X 1-phase DE
OCP
Threshold
(µA)
60
20
60
30
60
The Core VR can be configured for 3, 2- or 1-phase operation.
Table 6 shows Core VR configurations and operational modes,
programmed by the PWM3 and ISEN2 pin status and the PS
command. For 2-phase configuration, tie the PWM3 pin to 5V. In
this configuration, phases 1 and 2 are active. For 1-phase
configuration, tie the PWM3 pin and the ISEN2 pin to 5V. In this
configuration, only phase-1 is active and the controller operates
in DE mode and the PSI_L input is ignored.
In 3-phase configuration, Core VR operates in 3-phase CCM, with
PSI_L high. It enters 1-phase DE mode when PSI_L is low,
dropping phases 3 and 2, and reduces the overcurrent and the
way-overcurrent protection levels to one-third of the initial values.
In 2-phase configuration, Core VR operates in 2-phase CCM with
PSI_L high. It enters 1-phase DE mode with PSI_L low, by
dropping phase 2 and reduces the overcurrent and the
way-overcurrent protection levels to one-half of the initial values.
In 1-phase configuration, the Core VR operates in 1-phase DE and
ignores the PSI_L input. If a resistor is placed from COMP pin to
GND with a value less than 150kΩ, then the Core VR operates in
1-phase CCM with PSI_L high and enters 1-phase DE mode when
PSI_L is low. A resistor value of 100kΩ is recommended.
TABLE 7. NORTHBRIDGE VR MODES OF OPERATION
ISEN2_NB CONFIG. PSL_L
MODE
OCP
Threshold
To Power
Stage
2-phase NB
VR Config.
1 2-phase CCM
0 1-phase DE
60uA
30uA
Tied to 5V
1-phase NB
VR Config.
X 1-phase DE
60uA
ISL6267 Northbridge (NB) VR can be configured for 2- or 1-phase
operation. Table 7 shows the Northbridge VR configurations and
operational modes, which are programmed by the ISEN2 pin
status and the PSI_L command. For 1-phase configuration, tie
the ISEN2_NB pin to 5V.
In 1-phase configuration, the Northbridge VR operates in 1-phase
DE and ignores the PSI_L input. If a resistor is placed from
COMP_NB pin to GND with a value less than 150kΩ, then the
Northbridge VR operates in 1-phase CCM with PSI_L high and
enters 1-phase DE mode when PSI_L is low. A resistor value of
100kΩ is recommended.
The Northbridge VR can be disabled completely by tying
ISUMN_NB to 5V.
22
January 31, 2011
FN7801.0