ISL62773 Datasheet, PDF (19/37 Pages) Intersil Corporation – Multiphase PWM Regulator for AMD Fusion™ Desktop CPUs Using SVI 2.0

ISL62773
REP RATE = 10kHz
REP RATE = 25kHz
REP RATE = 50kHz
REP RATE = 100kHz
REP RATE = 200kHz
FIGURE 17. CURRENT BALANCING DURING DYNAMIC OPERATION.
CH1: I_L1, CH2: I_LOAD, CH3: I_L2, CH4: I_L3
Modes of Operation
TABLE 1. CORE VR MODES OF OPERATION
CONFIG. ISEN3
PSL0_L
&
ISEN2 PSI1_L
MODE
OCP
Threshold
(µA)
3-phase
Core VR
Config.
To Power To Power
Stage Stage
11 3-phase CCM 45
01 2-phase CCM
00 1-phase DE
2-phase
Core VR
Config.
Tied to 5V To Power
Stage
11 2-phase CCM 45
01 1-phase CCM
00 1-phase DE
1-phase
Core VR
Config.
Tied to 5V Tied to
5V
11 1-phase CMM 45
01
00 1-phase DE
The Core VR can be configured for 3, 2- or 1-phase operation.
Table 1 shows Core VR configurations and operational modes,
programmed by the ISEN3 and ISEN2 pin status and the PSL0_L
and PSL1_L commands via the SVI 2 interface, see Table 9.
For a 2-phase configuration, tie the ISEN3 pin to 5V. In this
configuration, phases 1 and 2 are active. To select a 1-phase
configuration, tie the ISEN3 pin and the ISEN2 pin to 5V. In this
configuration, only phase-1 is active.
In a 3-phase configuration, the Core VR operates in 3-phase CCM,
with PSI0_L and PSI_L both high. If PSI0_L is taken low via the
SVI 2 interface, the Core VR drops phase 3 and continues to
operate in CCM. When both PSI0_L and PSI1_L are taken low,
the Core VR drops phase 2 and enters 1-phase DE mode.
For 2-phase configurations, the Core VR operates in 2-phase CCM
with PSI0_L and PSI_L both high. If PSI0_L is taken low via the
SVI 2 interface, the Core VR drops phase 2 and continues to
operate in 1-phase CCM. When both PSI0_L and PSI1_L are
taken low, the Core VR enters 1-phase DE mode.
In a 1-phase configuration, the Core VR operates in 1-phase CCM
and enters 1-phase DE when both PSI0_L and PSI1_L are low.
The Core VR can be disabled completely by connecting ISEN1 to
+5V.
TABLE 2. NORTHBRIDGE VR MODES OF OPERATION
ISEN2_NB
PSL0_L &
CONFIG. PSI1_L
MODE
OCP
Threshold
To Power
Stage
2-phase NB
VR Config.
11 2-phase CCM 45µA
01 1-phase CCM
00 1-phase DE
Tied to 5V
1-phase NB
VR Config.
11 1-phase CCM 45µA
01 1-phase CCM
00 1-phase DE
ISL62773 Northbridge VR can be configured for 2- or 1-phase
operation. Table 2 shows the Northbridge VR configurations and
operational modes, which are programmed by the ISEN2_NB pin
status and the PSI0_L and PSI1_L bits of the SVI 2 command.
19
March 7, 2012
FN8263.0