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

4 Test Setup

Duty-cycling the LDC was tested on the LDC1614 EVM with only one channel (Channel 0) enabled. The current flowing through the LDC1614 was measured using a Keysight (Agilent) 34410A digital multi-meter. The test setup is shown in Figure 5 and the testing conditions are given in Table 1.

setup.gifFigure 5. Test Setup

Table 1. Testing Conditions

Channel 0
Internal Reference Frequency (MHz) 43.4
Sensor Frequency (MHz) 3.02
Amplitude (VP) 1.27
Programmed SETTLECOUNT 32
Current Drive Setting (mA) (IDRIVE) 0.196

The reference frequency was set by the internal oscillator and the current drive was set to achieve the recommended voltage amplitude for the oscillation waveform, which is between 1.2 and 1.8 VP.