6
FN4749.6
December 30, 2004
forces the FAULT pin low. The C
SS
capacitor is also used to
provide a controlled voltage slew rate during active-to-sleep
transitions on the 3.3V
DUAL
and 2.5/3.3V
MEM
outputs.
12V (Pin 14)
Connect this pin to the ATX (or equivalent) 12V output. This
pin is used to monitor the status of the power supply as well
as provide bias for the NMOS-compatible output drivers.
12V presence at the chip in the absence of bias voltage, or
severe 12V brownout during active states (S0, S1) operation
can lead to chip misbehavior.
VSEN2 (Pin 16)
Connect this pin to the memory output (V
OUT2
). In sleep
states, this pin is regulated to 2.5V or 3.3V (based on R
SEL
)
through an internal pass transistor capable of delivering
300mA (typically). When V
OUT2
is programmed to 2.5V, the
active-state voltage at this pin is regulated through an
external NPN transistor connected at the DRV2 pin. For the
3.3V setting, the ATX 3.3V is passed to this pin through a
fully on N-MOS transistor. During all operating states, the
voltage at this pin is monitored for under-voltage events.
DRV2 (Pin 15)
For the 2.5V RDRAM systems, connect this pin to the base
of a suitable NPN transistor. This pass transistor regulates
the 2.5V output from the ATX 3.3V during active states
operation. For 3.3V SDRAM systems connect this pin to the
gate of a suitable N-MOS transistor; this transistor is used to
switch in the ATX 3.3V output.
3V3DL (Pin 4)
Connect this pin to the 3.3V dual output (V
OUT1
). In sleep
states, the voltage at this pin is regulated to 3.3V; in active
states, ATX 3.3V output is delivered to this node through a
fully on N-MOS transistor. During all operating states, this
pin is monitored for under-voltage events.
3V3DLSB (Pin 3)
Connect this pin to the base of a suitable NPN transistor. In
sleep states, this transistor is used to regulate the voltage at
the 3V3DL pin to 3.3V.
DLA (Pin 10)
Connect this pin to the gates of suitable N-MOSFETs, which
in active states, are used to switch in the ATX 3.3V and 5V
outputs into the 3.3V
DUAL
and 5V
DUAL
outputs,
respectively.
5VDL (Pin 12)
Connect this pin to the 5V
DUAL
output (V
OUT3
). In either
operating state, the voltage at this pin is provided through a
fully on MOS transistor. This pin is also monitored for under-
voltage events.
5VDLSB (Pin 11)
Connect this pin to the gate of a suitable P-MOSFET or
bipolar PNP. In sleep states, this transistor is switched on,
connecting the ATX 5VSB output to the 5V
DUAL
regulator
output.
Description
Operation
The HIP6501A controls 3 output voltages (Refer to Figures
1, 2, and 3). It is designed for microprocessor computer
applications with 3.3V, 5V, 5VSB, and 12V outputs from an
ATX power supply. The IC is composed of two linear
controllers supplying the PCI slots’ 3.3V
AUX
power
(3.3V
DUAL
, V
OUT1
) and the 2.5V RDRAM or 3.3V SDRAM
memory power (2.5/3.3V
MEM
, V
OUT2
), and a dual switch
controller supplying the 5V
DUAL
voltage (V
OUT3
). In
addition, all the control and monitoring functions necessary
for complete ACPI implementation are integrated into the
HIP6501A.
Initialization
The HIP6501A automatically initializes upon receipt of input
power. The Power-On Reset (POR) function continually
monitors the 5VSB input supply voltage, initiating soft-start
operation after it exceeds its POR threshold (in either S3 or
S4/S5 states). To ensure stabilization of the 5VSB supply
before operation is allowed, POR is released 3.3ms
(typically) after 5VSB exceeds the POR threshold. The
5VSB POR trip event is also used to lock in the memory
voltage setting based on R
SEL
.
Operational Truth Tables
The EN3VDL and EN5VDL pins offer a host of choices in
terms of the overall system architecture and supported
features. Tables 1-3 describe the truth combinations
pertaining to each of the three outputs.
As seen in Table 1, EN3VDL
simply controls whether the
3.3VDUAL plane remains powered up during S4/S5 sleep
state.
TABLE 1. 3.3V
DUAL
OUTPUT (V
OUT1
) TRUTH TABLE
EN3VDL
S5 S3 3V3DL COMMENTS
0 1 1 3.3V S0, S1 STATES (Active)
0103.3VS3
0 0 1 Note 4 Maintains Previous State
0003.3VS4/S5
1 1 1 3.3V S0, S1 STATES (Active)
1103.3VS3
1 0 1 Note 4 Maintains Previous State
1000VS4/S5
NOTE:
4. Combination not allowed.
HIP6501A
