Figure 8. Soft-Start - STMicroelectronics STEVAL-IHM029V1 User Manual

UM0922 Oscilloscope waveforms
The ZVS signal is used by the MCU as a reference to calculate the firing angle and to
synchronize the Triac gate signal with the voltage mains.
The ZVS signal ranges from 0.6 V and 5.6 V. This is due to the cutting diodes inside the
MCU I/O port.
Figure 8. Soft-start
The waveform shows the output current behavior from start to the maximum output power.
The output current is slowly and smoothly increased until the working level is reached. In the
example, the working level is reached in about 4 seconds.
Doc ID 17259 Rev 1 13/23