We are going to make a TDA7297 stereo amplifier circuit, before that we need to know something about the TDA7297 stereo amplifier IC.
The TDA7297 is an amplifier component having dual bridge amplifier in build in it, and also they having standby and mute function with in the device.
It is a low-power stereo amplifier circuit having very few components onboard, this is a specialty of the TDA7297 IC and also having many protection systems in the device.
TDA7297 Application diagram
This is the application circuit given in the TDA7297 datasheet, at the diagram we can see the internal components of the TDA7297.
Four op-amps are used in the amplifier IC for the two outputs, then standby and mute functions are built with reference input of the device. We can these TDA7297 amplifiers as dual amplifiers due to both the op-amp combination, the amplifier will work as a bridge amplifier.
TDA7297 amplifier circuit diagram
This is a very simplified amplifier circuit using TDA7297 IC, this is a circuit taken from the application circuit of the TDA7297 datasheet.
But this circuit indicates many fixed values such as supply voltage and other passive components at the circuit, this circuit only works as a bridge amplifier.
TDA7297 stereo amplifier circuit
This is the circuit for low power stereo amplifier using TDA7297 IC, it is powered by a single polarity power supply or single power supply.
An input filtering component is added on both sides of the amplifier at the application circuit.
Working of amplifier
- The R1 and R4 resistor are the input resistor for both left and right sides of the amplifier signal lines.
- The R2, C4, and R3, C7 network is the low pass filter circuit, at this circuit we have a 3db cut-off for each side of the amplifier.
- And the C5 and C6 coupling capacitors will block DC incoming and they provide 30kΩ input impedance for the amplifier circuit.
- Then they combined to form a high filter at the input of the amplifier circuit.
- R5, R6, and C8 are used to provide standby and mute delay current to the amplifier board.
- Both the op-amp comparator produces two different audio output at this stereo amplifier.
TDA7297 power supply
For the TDA7297 power supply, we have two options to set power supply, first one is using a 12v transformer with 5A diodes as a rectifier circuit.
And next option is to connect 15Vdc SMPS with 4A for the amplifier board.
TDA7297 Heat sink
The heat sink for the TDA7297 stereo amplifier circuit is a must, we recommend a 2-inch heat sink for the amplifier.
Applications of TDA7297 stereo amplifier
- At Television audio section
- Portable radio sets
- Bluetooth amplifier speakers