DIY the 14W stereo amplifier with TDA7266SA

All the music lovers love to crank up the volume and listen to music. But decent stereo audio setup could cost a fortune. Then we have the DIY option although we can make our own circuit small mistake could burn the circuit and the speakers as well. Almost every high-end audio system has inbuilt speaker protection system with several other protection features. Today we are going to build a 14W RMS stereo amplifier with speaker protection. To do that we are going to use TDA7266SA audio amplifier IC and UPC1237 amplifier protection IC.

What is TDA7266SA?

TDA7266SA is a 14W stereo amplifier IC. It can output 7W for two channels. Also this ic only need few external components to work. You can see the physical appearance of the TDA7266SA is below given image.

Figure 1. — Physical Appearance of TDA7266SA

Pinout of TDA7266SA:

TDA7266SA stereo amplifier IC comes in it’s own liner dual row package with a massive heatsink in the back of the IC. You can see the pinout of the TDA7266SA amplifier IC in below image.

Figure 2. — Pinout of TDA7266SA

Lets discuss what are the functions of each pin of TDA7266SA amplifier IC.

· Pin 1 — OUT1+ — Positive pin of the first output

· Pin 2 — OUT1- — Negative pin of the first output.

· Pin 3 — Vcc — Power supply input pin.

· Pin 4 — IN1 — Input pin for the first channel audio signal.

· Pin 5 — N/C — Not connected to anything.

· Pin 6 — Mute — Mute signal logic pin

· Pin 7 — ST-BY — Standby signal logic pin

· Pin 8 — PW-GND — Ground connection for the Power supply

· Pin 9 — S-GND — Ground connection for the audio signal

· Pin 10 — N/C — Not connected to anything.

· Pin 11 — N/C — Not connected to anything.

· Pin 12 — IN2 — Input pin for the audio signal of channel 2

· Pin 13 — Vcc — Power supply input pin

· Pin 14 — OUT2- — Channel 2 output negative pin

· Pin 15 — OUT2+ — Channel 2 output positive pin

Features of TDA7266SA:

Lets discuss the main features of the TDA7266SA stereo amplifier IC.

· Wide operation voltage of 3.5V to 18V.

· Inbuilt short circuit protection

· 7W balanced stereo channels

· Low noise and high frequency response

What is UPC1237?

UPC1237 is an amplifier protection IC. It features short circuit, overload and AC voltage cutoff protections to a power amplifier. You can see the physical appearance of the UPC1237 amplifier protection IC in below image.

Figure 3. — Physical Appearance of UPC1237

Pinout of UPC1237:

UPC1237 comes in 8 pin linear single row package. You can see the pinout of the UPC1237 amplifier protection IC in below image.

Figure 4. — Pinout of UPC1237

Let’s see more details the pins of UPC1237 amplifier protection IC.

· Pin 1 — OL — Overload detection pin

· Pin 2 — Output Offset — Output offset detection pin

· Pin 3 — Reset — Reset pin of the UPC1237 IC

· Pin 3 — AC Detect — AC off detector pin

· Pin 3 — GND — ground pin for the power supply.

· Pin 3 — Rly — Output pin to the relay

· Pin 3 — Mute Vcc — Mute signal voltage pin.

· Pin 3 — Vcc — Supply voltage pin.

Features of UPC1237:

We can identify fallowing features of the UPC1237 amplifier protection IC.

· Overload and short circuit protection for the speakers

· Startup delay protection

· Wide supply voltage of 25V to 60V DC.

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Basic Circuit Diagram:

You can find the basic circuit diagram for the 14W stereo amplifier with protection circuit.

Figure 5. — 14W Stereo Amplifier Circuit

Key Components :

We will need following list of components to make the 14W stereo amplifier.

1. Utsource TDA7266SA 14W amplifier IC

2. Utsource UPC1237 Amplifier protection IC

3. 0.22mF capacitor

4. 470 uF capacitor

5. 100 nF capacitor

6. 22 nF capacitor

7. 33 uF capacitor

8. 56 kΩ resistor

9. 15 kΩ resistor

Tools Needed:

1. Soldering Iron

2. Iron Stand

3. Flux

4. Nose pliers

Step By Step Guide:

Step 1: Arrange all the components as shown in the above list.

Step 2: Connect all the component as per the circuit diagram

Step 3: Connect all two supply voltages

Step 4: Connect any audio source to the input pins and enjoy

How It Works:

TDA7266SA is amplifying the audio signal and UPC1237 is monitoring the output signal for any overload or short circuit situations. If a fault is detected by UPC1237 it will turn off the relay and protect the amplifier IC and the speakers as well.

Conclusion:

This is a basic amplifier with good level of protection that can be made with minimum amount of components.