SNOA949 May   2016 LDC1312 , LDC1312-Q1 , LDC1314 , LDC1314-Q1 , LDC1612 , LDC1612-Q1 , LDC1614 , LDC1614-Q1

 

  1.   Power Reduction Techniques for the Multichannel LDCs in Inductive Sensing Applications
    1.     Trademarks
    2. 1 Introduction
    3. 2 Duty Cycling
      1. 2.1 Operational Parameters That Affect Duty Cycling
    4. 3 Clock Gating
    5. 4 Test Setup
    6. 5 Measurement Results
      1. 5.1 Measurements with Internal Clock
      2. 5.2 Current Consumption Measurements vs Data Conversion Time
        1. 5.2.1 Data Readback Overhead
        2. 5.2.2 Comparison of Measured and Estimated Current Consumption
          1. 5.2.2.1 Estimating Current Consumption
        3. 5.2.3 Results
    7. 6 Summary

5.2.2.1 Estimating Current Consumption

The following procedure can be used to estimate the current consumption of the LDC. First, the active time, or time the device spends in normal mode, should be determined. As expressed in Equation 1, this includes the sensor startup time, tS, the sensor conversion time, tC, and the data readback time, tRB. The channel switch delay time, tSD, can be ignored while operating in single channel mode. Once tN has been calculated, the percentage of time the device spends in active mode, DN, can be calculated using Equation 7 where TS is the sampling period. The percentage of time the device spends in sleep mode, DS, can also be calculated by using Equation 8.

Equation 7. eq6.gif
Equation 8. eq7.gif

Equation 9 then estimates the amount of power the LDC will burn given the above percentages per period (DN and DS) where IN is the supply current in active mode and IS is the supply current in sleep mode (given in Table 2).

Equation 9. eq8.gif