SMM665B
Six-Channel Active DC Output Controller, Monitor, Marginer and Sequencer
FEATURES & APPLICATIONS
•
Extremely accurate (±0.1%) Active
DC Output Control (ADOC
TM
)
•
Undervoltage Lockout function (UVLO)
•
ADOC
TM
Automatically adjusts supply output
voltage level under all DC load conditions
•
Monitors, controls, sequences and margins up
to six supplies from 0.3V to 5.5V with 1.25V Vref
Wide Margin/ADOC range from 0.3V to VDD
•
Programmable Power-on/-off sequencing
•
Monitors internal temperature sensor
•
Operates from any intermediate bus supply
from 8V to 15V and from 2.7V to 5.5V
•
Monitors 12V input and VDD
•
Monitors two general-purpose 10-bit ADC inputs
•
Programmable threshold limits (2 OV/2 UV) for
each monitored input
•
Programmable RESET, HEALTHY and FAULT
•
4k-bit general purpose nonvolatile memory
•
I
2
C 2-wire serial bus for programming
configuration and monitoring status, including
10-bit ADC conversion results
Applications
•
Monitor/Control Distributed and POL Supplies
•
Multi-voltage Processors, DSPs, ASICs used in
Telecom, CompactPCI or server systems
Preliminary Information
1
(See Last Page)
INTRODUCTION
The SMM665B is an Active DC Output power supply
Controller (ADOC
TM
) that monitors, margins and
cascade sequences. The ADOC feature is unique and
maintains extremely accurate settings of system
supply voltages to within ±0.2% under full load. The
device actively controls up to six DC/DC converters
that use a Trim or Regulator VADJ/FB pin to adjust the
output voltage. For system test, the part also controls
margining of the supplies using I
2
C commands. It can
margin supplies with either positive or negative control
within a range of 0.3V to VDD depending on the
specified range of the converter. The SMM665B also
intelligently sequences or cascades the power
supplies on and off in any order using enable outputs
with programmable polarity. It can operate off any
intermediate bus supply ranging from 8V to 15V or
from 5.5V to as low as 2.7V. The part monitors six
power supply channels as well as VDD, 12V input, two
general-purpose analog inputs and an internal
temperature sensor using a 10-bit ADC. The 10-bit
ADC can measure the value on any one of the monitor
channels and output the data via the I
2
C bus. A host
system can communicate with the SMM665B status
register, optionally control Power-on/off, margining and
utilize 4K-bits of nonvolatile memory.
SIMPLIFIED APPLICATIONS DRAWING
12VIN (+8V to +15V Range)
3.3VIN (+2.7V to +5.5V Range)
12VIN
VDD
CAP
A
TRIM_CAP
A
DC/DC
Converter C, E
VIN
DC/DC
Converter A
Vout
TRIM
ON/OFF
2 of 6 DC-DC
Converters shown
VM
A
CAP
B
DC/DC
Converter D, F
VIN
DC/DC
Converter B
Vout
TRIM
ON/OFF
12V
3.3V
SDA
I
2
C
BUS
SCL
A2
External
or
Internal
TEMP
SENSOR
Environ
mental
SENSOR
External or
Internal
REFERENCE
2.5VIN
TRIM
A
PUP
A
AIN1
SMM665B
AIN2
VREF_CNTL
VREF_ADC
HEALTHY
TRIM_CAP
B
µP/
ASIC
1.2VIN
TRIM
B
PUP
B
RST
MR
VM
B
HEALTHY
RESET
READY
Figure 1 – Applications Schematic using the SMM665B Controller to actively control the output levels of
up to six DC/DC Converters while also providing power on/off, cascade sequencing and output margining.
Note: This is an applications example only. Some pins, components and values are not shown.
© SUMMIT
Microelectronics, Inc.
2004 • 1717 Fox Drive • San Jose CA 95131 • Phone 408 436-9890 • FAX 408 436-9897
The Summit Web Site can be accessed by “right” or “left” mouse clicking on the link:
http://www.summitmicro.com/
2089 1.1 10/20/04
1
SMM665B
Preliminary Information
VDD (+2.7V to +5.5V)
or 12VIN ( +8V to +15V)
2.7V
2.5V
2.0V
1.8V
1.5V
RST#
---
t1
---
Figure 2 – Example Power Supply Sequencing and System Start-up Initialization using the SMM665B. Any
order of supply sequencing can be applied using the SMM665B. Power supply ordering, trimming and Active
DC control allows supply cascade sequencing, automatic level adjustment, margin testing and reset control.
