SBAA347 June   2022 AMC1202 , AMC1300 , AMC1300B-Q1 , AMC1301 , AMC1301-Q1 , AMC1302 , AMC1302-Q1 , AMC1400 , AMC3301 , AMC3301-Q1 , AMC3302 , AMC3302-Q1 , AMC3330 , AMC3330-Q1 , TLV6002 , TLV9002

 

  1.   Design Goals
  2.   Design Description
  3.   Design Notes
  4.   Design Steps
  5.   Design Simulations
  6.   DC Simulation Results
  7.   Closed-Loop AC Simulation Results
  8.   Transient Simulation Results
  9.   Design References
  10.   Design Featured Isolated Amplifier
  11.   Design Alternate Isolated Amplifier

Design Description

This isolated current sensing circuit can accurately measure load currents from, but not limited to, –10 A to 10 A with a nominal power dissipation of 2.5 W across a 25-mΩ shunt resistor. The linear range of the isolated amplifier input is from –250 mV to 250 mV with a differential output swing of –2.05 V to 2.05 V and an output common-mode voltage (VCM) of 1.44 V. The gain of the isolated amplifier circuit is fixed at 8.2 V/V. A TLV9002 is used to transform the differential output signal to a single-ended signal that can be used with a single-ended ADC such as the ADS8326 as well as buffer the VCM derived from a voltage divider. A 1.65-V reference voltage is used to set the final output voltage range and the common-mode voltage level.