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DRIVING CIRCUITS FOR LIGHT EMITTING DIODES

  • US 3,740,570 A
  • Filed: 09/27/1971
  • Issued: 06/19/1973
  • Est. Priority Date: 09/27/1971
  • Status: Expired due to Term
First Claim
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1. Apparatus for driving selected ones of m times n light emitting diodes where m and n are whole numbers, comprising:

  • first register means having at least m outputs and second register means having n outputs, each output of said first register means being connected to one side of one diode in each of n mutually exclusive groups of diodes and each output of said second register means being connected to the other side of one diode in each of m mutually exclusive groups of diodes, each diode being in one of said groups of m diodes and in one of said groups of n diodes;

    storage means connected to said first register means for storing at least m times n bits representative of information to be displayed, said storage means having a feedback path for recycling m times n bits, and clock means connected to said storage means and to said first register means for initiating said storage means to transfer a binary code containing at least m bits to said first register means for conditioning selected groups of said m groups of diodes for conduction, said clock means further conditioning said second register means for conditioning a group of said n groups of diodes for conduction, diodes existing in both the selected groups of m diodes and the selected group of n diodes being operated for a predetermined period of time, said clock means sequentially conditioning said storage means to transfer successive said binary codes to said first register means and shifting said second register means to operate diodes existing in both the selected groups of m groups of Diodes and the selected group of n groups of diodes until selected diodes in each group of said n groups of diodes are operated, said storage recycling m times n bits to repeat the pattern of operating said diodes.

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