Datasheet, https://www.ti.com/lit/ds/symlink/o...Match%3DOPA455%26tisearch%3Dsearch-everything , figures 6-30 and 6-31. The ability of the OPA455 output to get close to the rail voltages. This is an important issue for class AB amplifiers because it adds power losses in the output transistors compared to the clipping level. Can be compensated by using a higher supply voltage for the OP-AMP than for the output stage but then the complexity of the supply is increased.
could one "bootstrap" the supply of the opa as its not a lot of current ? could be done with two diodes , two capacitors and a few resistors?
That way the losses are limited to those of the power stage itself.
Could be done with a voltage doubler at the mains transformer for two diodes and two caps ??
Could be done by adding a few thin windings to the Toroid by hand with thin wire ( DiY ! ) ??
That way the losses are limited to those of the power stage itself.
Could be done with a voltage doubler at the mains transformer for two diodes and two caps ??
Could be done by adding a few thin windings to the Toroid by hand with thin wire ( DiY ! ) ??
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One could do several things to provide a slightly higher voltage for the OPA455 to operate from. You mention several such possibilities. However, there is an important alternative to consider. Mainly in the past, class AB audio ICs including an output driver stage, but not including the actual power transistors, were popular and some (LME49810/30) had significantly better audio performance than the OPA455. Some are still available today. Thus, if you use one of these dedicated audio ICs, known since long, instead of a OPA455 with modification of the power supply, you probably end up with a significantly better audio performance.
Your consideration of OPA455 for a class AB power amplifier design is good training of your creativity. But, in the end you have to perform a "sanity check" against other types of solutions and there I am not sure the OPA455 is a winner.
Your consideration of OPA455 for a class AB power amplifier design is good training of your creativity. But, in the end you have to perform a "sanity check" against other types of solutions and there I am not sure the OPA455 is a winner.
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I´m not sure myself . Just trying to find a way to drive power-opamps rail to rail when used as a power-stage........I guess if I could cut a TDA7293 in half to get at its driving stage that might do. Unfortunately there is no pin to that so no way to do it that I can see, unless I use a TDA7293 to drive another TDA7293.
But one would have to check what happens when two of those work as master/slave on pin 11 as that must be the one to drive the power-stage of the slave I´ll have to dig into that.....maybe one can use the input and vas inside the TDA to drive another chip somehow
But one would have to check what happens when two of those work as master/slave on pin 11 as that must be the one to drive the power-stage of the slave I´ll have to dig into that.....maybe one can use the input and vas inside the TDA to drive another chip somehow
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