SPRADA5 April   2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Supplementary Information
    2. 1.2 Features
    3. 1.3 Block Diagram
    4. 1.4 Operation Modes
  5. 2Use Cases
    1. 2.1 Buffer Mode for High-Impedance Source
    2. 2.2 Battery Voltage and Current Monitoring
    3. 2.3 Low-Side Shunt Current Monitoring
    4. 2.4 Three-Phase Low-Side Current Sensing
    5. 2.5 Bidirectional Current Sensing
    6. 2.6 Non-Inverting Amplifier for Low-Voltage Sensors
    7. 2.7 Non-Inverting Amplifier for Bipolar Signals
    8. 2.8 Standalone Mode for Various Applications
  6. 3Summary
  7. 4References

2.5 Bidirectional Current Sensing

Bidirectional current sensing is needed in many battery-current monitoring applications to measure the battery's charge and discharge currents. To enable bidirectional current sensing, a positive voltage is applied to the non-inverting pin to offset the output voltage. If the differential input voltage is positive, the output voltage can be greater than the applied reference voltage; conversely, if the differential input voltage is negative, the output voltage can be lower than the applied reference voltage. As shown in Figure 2-8, the PGA module, in combination with DAC and ADC modules, senses the current flow through a sense resistor in both directions. An embedded buffered DAC module provides the reference voltage VREF. If the divider resisters R1=Rib and R2=Ria, the output voltage of the PGA is given by Equation 5.

Equation 5. V P G A _ O U T = R i b R i a ( R s h u n t I l o a d ) + V R E F
GUID-20230808-SS0I-CTTN-FBF4-MSNGZ4ZDRH5N-low.svg Figure 2-8 Bidirectional Current Sensing