This short app note (seven pages of main text) is the sad conclusion to the grand saga of cold-cathode fluorescent lamps (CCFLs). Just as a reminder:
- Part 1 is Figure 36 in App Note 45
- Part 2 is App Note 49
- Part 3a is App Note 55 (part 1 and part 2)
- Part 3b is Chapter 11 in his second book
- Part 4 is App Note 65 (part 1, part 2, part 3, part 4, and part 5)
- Part 5 is App Note 81
Piezoelectric transformers are not new to Jim. In fact, he discussed them in National Application Note 285, "An acoustic transformer powered super-high isolation amplifier", back in 1981. He also used one in Figure 51 of LTC App Note 29.
The enabling technology here is shown in Figure 7: the transformer terminal labeled "resonance feedback" allows for simplified drive circuitry, ensuring start-up and oscillation at resonance. The complete circuit is shown in Figure 9.
Appendices A and B were written by his coauthor at CTS Wireless Components. Appendix A is a short introduction to piezoelectric transformers, and Appendix B is a longer theoretical treatise.
Appendix C provides the best quote
Veterans of feedback loop compensation battles will exercise immediate caution when confronted with a pure and lengthy delay in a loop. Neophyte designers will gain a lesson they will not easily forget.Again, I think he's mocking me in footnote 2. I must admit that "glop comp" is not a terminology that I am familiar with (although I do use "dominant-pole compensation" in everyday conversation).
The app note ends with a cartoon. "I can't believe I've been replaced by that skinny nothing."