I have been looking at how some plate amplifiers get their power and how they function. I have been playing with Klipsch plate amplifier power supples. From what I have learned they use a self oscilating push pull AC/DC converter. This converter feeds what looks to be a buck converter to keep the rails at the needed levels to provide output. (class G or H?) I would like to learn how this works and use this setup for development.
If I ignore the initial AC/DC converter and just focus on the buck I will learn alot. I have ~90VDC that I would like to bring down to 48VDC. 1:2 should be easy to obtain with a simple buck and will not require any modifications to the existing transformer. This will also allow for a regulated output similar to the origonal design.
I am able to understand the component calculations but I do not know what exactly I need to control this.
My assumptions are that I will need a small switchmode regulator to power the controller but I do not see any controllers that show a setup like this. I see that there are some 100V controllers out there but I have measured excess of 108VDC on the output with no load. The input voltage for the buck will range from 65V to 110V.
Texas Instruments provides some design tools to give a starting point for the passive components but I do not know where to start with the switching controller, especially if the controller will require a seperate supply.
I have been looking at the following controller and similar others but they do not have an application that shows a simple buck.
AC/DC and Isolated DC/DC Power Supply - PWM and Resonant Controller - UCC38C40 - TI.com
I may not be doing this the correct way, so I am asking someone with greater knowledge to provide me some input.
The goal of the project is to use this power supply to power a TAS5630
If I ignore the initial AC/DC converter and just focus on the buck I will learn alot. I have ~90VDC that I would like to bring down to 48VDC. 1:2 should be easy to obtain with a simple buck and will not require any modifications to the existing transformer. This will also allow for a regulated output similar to the origonal design.
I am able to understand the component calculations but I do not know what exactly I need to control this.
My assumptions are that I will need a small switchmode regulator to power the controller but I do not see any controllers that show a setup like this. I see that there are some 100V controllers out there but I have measured excess of 108VDC on the output with no load. The input voltage for the buck will range from 65V to 110V.
Texas Instruments provides some design tools to give a starting point for the passive components but I do not know where to start with the switching controller, especially if the controller will require a seperate supply.
I have been looking at the following controller and similar others but they do not have an application that shows a simple buck.
AC/DC and Isolated DC/DC Power Supply - PWM and Resonant Controller - UCC38C40 - TI.com
I may not be doing this the correct way, so I am asking someone with greater knowledge to provide me some input.
The goal of the project is to use this power supply to power a TAS5630
Indigo Bash is the manufacturer of the origonal amp. They use this front end on alot of their models. I do not have an output current but I could do some testing if it is required information. Woud a schematic be more helpful?
I tried web bench from ti.com to design the buck converter but it could not design this voltage range.
I did the same thing. This is due to the fact that almost all of their controllers are powered from the input. That is also why I was thinking of using an aux supply to power the controller. I will try to make a schematic of the original buck and see how it works. If I draw it up maybe I can spice simulate it or someone can decode the functionality of it.
There are plenty of buck design documents around. The problem is the control loop is almost always left out of the design. You can not just copy values for it from the old one.
Google for this "design buck converter".
Google for this "design buck converter".
You could try a LLC resonant SMPS.
This can be buck or boost.
There are IC's out there to do the job.
IRS27951 is one I have used with some success if you dont mind SMD.
Sorry just read your post again and LLC doesn't like variable input voltages.
This can be buck or boost.
There are IC's out there to do the job.
IRS27951 is one I have used with some success if you dont mind SMD.
Sorry just read your post again and LLC doesn't like variable input voltages.
I am still working on reverse engineering the original design. I know that I will not be able to easily adapt it to my needs but I will at least be able to see what control loop was used and how the circuit functioned.
A lot of SMPS designs use a comparator with a sawtooth waveform on one input and a sample of the output voltage on the other. As the output voltaqe varies so does the Mark/Space ratio of the SMPS. AKA Pulse Width Modulation.
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