Driving LCD''s
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Posts: 46,084
LCDs I've messed with in the past have run off switched DC (i.e., a square
wave). The display of the segments was sensitive to both the peak to peak
voltage and to the duty cycle. If you can't find good documentation on the
display you're using, start with 1 khz and 5 volts and work from there. Perhaps
someone else on the list can recommend a better starting point?
I think 10 meg resistors would not be the way to go.
Good luck.
Clark Hughes
>
> Anyway, does anyone know how to drive an LCD without killing it?
>
> I've come up with a circuit using 4 4094's to drive 4 digits of an LCD and
> fed with 6 lines from the BS2. It works, in that the LCD segments light up.
> BUT, I think I may be driving the LCD too hard and may eventually kill it.
>
> I believe a maximum of 50mV DC component should be applied, but the average
> (as measured with my DMM) is 2.5v.
>
> However, I checked the voltage from the pins of a 7106 evaluation board I
> have, and the average on it's pins is 6.3V.
>
> Reason I'm concerned, is because after a few hours, segments seem to be a
> bit "lazy" turning off with my circuit. However, I'm a little miffed due to
> the reading from the 7106 board.
>
> Should I just throw in some 10Meg resistors on each line??
>
wave). The display of the segments was sensitive to both the peak to peak
voltage and to the duty cycle. If you can't find good documentation on the
display you're using, start with 1 khz and 5 volts and work from there. Perhaps
someone else on the list can recommend a better starting point?
I think 10 meg resistors would not be the way to go.
Good luck.
Clark Hughes
>
> Anyway, does anyone know how to drive an LCD without killing it?
>
> I've come up with a circuit using 4 4094's to drive 4 digits of an LCD and
> fed with 6 lines from the BS2. It works, in that the LCD segments light up.
> BUT, I think I may be driving the LCD too hard and may eventually kill it.
>
> I believe a maximum of 50mV DC component should be applied, but the average
> (as measured with my DMM) is 2.5v.
>
> However, I checked the voltage from the pins of a 7106 evaluation board I
> have, and the average on it's pins is 6.3V.
>
> Reason I'm concerned, is because after a few hours, segments seem to be a
> bit "lazy" turning off with my circuit. However, I'm a little miffed due to
> the reading from the 7106 board.
>
> Should I just throw in some 10Meg resistors on each line??
>