ISL6506BIBZ Datasheet, PDF (4/8 Pages) Intersil Corporation – Multiple Linear Power Controller with ACPI Control Interface

ISL6506BIBZ
Functional Pin Description
VCC (Pin 1)
Provide a very well decoupled 5V bias supply for the IC to
this pin by connecting it to the ATX 5V_SB output. This pin
provides all the bias for the IC as well as the input voltage for
the internal standby 3V3AUX LDO. The voltage at this pin is
monitored for power-on reset (POR) purposes.
GND (Pin 5, Pad)
Signal ground for the IC. These pins are also the ground
return for the internal 3V3AUX LDO that is active in
S3/S4/S5 sleep states. All voltage levels are measured with
respect to these pins.
S3 and S5 (Pins 3 and 4)
These pins switch the IC’s operating state from active (S0,
S1/S2) to S3 and S4/S5 sleep states. These are digital
inputs featuring internal 10µA pull-down current sources on
each pin. Additional circuitry blocks illegal state transitions,
such as S4/S5 to S3. Connect S3 and S5 to the computer
system’s SLP_S3 and SLP_S5 signals, respectively.
3V3AUX (Pin 2)
Connect this pin to the 3V3DUAL output. In sleep states, the
voltage at this pin is regulated to 3.3V through an internal
pass device powered from 5VSBY through the VCC pin. In
active states, ATX 3.3V output is delivered to this node
through a fully-on NMOS transistor. During S3 and S4/S5
states, this pin is monitored for undervoltage events.
DLA (Pin 6)
This pin is an open-drain output. A 1kΩ resistor must be
connected from this pin to the ATX 12V output. This resistor
is used to pull the gates of suitable N-MOSFETs to 12V,
which in active state, switch in the ATX 3.3V and 5V outputs
into the 3.3V_AUX and 5V_DUAL outputs, respectively. This pin
is also used to monitor the 12V rail during POR. If a resistor
other than 1kΩ is used, the POR level will be affected.
5VDLSB (Pin 7)
Connect this pin to the gate of a suitable P-MOSFET.
In S3 sleep state, this transistor is switched on, connecting
the ATX 5V_SB output to the 5V_DUAL regulator output.
Description
Operation
The ISL6506BIBZ controls 2 output voltages, 3.3V_DUAL and
5V_DUAL. It is designed for microprocessor computer
applications requiring 3.3V, 5V, 5V_SB, and 12V bias input
from an ATX power supply. The IC is composed of one linear
controller/regulator supplying the computer system’s
3.3V_DUAL power, a dual switch controller supplying the
5V_DUAL voltage, as well as all the control and monitoring
functions necessary for complete ACPI implementation.
Initialization
The ISL6506BIBZ automatically initializes upon receipt of
input power. The Power-On Reset (POR) function
continually monitors the 5V_SB input supply voltage. The
ISL6506BIBZ also monitors the 12V rail to insure that the
ATX rails are up before entering into the S0 state even if
both SLP_S3 and SLP_S5 are both high.
Dual Outputs Operational Truth Table
Table 1 describes the truth combinations pertaining to the
3.3V_DUAL and 5V_DUAL outputs. The internal circuitry does
not allow the transition from an S4/S5 state to an S3 state.
TABLE 1. 5V_DUAL OUTPUT TRUTH TABLE
S5 S3 3.3AUX
5VDL
COMMENTS
1
1
3.3V
5V S0/S1/S2 States (Active)
1
0
3.3V
5V S3
0
1
Note
Maintains Previous State
0
0
3.3V
0V S4/S5
NOTE: Combination Not Allowed.
Functional Timing Diagram
Figure 1 is a simplified timing diagram, detailing the power-
up/down sequences of all the outputs in response to the status
of the sleep-state pins (S3, S5), as well as the status of the
input ATX supply. Not shown in this diagram is the deglitching
feature used to protect against false sleep state tripping.
Additionally, the ISL6506BIBZ features a 60µs delay in
transitioning from S0 to S3 states. The transition from the S0
state to S4/S5 state is immediate.
5VSB
S3
S5
3.3V, 5V, 12V
DLA
3V3AUX
5VDLSB
5VDL
FIGURE 1. 5V_DUAL AND 3.3V_AUX TIMING DIAGRAM;
ISL6506BIBZ
Soft-Start
Figures 2 and 3 show the soft-start sequence for the typical
application start-up into a sleep state. At time t0, 5V_SB (bias)
is applied to the circuit. At time t1, the 5V_SB surpasses POR
level. Time t2, one soft-start interval after t1, denotes the
4
FN7814.0
June 8, 2011