Hiya I seem to have hit a brick wall in a project im doing at the moment, the trouble is I have an array of BDC counters which need to be connected to a driver array for conversion from binary to Decimal thats ok. My problem is finding the correct driver chip to use I have two choices 1. Use an 7-Segment display which is easy but slightly power consuming or, 2. Use an LCD display which uses much less power but requires a multiplexer or a microprocessor which I have NO experiance in each. So if someone could post a recommendation for an LCD driver chip that doesnt need multiplexing or a microprocessor that would be perfect, cost isnt an issue. Cheers guys ChromeX
Oh sorry in my haste i've worded my request kinda crappy! What I mean is, is that I need a driver chip that will drive a LCD without multiplexing all ones i've seen require a multiplexer circuit which I dont have time for. What I ment by my two choices were, I can either use an 7-seg arrangement which requires a fair bit of power but a simple IC chip OR an LCD arragnment which doesnt require alot of power but requires a complex chip.
You can use the same driver chips to drive 7-segment LCD's (like CPemma posted) and 7-segment LED display's If you only have a couple of digits you dont need to multiplex either.
Look at 4054, 4055 or a 4056 says BCD to 7-seg LCD on the tin. Unless your "BDC counter" is something else.
yeah my BDC counter is a 7493 and the driver I have is the 7447 I have 6 in a row when the D and B inputs are high (i.e. the decimal number 10) the AND gate they're connected to sends a pulse to the next one in the chain, until it gets to the 5th then the B and C inputs send the pulse the whole thing is a stopwach essentially with a few twists. To be honest i'd sooner use the 7-segs but 6 7-segs in a row is roughly 20mA(per seg)*7*6= 0.84 amps and that without the other IC's the clock generator and alarm sub-systems, so the ONLY reason i wanted the LCD display was to keep power consumption to a minimum. But by the looks of things im gonna have to stick with the 7-seg arrangment
But you can drive LCD's in exactly the same way As CPemma said the 4054, 4055 or 4056 are labelled as LCD drivers, they work exactly the same as a regular 7-segment driver. Just use the 74 series equivalent, dont know what that is offhand. The only difference when driving LCD's is the need to switch the current to prevent burn in. The 40xx chips mentioned have 'pulse' inputs which will switch the outputs between common cathode and common anode operation. The method I remember using was to drive the pulse input with a 1kHz 555 clock, and drive the common of the LCD with the inverse of the clock signal.
That sounds perfect! Looks like im gonna have to go with the 40xx series then, which to be honest I didnt know existed which is why I was having problems with the burn in effect which you mentioned on the 74xx. I was considering either a logic astable or using a quartz crystal which im sure I could adapt to work with the 40xx. Cheers for the help guys its very much appreciated
