Hello everyone!
I'm currently trying to redesign one of my old projects (a 24 hour clock with LED displays). The redesign only concerns the display, as I've found LED diplays consuming a bit too much energy, so I decided to swap them for a 4 digit LCD display. I've included the datasheet as an attachment. I have never worked with an LCD display before, but from what I was able to get together, they are quite different from LED displays. I have already bought the display (it operates from 5V supply-extended temperature type) and 4 CD4056 drivers, but I don't know if they can work together flawlessly, so I've decided to ask your opinion in the following questions:
a) The cd 4056 contains a level shifting function, so the display can have larger voltage swings when going from Vdd to Vee, than those of the BCD inputs of the driver. My question is why, if LCD displays usually work with voltages below 5 V, while the driver can tolerate as high as 15 V? The maximum voltage swings are actually smaller on the display than those on the driver.
b) Do I need to add any resistors or other components to the design? For example, LED displays always need current limiting resistors, do I need them with LCDs?
c) When I browsed through the CD 4055/4056 datasheet, I read something that I interpreted as the 4056 can't drive the display on its own, because it lacks the DF output that can be found on the 4055 chip (the 4056 has a strobe/latch pin instead). Can I use my display with just the 4056 or I will have to invest in some 4055s?
d) On the first page of the 4055/4056 datasheet the voltage swings from Vdd to Vee and Vdd to Vss are given as 0 to -3 and 0 to -15. Does that mean I need a negative voltage regulator like the 79xx series?
e) The displays datasheet marks pin 1 and 40 as BP. I know it means "backplane", is it the "common" pin of the display? Can I tie it simply to Vss or I need to connect that to the display frequency source too, like the drivers DF input?
f) If you can add any further tips with LCD displays, I would greatly appreciate it!
Thanks for the help in advance!
I'm currently trying to redesign one of my old projects (a 24 hour clock with LED displays). The redesign only concerns the display, as I've found LED diplays consuming a bit too much energy, so I decided to swap them for a 4 digit LCD display. I've included the datasheet as an attachment. I have never worked with an LCD display before, but from what I was able to get together, they are quite different from LED displays. I have already bought the display (it operates from 5V supply-extended temperature type) and 4 CD4056 drivers, but I don't know if they can work together flawlessly, so I've decided to ask your opinion in the following questions:
a) The cd 4056 contains a level shifting function, so the display can have larger voltage swings when going from Vdd to Vee, than those of the BCD inputs of the driver. My question is why, if LCD displays usually work with voltages below 5 V, while the driver can tolerate as high as 15 V? The maximum voltage swings are actually smaller on the display than those on the driver.
b) Do I need to add any resistors or other components to the design? For example, LED displays always need current limiting resistors, do I need them with LCDs?
c) When I browsed through the CD 4055/4056 datasheet, I read something that I interpreted as the 4056 can't drive the display on its own, because it lacks the DF output that can be found on the 4055 chip (the 4056 has a strobe/latch pin instead). Can I use my display with just the 4056 or I will have to invest in some 4055s?
d) On the first page of the 4055/4056 datasheet the voltage swings from Vdd to Vee and Vdd to Vss are given as 0 to -3 and 0 to -15. Does that mean I need a negative voltage regulator like the 79xx series?
e) The displays datasheet marks pin 1 and 40 as BP. I know it means "backplane", is it the "common" pin of the display? Can I tie it simply to Vss or I need to connect that to the display frequency source too, like the drivers DF input?
f) If you can add any further tips with LCD displays, I would greatly appreciate it!
Thanks for the help in advance!
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