Infineon XMC Series - ZCD Control Using Fast Compare Mode

Introduction to Digital Power Conversion
XMC4000/1000 Family
Sensing
Application Guide 49 V1.0, 2015-01
5.1.4 ZCD Control Using Fast Compare mode
This type of sensing is called Valley-Detection (the opposite of Peak-Detection).
In this example, the selected Valley-Detection level is Zero.
To utilize the hysteresis effectively, map:
 Hysteresis to the upper boundary(0)
 Reference to the lower boundary(1) close to 0(ε).
Figure 37 Sensing for ZCD Control by Boundary Flag
Note: In practical terms, the value of ‘ε’ is imagined as a very small value to cover a contingent offset
in the analog input signal, so that the lower boundary(1) detection conditions are realistic.