You are here: Home >> Technical >> Q & A
Q & A
Adjusting the contrast of a character LCD module. | ||
There are two means of adjusting the contrast: Please refer to the following drawing: | ||
1. Internal: J2 short, add the appropriate resister to R7 for contrast control.
2. External: J1 short, R7=0, By adding a VR the contrast can be controlled externally. |
||
|
Connecting and powering the backlight. | ||
There are two means of connecting and powering the backlight. Please refer to the below diagrams: | ||
1. PINS 1 & 2 (Vdd & Vss): J3 short, by adding a resistor on R9.
2. PINS 15 & 16: J4 short, by adding a resistor on R8. |
||
|
|
|||
There are two means of connecting and powering the backlight. Please refer to the below diagrams: | |||
|
Differences between a Driver IC, a Controller IC and a Controller/Driver IC: | |||
There are two types of driver IC’s. One is a “common” driver and the other a “segment” driver. Common drivers output signals to create the rows or number of lines while the segment drivers output the necessary signals to create the characters or columns.
Controller IC:
Driver/Controller IC: |
|||
|
|
|||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||
|
Comparison between TN, STN and FSTN technologies: | |||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||
|
Differences between reflective, transflective and transmissive displays? | |||
Transflective: As type of backing which is bonded to the rear polarizer. Enables light to pass through the back, as well as reflecting light from the front. Transmissive: A type of LCD which does not have a reflector or transflector laminated to the rear polarizer. A backlight must be used with this type of LCD configuration. The most common is a transmissive negative image. |
|||
|
Considerations for attaining a 3.0 Volt LCD module: | |||
Controller: KS0066U 2.7 ~ 5.5V KS0070B 2.7 ~ 5.5V HD44780U 2.7 ~ 5.5V Driver: KS0065 2.7 ~ 5.5V KS0063 2.7 ~ 5.5V SED1181 5.0V min.
SCI7660 2X, dice font available (at a much less expensive cost). If a NV IC must be incorporated onto the module PCB, there is apt to be two possible considerations:
2. The PCB is too small to accommodate the NV IC. If there is not sufficient space, a possible
Some TAB IC’s such as SED1560 series include a power circuit, which can amplify the input
LED: In an attempt to achieve this 3.3V requirement it is necessary to use an edge-lit LED. Note this |
|||
|
Reference to Viewing angle: | |||
|
|||
|
Clarification to the term “rainbow” effect: | |||
|
|||
|
Pin assignments for a Character module: | |||
PIN 1: Vss PIN 2: Vdd PIN 3: Vo PIN 4: RS PIN 5: R/W PIN 6: Enable PIN 7 ~ 14: DB0 ~ DB7 |
|||
|
What is temperature compensation and why is required? | |||
|
|||
|
Troubleshooting an LED backlit module in which the display is turning dark: | |||
|
|||
|
Controlling the LED backlight on a 14-pin module: | |||
Note: If the LED is drawing too much current it may cause the Vdd – Vo to lower and the contrast to become poor. If this should occur increasing the value of R9 should decrease the current draw to the LED backlight or another approach would be to increase the voltage input to the LCD by decreasing the value of R7. |
|||
|
Brief description of various controller IC’s: | |||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||
|
Following is the Vop range for a Character and Graphics LCD module: | |||||||||||||||||||||
Note: N.T. = normal temperature W.T.= wide temperature |
|||||||||||||||||||||