SAA1064 driving 14 segment display

Discussion in 'The Projects Forum' started by Titia, Feb 15, 2013.

  1. Titia

    Thread Starter New Member

    Feb 14, 2013
    Hello All,
    I plan to re-use a leftover display board with 4x dual alphanumeric display LA5422-11. Each dual display is driven by one SAA1064 LED driver in dynamic mode (total 4xSAA1064T). I don´t have any idea where from this board is issued and obviously no diagram. In order to identify this board some 3 lines labellings exist on the track side stating:
    FRONT 430 LS 03681156
    4303 012 6577.1 6577.1
    On the components side additional components exist

    • one mini-push button marked "up"
    • one mini-push button marked "down"
    • one infra-red receiver marked "TSOP1730" + 1x 4,7μF capacitor
    • one 8 pins connector.
    Looking through the web for several days I did not succeed to find a diagram or a data sheet [​IMG]. It is obvious the device was intended to be used as combined remote controlled IR-receiver and display. But for which purpose was it designed, to which equipment was it connected?
    Looking carefully at the board tracks and pinnings, one can say:

    • the pinnings correspondence of the drivers and the displays is as follows:
    SAA1064 LA5422-11
    pin segment
    3 F
    4 H
    5 I
    6 J
    7 G1
    8 A
    9 B
    10 C
    15 Dp
    16 D
    17 G2
    18 K
    19 L
    20 M
    21 E
    • the other pins of SAA1064 are connected as per data sheet.

    • Each SAA1064 is configured in dynamic mode because each is equipped with 2 x BC847 smd transistors and C.ext smd capacitor. That's explain why 1 display use 2 sets of segment output.
    Now the questions:

    1. does anyone have some idea of what is this stuff?
    2. how one 14 segment display could be driven with 2 segment output from the SAA1064?
    Thanks to all