TDA4780

The TDA4780 is a monolithic integrated circuit with a luminance and a colour difference interface for video processing in TV receivers. Its primary function is to process the luminance and colour difference signals from a colour decoder which is equipped e.g. with the multistandard decoder TDA4655 or TDA9160 plus delay line TDA4661 or TDA4665 and the Picture Signal Improvement (PSI) IC TDA467X or from a feature module. The required input signals are:

· Luminance and negative colour difference signals

· 2 or 3-level sandcastle pulse for internal timing pulse generation

· I2C-bus data and clock signals.

Two sets of analog RGB colour signals can also be inserted, e.g. one from a peritelevision connector (SCART plug) and the other one from an On-Screen Display (OSD) generator. The TDA4780 has I2C-bus control of all parameters and functions with automatic cut-off control of the picture tube cathode currents. It provides RGB output signals for the video output stages. In clamped output mode it can also be used as an RGB source.

The main differences with the sister type TDA4680 are:

· Additional features, namely gamma adjust, adaptive black, blue stretch and two different peak drive limiters

· The measurement lines are triggered by the trailing edge of the vertical component of the sandcastle pulse

· I²C-bus receiver only. Automatic white level control is not provided; the white levels are determined directly by the I2C-bus data.

· The TDA4780 is pin compatible (except pin 18) with the TDA4680. The I2C-bus slave address can be used for both ICs. When a function of the TDA4780 is not included in the TDA4680, the I2C-bus command is not executed. Special commands (except control bit FSWL) for the TDA4680 will be ignored by the TDA4780.