class-D driver chip...

[John Larkin]

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

 

[bitrex]

On 10/30/2020 5:54 PM, John Larkin wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

<https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon>

 

[bitrex]

On 10/30/2020 5:54 PM, John Larkin wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

300 watts is still two-mosfet territory these days if you can boost the
supply to 100.

 

[John Larkin]

On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon

That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.

 

[bitrex]

On 10/30/2020 7:39 PM, John Larkin wrote:

On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.

You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

<https://www.profusionplc.com/featured/icebricks.html>

If it\'s a big-money job $80 won\'t break the bank

 

[server]

On Fri, 30 Oct 2020 19:55:24 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 7:39 PM, John Larkin wrote:
On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.



You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

https://www.profusionplc.com/featured/icebricks.html

If it\'s a big-money job $80 won\'t break the bank

Another bipolar supply half-bridge.

Half-bridges are popular for audio because speakers are mostly ohmic.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[George Herold]

On Friday, October 30, 2020 at 8:58:38 PM UTC-4, jla...@highlandsniptechnology.com wrote:

On Fri, 30 Oct 2020 19:55:24 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 7:39 PM, John Larkin wrote:
On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.



You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

https://www.profusionplc.com/featured/icebricks.html

If it\'s a big-money job $80 won\'t break the bank

Another bipolar supply half-bridge.

Half-bridges are popular for audio because speakers are mostly ohmic.

Not sure I\'m able to tell the difference between full bridge and half.
Is BTL (bridge tied load) full bridge?
I found this on DK
https://www.nxp.com/docs/en/data-sheet/TDA8954.pdf

George H.

--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[server]

On Fri, 30 Oct 2020 21:21:42 -0700 (PDT), George Herold
<ggherold@gmail.com> wrote:

On Friday, October 30, 2020 at 8:58:38 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 19:55:24 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 7:39 PM, John Larkin wrote:
On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.



You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

https://www.profusionplc.com/featured/icebricks.html

If it\'s a big-money job $80 won\'t break the bank

Another bipolar supply half-bridge.

Half-bridges are popular for audio because speakers are mostly ohmic.

Not sure I\'m able to tell the difference between full bridge and half.
Is BTL (bridge tied load) full bridge?
I found this on DK
https://www.nxp.com/docs/en/data-sheet/TDA8954.pdf

George H.

I think that H-bridge, full bridge, and BTL are the same. 4 fets.

Half-bridge only needs two fets, and one side of the load is grounded.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[boB]

On Fri, 30 Oct 2020 21:39:59 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 30 Oct 2020 21:21:42 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Friday, October 30, 2020 at 8:58:38 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 19:55:24 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 7:39 PM, John Larkin wrote:
On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.



You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

https://www.profusionplc.com/featured/icebricks.html

If it\'s a big-money job $80 won\'t break the bank

Another bipolar supply half-bridge.

Half-bridges are popular for audio because speakers are mostly ohmic.

Not sure I\'m able to tell the difference between full bridge and half.
Is BTL (bridge tied load) full bridge?
I found this on DK
https://www.nxp.com/docs/en/data-sheet/TDA8954.pdf

George H.

I think that H-bridge, full bridge, and BTL are the same. 4 fets.

Half-bridge only needs two fets, and one side of the load is grounded.

Is this for full range audio frequencies or is it just for low
frequency ? LF is eaasier to do of course.

 

[server]

On Fri, 30 Oct 2020 22:41:50 -0700, boB <boB@K7IQ.com> wrote:

On Fri, 30 Oct 2020 21:39:59 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 30 Oct 2020 21:21:42 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Friday, October 30, 2020 at 8:58:38 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 19:55:24 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 7:39 PM, John Larkin wrote:
On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.



You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

https://www.profusionplc.com/featured/icebricks.html

If it\'s a big-money job $80 won\'t break the bank

Another bipolar supply half-bridge.

Half-bridges are popular for audio because speakers are mostly ohmic.

Not sure I\'m able to tell the difference between full bridge and half.
Is BTL (bridge tied load) full bridge?
I found this on DK
https://www.nxp.com/docs/en/data-sheet/TDA8954.pdf

George H.

I think that H-bridge, full bridge, and BTL are the same. 4 fets.

