SBOA562 april   2023 INA240

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2Total Output Error of CSA at Near-Zero Vsense
  5. 3Calibration-Enabled Near-Zero Vsense Measurement
  6. 4Near-Zero Vsense Operating Mode in Some Legacy CSA
  7. 5Recent Development in High-Voltage CSA
  8. 6Summary

1 Abstract

When operating a Current Sense Amplifier (CSA) with differential input Vsense that is near-zero, we must make sure that the amplifier output stays within linear range. One method to avoid swing limitations is output biasing or level shifting. As a result, zero Vsense is included in the linear input range. Bidirectional CSA provides a convenient option for output biasing. Further, at near-zero Vsense, the offset of the amplifier starts to dominate, resulting in high percentage output error. Offset calibration is effective in improving system accuracy at near-zero Vsense. Some legacy products exhibit large output error at low Vsense levels. This limitation is a tradeoff to accommodate wide input common mode range. Recent development addresses this issue and the low Vsense limitation is eliminated in newly released devices.