I have never used a potentiometer in my MAX1771-based supplies. The reason is, they make it more difficult to do a better PCB layout, and anyway the regulated output voltage from the supply using fixed 1 % resistors is accurate enough for the purpose of powering a Nixie display. I could always replace the resistors with different values if I wanted a different output voltage.
I wish you good luck with the TPS40210 design. By the way, I do use trimpots in the microcontroller-based supplies that power my more recent Nixie designs. This is because I use a built-in comparator instead of an ADC, and the reference voltage is not specified as precisely as a purpose-built controller. I'm probably as concerned as you are about the reliability of the controlling software. Safety can be improved somewhat by placing a high-pass filter between the uC and FET driver, and also making the software create a series of one-shot pulses instead of letting the PWM controller run freely. Ken -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
