I'm trying to figure out where the voltage boost comes from in the SMPS side of this audio amplifier.
In this case, the output stage is capable of 180w RMS into a 4-ohm load with a 1kHz sine wave. If my math is right this requires about 38Vpp. The input to the SMPS is 14v DC. I get that it uses a oscillator and some MOSFETs to create AC, and I was expecting to see a step-up transformer before it's rectified back into DC, but I don't see any sizable transformer at all? Can someone fill me in on how the voltage is boosted in this case? Is it likely that the larger toroid is wound like a transformer? Is it possibly charging the large caps in parallel, then switching them to series to get a voltage boost?
Here's a picture of the SMPS side of it, I unfortunately don't have an accurate schematic which is part of my confusion.
In this case, the output stage is capable of 180w RMS into a 4-ohm load with a 1kHz sine wave. If my math is right this requires about 38Vpp. The input to the SMPS is 14v DC. I get that it uses a oscillator and some MOSFETs to create AC, and I was expecting to see a step-up transformer before it's rectified back into DC, but I don't see any sizable transformer at all? Can someone fill me in on how the voltage is boosted in this case? Is it likely that the larger toroid is wound like a transformer? Is it possibly charging the large caps in parallel, then switching them to series to get a voltage boost?
Here's a picture of the SMPS side of it, I unfortunately don't have an accurate schematic which is part of my confusion.