LCD Drivers

An LCD Driver also referred to as an LCD Display Driver or LCD Controller is an integrated circuit that provides an interface between a microprocessor (MPU) or microcontroller (MCU) system and a liquid crystal display (LCD). It usually connects to the MPU or MCU system via a standard serial or parallel electronic interface (for example SPI or I2C) LCD Drivers can be discrete chips implemented in standard semiconductor chip packages, with large I/O interconnects to a separate LCD glass via technology like elastomeric connectors or bonded flexible looms. To overcome the very high I/O interconnection requirements of the controller to the glass, the controller chip can be bonded directly to the glass, with the serial interface and power supply being the only I/O connections between glass and PCB required.
Display drivers drive a matrix of liquid crystal dots or segments. The large number of dots extends the feasible number of ports that can be connected to the chip, and to overcome this special method of driving a dot matrix display is implemented. This is achieved by implementing the LCD as an array, or matrix of rows and columns, and driving the rows and columns by special waveform shapes that allow individual dots on each array to be driven by having these waveforms create voltage potentials at periodic, defined times – time multiplexing the array. To do this, each output port can output several voltage levels like a digital to analog converter. The patterns of signals on the LCD Controller ports are predefined to enable driving without contention and operate so as to not damage the LCD.
LCD Controller/Drivers also have stored characters in different language character sets to make driving the display efficient. They also have programmable shape memory, so that they can support user-defined characters. The controller/driver manufacturer will usually provide a generic software driver to enable interfacing to the device. They usually support voltage regulation for changing the port waveform amplitude and controlling the contrast and adapt to different ambient temperatures. They also usually have the inbuilt capability to control backlighting. Read more Read less