Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

how to omit noise of LCD driver in a one layer PCB board

Status
Not open for further replies.
M

matin-kh

Member level 3
Joined
Nov 9, 2013
Messages
67
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
iran
Activity points
1,955
hi every one,
In a project in a PCB board I use a nokia 1202 LCD, an atmega8 and 5 relays. the PCB board is connected to a 220 volt ac signal which with some diodes and resistors and capacitors it has changed to 20v DC and relays are connected to this voltage then with a LM317 20v is changed to 3.3 volt for vdd of micro and LCD, with generate a little noise the characters of LCD will be damaged and I think absolutely it's because of 220v ac signal noise on driver of LCD but i don't know how to solve it could you please help me?
with best regards
matin
 

Even though logic runs on 3,3V normally LCD analog signals are differential with analog bias voltages in the range of 12V. It seems these are the ones getting interference, not the logic or SPI interface.

Consider interface shielded wires, ferrite choke sleeve, ground plane, check all analog signals and voltages and ensure Analog ground is clean relative to analog driver. Imbalance from stray EMI can induce noise.

But scoping analog signals on LCD will show the problem, or show us.
 
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top