CIRCUIT FOR SYNCHRONIZING A SWITCHING POWER SUPPLY TO A LOAD CLOCK

摘要

POWER SUPPLY AND CIRCUITS THEREFOR Circuitry for use in a power supply of the type which includes a power switching means and uses a waveform of predetermined shape to control the power switching means such as in a first mode the supply regulates its output voltage and in a second mode controls the current in the power switching means. The circuitry synchronizes the frequency of the waveform to the master clock frequency of the load connected to the supply. The circuitry also inhibits the transfer of the supply from its first to second mode of operation in response to rapid variations in the power switching current by temporary disturbances in the load. The circuitry also provides constant drive current for the power switching means even if the input voltage to the supply is unregulated. Finally, the circuitry attempts to turn the supply off in response to an overvoltage condition at its output and failing that provides a short circuit path so that current sufficient to cause the fuse in the output to open will flow therethrough.