Hello,
I’m having a little trouble getting the UCC28950 working properly and would like a little tech support. In particular, the Vref output is ~7v, but according to the spec it should be 5v.
I have attached a schematic showing the pwm ic circuitry. All the delay resistors are 20kohms, and the master clock resistor is 60k ohms (100khz). The Rt_master now goes to Vref instead of AGND as shown below. The IC appears to function correctly with burst mode pulsing (not connected to real signals yet), but the voltage from Vref is ~6.8v instead of the specified 5.0v. Not shown is a 1ufd cap now connected to Vref.
Regards,
John Wiemeyer
(Please visit the site to view this file)