THERMAL INK JET PRINTHEAD SYSTEM WITH MULTIPLE OUTPUT DRIVER CIRCUIT FOR POWERING HEATING ELEMENT AND ASSOCIATED METHOD

摘要

A thermal ink jet printhead system has a printhead with base member and a plurality of ink flow channels formed in the base member that connect to an ink reservoir and terminate in a nozzle through which ink is expelled. A heating element is associated with each ink flow channel. A monolithically integrated multiple output power driver circuit is formed as a semiconductor integrated circuit and connected to each heating element in the printhead. The multiple output driver circuit includes a power MOS transistor connected to each heating element. A reference circuit is operatively connected to each gate of the power MOS transistor and includes a reference transistor having a gate and a reference amplifier that receives as inputs a reference voltage and a source of current. An amplifier output is operatively connected to the gates of the power output transistors and the gate of the reference transistor. The reference amplifier regulates the reference transistor directly and the power MOS transistors by matching.