SBOA595A May   2024  – October 2024 AMC1202 , INA169 , TMCS1108

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Current Sensing
  5. 2Key Challenges of Current Sensing for Negative Power Supply
  6. 3Proposed Current Sensing Designs for Negative Power Supply
    1. 3.1 Hall Current Sensor
    2. 3.2 Current Sensing Based Isolated Amplifier
    3. 3.3 Current Sensing Based Isolated ADC
    4. 3.4 Current Sensing Based Difference Amplifier
  7. 4Summary
  8. 5References
  9. 6Revision History

2 Key Challenges of Current Sensing for Negative Power Supply

Measure current of negative power supply is not straightforward like measure current for positive power supply since the common input voltage for most current sensing amplifier in market is large than -22V. for -24V or -48V negative power supply applications in industry, there is almost no current sensing amplifier can meet -24V or -48V common input voltage specification in market. By floating the ground pin of current sensing amplifier, designer can make the input common voltage in range of current sensing amplifier, but output voltage potential is a negative voltage and out of range for most ADC. Then, it is not convenient for the designer to do post processing.