Hello.
Recently, I have had to use UCx84x PWM-controllers many times.
On / off voltage for UCx842, UCx844 is 16V / 10V, and for UCx843, UCx845 it is 8.4V / 7.6V. And datasheet says that "Devices with higher turnon or turnoff hysteresis are ideal choices for off-line power supplies, while the devices with a narrower hysteresis range are suited for DC-DC applications".
I understand why PWM controllers with high hysteresis are better for off-line power supplies, but I do not understand why controllers with fairly low 8.4V / 7.6V thresholds are recommended for DC-DC converters. Explain, please, what is the essence of this recommendation?
