SLVAF41A March   2021  – November 2021 TPS61094

 

  1.   Trademarks
  2. 1Introduction of the Smart Meter
  3. 2The Traditional Power Solution of the Smart Meter
    1. 2.1 Connecting the Battery Directly
    2. 2.2 The Pure Boost TPS61094 or TPS610995 Solution
  4. 3The TPS61094 with Supercap Solution
    1. 3.1 TPS61094 Description
    2. 3.2 System Operation Description
  5. 4Solution Comparison
  6. 5Supercap Behavior and Design
    1. 5.1 Supercap Life Time
    2. 5.2 Supercap Leakage Currrent
    3. 5.3 Supercap Parameter Design in TPS61094 Solution
  7. 6Test Report Based on TPS61094 Solution
    1. 6.1 Test Waveform
      1. 6.1.1 NB-IoT Data Transmission
      2. 6.1.2 Supercap Charging
    2. 6.2 Efficiency
  8. 7References
  9. 8Revision History

5.1 Supercap Life Time

The supercap lifetime is related to the operating temperature and operating voltage. The classical aging model for supercapacitors is Eyring's law that estimates the aging rate, as the Equation 2. This law stipulates that a 200-mV voltage surplus increases the aging by a factor of 2 and have the same effect as a temperature increase of 10 °C. (reference 6, 7, 8)

Equation 2. GUID-20210201-CA0I-X5WN-N4L0-5SNTXXXLWNSM-low.gif

where

tref Reference lifetime (hours)

Vref Reference applied bias voltage (V)

Tref Reference aging temperature (K)

The smart meter customer can lower the operation voltage according to their life time and operation temperature requirement. There is the estimation lifetime from VINA Tech 3.0V series supercap, as shown in Table 5-1

Table 5-1 VINA Tech Estimation Lifetime – 3.0 V Series
Temp
Voltage (V)		 25 °C
Year		 30 °C
Year		 40 °C
Year		 50 °C
Year		 60 °C
Year		 70 °C
Year		 75 °C
Year		 80 °C
Year
2.1 180.5 127.7 63.8 31.9 16.0 8.0 5.6 4.0
2.2 127.7 90.3 45.1 22.6 11.3 5.6 4.0 2.8
2.3 90.3 63.8 31.9 16.0 8.0 4.0 2.8 2.0
2.4 63.8 45.1 22.6 11.3 5.6 2.8 2.0 1.4
2.5 45.1 31.9 16.0 8.0 4.0 2.0 1.4 1.0
2.6 31.9 22.6 11.3 5.6 2.8 1.4 1.0 0.7
2.7 22.6 16.0 8.0 4.0 2.0 1.0 0.7 0.5
2.8 16.0 11.3 5.6 2.8 1.4 0.7 0.5 0.4
2.9 11.3 8.0 4.0 2.0 1.0 0.5 0.4 0.3
3.0 8.0 5.6 2.8 1.4 0.7 0.4 0.3 0.2

Note: 30% capacitance degradation is considered as the end of life (reference 9).