I had misread that, thinking he was talking about making that many
units that included this circuit. But now re-reading it, I see it the
way you just mentioned. He's planning an array.
Makes me wonder if there are LEDs with different voltages (colors),
since with that many it might pay off dissipation-wise to use separate
switching supplies for each color/voltage.
Here's one possible arrangement that would provide about 60mA with a
Vcc of 5V.
: Vcc Vcc
: | |
: | |
: \ |
: / Rca_N |
: \ 47k |
: / |
: Rcb_N | |<e Qcol_N
: COL_N----------------/\/\-+-----| 2N3906
: 100 |\c
: |
: |
: | COL_N
: +----------------------------+-------------------------------------+------------,
: | | | |
: | | | |
: --- --- --- |
: \ / DN1 \ / DN2 \ / DNZ |
: --- --- --- \
: | | | / Rcc_3
: | | | \ 47k
: | | | /
: | | | |
: | | | |
: | | | |
: Vcc Vcc | | | |
: | | | | | gnd
: | | | | |
: \ | | | |
: / Rca_2 | | | |
: \ 47k | | | |
: / | | | |
: Rcb_2 | |<e | | |
: COL_2----------/\/\-+-----| 2N3906| | |
: 100 |\c | | |
: | | | |
: Qcol_2 | | | |
: | | | | COL_2
: +----------------------------+-------------------------------------+-------------------,
: | | | | | | |
: | | | | | | |
: --- | --- | --- | |
: \ / D2A | \ / D2B | \ / D2Z | |
: Vcc Vcc --- | --- | --- | \
: | | | | | | | | / Rcc_2
: | | | | | | | | \ 47k
: \ | | | | | | | /
: / Rca_1 | | | | | | | |
: \ 47k | | | | | | | |
: / | | | | | | | |
: Rcb_1 | |<e | | | | | | |
: COL_1---/\/\-+-----| 2N3906| | | | | | gnd
: 100 |\c | | | | | |
: | | | | | | |
: Qcol_1 | | | | | | |
: | | | | | | | COL_1
: +----------------------------+-------------------------------------+--------------------------,
: | | | | | | | | | |
: | | | | | | | | | |
: --- | | --- | | --- | | |
: \ / D1A | | ^ \ / D1B | | ^ \ / D1Z | | ^ |
: --- | | | --- | | | --- | | | \
: | | | | | | | | | | | | / Rcc_1
: | | | | | | | | | | | | \ 47k
: | | | | | | | | | | | | /
: +------+------+------' +------+------+------' +------+------+------' |
: | ROW_A | ROW_B | ROW_Z |
: | | | |
: | | | |
: Rrow_1 |/c Qrow_1 Rrow_2 |/c Qrow_2 Rrow_Z |/c Qrow_Z gnd
: ROW_A----/\/\------| 2N3904 ROW_B---/\/\----| 2N3904 ROW_Z----/\/\----| 2N3904
: 3300 |>e 3300 |>e 3300 |>e
: | | |
: | | |
: | | |
: | | |
: | | |
: \ \ \
: / Rset_1 / Rset_2 / Rset_Z
: \ 22 \ 22 \ 22
: / / /
: | | |
: | | |
: | | |
: | | |
: gnd gnd gnd
Jon