GENERAL DESCRIPTION
The SMM665B is a highly integrated and accurate
power supply controller, monitor and sequencer. It
has the ability to automatically control, monitor and
cascade sequence up to six power supplies. Also, the
SMM665B can monitor the VDD input, the 12V input,
two general-purpose analog inputs and the internal
temperature sensor.
The SMM665B has four
operating modes: Power-on sequencing mode,
monitor mode, supply margining mode using Active
DC Output Control (ADOC
TM
), and Power-off
sequencing mode.
Power-on sequencing can be initiated via the
PWR_ON/OFF pin or I
2
C control. In this mode, the
SMM665B will sequence the power supply channels
on in any order by activating the PUP outputs and
monitoring the respective converter voltages to ensure
cascading of the supplies. Cascade sequencing is the
ability to hold off the next sequenced supply until the
first supply reaches a programmed threshold. A
programmable sequence termination timer can be set
to disable all channels if the Power-on sequence
stalls. Once all supplies have sequenced on and the
voltages are above the UV settings, the Active DC
Control, if enabled, will bring the supply voltages to
their nominal settings.
During this mode, the
HEALTHY output will remain inactive and the RST
output will remain active.
Once the Power-on sequencing mode is complete, the
SMM665B enters monitor mode. In the monitor mode,
the SMM665B starts the ADOC control of the supplies
and adjusts the output voltage to the programmed
setting under all load conditions, especially useful for
supplies without sense lines. Typical converters have
±2%
accuracy ratings for their output voltage, the
Active DC Output Control feature of the SMM665B
increases the accuracy to
±0.2%
(using a ±0.1%
external voltage reference). The part also enables the
triggering of outputs by monitored fault conditions.
The 10-bit ADC cycles through all 11 channels every
Summit Microelectronics, Inc
2ms and checks the conversions against the
programmed threshold limits. The results can be used
to trigger RST, HEALTHY and FAULT outputs as well
as to trigger a Power-off or a Force Shutdown
operation.
While the SMM665B is in its monitoring mode, an I
2
C
command to margin the supply voltages can bring the
part into margining mode. In margining mode the
SMM665B can margin six supply voltages in any
combination of nominal, high and low voltage settings
using the ADOC feature, all to within ±0.2% using a
±0.1% external reference. The margin high and low
voltage settings can range from 0.3V to VDD around
the converters’ nominal output voltage setting
depending on the specified margin range of the DC-
DC converter. During this mode the HEALTHY output
is always active and the RST output is always inactive
regardless of the voltage threshold limit settings and
triggers. Furthermore, the triggers for Power-off and
Force Shutdown are temporarily disabled.
The Power-off sequencing mode can only be entered
while the SMM665B is in the monitoring mode. It can
be initiated by either bringing the PWR_ON/OFF pin
inactive, through I
2
C control or triggered by a channel
exceeding its programmed thresholds. Once Power-
off is initiated, it will disable the Active DC Control and
sequence the PUP outputs off in either the same or
reverse order as Power-on sequencing and monitor
the supply voltages to ensure cascading of the
supplies as they turn off. The sequence termination
timer can be programmed to immediately disable all
channels if the Power-off sequencing stalls. The RST
output will remain active throughout this mode while
the HEALTHY output remains inactive.
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SMM665B
Preliminary Information
INTERNAL FUNCTIONAL BLOCK DIAGRAM
12VIN
VDD
VDD_CAP
PWR_ON/OFF FS
VREF_ADC
AIN
1
AIN
2
VM
A
CAP
A
3.6V or
5.5V
Regulator
Power Supply
Arbitrator
UVLO
Control
Cascade
Sequence
Control
PUP
A
PUP
B
PUP
C
PUP
D
PUP
E
PUP
F
10-Bit ADC
Temperature
Sensor
VM
F
MR
CAP
F
RST
HEALTHY
FAULT
TRIM
A
TRIM_CAP
A
Output
Control
Active DC
Control
(ADOC
TM
)
TRIM
F
TRIM_CAP
F
VREF_CNTL
FILT_CAP
Memory, Limit
and Status
Registers
SDA
I
2
C
Interface
SCL
A2
GND
Figure 3 – SMM665B Internal Functional Block Diagram.
