advertisement Pushbutton On/Off Controller Simplifies System Design
Design Note 391
Victor Fleury
Introduction
Handheld designers often grapple with ways to de-bounce
and control the on/off pushbutton of portable devices.
Traditional de-bounce designs use discrete logic, flipflops, resistors and capacitors. Other designs include
an onboard microprocessor and discrete comparators
which continuously consume battery power. For high
voltage multicell battery applications, a high voltage
LDO is needed to drive the low voltage devices. All this
extra circuitry not only increases required board space
and design complexity, but also drains the battery when
the handheld device is turned off. Linear Technology addresses this pushbutton interface challenge with a pair
of tiny pushbutton controllers.
The LTC®2950 integrates all the flexible timing circuits
needed to de-bounce the on/off pushbutton of handheld
devices. The part also provides a simple yet powerful
interface that allows for controlled power up and power
down of the handheld device. The LTC2951 offers an
adjustable timer for applications that require more time
during power down. These two micropower, high voltage
(2.7V to 26V) parts are offered in space-saving 8-pin …