TIDUEO0C July 2019 – March 2021
Figure 3-10 highlights how using this power solution for an NB-IoT module, 61,000 transmissions (taken at 10% SOH) can be supported. Similarly to the buck converter discharge data, stand-by current will play an added role in a field application, in addition to the 250-mA pulses. Refer to Section 220.127.116.11 for analysis on battery lifetime estimations for this topology.
As detailed in Section 18.104.22.168, the BQ35100 device will perform best once the cell voltage starts decreasing more meaningfully. This can be observed around the midpoint at 35,000 transmissions where SOH equates to 50%, then the SOH reading becomes roughly linear and hones in on 0% SOH. See the FDK Lithium CR17500EP LiMnO2 Primary Battery Data Sheet to observe typical voltage discharge curves.
In this test, the TPS610995 device operates at VOUT = 3.6 V to power the NB-IoT modules. With a smaller voltage level difference between VIN and VOUT, it will deliver several percent points higher efficiency numbers than those in the data sheet plot.