EnerChip™ Bare Die Batteries

©2016 Cymbet Corporation • Tel: +1-763-633-1780 • www.cymbet.com

DS-72-41 Rev06

Page 6 of 13

Preliminary

ENERCHIP CHARGING GUIDELINES

As with other rechargeable batteries, discharge capacity and cycle life are a function of charge voltage,

discharge cutoff voltage, depth-of-discharge, temperature, and other factors. The system designer must

understand the effect of these factors when designing the charge control circuit. Cymbet encourages all

designers to utilize the CBC910 Power Management IC (datasheet is DS-72-11) to optimize performance.

• Never charge EnerChip batteries before soldering or exposing to temperatures above the specified

operating temperatures. The EnerChip will be damaged or may not work at all.

• Never apply more than 4.3V across the battery terminals as cycle life will be dramatically reduced.

• There is no need to externally limit the charging current of small surface-mount batteries. The intrinsic

cell resistance is sufficient to limit the current to an acceptable level as long as the applied voltage does

not exceed 4.3V.

• The charging voltage and charge time determine the amount of charge delivered to, and accessible

from, the battery. A higher charging voltage will deliver more charge, but will also result in greater

long-term capacity fade as a function of charge/discharge cycling. Figure 1 shows trade-offs between

charging voltage, charge capacity and cycle fade.

• The batteries may be charged at a constant current (CC) followed by a constant voltage (CV). During the

CC phase, the current may be set to any value that results in an acceptable charging time and does not

cause the battery voltage to exceed 4.3V.

• CV charging will normally result in faster charging times than the combined CC-CV approach. The latter

may become necessary with future, larger batteries with lower intrinsic cell resistance. Please refer to

the Operating Characteristics data tables for these batteries.

Figure 1: Effect of Charging Voltage on Battery Charge and Cycle Fade

0

10

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30

40

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60

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Cycles

4.3V

4.2V

4.15V

4.1V

4.0V