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Class D Switching Power Amplifiers and Power D/A conversion

BTL Bridge?
BTL Bridge?
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Old 12th March 2015, 05:18 PM   #1
martinpoldoja is offline martinpoldoja  Estonia
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Default BTL Bridge?

So, I've been looking for a straight answer for this, but every one of them is over-complicated (maybe I'm just dumb ).

If I buy a class D amp with 2 channels and BTL (like the one below), how do I bridge the two channels into one speaker? Basically I would like to know which wire goes to where.

New TDA7492 D Class High Power Digital Amplifier Board 2X50W Amp Board Radiator | eBay

Thanks
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Old 12th March 2015, 05:32 PM   #2
lutkeveld is offline lutkeveld
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You can't. You can use it in PBTL, tie + and - together respectively and connect to the speaker. This way you can drive speakers with half the impedance you could drive in stereo mode.
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Old 12th March 2015, 06:01 PM   #3
martinpoldoja is offline martinpoldoja  Estonia
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Quote:
Originally Posted by lutkeveld View Post
You can't. You can use it in PBTL, tie + and - together respectively and connect to the speaker. This way you can drive speakers with half the impedance you could drive in stereo mode.
Do you mean like that? And how do I connect the speaker?
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Old 12th March 2015, 06:36 PM   #4
martinpoldoja is offline martinpoldoja  Estonia
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And also, what does BTL do excatly then? Because in the description of the amp, it says:
Maximum power:50W*2/8Ohm
Mono BTL power 100W / 4 Ohms
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Old 12th March 2015, 07:14 PM   #5
gmarsh is offline gmarsh  Canada
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The TDA7492 can't be configured in PBTL mode.

Even if you could do it that way, what's the point? If you have a 4 ohm speaker, your maximum output power is going to be limited by your maximum 24V supply. If you want more power, get a higher power amp.
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Old 12th March 2015, 08:57 PM   #6
martinpoldoja is offline martinpoldoja  Estonia
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Well, I have a leftover 100W RMS/550W MAX 4-way car speaker and I just want to get as much power out of it as I can for home use, but I don't want to spend much. <30$ would be good. So, what's the best option?
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Old 12th March 2015, 09:03 PM   #7
martinpoldoja is offline martinpoldoja  Estonia
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I've also looked into 1-channel class D amps (obviously), but everyone, I've seen so far require dual power supply for both positive and negative DC, and as far as I've researched, that's pretty hard/expensive to do.
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Old 11th January 2017, 10:01 AM   #8
nicasiox2 is offline nicasiox2  United States
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Quote:
Originally Posted by gmarsh View Post
The TDA7492 can't be configured in PBTL mode.

Even if you could do it that way, what's the point? If you have a 4 ohm speaker, your maximum output power is going to be limited by your maximum 24V supply. If you want more power, get a higher power amp.
It seems TDA7492 does support PBTL. and you need about 19v for about 100w on a 4ohm load with pbtl setting, which is really convenient because you can use a notebook power supply and get more power than using a tpa3116 with the same power supply, that's what I have read today, maybe going to buy it a tda7492 because I already have some notebook psus.
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Old 12th January 2017, 02:37 AM   #9
DUG is offline DUG  Canada
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Quote:
Originally Posted by nicasiox2 View Post
It seems TDA7492 does support PBTL. and you need about 19v for about 100w on a 4ohm load with pbtl setting, which is really convenient because you can use a notebook power supply and get more power than using a tpa3116 with the same power supply, that's what I have read today, maybe going to buy it a tda7492 because I already have some notebook psus.
19V and 100W for 4R?

I calculate (without clipping) and using full 19V swing (not likely) into 4R you cannot get more than 45W.

Fig 20 shows 20V 4R @1% dist is about 34W. (but says 38W in text)

Could you please help me find the information you have about supporting PBTL for the TDA7492. I cannot seem to find anything in the data sheet.

http://www.st.com/content/ccc/resour...CD00205863.pdf

Or do you mean just hooking the + outputs together and the - outputs together and hope that the channel matching between the two is much better than the +/-1dB listed in the data sheet. If the channels you are paralleling have 2dB difference in gain then they will be fighting each other.

Not recommended.

Good luck.
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Last edited by DUG; 12th January 2017 at 02:43 AM.
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