This design provides a 4-channel signal conditioning solution for single-ended SAR ADCs integrated into a microcontroller measuring motor current using fluxgate sensors. Also provided is an alternative measurement circuit with external SAR ADCs as well as circuits for high-speed overcurrent and earth fault detection. Proper signal conditioning improves noise immunity on critical current measurements in motor drives. This reference design can help increase the effective resolution of the analog-to-digital conversion, improving motor drive efficiency.
Features
- Designed to measure all three phase motor currents along with DC link current through 6A Fluxgate Sensors (Scalable to 50A)
- Single-ended Signal Conditioning Circuit to interface Fluxgate Sensors with single-ended SAR ADCs
- Measures current and voltage through integrated SAR ADCs of TI Piccolo™ F28027 microcontroller with a provision to interface the signal conditioning circuit with External ADCs
- Two on-board 14-bit Dual Channel Simultaneous Sampling SAR ADCs with 4-wire SPI to interface with external motor controllers
- < 0.1% DC accuracy of Signal Conditioning Circuit
- Overload and Earth Fault Protections for each channel with < 100ns sensing delays