LOLbooster: Output Stage (Part 1)

Learn more about the LOLbooster, and purchase PCBs and kits. The output stage of a DCC booster is basically a class-D amplifier output stage. It takes the processed DCC signal, a square-wave signal of approximately 15KHz, and pumps it to the specified output voltage (~12Vp for N scale, less for Z and more for HO) and current (as required by what’s on the track, up to the specified maximum). Unlike audio signals, however, DCC signals are differential-mode—whatever signal is put onto rail A is mirrored and inverted on rail B. So, a booster output stage uses two push-pull amplifiers in...