DESCRIPTION
Demonstration circuit 1099 features the LTC2953, a
push button On/Off controller that manages system
power via a push button interface. An enable output
toggles system power while an interrupt output provides
debounced push button status. The interrupt
output can be used in menu driven applications to
request a system power down.
The length of time that the push button must be held
low for a power down is configurable with an external
capacitor. The LTC2953 allows a user to force an
immediate power down by tying /INT with /KILL and a
push button turn off.
The LTC2953 also features input and output supply
monitors. An uncommitted power fail comparator
provides real time input monitor threshold information,
while a de-glitched under voltage lockout comparator
gracefully initiates a system power down.
The under voltage lockout comparator prevents from
powering from a bad battery.
The adjustable supply monitor input is compared
against an accurate internal 0.5V reference. The reset
output remains low until the supply monitor input has
been in compliance for 200ms.
The DC1099 accepts voltages of 2.7V to 27V over the
operating range of the LTC2953 input voltage. The
LTC2953 draws only 12uA of current. Reverse polarity
protection is provided with RPP and CPP on the
DC1099. Two versions of the part accommodate either
positive or negative enable polarities. For the
DC1099, the LTC2953-1 with Enable active high is
shown.
On the DC1099, an LT3010 is used to demonstrate a
supply with its shutdown pin driven by the enable of
the LTC2953.
Design files for this circuit board are available. Call
the LTC factory.