Rainbow Electronics MAX16064 - Manual (Page 21)

MAX16064
±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface
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Figure 7 shows how the MAX16064 interfaces to an
external serial EEPROM using the A1/SCLE and
A2/SDAE in applications where a master controller
does not exist or is not required. Using the GUI, the
user can select each MAX16064 device and configure
all the required output-voltage settings and sequenc-
ing/tracking information. Once the configuration is com-
plete, the results can be saved to the external EEPROM
by using the STORE_DEFAULT_ALL command and
configuration restored on the MAX16064 power-on
reset. The EEPROM can also be preprogrammed prior
to board assembly in the manufacturing environment.
A3/CONTROL can be used as a control signal to turn
on/off the power supply in a similar fashion as the
OPERATION command.
Use a serial EEPROM IC with a minimum of 4kb of stor-
age to ensure proper device operation.
MAX16064 Operation
On power-up reset, the MAX16064 goes through an ini-
tialization process as shown in Figure 8.
After initialization, the MAX16064 monitors the PMBus and
executes the PMBus commands accordingly. In addition,
if the power supply has been commanded to turn on, the
MAX16064 also monitors the power-supply output voltage
and temperature at the MFR_SAMPLE_RATE. The
PMBus system controller can monitor the power-supply
health by issuing various inquiries and status com-
mands to the MAX16064.
RESET Output Operation
RESET is an active-low, open-drain output that is low when
the device is powering on. RESET is assigned to one of
the power supplies using the MFR_RESET_OUTPUT
command. When that power-supply output is at the target
voltage, RESET goes high after the reset timeout period
(see Figure 9). The reset timeout period (t
RP ) is set by the
MFR_RESET_DELAY command.
The MFR_RESET_OUTPUT value defines which power-
supply output affects RESET. If MFR_RESET_OUTPUT is
set to 0, 1, 2, or 3, then RESET goes high t
RP after that
output has reached its target value. If MFR_RESET_OUT-
PUT is any other value, RESET is permanently low.
If the power-supply output selected by
MFR_RESET_OUTPUT is later disabled for any reason
(either due to a fault condition, or an OPERATION OFF
command), then RESET goes low immediately. To
enable faults on any power supply to cause RESET to
go low, set the MFR_MODE_OUTPUT.GLOBALFAULTS
bit to a 1 for all the supplies.
RESET requires an external pullup resistor.
33kΩ 33kΩ
V CC
1µF
1µF
VO+ VO-
1µF
DVDD
AVDD
3.3V
RSVD EEPROM
24LCXX
SYSTEM
CONTROLLER
DGND
MAX16064
A1/SCLE
A2/SDAE
A3/CONTROL
SCL
SDA
RESET
SMBALERT
POWER
SUPPLY
A1
A2
A3
SCL
SDA GND
IRQ
AGND
RS_-
RS_+
RS_C
DACOUT_ REFIN
VIN+
VIN-
REFO
ENOUT_ EN
LOAD
Figure 7. Typical System Application with External EEPROM