advertisement Tiny Synchronous Step-Up Converter Starts Up at 700mV
Design Note 428 Lower Start-Up Devices for Energy Harvesting
Work Below 100mV—See the LTC3108 Dave Salerno
Introduction
Alkaline batteries are convenient because they’re easy to
п¬Ѓnd and relatively inexpensive, making them the power
source of choice for portable instruments and devices
used for outdoor recreation. Their long shelf life also
makes them an excellent choice for emergency equipment
that may see infrequent use but must be ready to go on a
moment’s notice. It is important that the DC/DC converters in portable devices operate over the widest possible
battery voltage range to extend battery run time, and thus
save the user from frequent battery replacement.
Single-cell alkaline batteries, with a 1.6V to 0.9V range,
present a special challenge to DC/DC converters because
of their low voltage and the fact that their internal resistance increases as the battery discharges. Thus, a DC/DC
converter that can both start up and operate efficiently at
low input voltages is ideally suited for single-cell alkaline
products.
The LTC В®3526L is a 1MHz, 550mA synchronous stepup (boost) converter with a wide input voltage range of
0.7V to 5V and an output voltage range of 1.5V to 5.25V.
Housed in a 2mm Г— 2mm DFN package, the LTC3526L has a typical startup voltage of just 700mV, with operation
down to 400mV once started. Despite the LTC3526L’s …