SNOA943 January   2016 FDC2112 , FDC2112-Q1 , FDC2114 , FDC2114-Q1 , FDC2212 , FDC2212-Q1 , FDC2214 , FDC2214-Q1

 

  1.   Power Reduction Techniques for the FDC2214/2212/2114/2112 in Capacitive Sensing Applications
    1.     Trademarks
    2. 1 Duty-Cycling
      1. 1.1 FDC2x1x Operational Parameters That Affect Duty Cycling
    3. 2 Clock Gating
    4. 3 Test Setup
    5. 4 Measurement Results
      1. 4.1 Measurements with Gated Clock
    6. 5 Current Consumption Measurements vs Data Conversion Time
      1. 5.1 Data Readback Overhead
    7. 6 Comparison of Measured and Estimated Current Consumption
      1. 6.1 Estimating Current Consumption
    8. 7 Results
    9. 8 Summary

8 Summary

Duty-cycling and clock gating are effective techniques that can be implemented in order to minimize power consumption of the FDC2x1x. In order to ensure that there is minimal current flowing through the device, the external oscillator used as the reference clock should be turned off while the device is in either sleep or shutdown mode. It is important to note that the data readback overhead can affect current consumption measurements, especially at lower RCOUNT values. The resulting current values for varying RCOUNT values at different sampling rates follow expected trends and the measured current values are similar to the estimated current values. The FDC211x/FDC221x Current Consumption Estimator provided by TI can be used as a reference tool for estimating a worst-case power consumption scenario.