What is an IC or LCD controller driver?

The majority of LCD displays contain a built in LCD controller. The exception to this is a segment, or glass-only, LCD that uses a multiplex method to drive the segments. All other display technologies such as: TFT, OLEDcharacter, graphic, UWVD and FSC contain a built-in LCD controller.

What is an LCD controller?

The LCD controller is a small microprocessor that converts the customer’s software code (aka firmware) to information that the LCD can understand. The LCD screen then displays graphics, characters, images and numbers to be seen by the end user.

If the display did not contain a controller, the engineer would have to address each segment and pixel independently. This would require a large amount of programming time and greatly increase development cost, not to mention the consumption of coffee.

Most controllers have the ability to send and receive data. This allows the customers product to monitor the LCD.

Where is it located?

Each LCD requires only one driver chip. Depending on the number of segments that need to be driven, additional driver chips may be required if there are a large number of segments to drive/refresh.

The black circular area on the back of the display pictured below is the area where the LCD controller is housed on the display.

This black ‘tar’ is a conformal coating that protects the controller from damage due to moisture and contact with metal or static charges.

What interfaces does a LCD controller provide?

One key advantage is that it provides a variety of standard bus interfaces that make it easy to program. These include SPI (Serial Peripheral Interface), i2C (I squared C), Parallel (4 bit, 8 bit, 16 bit) and LVDS (Low-voltage differential signaling).

Which LCD controller to choose?

The controller is chosen by the LCD supplier. Our goal is to choose a chip that will be in production for many years. It is possible to use a controller that is preferred by the customer, but we do not recommend this since some controllers have higher cost and longer lead-times than other controllers.

Companies that manufacture LCD controllers include: EpsonSurplus, and Sitronix.

What are the functions of the LCD Controller

The LCD controller/driver has the following functions:


The memory that is built into the LCD controller driver that drives the LCD module. It is also called on-board memory

Character Generator

This is a library that converts the customer’s data to letters, numbers and punctuation marks. This is built into the LCD Controller/Driver

The character generator is different for each language (English, French, German, Hebrew, etc.)

Segment Driver

The same chip that contains the LCD controller can also drive the segments located on the LCD

If you need to drive additional segments beyond the capability of the LCD controller/driver chip, you can add an additional driver chip, but there is always just one controller.

New product design with a LCD?

Do you need help with a new design and not sure which LCD or controller to choose? Make some coffee and pick up the phone to call FocusLCDs.com at 480-503-4295 or contact us. We’d be happy to help and assist you.