Dear sir ,
We are trying to operate the UCC28722 for buck converter design application (380 V Nominal Input and 15V Output ). We have used darlington pair instead of NPN transistors as Switching device .While operating the converter at 90V input voltage with 150mA Load we are getting vcs pin waveform as shown below. Clearly from the waveform it is clear even the voltage at vcs pin is below 1.5V but it is not a stable waveform .How to Stabilize the vcs pin voltage ?? The Yellow signal is DRV Pin Output and Pink is Vcs pin Voltage . Also Even though the DRV Signal is Off the Darlington pair takes around 4 microsecond to turn off .How to mitigate these issues ??
Regards,
