AN-1041 Datasheet, PDF (1/3 Pages) Cymbet Corporation – EnerChip CC Li-Ion Battery Charger with Integrated Energy Storage

AN-1041
Application Note
EnerChip™ CC Li-Ion Battery Charger with Integrated Energy Storage
Features
• Power Manager with Charge Control
• Capable of Charging Li-Ion Coin Cells
• Integrated Thin Film Energy Storage
• Built-in Energy Storage Protection
• Temperature Compensated Charge Voltage
• Operates Over a Wide Power Supply Range
• Low Standby Power and Cutoff Current
• Integrated Energy Storage: Low Self-Discharge
and Thousands of Recharge Cycles Available
• Eco-Friendly, RoHS Compliant
• Surface Mount - Lead-Free Reflow Tolerant
Applications
• Standby supply for non-volatile SRAM, real-time
clocks, controllers, and supply supervisors.
• Wireless sensors and RFID tags and other
powered, low duty cycle applications.
• Localized power source to keep microcontrollers
and other devices alert in standby mode.
• Power bridging to provide back-up power to the
system during exchange of main batteries.
• Consumer appliances that have real-time
clocks.
• Business and industrial systems such as
network routers, point-of-sale terminals, test
equipment, printers, and industrial controllers.
• Energy Harvesting by coupling the EnerChip
with energy transducers such as solar panels.
EnerChip CC: Battery Management
with Integrated Energy Storage
Description
The EnerChip CC product family consists of
devices having battery management circuitry
and rechargeable solid state energy storage - the
EnerChip - integrated in a single low profile, surface
mount package.
Each device functions as a backup power source
and supervisor for low power applications and has
the added capability to manage the charging and
discharge cutoff of Li-ion batteries such as LiR
coin cells. The EnerChip CC can deliver up to 1mA
charging current at 4.1V. It can charge up to 10
additional EnerChips connected in parallel.
During normal operation, the EnerChip CC derives
power from the main supply (2.5V to 5.5V) that
activates the internal charge pump, producing 4.1V
on the VCHG pin. This voltage not only charges
the internal EnerChips, but can also serve as a
charging source for small rechargeable Li-ion cells.
The EnerChip CC also has a discharge cutoff circuit
(3.0V typical) that prevents the battery from being
discharged too deeply - a condition that can destroy
Li-ion cells. When the primary power supply drops
below a user-defined threshold voltage, the EnerChip
CC monitors this event, routes the battery voltage to
VOUT, and signals the event by driving RESET/ low.
Figure 1: Application Circuit Showing Connection of External Li-Ion Rechargeable Cell.
©2010 Cymbet Corporation • Tel: [phone] • www.cymbet.com
AN-1041 Rev A
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