large 5x7 dot matrix display grid help - Electronic Circuits Projects Diagrams Free

4rvm · 11th September 2007, 03:36 AM

Hi, I would like to model a "billboard" for a display on a train layout. This display would be a grid of 60 ltp747r 5x7 common cathode matrices that would be driven from a pic 16f877. The display would be arranged as 12 5x7 chips across by 5 chips down. My initial question is a confirmation of what kind of power would be needed at a 20% duty cycle given a 13ma datasheet normal brightness level at 100% per led. I am trying to figure out what to drive the rows and columns with, especially the rows where I'm not finding too high a rating on what I think are needed pchannel mosfets (hexfets). Any initial advice on this project is much appreciated! Thanks.

AtilaPap · 11th October 2007, 12:45 PM

In datasheet you can find leds data and and with little math you will find out.
Power transistor will do the job but it must be fast.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Title	Starter	Forum	Replies	Latest
Problem with LCD code?	spondootre	Micro Controllers	15	29th April 2008 10:15 AM
Inchworm adapter bd	lemonyx	Micro Controllers	9	9th May 2007 08:01 AM
microchip application A590 /display is ok now	prosound90	Micro Controllers	20	18th November 2006 10:44 PM
Display Driver for 16 * 16 matrix display	pmphilip	General Electronics Chat	2	4th January 2006 08:15 PM
Need help for choosing a suitable Dot Matrix Display...	savagewilson	Electronic Projects Design/Ideas/Reviews	3	13th May 2004 07:15 PM

11th September 2007, 03:36 AM	(permalink)
4rvm	large 5x7 dot matrix display grid help Hi, I would like to model a "billboard" for a display on a train layout. This display would be a grid of 60 ltp747r 5x7 common cathode matrices that would be driven from a pic 16f877. The display would be arranged as 12 5x7 chips across by 5 chips down. My initial question is a confirmation of what kind of power would be needed at a 20% duty cycle given a 13ma datasheet normal brightness level at 100% per led. I am trying to figure out what to drive the rows and columns with, especially the rows where I'm not finding too high a rating on what I think are needed pchannel mosfets (hexfets). Any initial advice on this project is much appreciated! Thanks.

11th October 2007, 12:45 PM	(permalink)
AtilaPap	Will this help? In datasheet you can find leds data and and with little math you will find out. Power transistor will do the job but it must be fast. Last edited by AtilaPap; 12th October 2007 at 08:17 AM.