Half-bridge only needs two fets, and one side of the load is grounded.



Is this for full range audio frequencies or is it just for low
frequency ? LF is eaasier to do of course.

120 Hz to maybe 4K. This is a 3-phase power supply.

This works,

http://www.highlandtechnology.com/DSS/P900DS.shtml

but I have a customer who needs more power. We\'re using a TI TPA3255
per channel, and it limits at 17 amps. This is rude and crude, so I
figured that an open-loop switcher would be good enough.






--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[boB]

On Sat, 31 Oct 2020 08:07:27 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 30 Oct 2020 22:41:50 -0700, boB <boB@K7IQ.com> wrote:

On Fri, 30 Oct 2020 21:39:59 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 30 Oct 2020 21:21:42 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Friday, October 30, 2020 at 8:58:38 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 19:55:24 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 7:39 PM, John Larkin wrote:
On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.



You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

https://www.profusionplc.com/featured/icebricks.html

If it\'s a big-money job $80 won\'t break the bank

Another bipolar supply half-bridge.

Half-bridges are popular for audio because speakers are mostly ohmic.

Not sure I\'m able to tell the difference between full bridge and half.
Is BTL (bridge tied load) full bridge?
I found this on DK
https://www.nxp.com/docs/en/data-sheet/TDA8954.pdf

George H.

I think that H-bridge, full bridge, and BTL are the same. 4 fets.

Half-bridge only needs two fets, and one side of the load is grounded.



Is this for full range audio frequencies or is it just for low
frequency ? LF is eaasier to do of course.




120 Hz to maybe 4K. This is a 3-phase power supply.

This works,

http://www.highlandtechnology.com/DSS/P900DS.shtml

but I have a customer who needs more power. We\'re using a TI TPA3255
per channel, and it limits at 17 amps. This is rude and crude, so I
figured that an open-loop switcher would be good enough.

WoW ! Cool product !

I am surprised though that it doesn\'t go down to 60 or 50 Hz

I do inverters but they don\'t do the high frequencies that your boxes
do.

More and more inverters and audio amps are HF class D like switchers
these days. I\'m sure that GaN will play a big part in newer class D
amps and especially ones like yours.

 

[server]

On Sat, 31 Oct 2020 13:39:22 -0700, boB <boB@K7IQ.com> wrote:

On Sat, 31 Oct 2020 08:07:27 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 30 Oct 2020 22:41:50 -0700, boB <boB@K7IQ.com> wrote:

On Fri, 30 Oct 2020 21:39:59 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 30 Oct 2020 21:21:42 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Friday, October 30, 2020 at 8:58:38 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 19:55:24 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 7:39 PM, John Larkin wrote:
On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.



You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

https://www.profusionplc.com/featured/icebricks.html

If it\'s a big-money job $80 won\'t break the bank

Another bipolar supply half-bridge.

Half-bridges are popular for audio because speakers are mostly ohmic.

Not sure I\'m able to tell the difference between full bridge and half.
Is BTL (bridge tied load) full bridge?
I found this on DK
https://www.nxp.com/docs/en/data-sheet/TDA8954.pdf

George H.

I think that H-bridge, full bridge, and BTL are the same. 4 fets.

Half-bridge only needs two fets, and one side of the load is grounded.



Is this for full range audio frequencies or is it just for low
frequency ? LF is eaasier to do of course.




120 Hz to maybe 4K. This is a 3-phase power supply.

This works,

http://www.highlandtechnology.com/DSS/P900DS.shtml

but I have a customer who needs more power. We\'re using a TI TPA3255
per channel, and it limits at 17 amps. This is rude and crude, so I
figured that an open-loop switcher would be good enough.



WoW ! Cool product !

I am surprised though that it doesn\'t go down to 60 or 50 Hz

The transformers would have been huge, and the systems that we are
simulating are nominally 400 Hz. Aircraft \"wild power\" is roughly 300
to 800 Hz. Wild is what you get from an APU or a ram air turbine or,
in our case, an engine-driven alternator.

I do inverters but they don\'t do the high frequencies that your boxes
do.

More and more inverters and audio amps are HF class D like switchers
these days. I\'m sure that GaN will play a big part in newer class D
amps and especially ones like yours.

