| 摘要 |
A current-driven load such as LEDs or laser diodes is driven by a current driver having a two stages (or phases), the outputs of which have ripple which is forced to be out-of-phase with one another. In analog embodiments, an output (ripple or switching) of a master stage hysteresis controller is phase-shifted and scaled, and modulates the input of a slave stage hysteresis controller so that the slave stage pulls into a ripple-canceling phase. In digital embodiments, a faster of the two phases is designated“master”, maximum and minimum thresholds are set, and the slave phase's on time is based on a previous cycle's slave phase ON time, the master stage OFF time and an offset. The slave controller may“lock”to the anti-phase of the master stage (or phase). The ripple currents at the summed output of the master and slave stages substantially cancel. |
