Class D Sabove

This design was originally designed simply to understand that in reality it is possible to obtain from a Class D ensemble. Of course, the first thought was to find some prototype, but long searches on the Internet didn't give anything but the phrase, "Let's do it on TL494!" but there were no schemes anywhere. It was not possible to collect on a specialized integration scheme (TDA8920) because of its expensive and low capacity and the limited output capacity of such a force. Anyway, I had to make up for myself.

At first, I wanted to make a surgeon, based on UC3842/3843, and to use a powerful exit cascade on field tranches of a different structure, for example, as in the famous Schrytek book (page 231). This weekend cascade was also used in a design published recently in Radio magazine. The obvious advantage of such a cascade is simplicity, but there are significant shortcomings. First, there is a need for bipolar meals, secondly, possibly through tranzistors, thirdly, transistors of different structures have different resistance from the canal in open sympathies, which requires a different number of transistors in shoulders (p-canal transistors need to be placed more) and this leads to a substantial design. All enumerated results in the fact that this output cascade does not actually have a greater power.

In view of the reasons set out, it was decided to make a bridge cascade on the n-canal tranches. Despite the fact that such a cascade requires the use of sufficiently expensive divers (i have applied IR2110), it is free from all the shortcomings of the cascade ' s mere output, in particular by using such a scheme to increase the output power by increasing the power of the power supply, and at the power of the exit cascade to 70-80 volts, low-cost key tranches can be used, e.

With regard to the SIM moderator, two options were considered: UC3843 and TL494. UC3843 is very good, as it can be used by high tactical frequencies, but unfortunately it has a one-phase exit, so to use it to feed a two-stroke cascade, it would have to be a few more external elemens to invert the output signal, in the simplest case, a trench key, and better than another layer of logic. By contrast, UC3843, TL494 does not allow tactical frequencies above 300 KGz (by passport, and real and 100 KGs are not so smooth), but it contains everything within itself necessary to defuse the control unit by limiting itself to several passive components in the connection. That's why I thought, Make the force TL494.