Probably so. GaN switchers can run at many MHz. I don\'t need that now.

We do use the EPC GaN fets in fast pulse generators. It takes some
getting used to a part with essentially zero Cdg and zero lead
inductance. Circuits that look really stupid just work.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[boB]

On Sat, 31 Oct 2020 14:59:20 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Sat, 31 Oct 2020 13:39:22 -0700, boB <boB@K7IQ.com> wrote:

On Sat, 31 Oct 2020 08:07:27 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 30 Oct 2020 22:41:50 -0700, boB <boB@K7IQ.com> wrote:

On Fri, 30 Oct 2020 21:39:59 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Fri, 30 Oct 2020 21:21:42 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Friday, October 30, 2020 at 8:58:38 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 30 Oct 2020 19:55:24 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 7:39 PM, John Larkin wrote:
On Fri, 30 Oct 2020 18:30:54 -0400, bitrex <user@example.net> wrote:

On 10/30/2020 5:54 PM, John Larkin wrote:
I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.


500 watt-capable driver, 1 amp gate drivers, over-current protection,
programmable dead-time, audio input to PWM modulator is on-chip, all the
things. Available at Mouser:

https://www.mouser.com/ProductDetail/Infineon-IR/IRS2092STRPBF?qs=%2Fha2pyFadujIBJtUbZ4qF4PXIOEwi%2F42j2yuWhKJQVxZZQqFtIEPCA%3D%3D&utm_source=octopart&utm_medium=aggregator&utm_campaign=942-IRS2092STRPBF&utm_content=Infineon



That\'s half-bridge. Maybe I can use two of them somehow. I have a
single +48 volt supply.

I was thinking of making an open-loop full-bridge amp.

https://www.dropbox.com/s/hceua8czlkiykni/P902B_Sketch_1.jpg?raw=1

We might not even need the DC balance feedback.

If it\'s beefy enough, we don\'t need to be in any hurry to shut
anything down. It takes a while for transformers and inductors to
melt.



You can also buy class D bricks off-the-shelf that can be customized,
these are about the size of a credit card:

https://www.profusionplc.com/featured/icebricks.html

If it\'s a big-money job $80 won\'t break the bank

Another bipolar supply half-bridge.

Half-bridges are popular for audio because speakers are mostly ohmic.

Not sure I\'m able to tell the difference between full bridge and half.
Is BTL (bridge tied load) full bridge?
I found this on DK
https://www.nxp.com/docs/en/data-sheet/TDA8954.pdf

George H.

I think that H-bridge, full bridge, and BTL are the same. 4 fets.

Half-bridge only needs two fets, and one side of the load is grounded.



Is this for full range audio frequencies or is it just for low
frequency ? LF is eaasier to do of course.




120 Hz to maybe 4K. This is a 3-phase power supply.

This works,

http://www.highlandtechnology.com/DSS/P900DS.shtml

but I have a customer who needs more power. We\'re using a TI TPA3255
per channel, and it limits at 17 amps. This is rude and crude, so I
figured that an open-loop switcher would be good enough.



WoW ! Cool product !

I am surprised though that it doesn\'t go down to 60 or 50 Hz

The transformers would have been huge, and the systems that we are
simulating are nominally 400 Hz. Aircraft \"wild power\" is roughly 300
to 800 Hz. Wild is what you get from an APU or a ram air turbine or,
in our case, an engine-driven alternator.

Oh, OK. I thought you were using HF only so no LF transformer.

You could do that too I suppose. Maybe another product down the road.

I do inverters but they don\'t do the high frequencies that your boxes
do.

More and more inverters and audio amps are HF class D like switchers
these days. I\'m sure that GaN will play a big part in newer class D
amps and especially ones like yours.


Probably so. GaN switchers can run at many MHz. I don\'t need that now.

We do use the EPC GaN fets in fast pulse generators. It takes some
getting used to a part with essentially zero Cdg and zero lead
inductance. Circuits that look really stupid just work.

Yes, these new GaN and SiC parts are awesome and gettng more
affordable all the time.

 

[server]

On Fri, 30 Oct 2020 14:54:43 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

Later on, you said that the load is 3 phase. Is the load a motor ? To
use a full bridge, you would need access to both ends of each winding.

