LNK6766K - Voltage Range Settings
I am using the LNK6766K in a flyback design. Have had a couple issues.
1. I am using an OEM transformer with relatively low primary inductance. The part was dropping into the 3-5mS dead time causing my supplies to be unstable. Increased the cap on teh feedback pin which resolved this, but may be leading to a secondary problem...
2. My voltage limits are not working as calculated. Been awhile since originally designed, but believe the top resistor in the feedback path sets the input voltage range. I designed this to run from 30-100V, but the system does not start up at 72V (works fine at 48V.) My top feedback R = 22K.
Questions:
1. Is there something else I should be doing to fix item 1? The cap on the feedback line is now 100pF; was originally 18pF.
2. What other factors determine the voltage thresholds? As per the data sheet I thought I had this...
Hi,
Could you please share your schematic and PIExpert/PIxls design file?
Regards,
PI-NANO