Switchable feedback damping of drop-on-demand piezoelectric fluid-ejection mechanism

摘要

A control circuit for a drop-on-demand piezoelectric fluid-ejection mechanism includes a drive and sense circuit, and a switch. The drive and sense circuit has an input, a drive output, and a sense output. The drive output is to be coupled to the drop-on-demand piezoelectric fluid-ejection mechanism. The switch is to switch the input of the drive and sense circuit between a feed-forward driving mode of the drive and sense circuit and a feedback damping mode of the drive and sense circuit. In the feed-forward driving mode, the switch is to couple the input to a drive waveform to cause the fluid-ejection mechanism to eject a drop of fluid. In the feedback damping mode, the switch is to couple the input to the sense output to dampen the fluid-ejection mechanism after the fluid-ejection mechanism has ejected the drop of fluid.

主权项

1. A control circuit for a drop-on-demand piezoelectric fluid-ejection mechanism, comprising:
a drive and sense circuit comprising a sensing capacitor and having an input, a drive output, and a sense output, the drive output to be coupled to the drop-on-demand piezoelectric fluid-ejection mechanism; and, a switch to switch the input of the drive and sense circuit between a feed-forward driving mode of the drive and sense circuit and a feedback damping mode of the drive and sense circuit, wherein the drive and sense circuit is to compare a voltage over a capacitance of the sensing capacitor to a voltage over a capacitance of the fluid-ejection mechanism, wherein in the feed-forward driving mode, the switch is to couple the input to a drive waveform to cause the fluid-ejection mechanism to eject a drop of fluid, and wherein in the feedback damping mode, the switch is to couple the input to the sense output to dampen the fluid-ejection mechanism after the fluid-ejection mechanism has ejected the drop of fluid.