TPA3255: TPA3255 1 x BTL

erkan özden

Part Number: TPA3255
Other Parts Discussed in Thread: NE5532, OPA1632

Hello;

In latest TPA3255 datasheet Table 1. I saw new added 1 xBTL option. So In this configration typical application figure is not exist in datasheet.

1) If i go with this configration what i am going to do with OUT_C (pin 32), PVDD_CD (pin 29, 30 , 31), OUT_D (pin 27, 28), BTS_C (Pin 24) , BTS_D (pin 23)

2) Both PBTL and 1x BTL are working mono mode so what advantages 1X BTL has over PBTL?

over 6 years ago

0 Sam(MPAA) Zhang over 6 years ago

TI__Mastermind 19080 points

Hi,

1. I would recommend to float the OUT_x pins, and keep the bootstrap caps across the OUT_x and the BST_x pins.

2. I didn't see much benefit for 1BTL... except easier routing, lower idle power loss...

Thanks!

Regards,

Sam

0 erkan özden over 6 years ago in reply to Sam(MPAA) Zhang

Prodigy 140 points

Thanks. In datasheet PBTL is adviced for 2-4 ohms. But hifi speaker mainly 4-8 ohms. My main target is hifi. So do you think 1x BTL outperforms than PBTL for 8 ohms? Or PBTL is better in every aspect except if we ignore more part count and harder trace routing.

0 Sam(MPAA) Zhang over 6 years ago in reply to erkan özden

TI__Mastermind 19080 points

Hi,

What's the target output power? In most cases the PBTL distribute the current flow between the two parallel channels, decreasing the RMS current thus usually has higher efficiency in mid and high power applications.

PBTL is used to drive lower resistance speakers as where needs more current. There is no problem to drive larger resistance with PBTL.

Thanks!

Regards,

Sam

0 erkan özden over 6 years ago in reply to Sam(MPAA) Zhang

Prodigy 140 points

Hello Mr. Zhang;

Target output is 150-W into 8 Ω. I know this is possible with 2x BLT but we believe that PBLT has more control on speakers due to mono configuration.

We are using opa1632 as input instead of dual NE5532 as suggested in audio interface board. Also, with help of opa1632 12dB gain configuration we planning to eliminate the dB / gain penalty due to PFFB (post filter) configuration.

Now our main issue is, there is no PFFB implementation schematic or guide for PBLT + OPA1632 in PFFB datasheet. Only exist for NE5532 opams + BLT configuration. So, we do not know how to implement in a correct way. I wish you could help us.

Thanks in advance.

0 erkan özden over 6 years ago in reply to erkan özden

Prodigy 140 points

Please see the sketch i made regarding to question here above post.

I am glad if you can correct or confirm PFFB configration and fill the values with red question marked.

0 Sam(MPAA) Zhang over 6 years ago in reply to erkan özden

TI__Mastermind 19080 points

Hi,

For the PFFB configuration, please refer to below document,

It's a good start point and fine tuning can be further done. Thanks!

Regards,

Sam

0 erkan özden over 6 years ago in reply to Sam(MPAA) Zhang

Prodigy 140 points

Mr. Zhang;

We already read all the datasheet. As i wrote you here above, there is no PFFB implementation schematic or guide for PBLT + OPA1632 in PFFB datasheet. Only exist for NE5532 opams + BLT configuration. If you look at sample implementation picture (2 post above) example that we made with our guess. I ask you to correct or confirm PFFB configration and fill the values with red question marked.