| 摘要 |
<p>A light emitting diode printhead has a row of LED dice, with each die having one or more rows of LEDs. The LED die substrate forms a common cathode for the LEDs on that die. There is a time multiplex driver for a plurality of dice comprising a plurality of current sources. Each current source comprises a current driver FET and a data FET in series. Each data FET is connected in parallel to the anodes of corresponding LEDs on all of the dice. Switches selectively connect the substrate of each die to ground. A latching shift register is used for applying data for a selected die to the data FETs. The register is divided into the same number of blocks as the number of dice, and each block has the same number of bits as the LEDs on a die. At the same time a block of data for a selected die is connected to the data FETs, the substrate of the selected die is connected to ground, thereby enabling only the light emitting diodes on the selected die. <IMAGE></p> |
