isl6236a Intersil Corporation, isl6236a Datasheet - Page 31

• Manufacturer Part Number: isl6236a
• Description: High-efficiency, Quad-output, Main Power Supply Controllers For Notebook Computers
• Manufacturer: Intersil Corporation

Power-Up Sequencing and On/Off Controls (EN )
EN1 and EN2 control SMPS power-up sequencing. EN1 or
EN2 rising above 2.4V enables the respective outputs. EN1
or EN2 falling below 1.6V disables the respective outputs.
Connecting EN1 or EN2 to REF will force its outputs off while
the other output is below regulation. The sequenced SMPS
will start once the other SMPS reaches regulation. The
Power-Up
Run
Overvoltage
Protection
Undervoltage
Protection
Discharge
Standby
Shutdown
Thermal Shutdown
Low
“>2.5” → High
“>2.5” → High
“>2.5” → High
“>2.5” → High
“>2.5” → High
“>2.5” → High
VEN LDO
MODE
PVCC < UVLO threshold.
EN LDO = high, EN1 or EN2
enabled.
Either output > 111% (VOUT1) or
116% (VOUT2) of nominal level.
Either output < 70% of nominal after
20ms time-out expires and output is
enabled.
Either SMPS output is still high in
either standby mode or shutdown
mode
EN1, EN2 < startup threshold, EN
LDO= High
EN1, EN2, EN LDO = low
TJ > +150°C
VEN1 (V)
High
High
High
REF
Low
Low
Low
31
CONDITION
TABLE 4. SHUTDOWN AND STANDBY CONTROL LOGIS
VEN2 (V)
TABLE 3. OPERATING-MODE TRUTH TABLE
High
High
REF
High
Low
Low
Low
Transitions to discharge mode after a VIN POR and after REF becomes valid. LDO,
VREF3, and REF remain active.
Normal operation
LGATE is forced high. LDO, VREF3 and REF active. Exited by a VIN POR, or by
toggling EN1 or EN2.
The internal 25Ω switch turns on. LDO, VREF3 and REF are active. Exited by a VIN
POR or by toggling EN1 or EN2.
Discharge switch (25Ω) connects OUT to GND. One output may still run while the
other is in discharge mode. Activates when PVCC is in UVLO, or transition to UVLO,
standby, or shutdown has begun. LDO, VREF3 and REF active.
LDO, VREF3 and REF active.
Discharge switch (25Ω) connects OUT to PGND. All circuitry off except VREF3.
All circuitry off. Exited by VIN POR or cycling EN. VREF3 remain active.
ISL6236A
LDO
On
On
On
On
Off
On
On
second SMPS remains on until the first SMPS turns off, the
device shuts down, a fault occurs or PVCC goes into
undervoltage lockout. Both supplies begin their power-down
sequence immediately when the first supply turns off. Driving
EN below 0.8V clears the overvoltage, undervoltage and
thermal fault latches.
On (after SMPS2 is up)
SMPS1
COMMENT
Off
Off
On
On
Off
On
On (after SMPS1 is up)
SMPS2
Off
On
On
On
Off
Off
June 28, 2007
FN6453.1