TDA7379 amplifier IC or equivalent TDa7377, TDA7375 or ST540, stereo bridge, dual mono, power amplifier circuit diagram and pre amplifier with NE5532. Circuit to be used in stereo speaker systems, added preamplifier to raise the level of the input signal and take the maximum power from the power CIS.
Circuit to be used in stereo speaker systems, added preamplifier to raise the level of the input signal and take the maximum power from the power CIS.
About the circuit
R10/C14 and R12/C5 form a low pass filter to eliminate possible high frequency signals in our circuit, of course you can adapt the filter to your needs. IC1 Ne5532 is our preamplifier, using the non-inverter configuration we have gained about 4 times, that is, for a 50mV signal at the input we will have about 200mV at the output, enough to raise the signal of Bluetooth modules and the like. Of course you can change the relationship between R2/R4 and R3/R8 and we change the gain more or less, according to the application. Just for example, changing the resistor from 15K to 47K will have a gain of 11X, for 10K we will have a gain of 3X. Rounded values. IC3, 7812, is the voltage regulator for having 12V stabilized to power the IC NE5532.
The signal is coupled to the TDA7379 via C1 and C6, as the input impedance of this CI is about 10K to 15K in Bridge mode, our high pass filter will be 10 to 15Hz using a 1uF capacitor, of course, if necessary, it can also be changed the capacitor to a higher value and “lower” the cutoff frequency. As we are using polyester capacitors instead of electrolytic. Polyester capacitors are more expensive at higher capacitance values. Nor does anything prevent using electrolytic capacitors in position. Although 10Hz is enough for applications for which the amplifier is intended.
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The set R1, R11, C4 is responsible for the Stand-by and will prevent pop in the loudspeaker when activating the amplifier, the charge time with capacitor of 47uF is enough to avoid the pop.
For decoupling and filter we have C5 of 1500uF and C9 of 100nF, for powering the operational amplifier, we have C7 of 1000uF and C8 of 10nF.
As we will use a simple power supply in the Ne5532 or equivalent, we need a “Virtual Ground” equal to VCC/2. For this we use a voltage divider with 2 resistors of equal values, R5/R6 and a filter capacitor C12.
Circuit Diagram of the amplifier with TDa7379 amplifier
Suggestion of printed circuit board to mount the amplifier
The printed circuit board is from the #minimus series with reduced dimensions and double face. To reduce the spaces, the resistors are 1 / 6W or 1 / 8W, but you can use 1/4 Watt. R10 and R12 are of the SMD 0805 type and can be omitted, in this case make a “jumper” in the position.
Usage table for TDA73XX (TDA7379, TDA7375, TDA7377 and STA540)
| CI | TDA7375 | TDA7377 | TDA7379 | STA540 |
|---|---|---|---|---|
| Max. Voltage | 18V | 18V | 20V | 22V |
| Max. Power | 2X 25W @4 Ohms | 2x20W @4 Ohms | 28W @4 Ohms | 2X 34W @ 8 Ohms |
To power our circuit we have to use a DC power supply with a value that can be from 8V up to the maximum voltage in the table above. Usually uses with 12V DC power supply. On the current of the source, it will depend on the voltage used and maximum output power. To determine the maximum power use the graphics available in the Datasheet.
For example, choosing the STA540 and a 12V power supply, we will have up to about 18W of power per channel, 36W total. According to Ohm’s law, 3 amperes of current, however, as you are using a Class AB amplifier, the efficiency will be about 60%, so our power supply must have a current capacity of 4.2A. For other chips and other supply voltages, make the calculations with the data from the PDF Datasheet found at the end of the article.
Part list for the amplifier with tda7379 amplifier
| Part | Valor | Description | Amount |
| Capacitor’s | |||
| C1, C6 | 1uF/63V | Polyester capacitor pins 5mm body 6mm | 2 |
| C2, C3 | 4.7uF/16V | Electrolytic capacitor | 2 |
| C4, C11 | 47uF* | Electrolytic capacitor | 2 |
| C5 | 1500uF* | Electrolytic capacitor | 1 |
| C7 | 1000uF/16V | Electrolytic capacitor | 1 |
| C8, C9 | 100nF | Ceramic capacitor | 2 |
| C10, C13 | 10uF/25V | Electrolytic capacitor | 2 |
| C12 | 100uF/25V | Electrolytic capacitor | 1 |
| C14, C15 | 200pF | Ceramic capacitor | 2 |
| Semiconductors | |||
| IC1 | NE5532 or Tl072 or LM4558 or equivalent | Dual Operational Amplifier | 1 |
| IC2 | TDA7379 or equivalent ** | Integrated circuit audio amplifier | 1 |
| IC3 | LM7812 | Positive voltage regulator 12V 1A | 1 |
| Resistor’s 1/6W or 1/8W 5% | |||
| R1, R5, R6, R11 | 10k | Brown, Black, Orange, Gold | 4 |
| R2, R3, R10, R12 | 15k | Brown, Green, Orange, Gold | 4 |
| R4, R8 | 4.7k | Yellow, Violet, Red, Gold | 2 |
| R7, R9 | 47k | Yellow, Violet, Orange, Gold | 2 |
| R10, R12 | 100 Ohms a 8.2K*** – SMD 0805 | 101 or 823 | 2 |
| Several | |||
| Solder, Wires, Pci, Box, source, socket for the Operational Amplifier, heat sink, etc. | |||
* The working voltage of these electrolytic capacitors must be 25V for power supply up to 18V and 35V for power supply up to 24V.
** TDA7375, TDA7377 and STA540
*** It depends on the cutoff frequency you prefer.
Download the files, layout of the PCB in PDF, PNG and Gerber for making the printed circuit board
Download Datasheet in PDF
Datasheet do TDA7375 TDA7375V, tda7375AV
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