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

1 Introduction

The multichannel LDC devices utilize an LC tank-based sensor to determine the change in inductance by measuring (sampling) the change in oscillation frequency of the sensor. The sensor oscillation frequency (fOSC) is compared to an independent reference clock (fREF) to produce an output sample that represents fOSC as a fraction of fREF. This fraction is represented as a digitized output code which then can be used to determine position or proximity of a moving conductive target. The power consumption of these LDC devices is typically on the order of a few milliamps when in continuous sampling mode. One of the advantages of inductive sensing technology over a competitive Hall effect sensor is that Hall effect sensors typically lack a low-power mode which would make it more difficult to decrease the power consumption when compared to the LDC sensing technology.