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- Current Sense Ref Design for High-Switching Transient 3-Phase Inverters
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19 Sep 2017 26 views
The TIDA-01455 is a reinforced isolated, in-line, shunt-based, precision-phase current sensing reference design for three-phase inverters. One of the challenges with GaN or SiC inverters at high PWM switching is accurate phase current sensing across the shunt in presence of noise due to the high PWM frequency and high common-mode voltage transients. This challenge is solved by an isolation technology rated for common-mode transient immunity (CMTI) of 50 kV/µs, differential shunt voltage sensing, and a precise delta-sigma modulator, which is present in the AMC1306 modulators. The design features an interface to the C2000™ Delfino™ to generate up to a 20-MHz clock signal and receive and decode the modulated bit stream from the AMC1306 in Manchester coded bit format.
- ±10-A current range With 5-mΩ shunt due to AMC1306E05 unique low input voltage range (±50 mV) allows significant reduction of power dissipation through shunt
- Precision current sensing with accuracy better than ±0.25% (calibrated at 25°C) across temperature, tested with three-phase GaN inverter with high common-mode transients at 100-kHz switching frequency at 0°C, 25°C, and 55°C ambient
- Exceeds IEC 61800-3 EMC immunity requirements for fast electrical transients IEC 61000-4-4, achieves criterion A at ±4-kV EFT
- High CMTI of AMC1306 modulator (> 50 kV/μs) improves noise immunity to high switching transients
- Reinforced isolated delta-sigma modulator AMC1306E05 with small package (SOIC-8) and Manchester encoded data to simplify layout
- Short-circuit response time of < 1.5 μs with SINC3 filter and OSR of 8, protects fast switching inverters such as GaN inverters