Hello,
I use the Viper06LS in the Buck Converter topology.
The input voltage can vary between 100V and 530VDC. The output voltage is regulated to 10 V. (See "Viper_circuit"!)
Unfortunately, a problem arises when the input voltage increases to approx. 520 V.
The Viper06LS stops regulating the output voltage. The output voltage drops and the Viper restarts.
To check whether the Viper switches off due to an overcurrent, I looked at the choke current at the output.
However, the choke current does not exceed the shutdown current at this moment and the choke does not saturate. (See oscilloscope recording "Inductor_Current", blue = Drain-Source-Voltage, green = inductors current)
If I install the Viper06HS (f_osc = 115 kHz) in the same layout, the controller works without failures up to more than 570 VDC input voltage.
Now the questions:
Are there any experiences with this behavior?
What can cause this behavior?
Why does the Viper06HS with the clock frequency of 115 kHz work and the Viper06LS with 60 kHz doesn't work?
I look forward to your contributions!
Best regards