If the motor is fixed wye or delta connected or you are feeding a
wye/delta network, I don\'t see how you could use full bridge, but half
bridge would be OK.

What is the spectral purity requirements for the sine wave ?

 

[server]

On Sun, 01 Nov 2020 10:52:45 +0200, upsidedown@downunder.com wrote:

On Fri, 30 Oct 2020 14:54:43 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

Later on, you said that the load is 3 phase. Is the load a motor ? To
use a full bridge, you would need access to both ends of each winding.

Each class-D amp drives a transformer to make one AC phase. The
outputs usually simulate a 3-phase permanent-magnet alternator. This
is for testing FADECs. A FADEC starts up from aircraft 28 volts DC
but, once the engine spins up, runs off a dedicated PM alternator.

https://www.dropbox.com/s/15ccw3rppygvr5p/Class-D%20_and_toroid.jpg?raw=1

https://www.dropbox.com/s/rdejxjz8a6vbny7/P900_FA_Jun_15.jpg?raw=1

If the motor is fixed wye or delta connected or you are feeding a
wye/delta network, I don\'t see how you could use full bridge, but half
bridge would be OK.

What is the spectral purity requirements for the sine wave ?

Practically none! It\'s just an alternator, which should make an
open-loop class-D amp OK. The waveform from an alternator depends on
the shapes of bits of metal and tends a bit towards the triangular.

The alternator manufacturer claims all the specs are proprietary,
which sure didn\'t help. We had to get one and spin it and measure
stuff.

https://www.dropbox.com/s/oge2hs8sf4jmntl/PB180166.JPG?raw=1






--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[server]

On Sun, 01 Nov 2020 07:15:36 -0800, jlarkin@highlandsniptechnology.com
wrote:

On Sun, 01 Nov 2020 10:52:45 +0200, upsidedown@downunder.com wrote:

On Fri, 30 Oct 2020 14:54:43 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

Later on, you said that the load is 3 phase. Is the load a motor ? To
use a full bridge, you would need access to both ends of each winding.

Each class-D amp drives a transformer to make one AC phase. The
outputs usually simulate a 3-phase permanent-magnet alternator. This
is for testing FADECs. A FADEC starts up from aircraft 28 volts DC
but, once the engine spins up, runs off a dedicated PM alternator.

https://www.dropbox.com/s/15ccw3rppygvr5p/Class-D%20_and_toroid.jpg?raw=1

https://www.dropbox.com/s/rdejxjz8a6vbny7/P900_FA_Jun_15.jpg?raw=1


If the motor is fixed wye or delta connected or you are feeding a
wye/delta network, I don\'t see how you could use full bridge, but half
bridge would be OK.

What is the spectral purity requirements for the sine wave ?


Practically none! It\'s just an alternator, which should make an
open-loop class-D amp OK. The waveform from an alternator depends on
the shapes of bits of metal and tends a bit towards the triangular.

That may be by design. The inductance varies with angular position
too. The varying inductance, high at the voltage peak, probably
smooths the triangle towards sinusoidal current. Clever.

We\'ll make a constant-impedance sine.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Lasse Langwadt Christensen]

søndag den 1. november 2020 kl. 16.15.48 UTC+1 skrev jla...@highlandsniptechnology.com:

On Sun, 01 Nov 2020 10:52:45 +0200, upsidedown@downunder.com wrote:

On Fri, 30 Oct 2020 14:54:43 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

Later on, you said that the load is 3 phase. Is the load a motor ? To
use a full bridge, you would need access to both ends of each winding.

Each class-D amp drives a transformer to make one AC phase. The
outputs usually simulate a 3-phase permanent-magnet alternator. This
is for testing FADECs. A FADEC starts up from aircraft 28 volts DC
but, once the engine spins up, runs off a dedicated PM alternator.

https://www.dropbox.com/s/15ccw3rppygvr5p/Class-D%20_and_toroid.jpg?raw=1

https://www.dropbox.com/s/rdejxjz8a6vbny7/P900_FA_Jun_15.jpg?raw=1


If the motor is fixed wye or delta connected or you are feeding a
wye/delta network, I don\'t see how you could use full bridge, but half
bridge would be OK.

