600V Current Sensing IC Replaces Hall-Effect Sensors

The linear sensing of motor phase current in AC or BLDC motor drive applications is the forte of IR2171 IC. This 600V device integrates all motor phase current measurement, analog-to-digital conversion, noise filtering and feedback interfacing to a microcontroller in a single chip. The current measurement linearity is better than 0.5% over the specified usable range. Important performance parameters include 0.4% linearity with 0.0003% temperature drift, 1.5 mV total offset with 30 µV/°C drift, 1% gain error with 37 ppm/°C drift, and power supply rejection ratio of 0.06% at 6 kHz with 1 Vpp power supply noise. A current loop with better than 2 kHz usable bandwidth can easily be constructed using the IR2171 at the heart of the control loop. The IR2171 is housed in a SOIC-8 or DIP-8 package, with prices starting at $3.95 each in quantities of 1,000. Samples are now available.