JAJSHJ6B December 2011 – June 2019 AFE030
PRODUCTION DATA.
The AFE030 includes two zero crossing detectors. Zero crossing detectors can be used to synchronize communications signals to the ac line or sources of noise. Typically, in single-phase applications, only a single zero crossing detector is used. In three-phase applications, both zero crossing detectors can be used; one component detects phase A, and one detects phase B. Phase C zero crossings can then be inferred from the data gathered from the other phases. Figure 38 shows the AFE030 configured for non-isolated zero crossing detection.
Non-isolated zero crossing waveforms are shown in Figure 39.
For maximum protection of the AFE030 against line transients, it is recommended to use Schottky diodes as indicated in Figure 38. These diodes should limit the ZC_IN pins (pins 38 and 39) to within the maximum rating of (AVDD + 0.4 V) and (AGND – 0.4 V). Some applications may require an isolated zero crossing detection circuit. With a minimal amount of components, the AFE030 can be configured for isolated zero crossing detection, as Figure 40 shows.
Isolated zero crossing waveforms are shown in Figure 41.