This reference design demonstrates high-side primary current sensing in DC/DC converter and onboard charger (OBC) applications for hybrid and electric vehicles. Using an isolated shunt approach for current sensing has several advantages, including high accuracy, linearity and robustness. However, the large input range of isolated amplifiers causes the shunt to experience high power dissipation. To solve this problem, this reference design utilizes a lower input range isolated amplifier, reducing power dissipation while maintaining the advantages of the shunt-based approach.
Features
- Lower input range of +/-50 mV facilitates lower power dissipations on the shunt
- 3-us latency (fast response) with the isolated amplifier
- High-side current sense circuit with CMTI of 140 kV/μs (typical), 70 kV/μs (minimum)
- Un-calibrated accuracy of less than 1% across temperature range of -40ºC to 125ºC (AMC output)
- Interfaces directly with differential- or single-ended ADC