TPA3255:TPA3255 Problems with output connection in PBTL.

hi, 

can you kindly share me the schematic for refer? that can better help me understand you problems.

tks

jesse

Hello, good afternoon.
Here is a simplified diagram of how I need the connections.
Even without the loads being connected, and the inputs also disconnected, the fault occurs.

Here is the link with the simplified diagram.

Thank you.

drive.google.com/.../view

Hello,

A few things. Your schematic shows 2 ohm loads which is fine but your message say 1 ohm load which is out of spec for TAS3255. 

What are your referring to when you say (- NEG. TPA3255)? 

If the issue is resolved when using individual power supplies but present when using one common supply, I would say the issue is rooted in the power supply. Are you able to try different and or larger power supplies for the system?  

Regards,
Sydney Northcutt

Hello Sydney Northcutt, thank you for your attention.

When I said with a 1 Ohm load, it was the test performed with only one isolated amplifier (PBTL), and it worked perfectly with a 1 Ohm load, but it will work with 2 Ohms.

Regarding the (- NEG TPA3255) it is a designation for the output line (OUT D + OUTB in PBTL).

When I reported that with separate sources it worked perfectly, I made an analysis error, not paying attention to the outputs on the oscilloscope, but unfortunately when using separate sources the system still presents the fault, causing the shutdown.

When connecting the output lines after the LC filter (OUTD + OUTB amp 1 and amp 2 both in PBTL mode), even using a single or individual source, the faults and the following events occur.

I connected the FALUT and CLIP_OTW pins to the oscilloscope. CLIP_OTW is always at 1, and FALUT pulsates between 1 and 0 when reset. According to the manual (Overload (OLP) or undervoltage (UVP). Junction temperature lower than 125°C). However, there is no load attached.

* Fault signal -> 0, after RESET the fault signal -> 1 and then goes to 0 again and remains pulsating, showing that the fault signal is going to 0 and after reset it goes up to 1 and returns to 0.

I am on a business trip away from the lab, I will be back next week.

Here is a new diagram of the tests performed.

Link:

drive.google.com/.../view

Thank you for attention.

Hello,

Sorry I did not realize in the original schematic that you have the negative outputs connected. What is the purpose of this? If you break this connection between devices is the output correct? 

Regards,
Sydney Northcutt 

Hello Sydney.

I need it to be able to operate with the negative outputs connected, since these 4 amplifiers will be responsible for supplying alternating current to perform laboratory tests on electrical measurement and protection equipment, where the connections are often with the star point connected and common, and cannot be opened. 

In this case, the system consists of 8 sinusoidal signals generated by a dedicated DDS, with adjustable frequency, phase and amplitude, with 4 channels for voltage generation and 4 channels for current generation. 

Therefore, I only need the 4 current channels to be able to work with the negative point connected and in common. 

Here is the link to a simplified diagram of the device to be assembled using 4 TPA3255 amplifiers:

https://drive.google.com/file/d/1nWEt0HlBY0qDj1JMFKPTsqqXVbL0h4P_/view?usp=drive_link

Hello,

Responses will be delayed due to US Holiday. Thank you for your patience!

Regards,
Sydney Northcutt