A low Vf Diode makes the issue worse. Suggest a UF Diode, low TRR and higher Vf, such as the BAS316.
Also regulate the input of the VCC to 5V. 12V+5V -0.7V = 16.3V < 18V. If close to going to 18V overall conditions suggest setting Vibis to 4.5V, and…
Please check LM2745 and LM2748. Friendly with external bias. Operate at 300kHz and with the right fets this could be a viable solution.
Regards,
Mathew
Hi,
I've attached the 2013 User's Guide for power products. Starting on page 53 you will find a selection of PWM controllers. many of these teh frequency can be varied according to external criteria.
As an example if you use a UC3842 it is a simple…
Gary,
Most any of our power controllers with dual output capability will provide the control. See attached document starting at page 50 with the dual output controllers on page 53 and 54 and choose what features you want.
Regards,
John