What is the spectral purity requirements for the sine wave ?


Practically none! It\'s just an alternator, which should make an
open-loop class-D amp OK. The waveform from an alternator depends on
the shapes of bits of metal and tends a bit towards the triangular.

The alternator manufacturer claims all the specs are proprietary,
which sure didn\'t help. We had to get one and spin it and measure
stuff.

https://www.dropbox.com/s/oge2hs8sf4jmntl/PB180166.JPG?raw=1

so a couple of irxxxx type half bridge drivers some beefy fets and
a few pins doing PWM on a MCU would do?

not that different from a BLDC driver except you don\'t need at the
stuff to do sensor-less commutation

 

[John Larkin]

On Sun, 1 Nov 2020 07:59:11 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

søndag den 1. november 2020 kl. 16.15.48 UTC+1 skrev jla...@highlandsniptechnology.com:
On Sun, 01 Nov 2020 10:52:45 +0200, upsidedown@downunder.com wrote:

On Fri, 30 Oct 2020 14:54:43 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

Later on, you said that the load is 3 phase. Is the load a motor ? To
use a full bridge, you would need access to both ends of each winding.

Each class-D amp drives a transformer to make one AC phase. The
outputs usually simulate a 3-phase permanent-magnet alternator. This
is for testing FADECs. A FADEC starts up from aircraft 28 volts DC
but, once the engine spins up, runs off a dedicated PM alternator.

https://www.dropbox.com/s/15ccw3rppygvr5p/Class-D%20_and_toroid.jpg?raw=1

https://www.dropbox.com/s/rdejxjz8a6vbny7/P900_FA_Jun_15.jpg?raw=1


If the motor is fixed wye or delta connected or you are feeding a
wye/delta network, I don\'t see how you could use full bridge, but half
bridge would be OK.

What is the spectral purity requirements for the sine wave ?


Practically none! It\'s just an alternator, which should make an
open-loop class-D amp OK. The waveform from an alternator depends on
the shapes of bits of metal and tends a bit towards the triangular.

The alternator manufacturer claims all the specs are proprietary,
which sure didn\'t help. We had to get one and spin it and measure
stuff.

https://www.dropbox.com/s/oge2hs8sf4jmntl/PB180166.JPG?raw=1


so a couple of irxxxx type half bridge drivers some beefy fets and
a few pins doing PWM on a MCU would do?

IRS2108 maybe. Analog/Linear have some parts, but they are expensive
and weird. The upside is the LT Spice models, and the downside is that
the models only cover some of the parts and seem to be pretty bad when
they do. I suppose something this simple doesn\'t really need to be
simulated.

The existing board accepts a differential analog input, so I\'ll have
to do the PWM myself. Probably a classic triangle generator and a
comparator. Maybe a slow DC servo to make sure there isn\'t much offset
between the half bridges. Maybe even a trimpot for offset.

I\'m driving a big toroidal transformer that really doesn\'t want to see
any DC on its primary. So we have 60 mF of DC block caps, 6V
electrolytics, that wouldn\'t like much DC either, especially in the
reverse direction.

not that different from a BLDC driver except you don\'t need at the
stuff to do sensor-less commutation

Nope, dumb open-loop PWM is probably good enough. The easiest control
loop to stabilize is no loop.

 

[George Herold]

On Sunday, November 1, 2020 at 10:15:48 AM UTC-5, jla...@highlandsniptechnology.com wrote:

On Sun, 01 Nov 2020 10:52:45 +0200, upsidedown@downunder.com wrote:

On Fri, 30 Oct 2020 14:54:43 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

Later on, you said that the load is 3 phase. Is the load a motor ? To
use a full bridge, you would need access to both ends of each winding.

Each class-D amp drives a transformer to make one AC phase. The
outputs usually simulate a 3-phase permanent-magnet alternator. This
is for testing FADECs. A FADEC starts up from aircraft 28 volts DC
but, once the engine spins up, runs off a dedicated PM alternator.

https://www.dropbox.com/s/15ccw3rppygvr5p/Class-D%20_and_toroid.jpg?raw=1

https://www.dropbox.com/s/rdejxjz8a6vbny7/P900_FA_Jun_15.jpg?raw=1


If the motor is fixed wye or delta connected or you are feeding a
wye/delta network, I don\'t see how you could use full bridge, but half
bridge would be OK.

