I want to tell you about one development of an amplifier based on TPA3251. The amplifier was designed for relatively low power and versatility of assembly and operation.
Main characteristics, measured at a load of 4.7 ohms, 24 V power supply
The LPF filter uses full. diff. OPA1632 OPA. It is possible to connect both balanced and unbalanced. The maximum input voltage is 2Vrms. There is no thunder regulator, so an external one is required. Schematic TPA3251 with PFFB. When setting up the layout, it turned out that the sound quality at the output was unsatisfactory without PFFB, I consider this a necessity. Wima FKP2 are used as capacitors.
The output of TPA3251 uses coils WE 7443631000, capacitors Epcos B32521. The choice of these components is due to the desire to get the highest possible quality despite the price and the occupied area on the PP.
To filter the power supply, an LC filter is installed in front of the capacitor banks to protect the amplifier and the power supply from interference generated from each other. There are 2 power connectors on the board for each channel, for the optional possibility of connecting 2 independent power sources.
DC protection is used built-in from TPA3251 and is active only when BTL is turned on. The maximum PWM frequency of 600 kHz was selected.
As usual, there are seats for some experiments on all my boards, they are simply not installed on the final version.
A few pictures with measurements, they all repeat those that I showed on the layout
In principle, all measurements repeat the limit values and I can say that a miracle did not happen, it will not work out to get a better result than TI at 3251.
Main characteristics, measured at a load of 4.7 ohms, 24 V power supply
- output power 2X30W
- THD+N 1 kHz 0.002%, BW=20khz
- IMD CCIF 19.5kHz, 1k IMD freq - 0.0003%
- SNR 112 db
The LPF filter uses full. diff. OPA1632 OPA. It is possible to connect both balanced and unbalanced. The maximum input voltage is 2Vrms. There is no thunder regulator, so an external one is required. Schematic TPA3251 with PFFB. When setting up the layout, it turned out that the sound quality at the output was unsatisfactory without PFFB, I consider this a necessity. Wima FKP2 are used as capacitors.
The output of TPA3251 uses coils WE 7443631000, capacitors Epcos B32521. The choice of these components is due to the desire to get the highest possible quality despite the price and the occupied area on the PP.
To filter the power supply, an LC filter is installed in front of the capacitor banks to protect the amplifier and the power supply from interference generated from each other. There are 2 power connectors on the board for each channel, for the optional possibility of connecting 2 independent power sources.
DC protection is used built-in from TPA3251 and is active only when BTL is turned on. The maximum PWM frequency of 600 kHz was selected.
As usual, there are seats for some experiments on all my boards, they are simply not installed on the final version.
A few pictures with measurements, they all repeat those that I showed on the layout
In principle, all measurements repeat the limit values and I can say that a miracle did not happen, it will not work out to get a better result than TI at 3251.
