DS-72-40 Datasheet, PDF (7/17 Pages) Cymbet Corporation – EnerChip™ CC Energy Harvester Evaluation Kit

CBC-EVAL-10B EnerChip CC EH Evaluation Kit
External Control of the CBC-EVAL-10B Energy Harvesting Functions
In addition to protecting the EnerChips from being discharged too deeply in low ambient light conditions or ab-
normally high current load conditions, the CBC3150 power management circuit also ensures that the system
load is powered with a smooth power-on transition. The power management circuit has a control line (CHARGE/)
for indication to the system controller that the energy harvester is charging the EnerChips. A control line input
(BATOFF) is available for the external controller to disable the CBC3150 charge pump. Use of these two control
lines is optional.
There are two connectors on CBC-EVAL-10B for connection to target devices to be powered. Either the J9 or J10
connector can be used for low power microcontroller-based systems. In the case of a low power wireless end de-
vice, the CBC-EVAL-10B has storage energy for approximately 1000 radio transmissions - depending on protocol
used - in no/low ambient light conditions.
Microcontroller-based systems that are powered by the CBC-EVAL-10B should contain firmware that is “Energy
Harvesting Aware” and take advantage of the power management status and control signals available on CBC-
EVAL-10B.
Using Additional EnerChips and External Batteries
The CBC-EVAL-10B is designed to permit attachment of rechargeable or non-rechargeable batteries whereby the
energy harvesting circuitry extends the life of those batteries by operating from (i) PV cell power when sufficient
light is available, (ii) EnerChips when in an acceptable state-of-charge, and (iii) the external battery when neither
of those two conditions exists.
Two classes of external batteries may be attached to the CBC-EVAL-10B:
1. A primary battery (i.e., non-rechargeable) or series combination of primary batteries may be connected to
header pins J3 only. The acceptable voltage range is 2.7 to 3.6. Commonly used batteries in this category
are:
a single 3V CR-type or BR-type coin cell (e.g., CR2032, BR2032), or two alkaline cells (e.g., AAA, AA, C,
D) connected in series;
a single 3.6V thionyl chloride cell may also be used.
[Contact Cymbet for recommendations in selecting a primary battery for your Hybrid configuration.]
2. A secondary (i.e., rechargeable) battery may be connected to header pins J7 only. The acceptable charging
voltage range is 4.0V to 4.2V. The charging source for this battery is the VCHG output pin of the CBC3150
that normally charges the EnerChips to 4.1V. Maximum drive current of this pin is on the order of 1mA. VCHG
drive current can be adjusted by populating charge pump capacitor C9 (CBC-EVAL-10B module is shipped
without a capacitor C9 but the CBC51100 module has a default capacitor). See DS-72-03 EnerChip CC
CBC3150 Data Sheet for guidelines on sizing the charge pump capacitor. The discharge cutoff voltage is
fixed at 3.0V +/- 0.3V. Examples of rechargeable batteries supported by CBC-EVAL-10B are the LiR-type coin
cells, including LiR-1220 (~8mAh) and LiR-2032 (~40mAh). The charging rate for these external cells will be
a function of available light, to a maximum of 1mA as limited by the CBC3150 charge pump drive current.
To operate the CBC-EVAL-10B board for use with an external battery, configure the header pins as follows:
• Non-rechargeable (i.e., primary) battery connected to EXT BAT terminal block J3. Connect battery to J3, en-
suring polarity is correct.
• Rechargeable (i.e., secondary) battery connected to header pins J7. Connect battery to J7, ensuring polarity
is correct.
©2014 Cymbet Corporation • Tel: [phone] • www.cymbet.com
DS-72-40 Rev C

Page 7 of 17