3
dc1605bf
DEMO MANUAL DC1605B
theory of operation
GENERAL DESCRIPTION
The LTC2936 is a hex voltage supervisor which detects
an overvoltage or undervoltage and signals the system of
a fault condition. The chip has a dedicated power supply
pin, V
PWR
, and has an internal 3.3V regulator. The chip
may be powered either by powering V
PWR
with the on-
board 5V supply, with an external 3.4V to 13.9V supply,
or with an external 3.3V supply by tying V
PWR
and V
DD33
pins together.
THE CHIP
The LTC2936 integrates six voltage supervisors with as-
sociated comparator outputs, two GPIs, and three GPIOs.
The V1-V6 supervisors are comprised of OV/UV window
comparators that can be programmed to map the detec-
tion of a fault to one or more GPIO pin.
In LTpowerPlay, the user programs each voltage supervi-
sor’s range, polarity, mapping, and high and low threshold
voltages.
Each channel’s high/low comparators may be mapped
to any GPIO pin, and any comparator may be mapped to
multiple GPIO pins. Typically the high comparator is used
for the overvoltage condition and the low comparator is
used for the undervoltage condition. The high comparator is
not dedicated as the OV detection nor is the low comparator
dedicated for UV detection. For example, both comparators
may be configured as OV with the V
n
_THR_HI set to indicate
an OV Fault and the V
n
_THR_LO set for an OV Warning.
Figure 1. Simplified Block Diagram of Voltage Supervisor Input
V
n
GPIO & CMP
MAPPING
(V
n
_CONFIG)
HIGH THR
SETTING
LOW THR
SETTING
HIGH
COMPARATOR
LOW
COMPARATOR
LOW FAULT
HIGH FAULT
CMP1–CMP6
GPIO1–CPIO3
GPI1 GPI2
DC1605B F01
3
6
GPIO
INPUT OPTIONS
INPUT
/INPUT
OUTPUT OPTIONS
OUTPUT
/OUTPUT WITH OPEN DRAIN
OUTPUT
/OUTPUT WITH PULL-UP
SMBALERT
(LATCHED) WITH OPEN DRAIN OR WITH PULL-UP
INTERNAL
LOGIC
