Chip removes LCD flicker

STMicroelectronics' STVM100 Vcom calibrator chip can be designed into the TV set, allowing this Vcom adjustment to be made through the I2C interface.

STMicroelectronics has released a programmable Vcom calibrator chip, with I2C serial interface, that simplifies the process of removing flicker from TFT (thin-film transistor) LCD panels during manufacture.

The new STVM100 enables the adjustment to be automated through use with ST's proprietary Auto Flicker Detection solution, along with reducing labour costs and increasing product reliability by eliminating the need for mechanical potentiometers.

TFT-LCD panels have an inherent flicker that is eliminated in production by accurate adjustment of Vcom, or "common voltage" around the midpoint of the AVDD.

Instead of using a traditional potentiometer, the STVM100 Vcom Calibrator can be designed into the TV set, allowing this manufacturing adjustment to be made through the I2C interface, either through an operator control or as part of an automated process.

Once the desired Vcom setting is found, its value can be stored in the internal EEPROM of the STVM100.

This ensures the TV can recall the calibration value automatically whenever the TV is turned on.

The EEPROM can be programmed repeatedly, giving LCD manufacturers the flexibility to calibrate the display panel as many times as the production process requires.

The chip provides 128 steps of Vcom adjustment, with three external resistors determining the highest and lowest values.

It is available now in volume, in eight-pin 3 x 3mm TDFN8 or 3 x 3mm TSSOP8 packages.

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