Summit Microelectronics, Inc
2089 1.1 10/20/04
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SMM665B
Preliminary Information
PIN DESCRIPTIONS
Pin
Number
1
2
3
Pin
Type
DATA
CLK
IN
Pin Name
SDA
SCL
A2
Pin Description
I
2
C Bi-directional data line
I
2
C Clock line
The address pin is biased either to VDD_CAP or GND.
When
communicating with the SMM665B over the 2-wire bus A2 provides a
mechanism for assigning a unique bus address.
Programmable active high/low input. When asserted the RST output will be
go active. When de-asserted the RST output will go inactive immediately
after a reset timeout period (t
PRTO
) if there are no RST trigger sources active.
This timeout period makes it suitable to use a pushbutton for manual reset.
Programmable active high/low input signals the start of the power
sequencing. When asserted the part will sequence the supplies on and
when de-asserted the part will sequence the supplies off.
Note: The SMM665B does not monitor for faults during sequencing. The
PWR_ON/OFF pin is overridden by the I
2
C power on/off command. To get
the pin to work again requires the part be given an I
2
C 'Clear' command (see
page 16, “RESTART OF POWER-ON CASCADE SEQUENCING”).
Programmable active high/low input. Force shutdown is used to immediately
turn off all converter enable signals (PUP outputs) when a fault is detected.
Programmable active high/low open drain Fault output. Active when a
programmed fault condition exists on AIN1, AIN2, or the internal temperature
sensor.
Programmable active high/low open drain Healthy output. Active when all
programmed power supply inputs and monitored inputs are within OV and
UV limits.
Programmable active high/low open drain Reset output. Active when a
programmed fault condition exists on any power supply inputs or monitored
inputs or when MR is active. RST has a programmable timeout period with
options for 0.64ms, 25ms, 100ms and 200ms.
General purpose monitored analog input
General purpose monitored analog input
Ground
Voltage reference input used for A/D conversion where:
(4XVREF_ADC) = Full Scale (FS) for VM
A-F
and VDD
(12XVREF_ADC) = FS for 12VIN
(2XVREF_ADC) = FS for AIN1 and AIN2.
VREF_ADC can be connected to VREF_CNTL in most applications.
4
IN
MR
5
IN
PWR_ON/OFF
6
7
IN
OUT
FS
FAULT
8
OUT
HEALTHY
9
OUT
RST
10
11
12
IN
IN
GND
AIN1
AIN2
GND
13
IN
VREF_ADC
Summit Microelectronics, Inc
2089 1.1 10/20/04
4
SMM665B
Preliminary Information
PIN DESCRIPTIONS (Cont.)
Pin
Number
14
15
41,36,
31,26,
21,16
42,37,
32,27,
22,17
43,38,
33,28,
23,18
44,39,
34,29,
24,19
45,40,
35,30,
25,20
46
47
48
Pin
Type
I/O
CAP
IN
CAP
OUT
OUT
CAP
PWR
PWR
CAP
Pin Name
VREF_CNTL
FILT_CAP
VM
X
CAP
X
PUP
X
TRIM
X
TRIM_CAP
X
VDD
12VIN
VDD_CAP
Pin Description
Voltage reference input used for DC output control and margining.
VREF_CNTL can be programmed to output the internal 1.25V reference.
External capacitor input used to filter VM
X
inputs
Positive converter sense line, VM
A
through VM
F
External capacitor input used to filter the VM
X
inputs to the 10-bit ADC, CAP
A
through CAP
F
. This provides an RC filter where R = 25kΩ.
Programmable active high/low open drain converter enable output, PUP
A
through PUP
F
Output voltage used to control the output of DC/DC converters, TRIM
A
through TRIM
F
External sample and hold capacitor input used to set the voltage on the
TRIM pins, TRIM_CAP
A
through TRIM_CAP
F
Power supply of the part
12V power supply input internally regulated to either 3.6V or 5.5V
External capacitor input used to filter the internal supply
Summit Microelectronics, Inc
2089 1.1 10/20/04
5