What is the spectral purity requirements for the sine wave ?


Practically none! It\'s just an alternator, which should make an
open-loop class-D amp OK. The waveform from an alternator depends on
the shapes of bits of metal and tends a bit towards the triangular.

The alternator manufacturer claims all the specs are proprietary,
which sure didn\'t help. We had to get one and spin it and measure
stuff.

https://www.dropbox.com/s/oge2hs8sf4jmntl/PB180166.JPG?raw=1

I know little of 3 phase, but watching machinists flip the
spindle on a mill back and forth it\'s gotta both give and
take power... maybe your gizmo doesn\'t need to do that?

In the distant past I helped run a helium liquifier,
whose brake on the expansion engine was to send power
back into the AC line... 3-phase motor/ generator.

George H.

--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Lasse Langwadt Christensen]

mandag den 2. november 2020 kl. 19.18.57 UTC+1 skrev John Larkin:

On Sun, 1 Nov 2020 07:59:11 -0800 (PST), Lasse Langwadt Christensen
langwadt@fonz.dk> wrote:

søndag den 1. november 2020 kl. 16.15.48 UTC+1 skrev jla...@highlandsniptechnology.com:
On Sun, 01 Nov 2020 10:52:45 +0200, upsidedown@downunder.com wrote:

On Fri, 30 Oct 2020 14:54:43 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:

I may have to design a 300 watt or so full-bridge class D amp. I want
a driver chip that will drive four big mosfets, 48 volt supply.

I got excited about LM4651, which accepted an audio input and did all
the PWM and feedback stuff, but it turns out to be obsolete.

Does anyone here design class-D amps? Any favorite chips, full-bridge
drivers or more? Current limiting looks like a nuisance.

Later on, you said that the load is 3 phase. Is the load a motor ? To
use a full bridge, you would need access to both ends of each winding..

Each class-D amp drives a transformer to make one AC phase. The
outputs usually simulate a 3-phase permanent-magnet alternator. This
is for testing FADECs. A FADEC starts up from aircraft 28 volts DC
but, once the engine spins up, runs off a dedicated PM alternator.

https://www.dropbox.com/s/15ccw3rppygvr5p/Class-D%20_and_toroid.jpg?raw=1

https://www.dropbox.com/s/rdejxjz8a6vbny7/P900_FA_Jun_15.jpg?raw=1


If the motor is fixed wye or delta connected or you are feeding a
wye/delta network, I don\'t see how you could use full bridge, but half
bridge would be OK.

What is the spectral purity requirements for the sine wave ?


Practically none! It\'s just an alternator, which should make an
open-loop class-D amp OK. The waveform from an alternator depends on
the shapes of bits of metal and tends a bit towards the triangular.

The alternator manufacturer claims all the specs are proprietary,
which sure didn\'t help. We had to get one and spin it and measure
stuff.

https://www.dropbox.com/s/oge2hs8sf4jmntl/PB180166.JPG?raw=1


so a couple of irxxxx type half bridge drivers some beefy fets and
a few pins doing PWM on a MCU would do?

IRS2108 maybe. Analog/Linear have some parts, but they are expensive
and weird. The upside is the LT Spice models, and the downside is that
the models only cover some of the parts and seem to be pretty bad when
they do. I suppose something this simple doesn\'t really need to be
simulated.

The existing board accepts a differential analog input, so I\'ll have
to do the PWM myself. Probably a classic triangle generator and a
comparator. Maybe a slow DC servo to make sure there isn\'t much offset
between the half bridges. Maybe even a trimpot for offset.

I\'m driving a big toroidal transformer that really doesn\'t want to see
any DC on its primary. So we have 60 mF of DC block caps, 6V
electrolytics, that wouldn\'t like much DC either, especially in the
reverse direction.


not that different from a BLDC driver except you don\'t need at the
stuff to do sensor-less commutation

Nope, dumb open-loop PWM is probably good enough. The easiest control
loop to stabilize is no loop.

https://www.st.com/resource/en/datasheet/stspin32f0252.pdf

and some FETs ...