User Manual

USER MANUAL V1.05
© 2013 EnOcean | www.enocean.com STM 330 / STM 331 / STM 330C / STM 332U / STM 333U User Manual V1.10 | Page 20/33
STM 330 / STM 331 / STM 330C / STM 332U / STM 333U
3.10 Charging circuitry
The figure below shows the internal charging circuit. It is controlled via the WXODIO pin of
EO3000I which switches according to the status of the internal threshold detector. For de-
tails please refer to our Dolphin Core Description documentation. The WXIDIO pin is used to
disconnect the goldcap at voltages below VOFF to avoid deep discharge.
An external 3 V backup battery can be connected at VCHAR.
3.11 Energy consumption
Current Consumption of STM 33x
Charge needed for one measurement and transmit cycle: ~130 µC
Charge needed for one measurement cycle without transmit: ~30 µC
(current for external sensor circuits not included)
0.00001
0.0001
0.001
0.01
0.1
1
10
100
0 10 20 30 40 50 60 70 80 90 100
Time [ms]
Current [mA]