TEA2028

As depicted in Figure 1, the TEA2028 combines 3 major functionsof a TV set as follows : - Horizontal (line) and vertical (frame) time base generation for spot deviation. The video signal is used for the synchronization of both time bases. - On-chip switching power supply controller synchronized on line frequency.

This integrated circuit has been implemented in bipolar I²L technology, and various functions are digitally processed. In fact, resorting to logic functions has the advantage of working with pure and accurate signals while full benefit is drawn from high integration of logic gates (approx. 110 gates per mm²).

The main objective is to drive all functions using an accurate time base generated by a master 500kHz oscillator.

Also, horizontal and vertical time bases, are obtained by binary division of reference frequency. This has the advantage of eliminating the 2 adjustments which were necessary in former devices.

One section of this integrated circuit is designed to drive a switching power supply of recent implementation called "master-slave". Switching takes place on the primary side (i.e., directly on mains) of a transformer. The device ensures SMPS Control, Start-up and Protection functions.Control signals go through a small pulse transformer thereby providing full isolation from mains supply.

This new approach fully eliminates the bulky mains transformersused in the past. In addition, it offers optimized power consumption and reduction of TV cost-price.